Redesign iced_wgpu layering architecture

core/src/rectangle.rs

@@ -16,6 +16,22 @@ pub struct Rectangle<T = f32> {
     pub height: T,
 }
 
+impl<T> Rectangle<T>
+where
+    T: Default,
+{
+    /// Creates a new [`Rectangle`] with its top-left corner at the origin
+    /// and with the provided [`Size`].
+    pub fn with_size(size: Size<T>) -> Self {
+        Self {
+            x: T::default(),
+            y: T::default(),
+            width: size.width,
+            height: size.height,
+        }
+    }
+}
+
 impl Rectangle<f32> {
     /// Creates a new [`Rectangle`] with its top-left corner in the given
     /// [`Point`] and with the provided [`Size`].
@@ -28,17 +44,6 @@ impl Rectangle<f32> {
         }
     }
 
-    /// Creates a new [`Rectangle`] with its top-left corner at the origin
-    /// and with the provided [`Size`].
-    pub fn with_size(size: Size) -> Self {
-        Self {
-            x: 0.0,
-            y: 0.0,
-            width: size.width,
-            height: size.height,
-        }
-    }
-
     /// Returns the [`Point`] at the center of the [`Rectangle`].
     pub fn center(&self) -> Point {
         Point::new(self.center_x(), self.center_y())

core/src/renderer.rs

@@ -9,7 +9,7 @@ use crate::{
 /// A component that can be used by widgets to draw themselves on a screen.
 pub trait Renderer {
     /// Starts recording a new layer.
-    fn start_layer(&mut self);
+    fn start_layer(&mut self, bounds: Rectangle);
 
     /// Ends recording a new layer.
     ///
@@ -20,13 +20,13 @@ pub trait Renderer {
     ///
     /// The layer will clip its contents to the provided `bounds`.
     fn with_layer(&mut self, bounds: Rectangle, f: impl FnOnce(&mut Self)) {
-        self.start_layer();
+        self.start_layer(bounds);
         f(self);
         self.end_layer(bounds);
     }
 
     /// Starts recording with a new [`Transformation`].
-    fn start_transformation(&mut self);
+    fn start_transformation(&mut self, transformation: Transformation);
 
     /// Ends recording a new layer.
     ///
@@ -39,7 +39,7 @@ pub trait Renderer {
         transformation: Transformation,
         f: impl FnOnce(&mut Self),
     ) {
-        self.start_transformation();
+        self.start_transformation(transformation);
         f(self);
         self.end_transformation(transformation);
     }

core/src/renderer/null.rs

@@ -10,11 +10,11 @@ use crate::{
 use std::borrow::Cow;
 
 impl Renderer for () {
-    fn start_layer(&mut self) {}
+    fn start_layer(&mut self, _bounds: Rectangle) {}
 
     fn end_layer(&mut self, _bounds: Rectangle) {}
 
-    fn start_transformation(&mut self) {}
+    fn start_transformation(&mut self, _transformation: Transformation) {}
 
     fn end_transformation(&mut self, _transformation: Transformation) {}
 

core/src/size.rs

@@ -99,3 +99,17 @@ where
         }
     }
 }
+
+impl<T> std::ops::Mul<T> for Size<T>
+where
+    T: std::ops::Mul<Output = T> + Copy,
+{
+    type Output = Size<T>;
+
+    fn mul(self, rhs: T) -> Self::Output {
+        Size {
+            width: self.width * rhs,
+            height: self.height * rhs,
+        }
+    }
+}

core/src/transformation.rs

@@ -42,6 +42,12 @@ impl Transformation {
     }
 }
 
+impl Default for Transformation {
+    fn default() -> Self {
+        Transformation::IDENTITY
+    }
+}
+
 impl Mul for Transformation {
     type Output = Self;
 

examples/geometry/src/main.rs

@@ -6,7 +6,10 @@ mod rainbow {
     use iced::advanced::renderer;
     use iced::advanced::widget::{self, Widget};
     use iced::mouse;
-    use iced::{Element, Length, Rectangle, Renderer, Size, Theme, Vector};
+    use iced::{
+        Element, Length, Rectangle, Renderer, Size, Theme, Transformation,
+        Vector,
+    };
 
     #[derive(Debug, Clone, Copy, Default)]
     pub struct Rainbow;
@@ -130,6 +133,7 @@ mod rainbow {
                         0, 8, 1, // L
                     ],
                 },
+                transformation: Transformation::IDENTITY,
             };
 
             renderer.with_translation(

examples/integration/src/main.rs

@@ -5,12 +5,12 @@ use controls::Controls;
 use scene::Scene;
 
 use iced_wgpu::graphics::Viewport;
-use iced_wgpu::{wgpu, Backend, Renderer, Settings};
+use iced_wgpu::{wgpu, Engine, Renderer, Settings};
 use iced_winit::conversion;
 use iced_winit::core::mouse;
 use iced_winit::core::renderer;
 use iced_winit::core::window;
-use iced_winit::core::{Color, Font, Pixels, Size, Theme};
+use iced_winit::core::{Color, Size, Theme};
 use iced_winit::futures;
 use iced_winit::runtime::program;
 use iced_winit::runtime::Debug;
@@ -155,11 +155,8 @@ pub fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     // Initialize iced
     let mut debug = Debug::new();
-    let mut renderer = Renderer::new(
-        Backend::new(&adapter, &device, &queue, Settings::default(), format),
-        Font::default(),
-        Pixels(16.0),
-    );
+    let mut engine = Engine::new(&adapter, &device, &queue, format, None);
+    let mut renderer = Renderer::new(Settings::default(), &engine);
 
     let mut state = program::State::new(
         controls,
@@ -228,19 +225,17 @@ pub fn main() -> Result<(), Box<dyn std::error::Error>> {
                         }
 
                         // And then iced on top
-                        renderer.with_primitives(|backend, primitive| {
-                            backend.present(
-                                &device,
-                                &queue,
-                                &mut encoder,
-                                None,
-                                frame.texture.format(),
-                                &view,
-                                primitive,
-                                &viewport,
-                                &debug.overlay(),
-                            );
-                        });
+                        renderer.present(
+                            &mut engine,
+                            &device,
+                            &queue,
+                            &mut encoder,
+                            None,
+                            frame.texture.format(),
+                            &view,
+                            &viewport,
+                            &debug.overlay(),
+                        );
 
                         // Then we submit the work
                         queue.submit(Some(encoder.finish()));

graphics/src/cached.rs

@@ -5,7 +5,7 @@ use std::sync::Arc;
 /// A piece of data that can be cached.
 pub trait Cached: Sized {
     /// The type of cache produced.
-    type Cache;
+    type Cache: Clone;
 
     /// Loads the [`Cache`] into a proper instance.
     ///
@@ -15,7 +15,7 @@ pub trait Cached: Sized {
     /// Caches this value, producing its corresponding [`Cache`].
     ///
     /// [`Cache`]: Self::Cache
-    fn cache(self) -> Self::Cache;
+    fn cache(self, previous: Option<Self::Cache>) -> Self::Cache;
 }
 
 impl<T> Cached for Primitive<T> {
@@ -27,7 +27,7 @@ impl<T> Cached for Primitive<T> {
         }
     }
 
-    fn cache(self) -> Arc<Self> {
+    fn cache(self, _previous: Option<Arc<Self>>) -> Arc<Self> {
         Arc::new(self)
     }
 }
@@ -38,5 +38,5 @@ impl Cached for () {
 
     fn load(_cache: &Self::Cache) -> Self {}
 
-    fn cache(self) -> Self::Cache {}
+    fn cache(self, _previous: Option<Self::Cache>) -> Self::Cache {}
 }

graphics/src/geometry/cache.rs

@@ -49,7 +49,7 @@ where
     ) -> Renderer::Geometry {
         use std::ops::Deref;
 
-        if let State::Filled {
+        let previous = if let State::Filled {
             bounds: cached_bounds,
             geometry,
         } = self.state.borrow().deref()
@@ -57,12 +57,16 @@ where
             if *cached_bounds == bounds {
                 return Cached::load(geometry);
             }
-        }
+
+            Some(geometry.clone())
+        } else {
+            None
+        };
 
         let mut frame = Frame::new(renderer, bounds);
         draw_fn(&mut frame);
 
-        let geometry = frame.into_geometry().cache();
+        let geometry = frame.into_geometry().cache(previous);
         let result = Cached::load(&geometry);
 
         *self.state.borrow_mut() = State::Filled { bounds, geometry };

graphics/src/image.rs

@@ -1,14 +1,94 @@
 //! Load and operate on images.
-use crate::core::image::{Data, Handle};
-
-use bitflags::bitflags;
-
+#[cfg(feature = "image")]
 pub use ::image as image_rs;
 
+use crate::core::image;
+use crate::core::svg;
+use crate::core::{Color, Rectangle};
+
+/// A raster or vector image.
+#[derive(Debug, Clone)]
+pub enum Image {
+    /// A raster image.
+    Raster {
+        /// The handle of a raster image.
+        handle: image::Handle,
+
+        /// The filter method of a raster image.
+        filter_method: image::FilterMethod,
+
+        /// The bounds of the image.
+        bounds: Rectangle,
+    },
+    /// A vector image.
+    Vector {
+        /// The handle of a vector image.
+        handle: svg::Handle,
+
+        /// The [`Color`] filter
+        color: Option<Color>,
+
+        /// The bounds of the image.
+        bounds: Rectangle,
+    },
+}
+
+#[cfg(feature = "image")]
 /// Tries to load an image by its [`Handle`].
-pub fn load(handle: &Handle) -> image_rs::ImageResult<image_rs::DynamicImage> {
+pub fn load(
+    handle: &image::Handle,
+) -> ::image::ImageResult<::image::DynamicImage> {
+    use bitflags::bitflags;
+
+    bitflags! {
+        struct Operation: u8 {
+            const FLIP_HORIZONTALLY = 0b001;
+            const ROTATE_180 = 0b010;
+            const FLIP_DIAGONALLY = 0b100;
+        }
+    }
+
+    impl Operation {
+        // Meaning of the returned value is described e.g. at:
+        // https://magnushoff.com/articles/jpeg-orientation/
+        fn from_exif<R>(reader: &mut R) -> Result<Self, exif::Error>
+        where
+            R: std::io::BufRead + std::io::Seek,
+        {
+            let exif = exif::Reader::new().read_from_container(reader)?;
+
+            Ok(exif
+                .get_field(exif::Tag::Orientation, exif::In::PRIMARY)
+                .and_then(|field| field.value.get_uint(0))
+                .and_then(|value| u8::try_from(value).ok())
+                .and_then(|value| Self::from_bits(value.saturating_sub(1)))
+                .unwrap_or_else(Self::empty))
+        }
+
+        fn perform(
+            self,
+            mut image: ::image::DynamicImage,
+        ) -> ::image::DynamicImage {
+            use ::image::imageops;
+
+            if self.contains(Self::FLIP_DIAGONALLY) {
+                imageops::flip_vertical_in_place(&mut image);
+            }
+
+            if self.contains(Self::ROTATE_180) {
+                imageops::rotate180_in_place(&mut image);
+            }
+
+            if self.contains(Self::FLIP_HORIZONTALLY) {
+                imageops::flip_horizontal_in_place(&mut image);
+            }
+
+            image
+        }
+    }
+
     match handle.data() {
-        Data::Path(path) => {
+        image::Data::Path(path) => {
             let image = ::image::open(path)?;
 
             let operation = std::fs::File::open(path)
@@ -19,7 +99,7 @@ pub fn load(handle: &Handle) -> image_rs::ImageResult<image_rs::DynamicImage> {
 
             Ok(operation.perform(image))
         }
-        Data::Bytes(bytes) => {
+        image::Data::Bytes(bytes) => {
             let image = ::image::load_from_memory(bytes)?;
             let operation =
                 Operation::from_exif(&mut std::io::Cursor::new(bytes))
@@ -28,68 +108,22 @@ pub fn load(handle: &Handle) -> image_rs::ImageResult<image_rs::DynamicImage> {
 
             Ok(operation.perform(image))
         }
-        Data::Rgba {
+        image::Data::Rgba {
             width,
             height,
             pixels,
         } => {
-            if let Some(image) = image_rs::ImageBuffer::from_vec(
-                *width,
-                *height,
-                pixels.to_vec(),
-            ) {
-                Ok(image_rs::DynamicImage::ImageRgba8(image))
+            if let Some(image) =
+                ::image::ImageBuffer::from_vec(*width, *height, pixels.to_vec())
+            {
+                Ok(::image::DynamicImage::ImageRgba8(image))
             } else {
-                Err(image_rs::error::ImageError::Limits(
-                    image_rs::error::LimitError::from_kind(
-                        image_rs::error::LimitErrorKind::DimensionError,
+                Err(::image::error::ImageError::Limits(
+                    ::image::error::LimitError::from_kind(
+                        ::image::error::LimitErrorKind::DimensionError,
                     ),
                 ))
             }
         }
     }
 }
-
-bitflags! {
-    struct Operation: u8 {
-        const FLIP_HORIZONTALLY = 0b001;
-        const ROTATE_180 = 0b010;
-        const FLIP_DIAGONALLY = 0b100;
-    }
-}
-
-impl Operation {
-    // Meaning of the returned value is described e.g. at:
-    // https://magnushoff.com/articles/jpeg-orientation/
-    fn from_exif<R>(reader: &mut R) -> Result<Self, exif::Error>
-    where
-        R: std::io::BufRead + std::io::Seek,
-    {
-        let exif = exif::Reader::new().read_from_container(reader)?;
-
-        Ok(exif
-            .get_field(exif::Tag::Orientation, exif::In::PRIMARY)
-            .and_then(|field| field.value.get_uint(0))
-            .and_then(|value| u8::try_from(value).ok())
-            .and_then(|value| Self::from_bits(value.saturating_sub(1)))
-            .unwrap_or_else(Self::empty))
-    }
-
-    fn perform(self, mut image: image::DynamicImage) -> image::DynamicImage {
-        use image::imageops;
-
-        if self.contains(Self::FLIP_DIAGONALLY) {
-            imageops::flip_vertical_in_place(&mut image);
-        }
-
-        if self.contains(Self::ROTATE_180) {
-            imageops::rotate180_in_place(&mut image);
-        }
-
-        if self.contains(Self::FLIP_HORIZONTALLY) {
-            imageops::flip_horizontal_in_place(&mut image);
-        }
-
-        image
-    }
-}

graphics/src/layer.rs

@@ -0,0 +1,47 @@
+pub trait Layer {
+    type Cache;
+
+    fn new() -> Self;
+
+    fn clear(&mut self);
+}
+
+pub struct Recorder<T: Layer> {
+    layers: Vec<T>,
+    caches: Vec<T::Cache>,
+    stack: Vec<Kind>,
+    current: usize,
+}
+
+enum Kind {
+    Fresh(usize),
+    Cache(usize),
+}
+
+impl<T: Layer> Recorder<T> {
+    pub fn new() -> Self {
+        Self {
+            layers: vec![Layer::new()],
+            caches: Vec::new(),
+            stack: Vec::new(),
+            current: 0,
+        }
+    }
+
+    pub fn fill_quad(&mut self) {}
+
+    pub fn push_cache(&mut self, cache: T::Cache) {
+        self.caches.push(cache);
+    }
+
+    pub fn clear(&mut self) {
+        self.caches.clear();
+        self.stack.clear();
+
+        for mut layer in self.layers {
+            layer.clear();
+        }
+
+        self.current = 0;
+    }
+}

graphics/src/lib.rs

@@ -28,6 +28,7 @@ pub mod compositor;
 pub mod damage;
 pub mod error;
 pub mod gradient;
+pub mod image;
 pub mod mesh;
 pub mod renderer;
 pub mod text;
@@ -35,9 +36,6 @@ pub mod text;
 #[cfg(feature = "geometry")]
 pub mod geometry;
 
-#[cfg(feature = "image")]
-pub mod image;
-
 pub use antialiasing::Antialiasing;
 pub use backend::Backend;
 pub use cached::Cached;
@@ -45,10 +43,12 @@ pub use compositor::Compositor;
 pub use damage::Damage;
 pub use error::Error;
 pub use gradient::Gradient;
+pub use image::Image;
 pub use mesh::Mesh;
 pub use primitive::Primitive;
 pub use renderer::Renderer;
 pub use settings::Settings;
+pub use text::Text;
 pub use viewport::Viewport;
 
 pub use iced_core as core;

graphics/src/mesh.rs

@@ -1,8 +1,7 @@
 //! Draw triangles!
 use crate::color;
-use crate::core::{Rectangle, Size};
+use crate::core::{Rectangle, Size, Transformation};
 use crate::gradient;
-use crate::Damage;
 
 use bytemuck::{Pod, Zeroable};
 
@@ -14,9 +13,10 @@ pub enum Mesh {
         /// The vertices and indices of the mesh.
         buffers: Indexed<SolidVertex2D>,
 
-        /// The size of the drawable region of the mesh.
-        ///
-        /// Any geometry that falls out of this region will be clipped.
+        /// The [`Transformation`] for the vertices of the [`Mesh`].
+        transformation: Transformation,
+
+        /// The [`Size`] of the [`Mesh`].
         size: Size,
     },
     /// A mesh with a gradient.
@@ -24,19 +24,44 @@ pub enum Mesh {
         /// The vertices and indices of the mesh.
         buffers: Indexed<GradientVertex2D>,
 
-        /// The size of the drawable region of the mesh.
-        ///
-        /// Any geometry that falls out of this region will be clipped.
+        /// The [`Transformation`] for the vertices of the [`Mesh`].
+        transformation: Transformation,
+
+        /// The [`Size`] of the [`Mesh`].
         size: Size,
     },
 }
 
-impl Damage for Mesh {
-    fn bounds(&self) -> Rectangle {
+impl Mesh {
+    /// Returns the indices of the [`Mesh`].
+    pub fn indices(&self) -> &[u32] {
         match self {
-            Self::Solid { size, .. } | Self::Gradient { size, .. } => {
-                Rectangle::with_size(*size)
+            Self::Solid { buffers, .. } => &buffers.indices,
+            Self::Gradient { buffers, .. } => &buffers.indices,
+        }
+    }
+
+    /// Returns the [`Transformation`] of the [`Mesh`].
+    pub fn transformation(&self) -> Transformation {
+        match self {
+            Self::Solid { transformation, .. }
+            | Self::Gradient { transformation, .. } => *transformation,
+        }
+    }
+
+    /// Returns the clip bounds of the [`Mesh`].
+    pub fn clip_bounds(&self) -> Rectangle {
+        match self {
+            Self::Solid {
+                size,
+                transformation,
+                ..
             }
+            | Self::Gradient {
+                size,
+                transformation,
+                ..
+            } => Rectangle::with_size(*size) * *transformation,
         }
     }
 }
@@ -75,6 +100,47 @@ pub struct GradientVertex2D {
     pub gradient: gradient::Packed,
 }
 
+/// The result of counting the attributes of a set of meshes.
+#[derive(Debug, Clone, Copy, Default)]
+pub struct AttributeCount {
+    /// The total amount of solid vertices.
+    pub solid_vertices: usize,
+
+    /// The total amount of solid meshes.
+    pub solids: usize,
+
+    /// The total amount of gradient vertices.
+    pub gradient_vertices: usize,
+
+    /// The total amount of gradient meshes.
+    pub gradients: usize,
+
+    /// The total amount of indices.
+    pub indices: usize,
+}
+
+/// Returns the number of total vertices & total indices of all [`Mesh`]es.
+pub fn attribute_count_of(meshes: &[Mesh]) -> AttributeCount {
+    meshes
+        .iter()
+        .fold(AttributeCount::default(), |mut count, mesh| {
+            match mesh {
+                Mesh::Solid { buffers, .. } => {
+                    count.solids += 1;
+                    count.solid_vertices += buffers.vertices.len();
+                    count.indices += buffers.indices.len();
+                }
+                Mesh::Gradient { buffers, .. } => {
+                    count.gradients += 1;
+                    count.gradient_vertices += buffers.vertices.len();
+                    count.indices += buffers.indices.len();
+                }
+            }
+
+            count
+        })
+}
+
 /// A renderer capable of drawing a [`Mesh`].
 pub trait Renderer {
     /// Draws the given [`Mesh`].

graphics/src/renderer.rs

@@ -62,7 +62,7 @@ impl<B: Backend> Renderer<B> {
 }
 
 impl<B: Backend> iced_core::Renderer for Renderer<B> {
-    fn start_layer(&mut self) {
+    fn start_layer(&mut self, _bounds: Rectangle) {
         self.stack.push(std::mem::take(&mut self.primitives));
     }
 
