Apply HiDPI to text, images, and clip primitives

Quads are a bit trickier to handle. We may need to change the shaders a
bit.

wgpu/src/renderer.rs

@@ -98,6 +98,7 @@ impl Renderer {
         log::debug!("Drawing");
 
         let (width, height) = target.dimensions();
+        let dpi = target.dpi();
         let transformation = target.transformation();
         let frame = target.next_frame();
 
@@ -137,7 +138,7 @@ impl Renderer {
         self.draw_overlay(overlay, &mut layers);
 
         for layer in layers {
-            self.flush(transformation, &layer, &mut encoder, &frame.view);
+            self.flush(dpi, transformation, &layer, &mut encoder, &frame.view);
         }
 
         self.queue.submit(&[encoder.finish()]);
@@ -190,7 +191,10 @@ impl Renderer {
 
                 layer.text.push(Section {
                     text: &content,
-                    screen_position: (x, y),
+                    screen_position: (
+                        x - layer.offset.x as f32,
+                        y - layer.offset.y as f32,
+                    ),
                     bounds: (bounds.width, bounds.height),
                     scale: wgpu_glyph::Scale { x: *size, y: *size },
                     color: color.into_linear(),
@@ -225,6 +229,7 @@ impl Renderer {
                 background,
                 border_radius,
             } => {
+                // TODO: Move some of this computations to the GPU (?)
                 layer.quads.push(Quad {
                     position: [
                         bounds.x - layer.offset.x as f32,
@@ -234,7 +239,7 @@ impl Renderer {
                     color: match background {
                         Background::Color(color) => color.into_linear(),
                     },
-                    border_radius: u32::from(*border_radius),
+                    border_radius: *border_radius as u32,
                 });
             }
             Primitive::Image { path, bounds } => {
@@ -308,16 +313,13 @@ impl Renderer {
 
     fn flush(
         &mut self,
+        dpi: f32,
         transformation: Transformation,
         layer: &Layer,
         encoder: &mut wgpu::CommandEncoder,
         target: &wgpu::TextureView,
     ) {
-        let translated = transformation
-            * Transformation::translate(
-                -(layer.offset.x as f32),
-                -(layer.offset.y as f32),
-            );
+        let bounds = layer.bounds * dpi;
 
         if layer.quads.len() > 0 {
             self.quad_pipeline.draw(
@@ -325,18 +327,25 @@ impl Renderer {
                 encoder,
                 &layer.quads,
                 transformation,
-                layer.bounds,
+                bounds,
                 target,
             );
         }
 
         if layer.images.len() > 0 {
+            let translated = transformation
+                * Transformation::scale(dpi, dpi)
+                * Transformation::translate(
+                    -(layer.offset.x as f32),
+                    -(layer.offset.y as f32),
+                );
+
             self.image_pipeline.draw(
                 &mut self.device,
                 encoder,
                 &layer.images,
                 translated,
-                layer.bounds,
+                bounds,
                 target,
             );
         }
@@ -345,6 +354,20 @@ impl Renderer {
             let mut glyph_brush = self.glyph_brush.borrow_mut();
 
             for text in layer.text.iter() {
+                // Target physical coordinates directly to avoid blurry text
+                let text = Section {
+                    screen_position: (
+                        text.screen_position.0 * dpi,
+                        text.screen_position.1 * dpi,
+                    ),
+                    bounds: (text.bounds.0 * dpi, text.bounds.1 * dpi),
+                    scale: wgpu_glyph::Scale {
+                        x: text.scale.x * dpi,
+                        y: text.scale.y * dpi,
+                    },
+                    ..*text
+                };
+
                 glyph_brush.queue(text);
             }
 
@@ -353,12 +376,12 @@ impl Renderer {
                     &mut self.device,
                     encoder,
                     target,
-                    translated.into(),
+                    transformation.into(),
                     wgpu_glyph::Region {
-                        x: layer.bounds.x,
-                        y: layer.bounds.y,
-                        width: layer.bounds.width,
-                        height: layer.bounds.height,
+                        x: bounds.x,
+                        y: bounds.y,
+                        width: bounds.width,
+                        height: bounds.height,
                     },
                 )
                 .expect("Draw text");

wgpu/src/renderer/target.rs

@@ -6,6 +6,7 @@ pub struct Target {
     surface: wgpu::Surface,
     width: u16,
     height: u16,
+    dpi: f32,
     transformation: Transformation,
     swap_chain: wgpu::SwapChain,
 }
@@ -15,6 +16,10 @@ impl Target {
         (self.width, self.height)
     }
 
+    pub fn dpi(&self) -> f32 {
+        self.dpi
+    }
+
     pub fn transformation(&self) -> Transformation {
         self.transformation
     }
@@ -31,6 +36,7 @@ impl iced_native::renderer::Target for Target {
         window: &W,
         width: u16,
         height: u16,
+        dpi: f32,
         renderer: &Renderer,
     ) -> Target {
         let surface = wgpu::Surface::create(window);
@@ -41,14 +47,22 @@ impl iced_native::renderer::Target for Target {
             surface,
             width,
             height,
+            dpi,
             transformation: Transformation::orthographic(width, height),
             swap_chain,
         }
     }
 
-    fn resize(&mut self, width: u16, height: u16, renderer: &Renderer) {
+    fn resize(
+        &mut self,
+        width: u16,
+        height: u16,
+        dpi: f32,
+        renderer: &Renderer,
+    ) {
         self.width = width;
         self.height = height;
+        self.dpi = dpi;
         self.transformation = Transformation::orthographic(width, height);
         self.swap_chain =
             new_swap_chain(&self.surface, width, height, &renderer.device);

wgpu/src/transformation.rs

@@ -26,6 +26,11 @@ impl Transformation {
     pub fn translate(x: f32, y: f32) -> Transformation {
         Transformation(Mat4::from_translation(Vec3::new(x, y, 0.0)))
     }
+
+    /// Creates a scale transformation.
+    pub fn scale(x: f32, y: f32) -> Transformation {
+        Transformation(Mat4::from_scale(Vec3::new(x, y, 0.0)))
+    }
 }
 
 impl Mul for Transformation {