@@ -75,7 +75,7 @@ impl<B: Backend> iced_core::Renderer for Renderer<B> {
         self.primitives.push(Primitive::group(layer).clip(bounds));
     }
 
-    fn start_transformation(&mut self) {
+    fn start_transformation(&mut self, _transformation: Transformation) {
         self.stack.push(std::mem::take(&mut self.primitives));
     }
 

graphics/src/text.rs

@@ -9,14 +9,67 @@ pub use paragraph::Paragraph;
 
 pub use cosmic_text;
 
+use crate::core::alignment;
 use crate::core::font::{self, Font};
-use crate::core::text::Shaping;
-use crate::core::{Color, Point, Rectangle, Size};
+use crate::core::text::{LineHeight, Shaping};
+use crate::core::{Color, Pixels, Point, Rectangle, Size, Transformation};
 
 use once_cell::sync::OnceCell;
 use std::borrow::Cow;
 use std::sync::{Arc, RwLock, Weak};
 
+/// A text primitive.
+#[derive(Debug, Clone)]
+pub enum Text {
+    /// A paragraph.
+    #[allow(missing_docs)]
+    Paragraph {
+        paragraph: paragraph::Weak,
+        position: Point,
+        color: Color,
+        clip_bounds: Rectangle,
+        transformation: Transformation,
+    },
+    /// An editor.
+    #[allow(missing_docs)]
+    Editor {
+        editor: editor::Weak,
+        position: Point,
+        color: Color,
+        clip_bounds: Rectangle,
+        transformation: Transformation,
+    },
+    /// Some cached text.
+    Cached {
+        /// The contents of the text.
+        content: String,
+        /// The bounds of the text.
+        bounds: Rectangle,
+        /// The color of the text.
+        color: Color,
+        /// The size of the text in logical pixels.
+        size: Pixels,
+        /// The line height of the text.
+        line_height: LineHeight,
+        /// The font of the text.
+        font: Font,
+        /// The horizontal alignment of the text.
+        horizontal_alignment: alignment::Horizontal,
+        /// The vertical alignment of the text.
+        vertical_alignment: alignment::Vertical,
+        /// The shaping strategy of the text.
+        shaping: Shaping,
+        /// The clip bounds of the text.
+        clip_bounds: Rectangle,
+    },
+    /// Some raw text.
+    #[allow(missing_docs)]
+    Raw {
+        raw: Raw,
+        transformation: Transformation,
+    },
+}
+
 /// The regular variant of the [Fira Sans] font.
 ///
 /// It is loaded as part of the default fonts in Wasm builds.

renderer/Cargo.toml

@@ -16,7 +16,6 @@ tiny-skia = ["iced_tiny_skia"]
 image = ["iced_tiny_skia?/image", "iced_wgpu?/image"]
 svg = ["iced_tiny_skia?/svg", "iced_wgpu?/svg"]
 geometry = ["iced_graphics/geometry", "iced_tiny_skia?/geometry", "iced_wgpu?/geometry"]
-tracing = ["iced_wgpu?/tracing"]
 web-colors = ["iced_wgpu?/web-colors"]
 webgl = ["iced_wgpu?/webgl"]
 fira-sans = ["iced_graphics/fira-sans"]

renderer/src/fallback.rs

@@ -39,16 +39,20 @@ where
         delegate!(self, renderer, renderer.clear());
     }
 
-    fn start_layer(&mut self) {
-        delegate!(self, renderer, renderer.start_layer());
+    fn start_layer(&mut self, bounds: Rectangle) {
+        delegate!(self, renderer, renderer.start_layer(bounds));
     }
 
     fn end_layer(&mut self, bounds: Rectangle) {
         delegate!(self, renderer, renderer.end_layer(bounds));
     }
 
-    fn start_transformation(&mut self) {
-        delegate!(self, renderer, renderer.start_transformation());
+    fn start_transformation(&mut self, transformation: Transformation) {
+        delegate!(
+            self,
+            renderer,
+            renderer.start_transformation(transformation)
+        );
     }
 
     fn end_transformation(&mut self, transformation: Transformation) {
@@ -433,6 +437,7 @@ mod geometry {
         }
     }
 
+    #[derive(Clone)]
     pub enum Geometry<L, R> {
         Left(L),
         Right(R),
@@ -452,10 +457,21 @@ mod geometry {
             }
         }
 
-        fn cache(self) -> Self::Cache {
-            match self {
-                Self::Left(geometry) => Geometry::Left(geometry.cache()),
-                Self::Right(geometry) => Geometry::Right(geometry.cache()),
+        fn cache(self, previous: Option<Self::Cache>) -> Self::Cache {
+            match (self, previous) {
+                (Self::Left(geometry), Some(Geometry::Left(previous))) => {
+                    Geometry::Left(geometry.cache(Some(previous)))
+                }
+                (Self::Left(geometry), None) => {
+                    Geometry::Left(geometry.cache(None))
+                }
+                (Self::Right(geometry), Some(Geometry::Right(previous))) => {
+                    Geometry::Right(geometry.cache(Some(previous)))
+                }
+                (Self::Right(geometry), None) => {
+                    Geometry::Right(geometry.cache(None))
+                }
+                _ => unreachable!(),
             }
         }
     }

wgpu/Cargo.toml

@@ -41,6 +41,3 @@ lyon.optional = true
 
 resvg.workspace = true
 resvg.optional = true
-
-tracing.workspace = true
-tracing.optional = true

wgpu/src/backend.rs

@@ -1,432 +0,0 @@
-use crate::buffer;
-use crate::core::{Color, Size, Transformation};
-use crate::graphics::backend;
-use crate::graphics::color;
-use crate::graphics::Viewport;
-use crate::primitive::pipeline;
-use crate::primitive::{self, Primitive};
-use crate::quad;
-use crate::text;
-use crate::triangle;
-use crate::window;
-use crate::{Layer, Settings};
-
-#[cfg(feature = "tracing")]
-use tracing::info_span;
-
-#[cfg(any(feature = "image", feature = "svg"))]
-use crate::image;
-
-use std::borrow::Cow;
-
-/// A [`wgpu`] graphics backend for [`iced`].
-///
-/// [`wgpu`]: https://github.com/gfx-rs/wgpu-rs
-/// [`iced`]: https://github.com/iced-rs/iced
-#[allow(missing_debug_implementations)]
-pub struct Backend {
-    quad_pipeline: quad::Pipeline,
-    text_pipeline: text::Pipeline,
-    triangle_pipeline: triangle::Pipeline,
-    pipeline_storage: pipeline::Storage,
-    #[cfg(any(feature = "image", feature = "svg"))]
-    image_pipeline: image::Pipeline,
-    staging_belt: wgpu::util::StagingBelt,
-}
-
-impl Backend {
-    /// Creates a new [`Backend`].
-    pub fn new(
-        _adapter: &wgpu::Adapter,
-        device: &wgpu::Device,
-        queue: &wgpu::Queue,
-        settings: Settings,
-        format: wgpu::TextureFormat,
-    ) -> Self {
-        let text_pipeline = text::Pipeline::new(device, queue, format);
-        let quad_pipeline = quad::Pipeline::new(device, format);
-        let triangle_pipeline =
-            triangle::Pipeline::new(device, format, settings.antialiasing);
-
-        #[cfg(any(feature = "image", feature = "svg"))]
-        let image_pipeline = {
-            let backend = _adapter.get_info().backend;
-
-            image::Pipeline::new(device, format, backend)
-        };
-
-        Self {
-            quad_pipeline,
-            text_pipeline,
-            triangle_pipeline,
-            pipeline_storage: pipeline::Storage::default(),
-
-            #[cfg(any(feature = "image", feature = "svg"))]
-            image_pipeline,
-
-            // TODO: Resize belt smartly (?)
-            // It would be great if the `StagingBelt` API exposed methods
-            // for introspection to detect when a resize may be worth it.
-            staging_belt: wgpu::util::StagingBelt::new(
-                buffer::MAX_WRITE_SIZE as u64,
-            ),
-        }
-    }
-
-    /// Draws the provided primitives in the given `TextureView`.
-    ///
-    /// The text provided as overlay will be rendered on top of the primitives.
-    /// This is useful for rendering debug information.
-    pub fn present<T: AsRef<str>>(
-        &mut self,
-        device: &wgpu::Device,
-        queue: &wgpu::Queue,
-        encoder: &mut wgpu::CommandEncoder,
-        clear_color: Option<Color>,
-        format: wgpu::TextureFormat,
-        frame: &wgpu::TextureView,
-        primitives: &[Primitive],
-        viewport: &Viewport,
-        overlay_text: &[T],
-    ) {
-        log::debug!("Drawing");
-        #[cfg(feature = "tracing")]
-        let _ = info_span!("Wgpu::Backend", "PRESENT").entered();
-
-        let target_size = viewport.physical_size();
-        let scale_factor = viewport.scale_factor() as f32;
-        let transformation = viewport.projection();
-
-        let mut layers = Layer::generate(primitives, viewport);
-
-        if !overlay_text.is_empty() {
-            layers.push(Layer::overlay(overlay_text, viewport));
-        }
-
-        self.prepare(
-            device,
-            queue,
-            format,
-            encoder,
-            scale_factor,
-            target_size,
-            transformation,
-            &layers,
-        );
-
-        self.staging_belt.finish();
-
-        self.render(
-            device,
-            encoder,
-            frame,
-            clear_color,
-            scale_factor,
-            target_size,
-            &layers,
-        );
-
-        self.quad_pipeline.end_frame();
-        self.text_pipeline.end_frame();
-        self.triangle_pipeline.end_frame();
-
-        #[cfg(any(feature = "image", feature = "svg"))]
-        self.image_pipeline.end_frame();
-    }
-
-    /// Recalls staging memory for future uploads.
-    ///
-    /// This method should be called after the command encoder
-    /// has been submitted.
-    pub fn recall(&mut self) {
-        self.staging_belt.recall();
-    }
-
-    fn prepare(
-        &mut self,
-        device: &wgpu::Device,
-        queue: &wgpu::Queue,
-        format: wgpu::TextureFormat,
-        encoder: &mut wgpu::CommandEncoder,
-        scale_factor: f32,
-        target_size: Size<u32>,
-        transformation: Transformation,
-        layers: &[Layer<'_>],
-    ) {
-        for layer in layers {
-            let bounds = (layer.bounds * scale_factor).snap();
-
-            if bounds.width < 1 || bounds.height < 1 {
-                continue;
-            }
-
-            if !layer.quads.is_empty() {
-                self.quad_pipeline.prepare(
-                    device,
-                    encoder,
-                    &mut self.staging_belt,
-                    &layer.quads,
-                    transformation,
-                    scale_factor,
-                );
-            }
-
-            if !layer.meshes.is_empty() {
-                let scaled =
-                    transformation * Transformation::scale(scale_factor);
-
-                self.triangle_pipeline.prepare(
-                    device,
-                    encoder,
-                    &mut self.staging_belt,
-                    &layer.meshes,
-                    scaled,
-                );
-            }
-
-            #[cfg(any(feature = "image", feature = "svg"))]
-            {
-                if !layer.images.is_empty() {
-                    let scaled =
-                        transformation * Transformation::scale(scale_factor);
-
-                    self.image_pipeline.prepare(
-                        device,
-                        encoder,
-                        &mut self.staging_belt,
-                        &layer.images,
-                        scaled,
-                        scale_factor,
-                    );
-                }
-            }
-
-            if !layer.text.is_empty() {
-                self.text_pipeline.prepare(
-                    device,
-                    queue,
-                    encoder,
-                    &layer.text,
-                    layer.bounds,
-                    scale_factor,
-                    target_size,
-                );
-            }
-
-            if !layer.pipelines.is_empty() {
-                for pipeline in &layer.pipelines {
-                    pipeline.primitive.prepare(
-                        format,
-                        device,
-                        queue,
-                        pipeline.bounds,
-                        target_size,
-                        scale_factor,
-                        &mut self.pipeline_storage,
-                    );
-                }
-            }
-        }
-    }
-
-    fn render(
-        &mut self,
-        device: &wgpu::Device,
-        encoder: &mut wgpu::CommandEncoder,
-        target: &wgpu::TextureView,
-        clear_color: Option<Color>,
-        scale_factor: f32,
-        target_size: Size<u32>,
-        layers: &[Layer<'_>],
-    ) {
-        use std::mem::ManuallyDrop;
-
-        let mut quad_layer = 0;
-        let mut triangle_layer = 0;
-        #[cfg(any(feature = "image", feature = "svg"))]
-        let mut image_layer = 0;
-        let mut text_layer = 0;
-
-        let mut render_pass = ManuallyDrop::new(encoder.begin_render_pass(
-            &wgpu::RenderPassDescriptor {
-                label: Some("iced_wgpu render pass"),
-                color_attachments: &[Some(wgpu::RenderPassColorAttachment {
-                    view: target,
-                    resolve_target: None,
-                    ops: wgpu::Operations {
-                        load: match clear_color {
-                            Some(background_color) => wgpu::LoadOp::Clear({
-                                let [r, g, b, a] =
-                                    color::pack(background_color).components();
-
-                                wgpu::Color {
-                                    r: f64::from(r),
-                                    g: f64::from(g),
-                                    b: f64::from(b),
-                                    a: f64::from(a),
-                                }
-                            }),
-                            None => wgpu::LoadOp::Load,
-                        },
-                        store: wgpu::StoreOp::Store,
-                    },
-                })],
-                depth_stencil_attachment: None,
-                timestamp_writes: None,
-                occlusion_query_set: None,
-            },
-        ));
-
-        for layer in layers {
-            let bounds = (layer.bounds * scale_factor).snap();
-
-            if bounds.width < 1 || bounds.height < 1 {
-                continue;
-            }
-
-            if !layer.quads.is_empty() {
-                self.quad_pipeline.render(
-                    quad_layer,
-                    bounds,
-                    &layer.quads,
-                    &mut render_pass,
-                );
-
-                quad_layer += 1;
-            }
-
-            if !layer.meshes.is_empty() {
-                let _ = ManuallyDrop::into_inner(render_pass);
-
-                self.triangle_pipeline.render(
-                    device,
-                    encoder,
-                    target,
-                    triangle_layer,
-                    target_size,
-                    &layer.meshes,
-                    scale_factor,
-                );
-
-                triangle_layer += 1;
-
-                render_pass = ManuallyDrop::new(encoder.begin_render_pass(
-                    &wgpu::RenderPassDescriptor {
-                        label: Some("iced_wgpu render pass"),
-                        color_attachments: &[Some(
-                            wgpu::RenderPassColorAttachment {
-                                view: target,
-                                resolve_target: None,
-                                ops: wgpu::Operations {
-                                    load: wgpu::LoadOp::Load,
-                                    store: wgpu::StoreOp::Store,
-                                },
-                            },
-                        )],
-                        depth_stencil_attachment: None,
-                        timestamp_writes: None,
-                        occlusion_query_set: None,
-                    },
-                ));
-            }
-
-            #[cfg(any(feature = "image", feature = "svg"))]
-            {
-                if !layer.images.is_empty() {
-                    self.image_pipeline.render(
-                        image_layer,
-                        bounds,
-                        &mut render_pass,
-                    );
-
-                    image_layer += 1;
-                }
-            }
-
-            if !layer.text.is_empty() {
-                self.text_pipeline
-                    .render(text_layer, bounds, &mut render_pass);
-
-                text_layer += 1;
-            }
-
-            if !layer.pipelines.is_empty() {
-                let _ = ManuallyDrop::into_inner(render_pass);
-
-                for pipeline in &layer.pipelines {
-                    let viewport = (pipeline.viewport * scale_factor).snap();
-
-                    if viewport.width < 1 || viewport.height < 1 {
-                        continue;
-                    }
-
-                    pipeline.primitive.render(
-                        &self.pipeline_storage,
-                        target,
-                        target_size,
-                        viewport,
-                        encoder,
-                    );
-                }
-
-                render_pass = ManuallyDrop::new(encoder.begin_render_pass(
-                    &wgpu::RenderPassDescriptor {
-                        label: Some("iced_wgpu render pass"),
-                        color_attachments: &[Some(
-                            wgpu::RenderPassColorAttachment {
-                                view: target,
-                                resolve_target: None,
-                                ops: wgpu::Operations {
-                                    load: wgpu::LoadOp::Load,
-                                    store: wgpu::StoreOp::Store,
-                                },
-                            },
-                        )],
-                        depth_stencil_attachment: None,
-                        timestamp_writes: None,
-                        occlusion_query_set: None,
-                    },
-                ));
-            }
-        }
-
-        let _ = ManuallyDrop::into_inner(render_pass);
-    }
-}
-
-impl backend::Backend for Backend {
-    type Primitive = primitive::Custom;
-    type Compositor = window::Compositor;
-}
-
-impl backend::Text for Backend {
-    fn load_font(&mut self, font: Cow<'static, [u8]>) {
-        self.text_pipeline.load_font(font);
-    }
-}
-
-#[cfg(feature = "image")]
-impl backend::Image for Backend {
-    fn dimensions(&self, handle: &crate::core::image::Handle) -> Size<u32> {
-        self.image_pipeline.dimensions(handle)
-    }
-}
-
-#[cfg(feature = "svg")]
-impl backend::Svg for Backend {
-    fn viewport_dimensions(
-        &self,
-        handle: &crate::core::svg::Handle,
-    ) -> Size<u32> {
-        self.image_pipeline.viewport_dimensions(handle)
-    }
-}
-
-#[cfg(feature = "geometry")]
-impl crate::graphics::geometry::Backend for Backend {
-    type Frame = crate::geometry::Frame;
-
-    fn new_frame(&self, size: Size) -> Self::Frame {
-        crate::geometry::Frame::new(size)
-    }
-}

wgpu/src/engine.rs

@@ -0,0 +1,79 @@
+use crate::buffer;
+use crate::graphics::Antialiasing;
+use crate::primitive::pipeline;
+use crate::quad;
+use crate::text;
+use crate::triangle;
+
+#[allow(missing_debug_implementations)]
+pub struct Engine {
+    pub(crate) quad_pipeline: quad::Pipeline,
+    pub(crate) text_pipeline: text::Pipeline,
+    pub(crate) triangle_pipeline: triangle::Pipeline,
+    pub(crate) _pipeline_storage: pipeline::Storage,
+    #[cfg(any(feature = "image", feature = "svg"))]
+    pub(crate) image_pipeline: crate::image::Pipeline,
+    pub(crate) staging_belt: wgpu::util::StagingBelt,
+}
+
+impl Engine {
+    pub fn new(
+        _adapter: &wgpu::Adapter,
+        device: &wgpu::Device,
+        queue: &wgpu::Queue,
+        format: wgpu::TextureFormat,
+        antialiasing: Option<Antialiasing>, // TODO: Initialize AA pipelines lazily
+    ) -> Self {
+        let text_pipeline = text::Pipeline::new(device, queue, format);
+        let quad_pipeline = quad::Pipeline::new(device, format);
+        let triangle_pipeline =
+            triangle::Pipeline::new(device, format, antialiasing);
+
+        #[cfg(any(feature = "image", feature = "svg"))]
+        let image_pipeline = {
+            let backend = _adapter.get_info().backend;
+
+            crate::image::Pipeline::new(device, format, backend)
+        };
+
+        Self {
+            // TODO: Resize belt smartly (?)
+            // It would be great if the `StagingBelt` API exposed methods
+            // for introspection to detect when a resize may be worth it.
+            staging_belt: wgpu::util::StagingBelt::new(
+                buffer::MAX_WRITE_SIZE as u64,
+            ),
+            quad_pipeline,
+            text_pipeline,
+            triangle_pipeline,
+            _pipeline_storage: pipeline::Storage::default(),
+
+            #[cfg(any(feature = "image", feature = "svg"))]
+            image_pipeline,
+        }
+    }
+
+    #[cfg(any(feature = "image", feature = "svg"))]
+    pub fn image_cache(&self) -> &crate::image::cache::Shared {
+        self.image_pipeline.cache()
+    }
+
+    pub fn submit(
+        &mut self,
+        queue: &wgpu::Queue,
+        encoder: wgpu::CommandEncoder,
+    ) -> wgpu::SubmissionIndex {
+        self.staging_belt.finish();
+        let index = queue.submit(Some(encoder.finish()));
+        self.staging_belt.recall();
+
+        self.quad_pipeline.end_frame();
+        self.text_pipeline.end_frame();
+        self.triangle_pipeline.end_frame();
+
+        #[cfg(any(feature = "image", feature = "svg"))]
+        self.image_pipeline.end_frame();
+
+        index
+    }
+}

wgpu/src/geometry.rs

@@ -10,31 +10,82 @@ use crate::graphics::geometry::{
 };
 use crate::graphics::gradient::{self, Gradient};
 use crate::graphics::mesh::{self, Mesh};
-use crate::primitive::{self, Primitive};
+use crate::graphics::{self, Cached};
+use crate::layer;
+use crate::text;
 
 use lyon::geom::euclid;
 use lyon::tessellation;
 
 use std::borrow::Cow;
+use std::cell::RefCell;
+use std::rc::Rc;
 
 /// A frame for drawing some geometry.
 #[allow(missing_debug_implementations)]
 pub struct Frame {
     size: Size,
     buffers: BufferStack,
-    primitives: Vec<Primitive>,
+    layers: Vec<layer::Live>,
+    text: text::Batch,
     transforms: Transforms,
     fill_tessellator: tessellation::FillTessellator,
     stroke_tessellator: tessellation::StrokeTessellator,
 }
 
+pub enum Geometry {
+    Live(Vec<layer::Live>),
+    Cached(Rc<[Rc<RefCell<layer::Cached>>]>),
+}
+
+impl Cached for Geometry {
+    type Cache = Rc<[Rc<RefCell<layer::Cached>>]>;
+
+    fn load(cache: &Self::Cache) -> Self {
+        Geometry::Cached(cache.clone())
+    }
+
+    fn cache(self, previous: Option<Self::Cache>) -> Self::Cache {
+        match self {
+            Self::Live(live) => {
+                let mut layers = live.into_iter();
+
+                let mut new: Vec<_> = previous
+                    .map(|previous| {
+                        previous
+                            .iter()
+                            .cloned()
+                            .zip(layers.by_ref())
+                            .map(|(cached, live)| {
+                                cached.borrow_mut().update(live);
+                                cached
+                            })
+                            .collect()
+                    })
+                    .unwrap_or_default();
+
+                new.extend(
+                    layers
+                        .map(layer::Live::into_cached)
+                        .map(RefCell::new)
+                        .map(Rc::new),
+                );
+
+                Rc::from(new)
+            }
+            Self::Cached(cache) => cache,
+        }
+    }
+}
+
 impl Frame {
     /// Creates a new [`Frame`] with the given [`Size`].
     pub fn new(size: Size) -> Frame {
         Frame {
             size,
             buffers: BufferStack::new(),
-            primitives: Vec::new(),
+            layers: Vec::new(),
+            text: text::Batch::new(),
             transforms: Transforms {
                 previous: Vec::new(),
                 current: Transform(lyon::math::Transform::identity()),
@@ -44,49 +95,54 @@ impl Frame {
         }
     }
 
-    fn into_primitives(mut self) -> Vec<Primitive> {
-        for buffer in self.buffers.stack {
-            match buffer {
-                Buffer::Solid(buffer) => {
-                    if !buffer.indices.is_empty() {
-                        self.primitives.push(Primitive::Custom(
-                            primitive::Custom::Mesh(Mesh::Solid {
-                                buffers: mesh::Indexed {
-                                    vertices: buffer.vertices,
-                                    indices: buffer.indices,
-                                },
-                                size: self.size,
-                            }),
-                        ));
-                    }
-                }
-                Buffer::Gradient(buffer) => {
-                    if !buffer.indices.is_empty() {
-                        self.primitives.push(Primitive::Custom(
-                            primitive::Custom::Mesh(Mesh::Gradient {
-                                buffers: mesh::Indexed {
-                                    vertices: buffer.vertices,
-                                    indices: buffer.indices,
-                                },
-                                size: self.size,
-                            }),
-                        ));
-                    }
-                }
-            }
+    fn into_layers(mut self) -> Vec<layer::Live> {
+        if !self.text.is_empty() || !self.buffers.stack.is_empty() {
+            let clip_bounds = Rectangle::with_size(self.size);
+            let transformation = Transformation::IDENTITY;
+
+            // TODO: Generate different meshes for different transformations (?)
+            // Instead of transforming each path
+            let meshes = self
+                .buffers
+                .stack
+                .into_iter()
+                .map(|buffer| match buffer {
+                    Buffer::Solid(buffer) => Mesh::Solid {
+                        buffers: mesh::Indexed {
+                            vertices: buffer.vertices,
+                            indices: buffer.indices,
+                        },
+                        transformation: Transformation::IDENTITY,
+                        size: self.size,
+                    },
+                    Buffer::Gradient(buffer) => Mesh::Gradient {
+                        buffers: mesh::Indexed {
+                            vertices: buffer.vertices,
+                            indices: buffer.indices,
+                        },
+                        transformation: Transformation::IDENTITY,
+                        size: self.size,
+                    },
+                })
+                .collect();
+
+            let layer = layer::Live {
+                bounds: Some(clip_bounds),
+                transformation,
+                meshes,
+                text: self.text,
+                ..layer::Live::default()
+            };
+
+            self.layers.push(layer);
         }
 
-        self.primitives
+        self.layers
     }
 }
 
 impl geometry::frame::Backend for Frame {
-    type Geometry = Primitive;
-
-    /// Creates a new empty [`Frame`] with the given dimensions.
-    ///
-    /// The default coordinate system of a [`Frame`] has its origin at the
-    /// top-left corner of its bounds.
+    type Geometry = Geometry;
 
     #[inline]
     fn width(&self) -> f32 {
@@ -246,8 +302,7 @@ impl geometry::frame::Backend for Frame {
                 height: f32::INFINITY,
             };
 
-            // TODO: Honor layering!
-            self.primitives.push(Primitive::Text {
+            self.text.push(graphics::Text::Cached {
                 content: text.content,
                 bounds,
                 color: text.color,
@@ -313,37 +368,17 @@ impl geometry::frame::Backend for Frame {
     }
 
     fn paste(&mut self, frame: Frame, at: Point) {
-        let size = frame.size();
-        let primitives = frame.into_primitives();
-        let transformation = Transformation::translate(at.x, at.y);
+        let translation = Transformation::translate(at.x, at.y);
 
-        let (text, meshes) = primitives
-            .into_iter()
-            .partition(|primitive| matches!(primitive, Primitive::Text { .. }));
-
-        self.primitives.push(Primitive::Group {
-            primitives: vec![
-                Primitive::Transform {
-                    transformation,
-                    content: Box::new(Primitive::Group { primitives: meshes }),
-                },
-                Primitive::Transform {
-                    transformation,
-                    content: Box::new(Primitive::Clip {
-                        bounds: Rectangle::with_size(size),
-                        content: Box::new(Primitive::Group {
-                            primitives: text,
-                        }),
-                    }),
-                },
-            ],
-        });
+        self.layers
+            .extend(frame.into_layers().into_iter().map(|mut layer| {
+                layer.transformation = layer.transformation * translation;
+                layer
+            }));
     }
 
     fn into_geometry(self) -> Self::Geometry {
-        Primitive::Group {
-            primitives: self.into_primitives(),
-        }
+        Geometry::Live(self.into_layers())
     }
 }
 

wgpu/src/image/cache.rs

@@ -0,0 +1,107 @@
+use crate::core::{self, Size};
+use crate::image::atlas::{self, Atlas};
+
+use std::cell::{RefCell, RefMut};
+use std::rc::Rc;
+
+#[derive(Debug)]
+pub struct Cache {
+    atlas: Atlas,
+    #[cfg(feature = "image")]
+    raster: crate::image::raster::Cache,
+    #[cfg(feature = "svg")]
+    vector: crate::image::vector::Cache,
+}
+
+impl Cache {
+    pub fn new(device: &wgpu::Device, backend: wgpu::Backend) -> Self {
+        Self {
+            atlas: Atlas::new(device, backend),
+            #[cfg(feature = "image")]
+            raster: crate::image::raster::Cache::default(),
+            #[cfg(feature = "svg")]
+            vector: crate::image::vector::Cache::default(),
+        }
+    }
+
+    pub fn layer_count(&self) -> usize {
+        self.atlas.layer_count()
+    }
+
+    #[cfg(feature = "image")]
+    pub fn measure_image(&mut self, handle: &core::image::Handle) -> Size<u32> {
+        self.raster.load(handle).dimensions()
+    }
+
+    #[cfg(feature = "svg")]
+    pub fn measure_svg(&mut self, handle: &core::svg::Handle) -> Size<u32> {
+        self.vector.load(handle).viewport_dimensions()
+    }
+
+    #[cfg(feature = "image")]
+    pub fn upload_raster(
+        &mut self,
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        handle: &core::image::Handle,
+    ) -> Option<&atlas::Entry> {
+        self.raster.upload(device, encoder, handle, &mut self.atlas)
+    }
+
+    #[cfg(feature = "svg")]
+    pub fn upload_vector(
+        &mut self,
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        handle: &core::svg::Handle,
+        color: Option<core::Color>,
+        size: [f32; 2],
+        scale: f32,
+    ) -> Option<&atlas::Entry> {
+        self.vector.upload(
+            device,
+            encoder,
+            handle,
+            color,
+            size,
+            scale,
+            &mut self.atlas,
+        )
+    }
+
+    pub fn create_bind_group(
+        &self,
+        device: &wgpu::Device,
+        layout: &wgpu::BindGroupLayout,
+    ) -> wgpu::BindGroup {
+        device.create_bind_group(&wgpu::BindGroupDescriptor {
+            label: Some("iced_wgpu::image texture atlas bind group"),
+            layout,
+            entries: &[wgpu::BindGroupEntry {
+                binding: 0,
+                resource: wgpu::BindingResource::TextureView(self.atlas.view()),
+            }],
+        })
+    }
+
+    pub fn trim(&mut self) {
+        #[cfg(feature = "image")]
+        self.raster.trim(&mut self.atlas);
+
+        #[cfg(feature = "svg")]
+        self.vector.trim(&mut self.atlas);
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Shared(Rc<RefCell<Cache>>);
+
+impl Shared {
+    pub fn new(cache: Cache) -> Self {
+        Self(Rc::new(RefCell::new(cache)))
+    }
+
+    pub fn lock(&self) -> RefMut<'_, Cache> {
+        self.0.borrow_mut()
+    }
+}

wgpu/src/image/mod.rs

@@ -1,3 +1,6 @@
+pub(crate) mod cache;
+pub(crate) use cache::Cache;
+
 mod atlas;
 
 #[cfg(feature = "image")]
@@ -6,46 +9,331 @@ mod raster;
 #[cfg(feature = "svg")]
 mod vector;
 
-use atlas::Atlas;
-
+use crate::core::image;
 use crate::core::{Rectangle, Size, Transformation};
-use crate::layer;
 use crate::Buffer;
 
-use std::cell::RefCell;
+use bytemuck::{Pod, Zeroable};
 use std::mem;
 
-use bytemuck::{Pod, Zeroable};
+pub use crate::graphics::Image;
 
-#[cfg(feature = "image")]
-use crate::core::image;
-
-#[cfg(feature = "svg")]
-use crate::core::svg;
-
-#[cfg(feature = "tracing")]
-use tracing::info_span;
+pub type Batch = Vec<Image>;
 
 #[derive(Debug)]
 pub struct Pipeline {
-    #[cfg(feature = "image")]
-    raster_cache: RefCell<raster::Cache>,
-    #[cfg(feature = "svg")]
-    vector_cache: RefCell<vector::Cache>,
-
     pipeline: wgpu::RenderPipeline,
     nearest_sampler: wgpu::Sampler,
     linear_sampler: wgpu::Sampler,
     texture: wgpu::BindGroup,
     texture_version: usize,
-    texture_atlas: Atlas,
     texture_layout: wgpu::BindGroupLayout,
     constant_layout: wgpu::BindGroupLayout,
-
+    cache: cache::Shared,
     layers: Vec<Layer>,
     prepare_layer: usize,
 }
 
+impl Pipeline {
+    pub fn new(
+        device: &wgpu::Device,
+        format: wgpu::TextureFormat,
+        backend: wgpu::Backend,
+    ) -> Self {
+        let nearest_sampler = device.create_sampler(&wgpu::SamplerDescriptor {
+            address_mode_u: wgpu::AddressMode::ClampToEdge,
+            address_mode_v: wgpu::AddressMode::ClampToEdge,
+            address_mode_w: wgpu::AddressMode::ClampToEdge,
+            min_filter: wgpu::FilterMode::Nearest,
+            mag_filter: wgpu::FilterMode::Nearest,
+            mipmap_filter: wgpu::FilterMode::Nearest,
+            ..Default::default()
+        });
+
+        let linear_sampler = device.create_sampler(&wgpu::SamplerDescriptor {
+            address_mode_u: wgpu::AddressMode::ClampToEdge,
+            address_mode_v: wgpu::AddressMode::ClampToEdge,
+            address_mode_w: wgpu::AddressMode::ClampToEdge,
+            min_filter: wgpu::FilterMode::Linear,
+            mag_filter: wgpu::FilterMode::Linear,
+            mipmap_filter: wgpu::FilterMode::Linear,
+            ..Default::default()
+        });
+
+        let constant_layout =
+            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+                label: Some("iced_wgpu::image constants layout"),
+                entries: &[
+                    wgpu::BindGroupLayoutEntry {
+                        binding: 0,
+                        visibility: wgpu::ShaderStages::VERTEX,
+                        ty: wgpu::BindingType::Buffer {
+                            ty: wgpu::BufferBindingType::Uniform,
+                            has_dynamic_offset: false,
+                            min_binding_size: wgpu::BufferSize::new(
+                                mem::size_of::<Uniforms>() as u64,
+                            ),
+                        },
+                        count: None,
+                    },
+                    wgpu::BindGroupLayoutEntry {
+                        binding: 1,
+                        visibility: wgpu::ShaderStages::FRAGMENT,
+                        ty: wgpu::BindingType::Sampler(
+                            wgpu::SamplerBindingType::Filtering,
+                        ),
+                        count: None,
+                    },
+                ],
+            });
+
+        let texture_layout =
+            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+                label: Some("iced_wgpu::image texture atlas layout"),
+                entries: &[wgpu::BindGroupLayoutEntry {
+                    binding: 0,
+                    visibility: wgpu::ShaderStages::FRAGMENT,
+                    ty: wgpu::BindingType::Texture {
+                        sample_type: wgpu::TextureSampleType::Float {
+                            filterable: true,
+                        },
+                        view_dimension: wgpu::TextureViewDimension::D2Array,
+                        multisampled: false,
+                    },
+                    count: None,
+                }],
+            });
+
+        let layout =
+            device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
+                label: Some("iced_wgpu::image pipeline layout"),
+                push_constant_ranges: &[],
+                bind_group_layouts: &[&constant_layout, &texture_layout],
+            });
+
+        let shader =
+            device.create_shader_module(wgpu::ShaderModuleDescriptor {
+                label: Some("iced_wgpu image shader"),
+                source: wgpu::ShaderSource::Wgsl(std::borrow::Cow::Borrowed(
+                    concat!(
+                        include_str!("../shader/vertex.wgsl"),
+                        "\n",
+                        include_str!("../shader/image.wgsl"),
+                    ),
+                )),
+            });
+
+        let pipeline =
+            device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+                label: Some("iced_wgpu::image pipeline"),
+                layout: Some(&layout),
+                vertex: wgpu::VertexState {
+                    module: &shader,
+                    entry_point: "vs_main",
+                    buffers: &[wgpu::VertexBufferLayout {
+                        array_stride: mem::size_of::<Instance>() as u64,
+                        step_mode: wgpu::VertexStepMode::Instance,
+                        attributes: &wgpu::vertex_attr_array!(
+                            // Position
+                            0 => Float32x2,
+                            // Scale
+                            1 => Float32x2,
+                            // Atlas position
+                            2 => Float32x2,
+                            // Atlas scale
+                            3 => Float32x2,
+                            // Layer
+                            4 => Sint32,
+                        ),
+                    }],
+                },
+                fragment: Some(wgpu::FragmentState {
+                    module: &shader,
+                    entry_point: "fs_main",
+                    targets: &[Some(wgpu::ColorTargetState {
+                        format,
+                        blend: Some(wgpu::BlendState {
+                            color: wgpu::BlendComponent {
+                                src_factor: wgpu::BlendFactor::SrcAlpha,
+                                dst_factor: wgpu::BlendFactor::OneMinusSrcAlpha,
+                                operation: wgpu::BlendOperation::Add,
+                            },
+                            alpha: wgpu::BlendComponent {
+                                src_factor: wgpu::BlendFactor::One,
+                                dst_factor: wgpu::BlendFactor::OneMinusSrcAlpha,
+                                operation: wgpu::BlendOperation::Add,
+                            },
+                        }),
+                        write_mask: wgpu::ColorWrites::ALL,
+                    })],
+                }),
+                primitive: wgpu::PrimitiveState {
+                    topology: wgpu::PrimitiveTopology::TriangleList,
+                    front_face: wgpu::FrontFace::Cw,
+                    ..Default::default()
+                },
+                depth_stencil: None,
+                multisample: wgpu::MultisampleState {
+                    count: 1,
+                    mask: !0,
+                    alpha_to_coverage_enabled: false,
+                },
+                multiview: None,
+            });
+
+        let cache = Cache::new(device, backend);
+        let texture = cache.create_bind_group(device, &texture_layout);
+
+        Pipeline {
+            pipeline,
+            nearest_sampler,
+            linear_sampler,
+            texture,
+            texture_version: cache.layer_count(),
+            texture_layout,
+            constant_layout,
+            cache: cache::Shared::new(cache),
+            layers: Vec::new(),
+            prepare_layer: 0,
+        }
+    }
+
+    pub fn cache(&self) -> &cache::Shared {
+        &self.cache
+    }
+
+    pub fn prepare(
+        &mut self,
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        belt: &mut wgpu::util::StagingBelt,
+        images: &Batch,
+        transformation: Transformation,
+        scale: f32,
+    ) {
+        let transformation = transformation * Transformation::scale(scale);
+
+        let nearest_instances: &mut Vec<Instance> = &mut Vec::new();
+        let linear_instances: &mut Vec<Instance> = &mut Vec::new();
+
+        let mut cache = self.cache.lock();
+
+        for image in images {
+            match &image {
+                #[cfg(feature = "image")]
+                Image::Raster {
+                    handle,
+                    filter_method,
+                    bounds,
+                } => {
+                    if let Some(atlas_entry) =
+                        cache.upload_raster(device, encoder, handle)
+                    {
+                        add_instances(
+                            [bounds.x, bounds.y],
+                            [bounds.width, bounds.height],
+                            atlas_entry,
+                            match filter_method {
+                                image::FilterMethod::Nearest => {
+                                    nearest_instances
+                                }
+                                image::FilterMethod::Linear => linear_instances,
+                            },
+                        );
+                    }
+                }
+                #[cfg(not(feature = "image"))]
+                Image::Raster { .. } => {}
+
+                #[cfg(feature = "svg")]
+                Image::Vector {
+                    handle,
+                    color,
+                    bounds,
+                } => {
+                    let size = [bounds.width, bounds.height];
+
+                    if let Some(atlas_entry) = cache.upload_vector(
+                        device, encoder, handle, *color, size, scale,
+                    ) {
+                        add_instances(
+                            [bounds.x, bounds.y],
+                            size,
+                            atlas_entry,
+                            nearest_instances,
+                        );
+                    }
+                }
+                #[cfg(not(feature = "svg"))]
+                Image::Vector { .. } => {}
+            }
+        }
+
+        if nearest_instances.is_empty() && linear_instances.is_empty() {
+            return;
+        }
+
+        let texture_version = cache.layer_count();
+
+        if self.texture_version != texture_version {
+            log::info!("Atlas has grown. Recreating bind group...");
+
+            self.texture =
+                cache.create_bind_group(device, &self.texture_layout);
+            self.texture_version = texture_version;
+        }
+
+        if self.layers.len() <= self.prepare_layer {
+            self.layers.push(Layer::new(
+                device,
+                &self.constant_layout,
+                &self.nearest_sampler,
+                &self.linear_sampler,
+            ));
+        }
+
+        let layer = &mut self.layers[self.prepare_layer];
+
+        layer.prepare(
+            device,
+            encoder,
+            belt,
+            nearest_instances,
+            linear_instances,
+            transformation,
+        );
+
+        self.prepare_layer += 1;
+    }
+
+    pub fn render<'a>(
+        &'a self,
+        layer: usize,
+        bounds: Rectangle<u32>,
+        render_pass: &mut wgpu::RenderPass<'a>,
+    ) {
+        if let Some(layer) = self.layers.get(layer) {
+            render_pass.set_pipeline(&self.pipeline);
+
+            render_pass.set_scissor_rect(
+                bounds.x,
+                bounds.y,
+                bounds.width,
+                bounds.height,
+            );
+
+            render_pass.set_bind_group(1, &self.texture, &[]);
+
+            layer.render(render_pass);
+        }
+    }
+
+    pub fn end_frame(&mut self) {
+        self.cache.lock().trim();
+        self.prepare_layer = 0;
+    }
+}
+
 #[derive(Debug)]
 struct Layer {
     uniforms: wgpu::Buffer,
@@ -194,367 +482,6 @@ impl Data {
     }
 }
 
-impl Pipeline {
-    pub fn new(
-        device: &wgpu::Device,
-        format: wgpu::TextureFormat,
-        backend: wgpu::Backend,
-    ) -> Self {
-        let nearest_sampler = device.create_sampler(&wgpu::SamplerDescriptor {
-            address_mode_u: wgpu::AddressMode::ClampToEdge,
-            address_mode_v: wgpu::AddressMode::ClampToEdge,
-            address_mode_w: wgpu::AddressMode::ClampToEdge,
-            min_filter: wgpu::FilterMode::Nearest,
-            mag_filter: wgpu::FilterMode::Nearest,
-            mipmap_filter: wgpu::FilterMode::Nearest,
-            ..Default::default()
-        });
-
-        let linear_sampler = device.create_sampler(&wgpu::SamplerDescriptor {
-            address_mode_u: wgpu::AddressMode::ClampToEdge,
-            address_mode_v: wgpu::AddressMode::ClampToEdge,
-            address_mode_w: wgpu::AddressMode::ClampToEdge,
-            min_filter: wgpu::FilterMode::Linear,
-            mag_filter: wgpu::FilterMode::Linear,
-            mipmap_filter: wgpu::FilterMode::Linear,
-            ..Default::default()
-        });
-
-        let constant_layout =
-            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
-                label: Some("iced_wgpu::image constants layout"),
-                entries: &[
-                    wgpu::BindGroupLayoutEntry {
-                        binding: 0,
-                        visibility: wgpu::ShaderStages::VERTEX,
-                        ty: wgpu::BindingType::Buffer {
-                            ty: wgpu::BufferBindingType::Uniform,
-                            has_dynamic_offset: false,
-                            min_binding_size: wgpu::BufferSize::new(
-                                mem::size_of::<Uniforms>() as u64,
-                            ),
-                        },
-                        count: None,
-                    },
-                    wgpu::BindGroupLayoutEntry {
-                        binding: 1,
-                        visibility: wgpu::ShaderStages::FRAGMENT,
-                        ty: wgpu::BindingType::Sampler(
-                            wgpu::SamplerBindingType::Filtering,
-                        ),
-                        count: None,
-                    },
-                ],
-            });
-
-        let texture_layout =
-            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
-                label: Some("iced_wgpu::image texture atlas layout"),
-                entries: &[wgpu::BindGroupLayoutEntry {
-                    binding: 0,
-                    visibility: wgpu::ShaderStages::FRAGMENT,
-                    ty: wgpu::BindingType::Texture {
-                        sample_type: wgpu::TextureSampleType::Float {
-                            filterable: true,
-                        },
-                        view_dimension: wgpu::TextureViewDimension::D2Array,
-                        multisampled: false,
-                    },
-                    count: None,
-                }],
-            });
-
-        let layout =
-            device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
-                label: Some("iced_wgpu::image pipeline layout"),
-                push_constant_ranges: &[],
-                bind_group_layouts: &[&constant_layout, &texture_layout],
-            });
-
-        let shader =
-            device.create_shader_module(wgpu::ShaderModuleDescriptor {
-                label: Some("iced_wgpu image shader"),
-                source: wgpu::ShaderSource::Wgsl(std::borrow::Cow::Borrowed(
-                    concat!(
-                        include_str!("shader/vertex.wgsl"),
-                        "\n",
-                        include_str!("shader/image.wgsl"),
-                    ),
-                )),
-            });
-
-        let pipeline =
-            device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
-                label: Some("iced_wgpu::image pipeline"),
-                layout: Some(&layout),
-                vertex: wgpu::VertexState {
-                    module: &shader,
-                    entry_point: "vs_main",
-                    buffers: &[wgpu::VertexBufferLayout {
-                        array_stride: mem::size_of::<Instance>() as u64,
-                        step_mode: wgpu::VertexStepMode::Instance,
-                        attributes: &wgpu::vertex_attr_array!(
-                            // Position
-                            0 => Float32x2,
-                            // Scale
-                            1 => Float32x2,
-                            // Atlas position
-                            2 => Float32x2,
-                            // Atlas scale
-                            3 => Float32x2,
-                            // Layer
-                            4 => Sint32,
-                        ),
-                    }],
-                },
-                fragment: Some(wgpu::FragmentState {
-                    module: &shader,
-                    entry_point: "fs_main",
-                    targets: &[Some(wgpu::ColorTargetState {
-                        format,
-                        blend: Some(wgpu::BlendState {
-                            color: wgpu::BlendComponent {
-                                src_factor: wgpu::BlendFactor::SrcAlpha,
-                                dst_factor: wgpu::BlendFactor::OneMinusSrcAlpha,
-                                operation: wgpu::BlendOperation::Add,
-                            },
-                            alpha: wgpu::BlendComponent {
-                                src_factor: wgpu::BlendFactor::One,
-                                dst_factor: wgpu::BlendFactor::OneMinusSrcAlpha,
-                                operation: wgpu::BlendOperation::Add,
-                            },
-                        }),
-                        write_mask: wgpu::ColorWrites::ALL,
-                    })],
-                }),
-                primitive: wgpu::PrimitiveState {
-                    topology: wgpu::PrimitiveTopology::TriangleList,
-                    front_face: wgpu::FrontFace::Cw,
-                    ..Default::default()
-                },
-                depth_stencil: None,
-                multisample: wgpu::MultisampleState {
-                    count: 1,
-                    mask: !0,
-                    alpha_to_coverage_enabled: false,
-                },
-                multiview: None,
-            });
-
-        let texture_atlas = Atlas::new(device, backend);
-
-        let texture = device.create_bind_group(&wgpu::BindGroupDescriptor {
-            label: Some("iced_wgpu::image texture atlas bind group"),
-            layout: &texture_layout,
-            entries: &[wgpu::BindGroupEntry {
-                binding: 0,
-                resource: wgpu::BindingResource::TextureView(
-                    texture_atlas.view(),
-                ),
-            }],
-        });
-
-        Pipeline {
-            #[cfg(feature = "image")]
-            raster_cache: RefCell::new(raster::Cache::default()),
-
-            #[cfg(feature = "svg")]
-            vector_cache: RefCell::new(vector::Cache::default()),
-
-            pipeline,
-            nearest_sampler,
-            linear_sampler,
-            texture,
-            texture_version: texture_atlas.layer_count(),
-            texture_atlas,
-            texture_layout,
-            constant_layout,
-
-            layers: Vec::new(),
-            prepare_layer: 0,
-        }
-    }
-
-    #[cfg(feature = "image")]
-    pub fn dimensions(&self, handle: &image::Handle) -> Size<u32> {
-        let mut cache = self.raster_cache.borrow_mut();
-        let memory = cache.load(handle);
-
-        memory.dimensions()
-    }
-
-    #[cfg(feature = "svg")]
-    pub fn viewport_dimensions(&self, handle: &svg::Handle) -> Size<u32> {
-        let mut cache = self.vector_cache.borrow_mut();
-        let svg = cache.load(handle);
-
-        svg.viewport_dimensions()
-    }
-
-    pub fn prepare(
-        &mut self,
-        device: &wgpu::Device,
-        encoder: &mut wgpu::CommandEncoder,
-        belt: &mut wgpu::util::StagingBelt,
-        images: &[layer::Image],
-        transformation: Transformation,
-        _scale: f32,
-    ) {
-        #[cfg(feature = "tracing")]
-        let _ = info_span!("Wgpu::Image", "PREPARE").entered();
-
-        #[cfg(feature = "tracing")]
-        let _ = info_span!("Wgpu::Image", "DRAW").entered();
-
-        let nearest_instances: &mut Vec<Instance> = &mut Vec::new();
-        let linear_instances: &mut Vec<Instance> = &mut Vec::new();
-
-        #[cfg(feature = "image")]
-        let mut raster_cache = self.raster_cache.borrow_mut();
-
-        #[cfg(feature = "svg")]
-        let mut vector_cache = self.vector_cache.borrow_mut();
-
-        for image in images {
-            match &image {
-                #[cfg(feature = "image")]
-                layer::Image::Raster {
-                    handle,
-                    filter_method,
-                    bounds,
-                } => {
-                    if let Some(atlas_entry) = raster_cache.upload(
-                        device,
-                        encoder,
-                        handle,
-                        &mut self.texture_atlas,
-                    ) {
-                        add_instances(
-                            [bounds.x, bounds.y],
-                            [bounds.width, bounds.height],
-                            atlas_entry,
-                            match filter_method {
-                                image::FilterMethod::Nearest => {
-                                    nearest_instances
-                                }
-                                image::FilterMethod::Linear => linear_instances,
-                            },
-                        );
-                    }
-                }
-                #[cfg(not(feature = "image"))]
-                layer::Image::Raster { .. } => {}
-
-                #[cfg(feature = "svg")]
-                layer::Image::Vector {
-                    handle,
-                    color,
-                    bounds,
-                } => {
-                    let size = [bounds.width, bounds.height];
-
-                    if let Some(atlas_entry) = vector_cache.upload(
-                        device,
-                        encoder,
-                        handle,
-                        *color,
-                        size,
-                        _scale,
-                        &mut self.texture_atlas,
-                    ) {
-                        add_instances(
-                            [bounds.x, bounds.y],
-                            size,
-                            atlas_entry,
-                            nearest_instances,
-                        );
-                    }
-                }
-                #[cfg(not(feature = "svg"))]
-                layer::Image::Vector { .. } => {}
-            }
-        }
-
-        if nearest_instances.is_empty() && linear_instances.is_empty() {
-            return;
-        }
-
-        let texture_version = self.texture_atlas.layer_count();
-
-        if self.texture_version != texture_version {
-            log::info!("Atlas has grown. Recreating bind group...");
-
-            self.texture =
-                device.create_bind_group(&wgpu::BindGroupDescriptor {
-                    label: Some("iced_wgpu::image texture atlas bind group"),
-                    layout: &self.texture_layout,
-                    entries: &[wgpu::BindGroupEntry {
-                        binding: 0,
-                        resource: wgpu::BindingResource::TextureView(
-                            self.texture_atlas.view(),
-                        ),
-                    }],
-                });
-
-            self.texture_version = texture_version;
-        }
-
-        if self.layers.len() <= self.prepare_layer {
-            self.layers.push(Layer::new(
-                device,
-                &self.constant_layout,
-                &self.nearest_sampler,
-                &self.linear_sampler,
-            ));
-        }
-
-        let layer = &mut self.layers[self.prepare_layer];
-
-        layer.prepare(
-            device,
-            encoder,
-            belt,
-            nearest_instances,
-            linear_instances,
-            transformation,
-        );
-
-        self.prepare_layer += 1;
-    }
-
-    pub fn render<'a>(
-        &'a self,
-        layer: usize,
-        bounds: Rectangle<u32>,
-        render_pass: &mut wgpu::RenderPass<'a>,
-    ) {
-        if let Some(layer) = self.layers.get(layer) {
-            render_pass.set_pipeline(&self.pipeline);
-
-            render_pass.set_scissor_rect(
-                bounds.x,
-                bounds.y,
-                bounds.width,
-                bounds.height,
-            );
-
-            render_pass.set_bind_group(1, &self.texture, &[]);
-
-            layer.render(render_pass);
-        }
-    }
-
-    pub fn end_frame(&mut self) {
-        #[cfg(feature = "image")]
-        self.raster_cache.borrow_mut().trim(&mut self.texture_atlas);
-
-        #[cfg(feature = "svg")]
-        self.vector_cache.borrow_mut().trim(&mut self.texture_atlas);
-
-        self.prepare_layer = 0;
-    }
-}
-
 #[repr(C)]
 #[derive(Debug, Clone, Copy, Zeroable, Pod)]
 struct Instance {

wgpu/src/image/null.rs

@@ -0,0 +1,10 @@
+pub use crate::graphics::Image;
+
+#[derive(Default)]
+pub struct Batch;
+
+impl Batch {
+    pub fn push(&mut self, _image: Image) {}
+
+    pub fn clear(&mut self) {}
+}

wgpu/src/layer.rs

@@ -1,343 +1,326 @@
-//! Organize rendering primitives into a flattened list of layers.
-mod image;
-mod pipeline;
-mod text;
-
-pub mod mesh;
-
-pub use image::Image;
-pub use mesh::Mesh;
-pub use pipeline::Pipeline;
-pub use text::Text;
-
-use crate::core;
-use crate::core::alignment;
-use crate::core::{
-    Color, Font, Pixels, Point, Rectangle, Size, Transformation, Vector,
-};
-use crate::graphics;
+use crate::core::renderer;
+use crate::core::{Background, Color, Point, Rectangle, Transformation};
 use crate::graphics::color;
-use crate::graphics::Viewport;
-use crate::primitive::{self, Primitive};
+use crate::graphics::text::{Editor, Paragraph};
+use crate::graphics::Mesh;
+use crate::image::{self, Image};
 use crate::quad::{self, Quad};
+use crate::text::{self, Text};
+use crate::triangle;
 
-/// A group of primitives that should be clipped together.
-#[derive(Debug)]
-pub struct Layer<'a> {
-    /// The clipping bounds of the [`Layer`].
-    pub bounds: Rectangle,
+use std::cell::{self, RefCell};
+use std::rc::Rc;
 
-    /// The quads of the [`Layer`].
-    pub quads: quad::Batch,
-
-    /// The triangle meshes of the [`Layer`].
-    pub meshes: Vec<Mesh<'a>>,
-
-    /// The text of the [`Layer`].
-    pub text: Vec<Text<'a>>,
-
-    /// The images of the [`Layer`].
-    pub images: Vec<Image>,
-
-    /// The custom pipelines of this [`Layer`].
-    pub pipelines: Vec<Pipeline>,
+pub enum Layer<'a> {
+    Live(&'a Live),
+    Cached(cell::Ref<'a, Cached>),
 }
 
-impl<'a> Layer<'a> {
-    /// Creates a new [`Layer`] with the given clipping bounds.
-    pub fn new(bounds: Rectangle) -> Self {
+pub enum LayerMut<'a> {
+    Live(&'a mut Live),
+    Cached(cell::RefMut<'a, Cached>),
+}
+
+pub struct Stack {
+    live: Vec<Live>,
+    cached: Vec<Rc<RefCell<Cached>>>,
+    order: Vec<Kind>,
+    transformations: Vec<Transformation>,
+    previous: Vec<usize>,
+    current: usize,
+    live_count: usize,
+}
+
+impl Stack {
+    pub fn new() -> Self {
         Self {
-            bounds,
-            quads: quad::Batch::default(),
-            meshes: Vec::new(),
-            text: Vec::new(),
-            images: Vec::new(),
-            pipelines: Vec::new(),
+            live: vec![Live::default()],
+            cached: Vec::new(),
+            order: vec![Kind::Live],
+            transformations: vec![Transformation::IDENTITY],
+            previous: Vec::new(),
+            current: 0,
+            live_count: 1,
         }
     }
 
-    /// Creates a new [`Layer`] for the provided overlay text.
-    ///
-    /// This can be useful for displaying debug information.
-    pub fn overlay(lines: &'a [impl AsRef<str>], viewport: &Viewport) -> Self {
-        let mut overlay =
-            Layer::new(Rectangle::with_size(viewport.logical_size()));
+    pub fn draw_quad(&mut self, quad: renderer::Quad, background: Background) {
+        let transformation = self.transformations.last().unwrap();
+        let bounds = quad.bounds * *transformation;
 
-        for (i, line) in lines.iter().enumerate() {
-            let text = text::Cached {
-                content: line.as_ref(),
-                bounds: Rectangle::new(
-                    Point::new(11.0, 11.0 + 25.0 * i as f32),
-                    Size::INFINITY,
-                ),
-                color: Color::new(0.9, 0.9, 0.9, 1.0),
-                size: Pixels(20.0),
-                line_height: core::text::LineHeight::default(),
-                font: Font::MONOSPACE,
-                horizontal_alignment: alignment::Horizontal::Left,
-                vertical_alignment: alignment::Vertical::Top,
-                shaping: core::text::Shaping::Basic,
-                clip_bounds: Rectangle::with_size(Size::INFINITY),
-            };
+        let quad = Quad {
+            position: [bounds.x, bounds.y],
+            size: [bounds.width, bounds.height],
+            border_color: color::pack(quad.border.color),
+            border_radius: quad.border.radius.into(),
+            border_width: quad.border.width,
+            shadow_color: color::pack(quad.shadow.color),
+            shadow_offset: quad.shadow.offset.into(),
+            shadow_blur_radius: quad.shadow.blur_radius,
+        };
 
-            overlay.text.push(Text::Cached(text.clone()));
-
-            overlay.text.push(Text::Cached(text::Cached {
-                bounds: text.bounds + Vector::new(-1.0, -1.0),
-                color: Color::BLACK,
-                ..text
-            }));
-        }
-
-        overlay
+        self.live[self.current].quads.add(quad, &background);
     }
 
-    /// Distributes the given [`Primitive`] and generates a list of layers based
-    /// on its contents.
-    pub fn generate(
-        primitives: &'a [Primitive],
-        viewport: &Viewport,
-    ) -> Vec<Self> {
-        let first_layer =
-            Layer::new(Rectangle::with_size(viewport.logical_size()));
-
-        let mut layers = vec![first_layer];
-
-        for primitive in primitives {
-            Self::process_primitive(
-                &mut layers,
-                Transformation::IDENTITY,
-                primitive,
-                0,
-            );
-        }
-
-        layers
-    }
-
-    fn process_primitive(
-        layers: &mut Vec<Self>,
-        transformation: Transformation,
-        primitive: &'a Primitive,
-        current_layer: usize,
+    pub fn draw_paragraph(
+        &mut self,
+        paragraph: &Paragraph,
+        position: Point,
+        color: Color,
+        clip_bounds: Rectangle,
     ) {
-        match primitive {
-            Primitive::Paragraph {
-                paragraph,
-                position,
-                color,
-                clip_bounds,
-            } => {
-                let layer = &mut layers[current_layer];
+        let paragraph = Text::Paragraph {
+            paragraph: paragraph.downgrade(),
+            position,
+            color,
+            clip_bounds,
+            transformation: self.transformations.last().copied().unwrap(),
+        };
 
-                layer.text.push(Text::Paragraph {
-                    paragraph: paragraph.clone(),
-                    position: *position,
-                    color: *color,
-                    clip_bounds: *clip_bounds,
-                    transformation,
-                });
-            }
-            Primitive::Editor {
-                editor,
-                position,
-                color,
-                clip_bounds,
-            } => {
-                let layer = &mut layers[current_layer];
+        self.live[self.current].text.push(paragraph);
+    }
 
-                layer.text.push(Text::Editor {
-                    editor: editor.clone(),
-                    position: *position,
-                    color: *color,
-                    clip_bounds: *clip_bounds,
-                    transformation,
-                });
+    pub fn draw_editor(
+        &mut self,
+        editor: &Editor,
+        position: Point,
+        color: Color,
+        clip_bounds: Rectangle,
+    ) {
+        let paragraph = Text::Editor {
+            editor: editor.downgrade(),
+            position,
+            color,
+            clip_bounds,
+            transformation: self.transformations.last().copied().unwrap(),
+        };
+
+        self.live[self.current].text.push(paragraph);
+    }
+
+    pub fn draw_text(
+        &mut self,
+        text: crate::core::Text,
+        position: Point,
+        color: Color,
+        clip_bounds: Rectangle,
+    ) {
+        let transformation = self.transformation();
+
+        let paragraph = Text::Cached {
+            content: text.content,
+            bounds: Rectangle::new(position, text.bounds) * transformation,
+            color,
+            size: text.size * transformation.scale_factor(),
+            line_height: text.line_height,
+            font: text.font,
+            horizontal_alignment: text.horizontal_alignment,
+            vertical_alignment: text.vertical_alignment,
+            shaping: text.shaping,
+            clip_bounds: clip_bounds * transformation,
+        };
+
+        self.live[self.current].text.push(paragraph);
+    }
+
+    pub fn draw_image(
+        &mut self,
+        handle: crate::core::image::Handle,
+        filter_method: crate::core::image::FilterMethod,
+        bounds: Rectangle,
+    ) {
+        let image = Image::Raster {
+            handle,
+            filter_method,
+            bounds: bounds * self.transformation(),
+        };
+
+        self.live[self.current].images.push(image);
+    }
+
+    pub fn draw_svg(
+        &mut self,
+        handle: crate::core::svg::Handle,
+        color: Option<Color>,
+        bounds: Rectangle,
+    ) {
+        let svg = Image::Vector {
+            handle,
+            color,
+            bounds: bounds * self.transformation(),
+        };
+
+        self.live[self.current].images.push(svg);
+    }
+
+    pub fn draw_mesh(&mut self, mut mesh: Mesh) {
+        match &mut mesh {
+            Mesh::Solid { transformation, .. }
+            | Mesh::Gradient { transformation, .. } => {
+                *transformation = *transformation * self.transformation();
             }
-            Primitive::Text {
-                content,
+        }
+
+        self.live[self.current].meshes.push(mesh);
+    }
+
+    pub fn draw_layer(&mut self, mut layer: Live) {
+        layer.transformation = layer.transformation * self.transformation();
+
+        if self.live_count == self.live.len() {
+            self.live.push(layer);
+        } else {
+            self.live[self.live_count] = layer;
+        }
+
+        self.live_count += 1;
+        self.order.push(Kind::Live);
+    }
+
+    pub fn draw_cached_layer(&mut self, layer: &Rc<RefCell<Cached>>) {
+        {
+            let mut layer = layer.borrow_mut();
+            layer.transformation = self.transformation() * layer.transformation;
+        }
+
+        self.cached.push(layer.clone());
+        self.order.push(Kind::Cache);
+    }
+
+    pub fn push_clip(&mut self, bounds: Option<Rectangle>) {
+        self.previous.push(self.current);
+        self.order.push(Kind::Live);
+
+        self.current = self.live_count;
+        self.live_count += 1;
+
+        let bounds = bounds.map(|bounds| bounds * self.transformation());
+
+        if self.current == self.live.len() {
+            self.live.push(Live {
                 bounds,
-                size,
-                line_height,
-                color,
-                font,
-                horizontal_alignment,
-                vertical_alignment,
-                shaping,
-                clip_bounds,
-            } => {
-                let layer = &mut layers[current_layer];
+                ..Live::default()
+            });
+        } else {
+            self.live[self.current].bounds = bounds;
+        }
+    }
 
-                layer.text.push(Text::Cached(text::Cached {
-                    content,
-                    bounds: *bounds + transformation.translation(),
-                    size: *size * transformation.scale_factor(),
-                    line_height: *line_height,
-                    color: *color,
-                    font: *font,
-                    horizontal_alignment: *horizontal_alignment,
-                    vertical_alignment: *vertical_alignment,
-                    shaping: *shaping,
-                    clip_bounds: *clip_bounds * transformation,
-                }));
+    pub fn pop_clip(&mut self) {
+        self.current = self.previous.pop().unwrap();
+    }
+
+    pub fn push_transformation(&mut self, transformation: Transformation) {
+        self.transformations
+            .push(self.transformation() * transformation);
+    }
+
+    pub fn pop_transformation(&mut self) {
+        let _ = self.transformations.pop();
+    }
+
+    fn transformation(&self) -> Transformation {
+        self.transformations.last().copied().unwrap()
+    }
+
+    pub fn iter_mut(&mut self) -> impl Iterator<Item = LayerMut<'_>> {
+        let mut live = self.live.iter_mut();
+        let mut cached = self.cached.iter_mut();
+
+        self.order.iter().map(move |kind| match kind {
+            Kind::Live => LayerMut::Live(live.next().unwrap()),
+            Kind::Cache => {
+                LayerMut::Cached(cached.next().unwrap().borrow_mut())
             }
-            graphics::Primitive::RawText(raw) => {
-                let layer = &mut layers[current_layer];
+        })
+    }
 
-                layer.text.push(Text::Raw {
-                    raw: raw.clone(),
-                    transformation,
-                });
-            }
-            Primitive::Quad {
-                bounds,
-                background,
-                border,
-                shadow,
-            } => {
-                let layer = &mut layers[current_layer];
-                let bounds = *bounds * transformation;
+    pub fn iter(&self) -> impl Iterator<Item = Layer<'_>> {
+        let mut live = self.live.iter();
+        let mut cached = self.cached.iter();
 
-                let quad = Quad {
-                    position: [bounds.x, bounds.y],
-                    size: [bounds.width, bounds.height],
-                    border_color: color::pack(border.color),
-                    border_radius: border.radius.into(),
-                    border_width: border.width,
-                    shadow_color: shadow.color.into_linear(),
-                    shadow_offset: shadow.offset.into(),
-                    shadow_blur_radius: shadow.blur_radius,
-                };
+        self.order.iter().map(move |kind| match kind {
+            Kind::Live => Layer::Live(live.next().unwrap()),
+            Kind::Cache => Layer::Cached(cached.next().unwrap().borrow()),
+        })
+    }
 
-                layer.quads.add(quad, background);
-            }
-            Primitive::Image {
-                handle,
-                filter_method,
-                bounds,
-            } => {
-                let layer = &mut layers[current_layer];
+    pub fn clear(&mut self) {
+        for live in &mut self.live[..self.live_count] {
+            live.bounds = None;
+            live.transformation = Transformation::IDENTITY;
 
-                layer.images.push(Image::Raster {
-                    handle: handle.clone(),
-                    filter_method: *filter_method,
-                    bounds: *bounds * transformation,
-                });
-            }
-            Primitive::Svg {
-                handle,
-                color,
-                bounds,
-            } => {
-                let layer = &mut layers[current_layer];
+            live.quads.clear();
+            live.meshes.clear();
+            live.text.clear();
+            live.images.clear();
+        }
 
-                layer.images.push(Image::Vector {
-                    handle: handle.clone(),
-                    color: *color,
-                    bounds: *bounds * transformation,
-                });
-            }
-            Primitive::Group { primitives } => {
-                // TODO: Inspect a bit and regroup (?)
-                for primitive in primitives {
-                    Self::process_primitive(
-                        layers,
-                        transformation,
-                        primitive,
-                        current_layer,
-                    );
-                }
-            }
-            Primitive::Clip { bounds, content } => {
-                let layer = &mut layers[current_layer];
-                let translated_bounds = *bounds * transformation;
+        self.current = 0;
+        self.live_count = 1;
 
-                // Only draw visible content
-                if let Some(clip_bounds) =
-                    layer.bounds.intersection(&translated_bounds)
-                {
-                    let clip_layer = Layer::new(clip_bounds);
-                    layers.push(clip_layer);
+        self.order.clear();
+        self.order.push(Kind::Live);
 
-                    Self::process_primitive(
-                        layers,
-                        transformation,
-                        content,
-                        layers.len() - 1,
-                    );
-                }
-            }
-            Primitive::Transform {
-                transformation: new_transformation,
-                content,
-            } => {
-                Self::process_primitive(
-                    layers,
-                    transformation * *new_transformation,
-                    content,
-                    current_layer,
-                );
-            }
-            Primitive::Cache { content } => {
-                Self::process_primitive(
-                    layers,
-                    transformation,
-                    content,
-                    current_layer,
-                );
-            }
-            Primitive::Custom(custom) => match custom {
-                primitive::Custom::Mesh(mesh) => match mesh {
-                    graphics::Mesh::Solid { buffers, size } => {
-                        let layer = &mut layers[current_layer];
+        self.cached.clear();
+        self.previous.clear();
+    }
+}
 
-                        let bounds =
-                            Rectangle::with_size(*size) * transformation;
+impl Default for Stack {
+    fn default() -> Self {
+        Self::new()
+    }
+}
 
-                        // Only draw visible content
-                        if let Some(clip_bounds) =
-                            layer.bounds.intersection(&bounds)
-                        {
-                            layer.meshes.push(Mesh::Solid {
-                                transformation,
-                                buffers,
-                                clip_bounds,
-                            });
-                        }
-                    }
-                    graphics::Mesh::Gradient { buffers, size } => {
-                        let layer = &mut layers[current_layer];
+#[derive(Default)]
+pub struct Live {
+    pub bounds: Option<Rectangle>,
+    pub transformation: Transformation,
+    pub quads: quad::Batch,
+    pub meshes: triangle::Batch,
+    pub text: text::Batch,
+    pub images: image::Batch,
+}
 
-                        let bounds =
-                            Rectangle::with_size(*size) * transformation;
-
-                        // Only draw visible content
-                        if let Some(clip_bounds) =
-                            layer.bounds.intersection(&bounds)
-                        {
-                            layer.meshes.push(Mesh::Gradient {
-                                transformation,
-                                buffers,
-                                clip_bounds,
-                            });
-                        }
-                    }
-                },
-                primitive::Custom::Pipeline(pipeline) => {
-                    let layer = &mut layers[current_layer];
-                    let bounds = pipeline.bounds * transformation;
-
-                    if let Some(clip_bounds) =
-                        layer.bounds.intersection(&bounds)
-                    {
-                        layer.pipelines.push(Pipeline {
-                            bounds,
-                            viewport: clip_bounds,
-                            primitive: pipeline.primitive.clone(),
-                        });
-                    }
-                }
-            },
+impl Live {
+    pub fn into_cached(self) -> Cached {
+        Cached {
+            bounds: self.bounds,
+            transformation: self.transformation,
+            last_transformation: None,
+            quads: quad::Cache::Staged(self.quads),
+            meshes: triangle::Cache::Staged(self.meshes),
+            text: text::Cache::Staged(self.text),
+            images: self.images,
         }
     }
 }
+
+#[derive(Default)]
+pub struct Cached {
+    pub bounds: Option<Rectangle>,
+    pub transformation: Transformation,
+    pub last_transformation: Option<Transformation>,
+    pub quads: quad::Cache,
+    pub meshes: triangle::Cache,
+    pub text: text::Cache,
+    pub images: image::Batch,
+}
+
+impl Cached {
+    pub fn update(&mut self, live: Live) {
+        self.bounds = live.bounds;
+        self.transformation = live.transformation;
+
+        self.quads.update(live.quads);
+        self.meshes.update(live.meshes);
+        self.text.update(live.text);
+        self.images = live.images;
+    }
+}
+
+enum Kind {
+    Live,
+    Cache,
+}

wgpu/src/layer/image.rs

@@ -1,30 +0,0 @@
-use crate::core::image;
-use crate::core::svg;
-use crate::core::{Color, Rectangle};
-
-/// A raster or vector image.
-#[derive(Debug, Clone)]
-pub enum Image {
-    /// A raster image.
-    Raster {
-        /// The handle of a raster image.
-        handle: image::Handle,
-
-        /// The filter method of a raster image.
-        filter_method: image::FilterMethod,
-
-        /// The bounds of the image.
-        bounds: Rectangle,
-    },
-    /// A vector image.
-    Vector {
-        /// The handle of a vector image.
-        handle: svg::Handle,
-
-        /// The [`Color`] filter
-        color: Option<Color>,
-
-        /// The bounds of the image.
-        bounds: Rectangle,
-    },
-}

wgpu/src/layer/mesh.rs

@@ -1,97 +0,0 @@
-//! A collection of triangle primitives.
-use crate::core::{Rectangle, Transformation};
-use crate::graphics::mesh;
-
-/// A mesh of triangles.
-#[derive(Debug, Clone, Copy)]
-pub enum Mesh<'a> {
-    /// A mesh of triangles with a solid color.
-    Solid {
-        /// The [`Transformation`] for the vertices of the [`Mesh`].
-        transformation: Transformation,
-
-        /// The vertex and index buffers of the [`Mesh`].
-        buffers: &'a mesh::Indexed<mesh::SolidVertex2D>,
-
-        /// The clipping bounds of the [`Mesh`].
-        clip_bounds: Rectangle<f32>,
-    },
-    /// A mesh of triangles with a gradient color.
-    Gradient {
-        /// The [`Transformation`] for the vertices of the [`Mesh`].
-        transformation: Transformation,
-
-        /// The vertex and index buffers of the [`Mesh`].
-        buffers: &'a mesh::Indexed<mesh::GradientVertex2D>,
-
-        /// The clipping bounds of the [`Mesh`].
-        clip_bounds: Rectangle<f32>,
-    },
-}
-
-impl Mesh<'_> {
-    /// Returns the origin of the [`Mesh`].
-    pub fn transformation(&self) -> Transformation {
-        match self {
-            Self::Solid { transformation, .. }
-            | Self::Gradient { transformation, .. } => *transformation,
-        }
-    }
-
-    /// Returns the indices of the [`Mesh`].
-    pub fn indices(&self) -> &[u32] {
-        match self {
-            Self::Solid { buffers, .. } => &buffers.indices,
-            Self::Gradient { buffers, .. } => &buffers.indices,
-        }
-    }
-
-    /// Returns the clip bounds of the [`Mesh`].
-    pub fn clip_bounds(&self) -> Rectangle<f32> {
-        match self {
-            Self::Solid { clip_bounds, .. }
-            | Self::Gradient { clip_bounds, .. } => *clip_bounds,
-        }
-    }
-}
-
-/// The result of counting the attributes of a set of meshes.
-#[derive(Debug, Clone, Copy, Default)]
-pub struct AttributeCount {
-    /// The total amount of solid vertices.
-    pub solid_vertices: usize,
-
-    /// The total amount of solid meshes.
-    pub solids: usize,
-
-    /// The total amount of gradient vertices.
-    pub gradient_vertices: usize,
-
-    /// The total amount of gradient meshes.
-    pub gradients: usize,
-
-    /// The total amount of indices.
-    pub indices: usize,
-}
-
-/// Returns the number of total vertices & total indices of all [`Mesh`]es.
-pub fn attribute_count_of<'a>(meshes: &'a [Mesh<'a>]) -> AttributeCount {
-    meshes
-        .iter()
-        .fold(AttributeCount::default(), |mut count, mesh| {
-            match mesh {
-                Mesh::Solid { buffers, .. } => {
-                    count.solids += 1;
-                    count.solid_vertices += buffers.vertices.len();
-                    count.indices += buffers.indices.len();
-                }
-                Mesh::Gradient { buffers, .. } => {
-                    count.gradients += 1;
-                    count.gradient_vertices += buffers.vertices.len();
-                    count.indices += buffers.indices.len();
-                }
-            }
-
-            count
-        })
-}

wgpu/src/layer/pipeline.rs

@@ -1,17 +0,0 @@
-use crate::core::Rectangle;
-use crate::primitive::pipeline::Primitive;
-
-use std::sync::Arc;
-
-#[derive(Clone, Debug)]
-/// A custom primitive which can be used to render primitives associated with a custom pipeline.
-pub struct Pipeline {
-    /// The bounds of the [`Pipeline`].
-    pub bounds: Rectangle,
-
-    /// The viewport of the [`Pipeline`].
-    pub viewport: Rectangle,
-
-    /// The [`Primitive`] to render.
-    pub primitive: Arc<dyn Primitive>,
-}

wgpu/src/layer/text.rs

@@ -1,70 +0,0 @@
-use crate::core::alignment;
-use crate::core::text;
-use crate::core::{Color, Font, Pixels, Point, Rectangle, Transformation};
-use crate::graphics;
-use crate::graphics::text::editor;
-use crate::graphics::text::paragraph;
-
-/// A text primitive.
-#[derive(Debug, Clone)]
-pub enum Text<'a> {
-    /// A paragraph.
-    #[allow(missing_docs)]
-    Paragraph {
-        paragraph: paragraph::Weak,
-        position: Point,
-        color: Color,
-        clip_bounds: Rectangle,
-        transformation: Transformation,
-    },
-    /// An editor.
-    #[allow(missing_docs)]
-    Editor {
-        editor: editor::Weak,
-        position: Point,
-        color: Color,
-        clip_bounds: Rectangle,
-        transformation: Transformation,
-    },
-    /// Some cached text.
-    Cached(Cached<'a>),
-    /// Some raw text.
-    #[allow(missing_docs)]
-    Raw {
-        raw: graphics::text::Raw,
-        transformation: Transformation,
-    },
-}
-
-#[derive(Debug, Clone)]
-pub struct Cached<'a> {
-    /// The content of the [`Text`].
-    pub content: &'a str,
-
-    /// The layout bounds of the [`Text`].
-    pub bounds: Rectangle,
-
-    /// The color of the [`Text`], in __linear RGB_.
-    pub color: Color,
-
-    /// The size of the [`Text`] in logical pixels.
-    pub size: Pixels,
-
-    /// The line height of the [`Text`].
-    pub line_height: text::LineHeight,
-
-    /// The font of the [`Text`].
-    pub font: Font,
-
-    /// The horizontal alignment of the [`Text`].
-    pub horizontal_alignment: alignment::Horizontal,
-
-    /// The vertical alignment of the [`Text`].
-    pub vertical_alignment: alignment::Vertical,
-
-    /// The shaping strategy of the text.
-    pub shaping: text::Shaping,
-
-    /// The clip bounds of the text.
-    pub clip_bounds: Rectangle,
-}

wgpu/src/lib.rs

@@ -22,8 +22,8 @@
 )]
 #![forbid(rust_2018_idioms)]
 #![deny(
-    missing_debug_implementations,
-    missing_docs,
+    // missing_debug_implementations,
+    //missing_docs,
     unsafe_code,
     unused_results,
     rustdoc::broken_intra_doc_links
@@ -37,13 +37,21 @@ pub mod window;
 #[cfg(feature = "geometry")]
 pub mod geometry;
 
-mod backend;
 mod buffer;
 mod color;
+mod engine;
 mod quad;
 mod text;
 mod triangle;
 
+#[cfg(any(feature = "image", feature = "svg"))]
+#[path = "image/mod.rs"]
+mod image;
+
+#[cfg(not(any(feature = "image", feature = "svg")))]
+#[path = "image/null.rs"]
+mod image;
+
 use buffer::Buffer;
 
 pub use iced_graphics as graphics;
@@ -51,16 +59,570 @@ pub use iced_graphics::core;
 
 pub use wgpu;
 
-pub use backend::Backend;
-pub use layer::Layer;
+pub use engine::Engine;
+pub use layer::{Layer, LayerMut};
 pub use primitive::Primitive;
 pub use settings::Settings;
 
-#[cfg(any(feature = "image", feature = "svg"))]
-mod image;
+#[cfg(feature = "geometry")]
+pub use geometry::Geometry;
+
+use crate::core::{
+    Background, Color, Font, Pixels, Point, Rectangle, Size, Transformation,
+};
+use crate::graphics::text::{Editor, Paragraph};
+use crate::graphics::Viewport;
+
+use std::borrow::Cow;
 
 /// A [`wgpu`] graphics renderer for [`iced`].
 ///
 /// [`wgpu`]: https://github.com/gfx-rs/wgpu-rs
 /// [`iced`]: https://github.com/iced-rs/iced
-pub type Renderer = iced_graphics::Renderer<Backend>;
+#[allow(missing_debug_implementations)]
+pub struct Renderer {
+    default_font: Font,
+    default_text_size: Pixels,
+    layers: layer::Stack,
+
+    // TODO: Centralize all the image feature handling
+    #[cfg(any(feature = "svg", feature = "image"))]
+    image_cache: image::cache::Shared,
+}
+
+impl Renderer {
+    pub fn new(settings: Settings, _engine: &Engine) -> Self {
+        Self {
+            default_font: settings.default_font,
+            default_text_size: settings.default_text_size,
+            layers: layer::Stack::new(),
+
+            #[cfg(any(feature = "svg", feature = "image"))]
+            image_cache: _engine.image_cache().clone(),
+        }
+    }
+
+    pub fn draw_primitive(&mut self, _primitive: Primitive) {}
+
+    pub fn present<T: AsRef<str>>(
+        &mut self,
+        engine: &mut Engine,
+        device: &wgpu::Device,
+        queue: &wgpu::Queue,
+        encoder: &mut wgpu::CommandEncoder,
+        clear_color: Option<Color>,
+        format: wgpu::TextureFormat,
+        frame: &wgpu::TextureView,
+        viewport: &Viewport,
+        overlay: &[T],
+    ) {
+        let target_size = viewport.physical_size();
+        let scale_factor = viewport.scale_factor() as f32;
+        let transformation = viewport.projection();
+
+        for line in overlay {
+            println!("{}", line.as_ref());
+        }
+
+        self.prepare(
+            engine,
+            device,
+            queue,
+            format,
+            encoder,
+            scale_factor,
+            target_size,
+            transformation,
+        );
+
+        self.render(
+            engine,
+            device,
+            encoder,
+            frame,
+            clear_color,
+            scale_factor,
+            target_size,
+        );
+    }
+
+    fn prepare(
+        &mut self,
+        engine: &mut Engine,
+        device: &wgpu::Device,
+        queue: &wgpu::Queue,
+        _format: wgpu::TextureFormat,
+        encoder: &mut wgpu::CommandEncoder,
+        scale_factor: f32,
+        target_size: Size<u32>,
+        transformation: Transformation,
+    ) {
+        for layer in self.layers.iter_mut() {
+            match layer {
+                LayerMut::Live(live) => {
+                    if !live.quads.is_empty() {
+                        engine.quad_pipeline.prepare_batch(
+                            device,
+                            encoder,
+                            &mut engine.staging_belt,
+                            &live.quads,
+                            transformation,
+                            scale_factor,
+                        );
+                    }
+
+                    if !live.meshes.is_empty() {
+                        engine.triangle_pipeline.prepare_batch(
+                            device,
+                            encoder,
+                            &mut engine.staging_belt,
+                            &live.meshes,
+                            transformation
+                                * Transformation::scale(scale_factor),
+                        );
+                    }
+
+                    if !live.text.is_empty() {
+                        engine.text_pipeline.prepare_batch(
+                            device,
+                            queue,
+                            encoder,
+                            &live.text,
+                            live.bounds.unwrap_or(Rectangle::with_size(
+                                Size::INFINITY,
+                            )),
+                            scale_factor,
+                            target_size,
+                        );
+                    }
+
+                    #[cfg(any(feature = "svg", feature = "image"))]
+                    if !live.images.is_empty() {
+                        engine.image_pipeline.prepare(
+                            device,
+                            encoder,
+                            &mut engine.staging_belt,
+                            &live.images,
+                            transformation,
+                            scale_factor,
+                        );
+                    }
+                }
+                LayerMut::Cached(mut cached) => {
+                    if !cached.quads.is_empty() {
+                        engine.quad_pipeline.prepare_cache(
+                            device,
+                            encoder,
+                            &mut engine.staging_belt,
+                            &mut cached.quads,
+                            transformation,
+                            scale_factor,
+                        );
+                    }
+
+                    if !cached.meshes.is_empty() {
+                        engine.triangle_pipeline.prepare_cache(
+                            device,
+                            encoder,
+                            &mut engine.staging_belt,
+                            &mut cached.meshes,
+                            transformation
+                                * Transformation::scale(scale_factor),
+                        );
+                    }
+
+                    if !cached.text.is_empty() {
+                        let bounds = cached
+                            .bounds
+                            .unwrap_or(Rectangle::with_size(Size::INFINITY));
+
+                        engine.text_pipeline.prepare_cache(
+                            device,
+                            queue,
+                            encoder,
+                            &mut cached.text,
+                            bounds,
+                            scale_factor,
+                            target_size,
+                        );
+                    }
+
+                    #[cfg(any(feature = "svg", feature = "image"))]
+                    if !cached.images.is_empty() {
+                        engine.image_pipeline.prepare(
+                            device,
+                            encoder,
+                            &mut engine.staging_belt,
+                            &cached.images,
+                            transformation,
+                            scale_factor,
+                        );
+                    }
+                }
+            }
+        }
+    }
+
+    fn render(
+        &mut self,
+        engine: &mut Engine,
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        frame: &wgpu::TextureView,
+        clear_color: Option<Color>,
+        scale_factor: f32,
+        target_size: Size<u32>,
+    ) {
+        use std::mem::ManuallyDrop;
+
+        let mut render_pass = ManuallyDrop::new(encoder.begin_render_pass(
+            &wgpu::RenderPassDescriptor {
+                label: Some("iced_wgpu render pass"),
+                color_attachments: &[Some(wgpu::RenderPassColorAttachment {
+                    view: frame,
+                    resolve_target: None,
+                    ops: wgpu::Operations {
+                        load: match clear_color {
+                            Some(background_color) => wgpu::LoadOp::Clear({
+                                let [r, g, b, a] =
+                                    graphics::color::pack(background_color)
+                                        .components();
+
+                                wgpu::Color {
+                                    r: f64::from(r),
+                                    g: f64::from(g),
+                                    b: f64::from(b),
+                                    a: f64::from(a),
+                                }
+                            }),
+                            None => wgpu::LoadOp::Load,
+                        },
+                        store: wgpu::StoreOp::Store,
+                    },
+                })],
+                depth_stencil_attachment: None,
+                timestamp_writes: None,
+                occlusion_query_set: None,
+            },
+        ));
+
+        let mut quad_layer = 0;
+        let mut mesh_layer = 0;
+        let mut text_layer = 0;
+
+        #[cfg(any(feature = "svg", feature = "image"))]
+        let mut image_layer = 0;
+
+        // TODO: Can we avoid collecting here?
+        let layers: Vec<_> = self.layers.iter().collect();
+
+        for layer in &layers {
+            match layer {
+                Layer::Live(live) => {
+                    let bounds = live
+                        .bounds
+                        .map(|bounds| bounds * scale_factor)
+                        .map(Rectangle::snap)
+                        .unwrap_or(Rectangle::with_size(target_size));
+
+                    if !live.quads.is_empty() {
+                        engine.quad_pipeline.render_batch(
+                            quad_layer,
+                            bounds,
+                            &live.quads,
+                            &mut render_pass,
+                        );
+
+                        quad_layer += 1;
+                    }
+
+                    if !live.meshes.is_empty() {
+                        let _ = ManuallyDrop::into_inner(render_pass);
+
+                        engine.triangle_pipeline.render_batch(
+                            device,
+                            encoder,
+                            frame,
+                            mesh_layer,
+                            target_size,
+                            &live.meshes,
+                            bounds,
+                            scale_factor,
+                        );
+
+                        mesh_layer += 1;
+
+                        render_pass =
+                            ManuallyDrop::new(encoder.begin_render_pass(
+                                &wgpu::RenderPassDescriptor {
+                                    label: Some("iced_wgpu render pass"),
+                                    color_attachments: &[Some(
+                                        wgpu::RenderPassColorAttachment {
+                                            view: frame,
+                                            resolve_target: None,
+                                            ops: wgpu::Operations {
+                                                load: wgpu::LoadOp::Load,
+                                                store: wgpu::StoreOp::Store,
+                                            },
+                                        },
+                                    )],
+                                    depth_stencil_attachment: None,
+                                    timestamp_writes: None,
+                                    occlusion_query_set: None,
+                                },
+                            ));
+                    }
+
+                    if !live.text.is_empty() {
+                        engine.text_pipeline.render_batch(
+                            text_layer,
+                            bounds,
+                            &mut render_pass,
+                        );
+
+                        text_layer += 1;
+                    }
+
+                    #[cfg(any(feature = "svg", feature = "image"))]
+                    if !live.images.is_empty() {
+                        engine.image_pipeline.render(
+                            image_layer,
+                            bounds,
+                            &mut render_pass,
+                        );
+
+                        image_layer += 1;
+                    }
+                }
+                Layer::Cached(cached) => {
+                    let bounds = cached
+                        .bounds
+                        .map(|bounds| bounds * scale_factor)
+                        .map(Rectangle::snap)
+                        .unwrap_or(Rectangle::with_size(target_size));
+
+                    if !cached.quads.is_empty() {
+                        engine.quad_pipeline.render_cache(
+                            &cached.quads,
+                            bounds,
+                            &mut render_pass,
+                        );
+                    }
+
+                    if !cached.meshes.is_empty() {
+                        let _ = ManuallyDrop::into_inner(render_pass);
+
+                        engine.triangle_pipeline.render_cache(
+                            device,
+                            encoder,
+                            frame,
+                            target_size,
+                            &cached.meshes,
+                            bounds,
+                            scale_factor,
+                        );
+
+                        render_pass =
+                            ManuallyDrop::new(encoder.begin_render_pass(
+                                &wgpu::RenderPassDescriptor {
+                                    label: Some("iced_wgpu render pass"),
+                                    color_attachments: &[Some(
+                                        wgpu::RenderPassColorAttachment {
+                                            view: frame,
+                                            resolve_target: None,
+                                            ops: wgpu::Operations {
+                                                load: wgpu::LoadOp::Load,
+                                                store: wgpu::StoreOp::Store,
+                                            },
+                                        },
+                                    )],
+                                    depth_stencil_attachment: None,
+                                    timestamp_writes: None,
+                                    occlusion_query_set: None,
+                                },
+                            ));
+                    }
+
+                    if !cached.text.is_empty() {
+                        engine.text_pipeline.render_cache(
+                            &cached.text,
+                            bounds,
+                            &mut render_pass,
+                        );
+                    }
+
+                    #[cfg(any(feature = "svg", feature = "image"))]
+                    if !cached.images.is_empty() {
+                        engine.image_pipeline.render(
+                            image_layer,
+                            bounds,
+                            &mut render_pass,
+                        );
+
+                        image_layer += 1;
+                    }
+                }
+            }
+        }
+
+        let _ = ManuallyDrop::into_inner(render_pass);
+    }
+}
+
+impl core::Renderer for Renderer {
+    fn start_layer(&mut self, bounds: Rectangle) {
+        self.layers.push_clip(Some(bounds));
+    }
+
+    fn end_layer(&mut self, _bounds: Rectangle) {
+        self.layers.pop_clip();
+    }
+
+    fn start_transformation(&mut self, transformation: Transformation) {
+        self.layers.push_transformation(transformation);
+    }
+
+    fn end_transformation(&mut self, _transformation: Transformation) {
+        self.layers.pop_transformation();
+    }
+
+    fn fill_quad(
+        &mut self,
+        quad: core::renderer::Quad,
+        background: impl Into<Background>,
+    ) {
+        self.layers.draw_quad(quad, background.into());
+    }
+
+    fn clear(&mut self) {
+        self.layers.clear();
+    }
+}
+
+impl core::text::Renderer for Renderer {
+    type Font = Font;
+    type Paragraph = Paragraph;
+    type Editor = Editor;
+
+    const ICON_FONT: Font = Font::with_name("Iced-Icons");
+    const CHECKMARK_ICON: char = '\u{f00c}';
+    const ARROW_DOWN_ICON: char = '\u{e800}';
+
+    fn default_font(&self) -> Self::Font {
+        self.default_font
+    }
+
+    fn default_size(&self) -> Pixels {
+        self.default_text_size
+    }
+
+    fn load_font(&mut self, font: Cow<'static, [u8]>) {
+        graphics::text::font_system()
+            .write()
+            .expect("Write font system")
+            .load_font(font);
+
+        // TODO: Invalidate buffer cache
+    }
+
+    fn fill_paragraph(
+        &mut self,
+        text: &Self::Paragraph,
+        position: Point,
+        color: Color,
+        clip_bounds: Rectangle,
+    ) {
+        self.layers
+            .draw_paragraph(text, position, color, clip_bounds);
+    }
+
+    fn fill_editor(
+        &mut self,
+        editor: &Self::Editor,
+        position: Point,
+        color: Color,
+        clip_bounds: Rectangle,
+    ) {
+        self.layers
+            .draw_editor(editor, position, color, clip_bounds);
+    }
+
+    fn fill_text(
+        &mut self,
+        text: core::Text,
+        position: Point,
+        color: Color,
+        clip_bounds: Rectangle,
+    ) {
+        self.layers.draw_text(text, position, color, clip_bounds);
+    }
+}
+
+#[cfg(feature = "image")]
+impl core::image::Renderer for Renderer {
+    type Handle = core::image::Handle;
+
+    fn measure_image(&self, handle: &Self::Handle) -> Size<u32> {
+        self.image_cache.lock().measure_image(handle)
+    }
+
+    fn draw_image(
+        &mut self,
+        handle: Self::Handle,
+        filter_method: core::image::FilterMethod,
+        bounds: Rectangle,
+    ) {
+        self.layers.draw_image(handle, filter_method, bounds);
+    }
+}
+
+#[cfg(feature = "svg")]
+impl core::svg::Renderer for Renderer {
+    fn measure_svg(&self, handle: &core::svg::Handle) -> Size<u32> {
+        self.image_cache.lock().measure_svg(handle)
+    }
+
+    fn draw_svg(
+        &mut self,
+        handle: core::svg::Handle,
+        color_filter: Option<Color>,
+        bounds: Rectangle,
+    ) {
+        self.layers.draw_svg(handle, color_filter, bounds);
+    }
+}
+
+impl graphics::mesh::Renderer for Renderer {
+    fn draw_mesh(&mut self, mesh: graphics::Mesh) {
+        self.layers.draw_mesh(mesh);
+    }
+}
+
+#[cfg(feature = "geometry")]
+impl graphics::geometry::Renderer for Renderer {
+    type Geometry = Geometry;
+    type Frame = geometry::Frame;
+
+    fn new_frame(&self, size: Size) -> Self::Frame {
+        geometry::Frame::new(size)
+    }
+
+    fn draw_geometry(&mut self, geometry: Self::Geometry) {
+        match geometry {
+            Geometry::Live(layers) => {
+                for layer in layers {
+                    self.layers.draw_layer(layer);
+                }
+            }
+            Geometry::Cached(layers) => {
+                for layer in layers.as_ref() {
+                    self.layers.draw_cached_layer(layer);
+                }
+            }
+        }
+    }
+}
+
+impl graphics::compositor::Default for crate::Renderer {
+    type Compositor = window::Compositor;
+}

wgpu/src/primitive.rs

@@ -3,8 +3,7 @@ pub mod pipeline;
 
 pub use pipeline::Pipeline;
 
-use crate::core::Rectangle;
-use crate::graphics::{Damage, Mesh};
+use crate::graphics::Mesh;
 
 use std::fmt::Debug;
 
@@ -19,20 +18,3 @@ pub enum Custom {
     /// A custom pipeline primitive.
     Pipeline(Pipeline),
 }
-
-impl Damage for Custom {
-    fn bounds(&self) -> Rectangle {
-        match self {
-            Self::Mesh(mesh) => mesh.bounds(),
-            Self::Pipeline(pipeline) => pipeline.bounds,
-        }
-    }
-}
-
-impl TryFrom<Mesh> for Custom {
-    type Error = &'static str;
-
-    fn try_from(mesh: Mesh) -> Result<Self, Self::Error> {
-        Ok(Custom::Mesh(mesh))
-    }
-}

wgpu/src/quad.rs

@@ -12,11 +12,37 @@ use bytemuck::{Pod, Zeroable};
 
 use std::mem;
 
-#[cfg(feature = "tracing")]
-use tracing::info_span;
-
 const INITIAL_INSTANCES: usize = 2_000;
 
+/// The properties of a quad.
+#[derive(Clone, Copy, Debug, Pod, Zeroable)]
+#[repr(C)]
+pub struct Quad {
+    /// The position of the [`Quad`].
+    pub position: [f32; 2],
+
+    /// The size of the [`Quad`].
+    pub size: [f32; 2],
+
+    /// The border color of the [`Quad`], in __linear RGB__.
+    pub border_color: color::Packed,
+
+    /// The border radii of the [`Quad`].
+    pub border_radius: [f32; 4],
+
+    /// The border width of the [`Quad`].
+    pub border_width: f32,
+
+    /// The shadow color of the [`Quad`].
+    pub shadow_color: color::Packed,
+
+    /// The shadow offset of the [`Quad`].
+    pub shadow_offset: [f32; 2],
+
+    /// The shadow blur radius of the [`Quad`].
+    pub shadow_blur_radius: f32,
+}
+
 #[derive(Debug)]
 pub struct Pipeline {
     solid: solid::Pipeline,
@@ -54,7 +80,7 @@ impl Pipeline {
         }
     }
 
-    pub fn prepare(
+    pub fn prepare_batch(
         &mut self,
         device: &wgpu::Device,
         encoder: &mut wgpu::CommandEncoder,
@@ -73,7 +99,64 @@ impl Pipeline {
         self.prepare_layer += 1;
     }
 
-    pub fn render<'a>(
+    pub fn prepare_cache(
+        &self,
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        belt: &mut wgpu::util::StagingBelt,
+        cache: &mut Cache,
+        transformation: Transformation,
+        scale: f32,
+    ) {
+        match cache {
+            Cache::Staged(_) => {
+                let Cache::Staged(batch) =
+                    std::mem::replace(cache, Cache::Staged(Batch::default()))
+                else {
+                    unreachable!()
+                };
+
+                let mut layer = Layer::new(device, &self.constant_layout);
+                layer.prepare(
+                    device,
+                    encoder,
+                    belt,
+                    &batch,
+                    transformation,
+                    scale,
+                );
+
+                *cache = Cache::Uploaded {
+                    layer,
+                    batch,
+                    needs_reupload: false,
+                }
+            }
+
+            Cache::Uploaded {
+                batch,
+                layer,
+                needs_reupload,
+            } => {
+                if *needs_reupload {
+                    layer.prepare(
+                        device,
+                        encoder,
+                        belt,
+                        batch,
+                        transformation,
+                        scale,
+                    );
+
+                    *needs_reupload = false;
+                } else {
+                    layer.update(device, encoder, belt, transformation, scale);
+                }
+            }
+        }
+    }
+
+    pub fn render_batch<'a>(
         &'a self,
         layer: usize,
         bounds: Rectangle<u32>,
@@ -81,38 +164,59 @@ impl Pipeline {
         render_pass: &mut wgpu::RenderPass<'a>,
     ) {
         if let Some(layer) = self.layers.get(layer) {
-            render_pass.set_scissor_rect(
-                bounds.x,
-                bounds.y,
-                bounds.width,
-                bounds.height,
-            );
+            self.render(bounds, layer, &quads.order, render_pass);
+        }
+    }
 
-            let mut solid_offset = 0;
-            let mut gradient_offset = 0;
+    pub fn render_cache<'a>(
+        &'a self,
+        cache: &'a Cache,
+        bounds: Rectangle<u32>,
+        render_pass: &mut wgpu::RenderPass<'a>,
+    ) {
+        if let Cache::Uploaded { layer, batch, .. } = cache {
+            self.render(bounds, layer, &batch.order, render_pass);
+        }
+    }
 
-            for (kind, count) in &quads.order {
-                match kind {
-                    Kind::Solid => {
-                        self.solid.render(
-                            render_pass,
-                            &layer.constants,
-                            &layer.solid,
-                            solid_offset..(solid_offset + count),
-                        );
+    fn render<'a>(
+        &'a self,
+        bounds: Rectangle<u32>,
+        layer: &'a Layer,
+        order: &Order,
+        render_pass: &mut wgpu::RenderPass<'a>,
+    ) {
+        render_pass.set_scissor_rect(
+            bounds.x,
+            bounds.y,
+            bounds.width,
+            bounds.height,
+        );
 
-                        solid_offset += count;
-                    }
-                    Kind::Gradient => {
-                        self.gradient.render(
-                            render_pass,
-                            &layer.constants,
-                            &layer.gradient,
-                            gradient_offset..(gradient_offset + count),
-                        );
+        let mut solid_offset = 0;
+        let mut gradient_offset = 0;
 
-                        gradient_offset += count;
-                    }
+        for (kind, count) in order {
+            match kind {
+                Kind::Solid => {
+                    self.solid.render(
+                        render_pass,
+                        &layer.constants,
+                        &layer.solid,
+                        solid_offset..(solid_offset + count),
+                    );
+
+                    solid_offset += count;
+                }
+                Kind::Gradient => {
+                    self.gradient.render(
+                        render_pass,
+                        &layer.constants,
+                        &layer.gradient,
+                        gradient_offset..(gradient_offset + count),
+                    );
+
+                    gradient_offset += count;
                 }
             }
         }
@@ -124,7 +228,49 @@ impl Pipeline {
 }
 
 #[derive(Debug)]
-struct Layer {
+pub enum Cache {
+    Staged(Batch),
+    Uploaded {
+        batch: Batch,
+        layer: Layer,
+        needs_reupload: bool,
+    },
+}
+
+impl Cache {
+    pub fn is_empty(&self) -> bool {
+        match self {
+            Cache::Staged(batch) | Cache::Uploaded { batch, .. } => {
+                batch.is_empty()
+            }
+        }
+    }
+
+    pub fn update(&mut self, new_batch: Batch) {
+        match self {
+            Self::Staged(batch) => {
+                *batch = new_batch;
+            }
+            Self::Uploaded {
+                batch,
+                needs_reupload,
+                ..
+            } => {
+                *batch = new_batch;
+                *needs_reupload = true;
+            }
+        }
+    }
+}
+
+impl Default for Cache {
+    fn default() -> Self {
+        Self::Staged(Batch::default())
+    }
+}
+
+#[derive(Debug)]
+pub struct Layer {
     constants: wgpu::BindGroup,
     constants_buffer: wgpu::Buffer,
     solid: solid::Layer,
@@ -169,9 +315,26 @@ impl Layer {
         transformation: Transformation,
         scale: f32,
     ) {
-        #[cfg(feature = "tracing")]
-        let _ = info_span!("Wgpu::Quad", "PREPARE").entered();
+        self.update(device, encoder, belt, transformation, scale);
 
+        if !quads.solids.is_empty() {
+            self.solid.prepare(device, encoder, belt, &quads.solids);
+        }
+
+        if !quads.gradients.is_empty() {
+            self.gradient
+                .prepare(device, encoder, belt, &quads.gradients);
+        }
+    }
+
+    pub fn update(
+        &mut self,
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        belt: &mut wgpu::util::StagingBelt,
+        transformation: Transformation,
+        scale: f32,
+    ) {
         let uniforms = Uniforms::new(transformation, scale);
         let bytes = bytemuck::bytes_of(&uniforms);
 
@@ -183,47 +346,9 @@ impl Layer {
             device,
         )
         .copy_from_slice(bytes);
-
-        if !quads.solids.is_empty() {
-            self.solid.prepare(device, encoder, belt, &quads.solids);
-        }
-
-        if !quads.gradients.is_empty() {
-            self.gradient
-                .prepare(device, encoder, belt, &quads.gradients);
-        }
     }
 }
 
-/// The properties of a quad.
-#[derive(Clone, Copy, Debug, Pod, Zeroable)]
-#[repr(C)]
-pub struct Quad {
-    /// The position of the [`Quad`].
-    pub position: [f32; 2],
-
-    /// The size of the [`Quad`].
-    pub size: [f32; 2],
-
-    /// The border color of the [`Quad`], in __linear RGB__.
-    pub border_color: color::Packed,
-
-    /// The border radii of the [`Quad`].
-    pub border_radius: [f32; 4],
-
-    /// The border width of the [`Quad`].
-    pub border_width: f32,
-
-    /// The shadow color of the [`Quad`].
-    pub shadow_color: [f32; 4],
-
-    /// The shadow offset of the [`Quad`].
-    pub shadow_offset: [f32; 2],
-
-    /// The shadow blur radius of the [`Quad`].
-    pub shadow_blur_radius: f32,
-}
-
 /// A group of [`Quad`]s rendered together.
 #[derive(Default, Debug)]
 pub struct Batch {
@@ -233,10 +358,13 @@ pub struct Batch {
     /// The gradient quads of the [`Layer`].
     gradients: Vec<Gradient>,
 
-    /// The quad order of the [`Layer`]; stored as a tuple of the quad type & its count.
-    order: Vec<(Kind, usize)>,
+    /// The quad order of the [`Layer`].
+    order: Order,
 }
 
+/// The quad order of a [`Layer`]; stored as a tuple of the quad type & its count.
+type Order = Vec<(Kind, usize)>;
+
 impl Batch {
     /// Returns true if there are no quads of any type in [`Quads`].
     pub fn is_empty(&self) -> bool {
@@ -276,6 +404,12 @@ impl Batch {
             }
         }
     }
+
+    pub fn clear(&mut self) {
+        self.solids.clear();
+        self.gradients.clear();
+        self.order.clear();
+    }
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]

wgpu/src/text.rs

@@ -1,20 +1,67 @@
 use crate::core::alignment;
 use crate::core::{Rectangle, Size, Transformation};
 use crate::graphics::color;
-use crate::graphics::text::cache::{self, Cache};
+use crate::graphics::text::cache::{self, Cache as BufferCache};
 use crate::graphics::text::{font_system, to_color, Editor, Paragraph};
-use crate::layer::Text;
 
-use std::borrow::Cow;
-use std::cell::RefCell;
 use std::sync::Arc;
 
+pub use crate::graphics::Text;
+
+pub type Batch = Vec<Text>;
+
 #[allow(missing_debug_implementations)]
 pub struct Pipeline {
-    renderers: Vec<glyphon::TextRenderer>,
+    format: wgpu::TextureFormat,
     atlas: glyphon::TextAtlas,
+    renderers: Vec<glyphon::TextRenderer>,
     prepare_layer: usize,
-    cache: RefCell<Cache>,
+    cache: BufferCache,
+}
+
+pub enum Cache {
+    Staged(Batch),
+    Uploaded {
+        batch: Batch,
+        renderer: glyphon::TextRenderer,
+        atlas: Option<glyphon::TextAtlas>,
+        buffer_cache: Option<BufferCache>,
+        scale_factor: f32,
+        target_size: Size<u32>,
+        needs_reupload: bool,
+    },
+}
+
+impl Cache {
+    pub fn is_empty(&self) -> bool {
+        match self {
+            Cache::Staged(batch) | Cache::Uploaded { batch, .. } => {
+                batch.is_empty()
+            }
+        }
+    }
+
+    pub fn update(&mut self, new_batch: Batch) {
+        match self {
+            Self::Staged(batch) => {
+                *batch = new_batch;
+            }
+            Self::Uploaded {
+                batch,
+                needs_reupload,
+                ..
+            } => {
+                *batch = new_batch;
+                *needs_reupload = true;
+            }
+        }
+    }
+}
+
+impl Default for Cache {
+    fn default() -> Self {
+        Self::Staged(Batch::default())
+    }
 }
 
 impl Pipeline {
@@ -24,6 +71,7 @@ impl Pipeline {
         format: wgpu::TextureFormat,
     ) -> Self {
         Pipeline {
+            format,
             renderers: Vec::new(),
             atlas: glyphon::TextAtlas::with_color_mode(
                 device,
@@ -36,25 +84,16 @@ impl Pipeline {
                 },
             ),
             prepare_layer: 0,
-            cache: RefCell::new(Cache::new()),
+            cache: BufferCache::new(),
         }
     }
 
-    pub fn load_font(&mut self, bytes: Cow<'static, [u8]>) {
-        font_system()
-            .write()
-            .expect("Write font system")
-            .load_font(bytes);
-
-        self.cache = RefCell::new(Cache::new());
-    }
-
-    pub fn prepare(
+    pub fn prepare_batch(
         &mut self,
         device: &wgpu::Device,
         queue: &wgpu::Queue,
         encoder: &mut wgpu::CommandEncoder,
-        sections: &[Text<'_>],
+        sections: &Batch,
         layer_bounds: Rectangle,
         scale_factor: f32,
         target_size: Size<u32>,
@@ -68,210 +107,18 @@ impl Pipeline {
             ));
         }
 
-        let mut font_system = font_system().write().expect("Write font system");
-        let font_system = font_system.raw();
-
         let renderer = &mut self.renderers[self.prepare_layer];
-        let cache = self.cache.get_mut();
-
-        enum Allocation {
-            Paragraph(Paragraph),
-            Editor(Editor),
-            Cache(cache::KeyHash),
-            Raw(Arc<glyphon::Buffer>),
-        }
-
-        let allocations: Vec<_> = sections
-            .iter()
-            .map(|section| match section {
-                Text::Paragraph { paragraph, .. } => {
-                    paragraph.upgrade().map(Allocation::Paragraph)
-                }
-                Text::Editor { editor, .. } => {
-                    editor.upgrade().map(Allocation::Editor)
-                }
-                Text::Cached(text) => {
-                    let (key, _) = cache.allocate(
-                        font_system,
-                        cache::Key {
-                            content: text.content,
-                            size: text.size.into(),
-                            line_height: f32::from(
-                                text.line_height.to_absolute(text.size),
-                            ),
-                            font: text.font,
-                            bounds: Size {
-                                width: text.bounds.width,
-                                height: text.bounds.height,
-                            },
-                            shaping: text.shaping,
-                        },
-                    );
-
-                    Some(Allocation::Cache(key))
-                }
-                Text::Raw { raw, .. } => {
-                    raw.buffer.upgrade().map(Allocation::Raw)
-                }
-            })
-            .collect();
-
-        let layer_bounds = layer_bounds * scale_factor;
-
-        let text_areas = sections.iter().zip(allocations.iter()).filter_map(
-            |(section, allocation)| {
-                let (
-                    buffer,
-                    bounds,
-                    horizontal_alignment,
-                    vertical_alignment,
-                    color,
-                    clip_bounds,
-                    transformation,
-                ) = match section {
-                    Text::Paragraph {
-                        position,
-                        color,
-                        clip_bounds,
-                        transformation,
-                        ..
-                    } => {
-                        use crate::core::text::Paragraph as _;
-
-                        let Some(Allocation::Paragraph(paragraph)) = allocation
-                        else {
-                            return None;
-                        };
-
-                        (
-                            paragraph.buffer(),
-                            Rectangle::new(*position, paragraph.min_bounds()),
-                            paragraph.horizontal_alignment(),
-                            paragraph.vertical_alignment(),
-                            *color,
-                            *clip_bounds,
-                            *transformation,
-                        )
-                    }
-                    Text::Editor {
-                        position,
-                        color,
-                        clip_bounds,
-                        transformation,
-                        ..
-                    } => {
-                        use crate::core::text::Editor as _;
-
-                        let Some(Allocation::Editor(editor)) = allocation
-                        else {
-                            return None;
-                        };
-
-                        (
-                            editor.buffer(),
-                            Rectangle::new(*position, editor.bounds()),
-                            alignment::Horizontal::Left,
-                            alignment::Vertical::Top,
-                            *color,
-                            *clip_bounds,
-                            *transformation,
-                        )
-                    }
-                    Text::Cached(text) => {
-                        let Some(Allocation::Cache(key)) = allocation else {
-                            return None;
-                        };
-
-                        let entry = cache.get(key).expect("Get cached buffer");
-
-                        (
-                            &entry.buffer,
-                            Rectangle::new(
-                                text.bounds.position(),
-                                entry.min_bounds,
-                            ),
-                            text.horizontal_alignment,
-                            text.vertical_alignment,
-                            text.color,
-                            text.clip_bounds,
-                            Transformation::IDENTITY,
-                        )
-                    }
-                    Text::Raw {
-                        raw,
-                        transformation,
-                    } => {
-                        let Some(Allocation::Raw(buffer)) = allocation else {
-                            return None;
-                        };
-
-                        let (width, height) = buffer.size();
-
-                        (
-                            buffer.as_ref(),
-                            Rectangle::new(
-                                raw.position,
-                                Size::new(width, height),
-                            ),
-                            alignment::Horizontal::Left,
-                            alignment::Vertical::Top,
-                            raw.color,
-                            raw.clip_bounds,
-                            *transformation,
-                        )
-                    }
-                };
-
-                let bounds = bounds * transformation * scale_factor;
-
-                let left = match horizontal_alignment {
-                    alignment::Horizontal::Left => bounds.x,
-                    alignment::Horizontal::Center => {
-                        bounds.x - bounds.width / 2.0
-                    }
-                    alignment::Horizontal::Right => bounds.x - bounds.width,
-                };
-
-                let top = match vertical_alignment {
-                    alignment::Vertical::Top => bounds.y,
-                    alignment::Vertical::Center => {
-                        bounds.y - bounds.height / 2.0
-                    }
-                    alignment::Vertical::Bottom => bounds.y - bounds.height,
-                };
-
-                let clip_bounds = layer_bounds.intersection(
-                    &(clip_bounds * transformation * scale_factor),
-                )?;
-
-                Some(glyphon::TextArea {
-                    buffer,
-                    left,
-                    top,
-                    scale: scale_factor * transformation.scale_factor(),
-                    bounds: glyphon::TextBounds {
-                        left: clip_bounds.x as i32,
-                        top: clip_bounds.y as i32,
-                        right: (clip_bounds.x + clip_bounds.width) as i32,
-                        bottom: (clip_bounds.y + clip_bounds.height) as i32,
-                    },
-                    default_color: to_color(color),
-                })
-            },
-        );
-
-        let result = renderer.prepare(
+        let result = prepare(
             device,
             queue,
             encoder,
-            font_system,
+            renderer,
             &mut self.atlas,
-            glyphon::Resolution {
-                width: target_size.width,
-                height: target_size.height,
-            },
-            text_areas,
-            &mut glyphon::SwashCache::new(),
+            &mut self.cache,
+            sections,
+            layer_bounds,
+            scale_factor,
+            target_size,
         );
 
         match result {
@@ -286,7 +133,109 @@ impl Pipeline {
         }
     }
 
-    pub fn render<'a>(
+    pub fn prepare_cache(
+        &mut self,
+        device: &wgpu::Device,
+        queue: &wgpu::Queue,
+        encoder: &mut wgpu::CommandEncoder,
+        cache: &mut Cache,
+        layer_bounds: Rectangle,
+        new_scale_factor: f32,
+        new_target_size: Size<u32>,
+    ) {
+        match cache {
+            Cache::Staged(_) => {
+                let Cache::Staged(batch) =
+                    std::mem::replace(cache, Cache::Staged(Batch::default()))
+                else {
+                    unreachable!()
+                };
+
+                // TODO: Find a better heuristic (?)
+                let (mut atlas, mut buffer_cache) = if batch.len() > 10 {
+                    (
+                        Some(glyphon::TextAtlas::with_color_mode(
+                            device,
+                            queue,
+                            self.format,
+                            if color::GAMMA_CORRECTION {
+                                glyphon::ColorMode::Accurate
+                            } else {
+                                glyphon::ColorMode::Web
+                            },
+                        )),
+                        Some(BufferCache::new()),
+                    )
+                } else {
+                    (None, None)
+                };
+
+                let mut renderer = glyphon::TextRenderer::new(
+                    atlas.as_mut().unwrap_or(&mut self.atlas),
+                    device,
+                    wgpu::MultisampleState::default(),
+                    None,
+                );
+
+                let _ = prepare(
+                    device,
+                    queue,
+                    encoder,
+                    &mut renderer,
+                    atlas.as_mut().unwrap_or(&mut self.atlas),
+                    buffer_cache.as_mut().unwrap_or(&mut self.cache),
+                    &batch,
+                    layer_bounds,
+                    new_scale_factor,
+                    new_target_size,
+                );
+
+                *cache = Cache::Uploaded {
+                    batch,
+                    needs_reupload: false,
+                    renderer,
+                    atlas,
+                    buffer_cache,
+                    scale_factor: new_scale_factor,
+                    target_size: new_target_size,
+                }
+            }
+            Cache::Uploaded {
+                batch,
+                needs_reupload,
+                renderer,
+                atlas,
+                buffer_cache,
+                scale_factor,
+                target_size,
+            } => {
+                if *needs_reupload
+                    || atlas.is_none()
+                    || buffer_cache.is_none()
+                    || new_scale_factor != *scale_factor
+                    || new_target_size != *target_size
+                {
+                    let _ = prepare(
+                        device,
+                        queue,
+                        encoder,
+                        renderer,
+                        atlas.as_mut().unwrap_or(&mut self.atlas),
+                        buffer_cache.as_mut().unwrap_or(&mut self.cache),
+                        batch,
+                        layer_bounds,
+                        *scale_factor,
+                        *target_size,
+                    );
+
+                    *scale_factor = new_scale_factor;
+                    *target_size = new_target_size;
+                }
+            }
+        }
+    }
+
+    pub fn render_batch<'a>(
         &'a self,
         layer: usize,
         bounds: Rectangle<u32>,
@@ -306,10 +255,251 @@ impl Pipeline {
             .expect("Render text");
     }
 
+    pub fn render_cache<'a>(
+        &'a self,
+        cache: &'a Cache,
+        bounds: Rectangle<u32>,
+        render_pass: &mut wgpu::RenderPass<'a>,
+    ) {
+        let Cache::Uploaded {
+            renderer, atlas, ..
+        } = cache
+        else {
+            return;
+        };
+
+        render_pass.set_scissor_rect(
+            bounds.x,
+            bounds.y,
+            bounds.width,
+            bounds.height,
+        );
+
+        renderer
+            .render(atlas.as_ref().unwrap_or(&self.atlas), render_pass)
+            .expect("Render text");
+    }
+
     pub fn end_frame(&mut self) {
         self.atlas.trim();
-        self.cache.get_mut().trim();
+        self.cache.trim();
 
         self.prepare_layer = 0;
     }
 }
+
+fn prepare(
+    device: &wgpu::Device,
+    queue: &wgpu::Queue,
+    encoder: &mut wgpu::CommandEncoder,
+    renderer: &mut glyphon::TextRenderer,
+    atlas: &mut glyphon::TextAtlas,
+    buffer_cache: &mut BufferCache,
+    sections: &Batch,
+    layer_bounds: Rectangle,
+    scale_factor: f32,
+    target_size: Size<u32>,
+) -> Result<(), glyphon::PrepareError> {
+    let mut font_system = font_system().write().expect("Write font system");
+    let font_system = font_system.raw();
+
+    enum Allocation {
+        Paragraph(Paragraph),
+        Editor(Editor),
+        Cache(cache::KeyHash),
+        Raw(Arc<glyphon::Buffer>),
+    }
+
+    let allocations: Vec<_> = sections
+        .iter()
+        .map(|section| match section {
+            Text::Paragraph { paragraph, .. } => {
+                paragraph.upgrade().map(Allocation::Paragraph)
+            }
+            Text::Editor { editor, .. } => {
+                editor.upgrade().map(Allocation::Editor)
+            }
+            Text::Cached {
+                content,
+                bounds,
+                size,
+                line_height,
+                font,
+                shaping,
+                ..
+            } => {
+                let (key, _) = buffer_cache.allocate(
+                    font_system,
+                    cache::Key {
+                        content,
+                        size: (*size).into(),
+                        line_height: f32::from(line_height.to_absolute(*size)),
+                        font: *font,
+                        bounds: Size {
+                            width: bounds.width,
+                            height: bounds.height,
+                        },
+                        shaping: *shaping,
+                    },
+                );
+
+                Some(Allocation::Cache(key))
+            }
+            Text::Raw { raw, .. } => raw.buffer.upgrade().map(Allocation::Raw),
+        })
+        .collect();
+
+    let layer_bounds = layer_bounds * scale_factor;
+
+    let text_areas = sections.iter().zip(allocations.iter()).filter_map(
+        |(section, allocation)| {
+            let (
+                buffer,
+                bounds,
+                horizontal_alignment,
+                vertical_alignment,
+                color,
+                clip_bounds,
+                transformation,
+            ) = match section {
+                Text::Paragraph {
+                    position,
+                    color,
+                    clip_bounds,
+                    transformation,
+                    ..
+                } => {
+                    use crate::core::text::Paragraph as _;
+
+                    let Some(Allocation::Paragraph(paragraph)) = allocation
+                    else {
+                        return None;
+                    };
+
+                    (
+                        paragraph.buffer(),
+                        Rectangle::new(*position, paragraph.min_bounds()),
+                        paragraph.horizontal_alignment(),
+                        paragraph.vertical_alignment(),
+                        *color,
+                        *clip_bounds,
+                        *transformation,
+                    )
+                }
+                Text::Editor {
+                    position,
+                    color,
+                    clip_bounds,
+                    transformation,
+                    ..
+                } => {
+                    use crate::core::text::Editor as _;
+
+                    let Some(Allocation::Editor(editor)) = allocation else {
+                        return None;
+                    };
+
+                    (
+                        editor.buffer(),
+                        Rectangle::new(*position, editor.bounds()),
+                        alignment::Horizontal::Left,
+                        alignment::Vertical::Top,
+                        *color,
+                        *clip_bounds,
+                        *transformation,
+                    )
+                }
+                Text::Cached {
+                    bounds,
+                    horizontal_alignment,
+                    vertical_alignment,
+                    color,
+                    clip_bounds,
+                    ..
+                } => {
+                    let Some(Allocation::Cache(key)) = allocation else {
+                        return None;
+                    };
+
+                    let entry =
+                        buffer_cache.get(key).expect("Get cached buffer");
+
+                    (
+                        &entry.buffer,
+                        Rectangle::new(bounds.position(), entry.min_bounds),
+                        *horizontal_alignment,
+                        *vertical_alignment,
+                        *color,
+                        *clip_bounds,
+                        Transformation::IDENTITY,
+                    )
+                }
+                Text::Raw {
+                    raw,
+                    transformation,
+                } => {
+                    let Some(Allocation::Raw(buffer)) = allocation else {
+                        return None;
+                    };
+
+                    let (width, height) = buffer.size();
+
+                    (
+                        buffer.as_ref(),
+                        Rectangle::new(raw.position, Size::new(width, height)),
+                        alignment::Horizontal::Left,
+                        alignment::Vertical::Top,
+                        raw.color,
+                        raw.clip_bounds,
+                        *transformation,
+                    )
+                }
+            };
+
+            let bounds = bounds * transformation * scale_factor;
+
+            let left = match horizontal_alignment {
+                alignment::Horizontal::Left => bounds.x,
+                alignment::Horizontal::Center => bounds.x - bounds.width / 2.0,
+                alignment::Horizontal::Right => bounds.x - bounds.width,
+            };
+
+            let top = match vertical_alignment {
+                alignment::Vertical::Top => bounds.y,
+                alignment::Vertical::Center => bounds.y - bounds.height / 2.0,
+                alignment::Vertical::Bottom => bounds.y - bounds.height,
+            };
+
+            let clip_bounds = layer_bounds
+                .intersection(&(clip_bounds * transformation * scale_factor))?;
+
+            Some(glyphon::TextArea {
+                buffer,
+                left,
+                top,
+                scale: scale_factor * transformation.scale_factor(),
+                bounds: glyphon::TextBounds {
+                    left: clip_bounds.x as i32,
+                    top: clip_bounds.y as i32,
+                    right: (clip_bounds.x + clip_bounds.width) as i32,
+                    bottom: (clip_bounds.y + clip_bounds.height) as i32,
+                },
+                default_color: to_color(color),
+            })
+        },
+    );
+
+    renderer.prepare(
+        device,
+        queue,
+        encoder,
+        font_system,
+        atlas,
+        glyphon::Resolution {
+            width: target_size.width,
+            height: target_size.height,
+        },
+        text_areas,
+        &mut glyphon::SwashCache::new(),
+    )
+}

wgpu/src/triangle.rs

@@ -1,14 +1,16 @@
 //! Draw meshes of triangles.
 mod msaa;
 
-use crate::core::{Size, Transformation};
+use crate::core::{Rectangle, Size, Transformation};
+use crate::graphics::mesh::{self, Mesh};
 use crate::graphics::Antialiasing;
-use crate::layer::mesh::{self, Mesh};
 use crate::Buffer;
 
 const INITIAL_INDEX_COUNT: usize = 1_000;
 const INITIAL_VERTEX_COUNT: usize = 1_000;
 
+pub type Batch = Vec<Mesh>;
+
 #[derive(Debug)]
 pub struct Pipeline {
     blit: Option<msaa::Blit>,
@@ -18,8 +20,270 @@ pub struct Pipeline {
     prepare_layer: usize,
 }
 
+impl Pipeline {
+    pub fn new(
+        device: &wgpu::Device,
+        format: wgpu::TextureFormat,
+        antialiasing: Option<Antialiasing>,
+    ) -> Pipeline {
+        Pipeline {
+            blit: antialiasing.map(|a| msaa::Blit::new(device, format, a)),
+            solid: solid::Pipeline::new(device, format, antialiasing),
+            gradient: gradient::Pipeline::new(device, format, antialiasing),
+            layers: Vec::new(),
+            prepare_layer: 0,
+        }
+    }
+
+    pub fn prepare_batch(
+        &mut self,
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        belt: &mut wgpu::util::StagingBelt,
+        meshes: &Batch,
+        transformation: Transformation,
+    ) {
+        if self.layers.len() <= self.prepare_layer {
+            self.layers
+                .push(Layer::new(device, &self.solid, &self.gradient));
+        }
+
+        let layer = &mut self.layers[self.prepare_layer];
+        layer.prepare(
+            device,
+            encoder,
+            belt,
+            &self.solid,
+            &self.gradient,
+            meshes,
+            transformation,
+        );
+
+        self.prepare_layer += 1;
+    }
+
+    pub fn prepare_cache(
+        &mut self,
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        belt: &mut wgpu::util::StagingBelt,
+        cache: &mut Cache,
+        transformation: Transformation,
+    ) {
+        match cache {
+            Cache::Staged(_) => {
+                let Cache::Staged(batch) =
+                    std::mem::replace(cache, Cache::Staged(Batch::default()))
+                else {
+                    unreachable!()
+                };
+
+                let mut layer = Layer::new(device, &self.solid, &self.gradient);
+                layer.prepare(
+                    device,
+                    encoder,
+                    belt,
+                    &self.solid,
+                    &self.gradient,
+                    &batch,
+                    transformation,
+                );
+
+                *cache = Cache::Uploaded {
+                    layer,
+                    batch,
+                    needs_reupload: false,
+                }
+            }
+
+            Cache::Uploaded {
+                batch,
+                layer,
+                needs_reupload,
+            } => {
+                if *needs_reupload {
+                    layer.prepare(
+                        device,
+                        encoder,
+                        belt,
+                        &self.solid,
+                        &self.gradient,
+                        batch,
+                        transformation,
+                    );
+
+                    *needs_reupload = false;
+                }
+            }
+        }
+    }
+
+    pub fn render_batch(
+        &mut self,
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        target: &wgpu::TextureView,
+        layer: usize,
+        target_size: Size<u32>,
+        meshes: &Batch,
+        bounds: Rectangle<u32>,
+        scale_factor: f32,
+    ) {
+        Self::render(
+            device,
+            encoder,
+            target,
+            self.blit.as_mut(),
+            &self.solid,
+            &self.gradient,
+            &self.layers[layer],
+            target_size,
+            meshes,
+            bounds,
+            scale_factor,
+        );
+    }
+
+    pub fn render_cache(
+        &mut self,
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        target: &wgpu::TextureView,
+        target_size: Size<u32>,
+        cache: &Cache,
+        bounds: Rectangle<u32>,
+        scale_factor: f32,
+    ) {
+        let Cache::Uploaded { batch, layer, .. } = cache else {
+            return;
+        };
+
+        Self::render(
+            device,
+            encoder,
+            target,
+            self.blit.as_mut(),
+            &self.solid,
+            &self.gradient,
+            layer,
+            target_size,
+            batch,
+            bounds,
+            scale_factor,
+        );
+    }
+
+    fn render(
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        target: &wgpu::TextureView,
+        mut blit: Option<&mut msaa::Blit>,
+        solid: &solid::Pipeline,
+        gradient: &gradient::Pipeline,
+        layer: &Layer,
+        target_size: Size<u32>,
+        meshes: &Batch,
+        bounds: Rectangle<u32>,
+        scale_factor: f32,
+    ) {
+        {
+            let (attachment, resolve_target, load) = if let Some(blit) =
+                &mut blit
+            {
+                let (attachment, resolve_target) =
+                    blit.targets(device, target_size.width, target_size.height);
+
+                (
+                    attachment,
+                    Some(resolve_target),
+                    wgpu::LoadOp::Clear(wgpu::Color::TRANSPARENT),
+                )
+            } else {
+                (target, None, wgpu::LoadOp::Load)
+            };
+
+            let mut render_pass =
+                encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
+                    label: Some("iced_wgpu.triangle.render_pass"),
+                    color_attachments: &[Some(
+                        wgpu::RenderPassColorAttachment {
+                            view: attachment,
+                            resolve_target,
+                            ops: wgpu::Operations {
+                                load,
+                                store: wgpu::StoreOp::Store,
+                            },
+                        },
+                    )],
+                    depth_stencil_attachment: None,
+                    timestamp_writes: None,
+                    occlusion_query_set: None,
+                });
+
+            layer.render(
+                solid,
+                gradient,
+                meshes,
+                bounds,
+                scale_factor,
+                &mut render_pass,
+            );
+        }
+
+        if let Some(blit) = blit {
+            blit.draw(encoder, target);
+        }
+    }
+
+    pub fn end_frame(&mut self) {
+        self.prepare_layer = 0;
+    }
+}
+
 #[derive(Debug)]
-struct Layer {
+pub enum Cache {
+    Staged(Batch),
+    Uploaded {
+        batch: Batch,
+        layer: Layer,
+        needs_reupload: bool,
+    },
+}
+
+impl Cache {
+    pub fn is_empty(&self) -> bool {
+        match self {
+            Cache::Staged(batch) | Cache::Uploaded { batch, .. } => {
+                batch.is_empty()
+            }
+        }
+    }
+
+    pub fn update(&mut self, new_batch: Batch) {
+        match self {
+            Self::Staged(batch) => {
+                *batch = new_batch;
+            }
+            Self::Uploaded {
+                batch,
+                needs_reupload,
+                ..
+            } => {
+                *batch = new_batch;
+                *needs_reupload = true;
+            }
+        }
+    }
+}
+
+impl Default for Cache {
+    fn default() -> Self {
+        Self::Staged(Batch::default())
+    }
+}
+
+#[derive(Debug)]
+pub struct Layer {
     index_buffer: Buffer<u32>,
     index_strides: Vec<u32>,
     solid: solid::Layer,
@@ -52,7 +316,7 @@ impl Layer {
         belt: &mut wgpu::util::StagingBelt,
         solid: &solid::Pipeline,
         gradient: &gradient::Pipeline,
-        meshes: &[Mesh<'_>],
+        meshes: &Batch,
         transformation: Transformation,
     ) {
         // Count the total amount of vertices & indices we need to handle
@@ -100,7 +364,6 @@ impl Layer {
 
         for mesh in meshes {
             let indices = mesh.indices();
-
             let uniforms =
                 Uniforms::new(transformation * mesh.transformation());
 
@@ -157,7 +420,8 @@ impl Layer {
         &'a self,
         solid: &'a solid::Pipeline,
         gradient: &'a gradient::Pipeline,
-        meshes: &[Mesh<'_>],
+        meshes: &Batch,
+        layer_bounds: Rectangle<u32>,
         scale_factor: f32,
         render_pass: &mut wgpu::RenderPass<'a>,
     ) {
@@ -166,7 +430,12 @@ impl Layer {
         let mut last_is_solid = None;
 
         for (index, mesh) in meshes.iter().enumerate() {
-            let clip_bounds = (mesh.clip_bounds() * scale_factor).snap();
+            let Some(clip_bounds) = Rectangle::<f32>::from(layer_bounds)
+                .intersection(&(mesh.clip_bounds() * scale_factor))
+                .map(Rectangle::snap)
+            else {
+                continue;
+            };
 
             if clip_bounds.width < 1 || clip_bounds.height < 1 {
                 continue;
@@ -234,119 +503,6 @@ impl Layer {
     }
 }
 
-impl Pipeline {
-    pub fn new(
-        device: &wgpu::Device,
-        format: wgpu::TextureFormat,
-        antialiasing: Option<Antialiasing>,
-    ) -> Pipeline {
-        Pipeline {
-            blit: antialiasing.map(|a| msaa::Blit::new(device, format, a)),
-            solid: solid::Pipeline::new(device, format, antialiasing),
-            gradient: gradient::Pipeline::new(device, format, antialiasing),
-            layers: Vec::new(),
-            prepare_layer: 0,
-        }
-    }
-
-    pub fn prepare(
-        &mut self,
-        device: &wgpu::Device,
-        encoder: &mut wgpu::CommandEncoder,
-        belt: &mut wgpu::util::StagingBelt,
-        meshes: &[Mesh<'_>],
-        transformation: Transformation,
-    ) {
-        #[cfg(feature = "tracing")]
-        let _ = tracing::info_span!("Wgpu::Triangle", "PREPARE").entered();
-
-        if self.layers.len() <= self.prepare_layer {
-            self.layers
-                .push(Layer::new(device, &self.solid, &self.gradient));
-        }
-
-        let layer = &mut self.layers[self.prepare_layer];
-        layer.prepare(
-            device,
-            encoder,
-            belt,
-            &self.solid,
-            &self.gradient,
-            meshes,
-            transformation,
-        );
-
-        self.prepare_layer += 1;
-    }
-
-    pub fn render(
-        &mut self,
-        device: &wgpu::Device,
-        encoder: &mut wgpu::CommandEncoder,
-        target: &wgpu::TextureView,
-        layer: usize,
-        target_size: Size<u32>,
-        meshes: &[Mesh<'_>],
-        scale_factor: f32,
-    ) {
-        #[cfg(feature = "tracing")]
-        let _ = tracing::info_span!("Wgpu::Triangle", "DRAW").entered();
-
-        {
-            let (attachment, resolve_target, load) = if let Some(blit) =
-                &mut self.blit
-            {
-                let (attachment, resolve_target) =
-                    blit.targets(device, target_size.width, target_size.height);
-
-                (
-                    attachment,
-                    Some(resolve_target),
-                    wgpu::LoadOp::Clear(wgpu::Color::TRANSPARENT),
-                )
-            } else {
-                (target, None, wgpu::LoadOp::Load)
-            };
-
-            let mut render_pass =
-                encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
-                    label: Some("iced_wgpu.triangle.render_pass"),
-                    color_attachments: &[Some(
-                        wgpu::RenderPassColorAttachment {
-                            view: attachment,
-                            resolve_target,
-                            ops: wgpu::Operations {
-                                load,
-                                store: wgpu::StoreOp::Store,
-                            },
-                        },
-                    )],
-                    depth_stencil_attachment: None,
-                    timestamp_writes: None,
-                    occlusion_query_set: None,
-                });
-
-            let layer = &mut self.layers[layer];
-
-            layer.render(
-                &self.solid,
-                &self.gradient,
-                meshes,
-                scale_factor,
-                &mut render_pass,
-            );
-        }
-
-        if let Some(blit) = &mut self.blit {
-            blit.draw(encoder, target);
-        }
-    }
-
-    pub fn end_frame(&mut self) {
-        self.prepare_layer = 0;
-    }
-}
-
 fn fragment_target(
     texture_format: wgpu::TextureFormat,
 ) -> wgpu::ColorTargetState {

wgpu/src/window/compositor.rs

@@ -4,18 +4,19 @@ use crate::graphics::color;
 use crate::graphics::compositor;
 use crate::graphics::error;
 use crate::graphics::{self, Viewport};
-use crate::{Backend, Primitive, Renderer, Settings};
+use crate::{Engine, Renderer, Settings};
 
 /// A window graphics backend for iced powered by `wgpu`.
 #[allow(missing_debug_implementations)]
 pub struct Compositor {
-    settings: Settings,
     instance: wgpu::Instance,
     adapter: wgpu::Adapter,
     device: wgpu::Device,
     queue: wgpu::Queue,
     format: wgpu::TextureFormat,
     alpha_mode: wgpu::CompositeAlphaMode,
+    engine: Engine,
+    settings: Settings,
 }
 
 /// A compositor error.
@@ -167,15 +168,24 @@ impl Compositor {
 
             match result {
                 Ok((device, queue)) => {
+                    let engine = Engine::new(
+                        &adapter,
+                        &device,
+                        &queue,
+                        format,
+                        settings.antialiasing,
+                    );
+
                     return Ok(Compositor {
                         instance,
-                        settings,
                         adapter,
                         device,
                         queue,
                         format,
                         alpha_mode,
-                    })
+                        engine,
+                        settings,
+                    });
                 }
                 Err(error) => {
                     errors.push((required_limits, error));
@@ -185,17 +195,6 @@ impl Compositor {
 
         Err(Error::RequestDeviceFailed(errors))
     }
-
-    /// Creates a new rendering [`Backend`] for this [`Compositor`].
-    pub fn create_backend(&self) -> Backend {
-        Backend::new(
-            &self.adapter,
-            &self.device,
-            &self.queue,
-            self.settings,
-            self.format,
-        )
-    }
 }
 
 /// Creates a [`Compositor`] and its [`Backend`] for the given [`Settings`] and
@@ -210,9 +209,8 @@ pub async fn new<W: compositor::Window>(
 /// Presents the given primitives with the given [`Compositor`] and [`Backend`].
 pub fn present<T: AsRef<str>>(
     compositor: &mut Compositor,
-    backend: &mut Backend,
+    renderer: &mut Renderer,
     surface: &mut wgpu::Surface<'static>,
-    primitives: &[Primitive],
     viewport: &Viewport,
     background_color: Color,
     overlay: &[T],
@@ -229,21 +227,21 @@ pub fn present<T: AsRef<str>>(
                 .texture
                 .create_view(&wgpu::TextureViewDescriptor::default());
 
-            backend.present(
+            renderer.present(
+                &mut compositor.engine,
                 &compositor.device,
                 &compositor.queue,
                 &mut encoder,
                 Some(background_color),
                 frame.texture.format(),
                 view,
-                primitives,
                 viewport,
                 overlay,
             );
 
-            // Submit work
-            let _submission = compositor.queue.submit(Some(encoder.finish()));
-            backend.recall();
+            let _ = compositor.engine.submit(&compositor.queue, encoder);
+
+            // Present the frame
             frame.present();
 
             Ok(())
@@ -292,11 +290,7 @@ impl graphics::Compositor for Compositor {
     }
 
     fn create_renderer(&self) -> Self::Renderer {
-        Renderer::new(
-            self.create_backend(),
-            self.settings.default_font,
-            self.settings.default_text_size,
-        )
+        Renderer::new(self.settings, &self.engine)
     }
 
     fn create_surface<W: compositor::Window>(
@@ -328,7 +322,7 @@ impl graphics::Compositor for Compositor {
             &wgpu::SurfaceConfiguration {
                 usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
                 format: self.format,
-                present_mode: self.settings.present_mode,
+                present_mode: wgpu::PresentMode::Immediate,
                 width,
                 height,
                 alpha_mode: self.alpha_mode,
@@ -355,17 +349,7 @@ impl graphics::Compositor for Compositor {
         background_color: Color,
         overlay: &[T],
     ) -> Result<(), compositor::SurfaceError> {
-        renderer.with_primitives(|backend, primitives| {
-            present(
-                self,
-                backend,
-                surface,
-                primitives,
-                viewport,
-                background_color,
-                overlay,
-            )
-        })
+        present(self, renderer, surface, viewport, background_color, overlay)
     }
 
     fn screenshot<T: AsRef<str>>(
@@ -376,16 +360,7 @@ impl graphics::Compositor for Compositor {
         background_color: Color,
         overlay: &[T],
     ) -> Vec<u8> {
-        renderer.with_primitives(|backend, primitives| {
-            screenshot(
-                self,
-                backend,
-                primitives,
-                viewport,
-                background_color,
-                overlay,
-            )
-        })
+        screenshot(self, renderer, viewport, background_color, overlay)
     }
 }
 
@@ -393,19 +368,12 @@ impl graphics::Compositor for Compositor {
 ///
 /// Returns RGBA bytes of the texture data.
 pub fn screenshot<T: AsRef<str>>(
-    compositor: &Compositor,
-    backend: &mut Backend,
-    primitives: &[Primitive],
+    compositor: &mut Compositor,
+    renderer: &mut Renderer,
     viewport: &Viewport,
     background_color: Color,
     overlay: &[T],
 ) -> Vec<u8> {
-    let mut encoder = compositor.device.create_command_encoder(
-        &wgpu::CommandEncoderDescriptor {
-            label: Some("iced_wgpu.offscreen.encoder"),
-        },
-    );
-
     let dimensions = BufferDimensions::new(viewport.physical_size());
 
     let texture_extent = wgpu::Extent3d {
@@ -429,14 +397,20 @@ pub fn screenshot<T: AsRef<str>>(
 
     let view = texture.create_view(&wgpu::TextureViewDescriptor::default());
 
-    backend.present(
+    let mut encoder = compositor.device.create_command_encoder(
+        &wgpu::CommandEncoderDescriptor {
+            label: Some("iced_wgpu.offscreen.encoder"),
+        },
+    );
+
+    renderer.present(
+        &mut compositor.engine,
         &compositor.device,
         &compositor.queue,
         &mut encoder,
         Some(background_color),
         texture.format(),
         &view,
-        primitives,
         viewport,
         overlay,
     );
@@ -474,7 +448,7 @@ pub fn screenshot<T: AsRef<str>>(
         texture_extent,
     );
 
-    let index = compositor.queue.submit(Some(encoder.finish()));
+    let index = compositor.engine.submit(&compositor.queue, encoder);
 
     let slice = output_buffer.slice(..);
     slice.map_async(wgpu::MapMode::Read, |_| {});

widget/src/scrollable.rs

@@ -651,7 +651,7 @@ where
         defaults: &renderer::Style,
         layout: Layout<'_>,
         cursor: mouse::Cursor,
-        _viewport: &Rectangle,
+        viewport: &Rectangle,
     ) {
         let state = tree.state.downcast_ref::<State>();
 
@@ -767,8 +767,8 @@ where
 
             renderer.with_layer(
                 Rectangle {
-                    width: bounds.width + 2.0,
-                    height: bounds.height + 2.0,
+                    width: (bounds.width + 2.0).min(viewport.width),
+                    height: (bounds.height + 2.0).min(viewport.height),
                     ..bounds
                 },
                 |renderer| {