Implement font::load command in iced_native

native/src/command/action.rs

@@ -1,10 +1,12 @@
 use crate::clipboard;
+use crate::font;
 use crate::system;
 use crate::widget;
 use crate::window;
 
 use iced_futures::MaybeSend;
 
+use std::borrow::Cow;
 use std::fmt;
 
 /// An action that a [`Command`] can perform.
@@ -27,6 +29,15 @@ pub enum Action<T> {
 
     /// Run a widget action.
     Widget(widget::Action<T>),
+
+    /// Load a font from its bytes.
+    LoadFont {
+        /// The bytes of the font to load.
+        bytes: Cow<'static, [u8]>,
+
+        /// The message to produce when the font has been loaded.
+        tagger: Box<dyn Fn(Result<(), font::Error>) -> T>,
+    },
 }
 
 impl<T> Action<T> {
@@ -49,6 +60,10 @@ impl<T> Action<T> {
             Self::Window(window) => Action::Window(window.map(f)),
             Self::System(system) => Action::System(system.map(f)),
             Self::Widget(widget) => Action::Widget(widget.map(f)),
+            Self::LoadFont { bytes, tagger } => Action::LoadFont {
+                bytes,
+                tagger: Box::new(move |result| f(tagger(result))),
+            },
         }
     }
 }
@@ -63,6 +78,7 @@ impl<T> fmt::Debug for Action<T> {
             Self::Window(action) => write!(f, "Action::Window({action:?})"),
             Self::System(action) => write!(f, "Action::System({action:?})"),
             Self::Widget(_action) => write!(f, "Action::Widget"),
+            Self::LoadFont { .. } => write!(f, "Action::LoadFont"),
         }
     }
 }

native/src/font.rs

@@ -0,0 +1,19 @@
+//! Load and use fonts.
+pub use iced_core::Font;
+
+use crate::command::{self, Command};
+use std::borrow::Cow;
+
+/// An error while loading a font.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Error {}
+
+/// Load a font from its bytes.
+pub fn load(
+    bytes: impl Into<Cow<'static, [u8]>>,
+) -> Command<Result<(), Error>> {
+    Command::single(command::Action::LoadFont {
+        bytes: bytes.into(),
+        tagger: Box::new(std::convert::identity),
+    })
+}

native/src/lib.rs

@@ -47,6 +47,7 @@
 pub mod clipboard;
 pub mod command;
 pub mod event;
+pub mod font;
 pub mod image;
 pub mod keyboard;
 pub mod layout;
@@ -80,8 +81,8 @@ mod debug;
 pub use iced_core::alignment;
 pub use iced_core::time;
 pub use iced_core::{
-    color, Alignment, Background, Color, ContentFit, Font, Length, Padding,
-    Pixels, Point, Rectangle, Size, Vector,
+    color, Alignment, Background, Color, ContentFit, Length, Padding, Pixels,
+    Point, Rectangle, Size, Vector,
 };
 pub use iced_futures::{executor, futures};
 pub use iced_style::application;
@@ -95,6 +96,7 @@ pub use command::Command;
 pub use debug::Debug;
 pub use element::Element;
 pub use event::Event;
+pub use font::Font;
 pub use hasher::Hasher;
 pub use layout::Layout;
 pub use overlay::Overlay;

native/src/program.rs

@@ -1,4 +1,5 @@
 //! Build interactive programs using The Elm Architecture.
+use crate::text;
 use crate::{Command, Element, Renderer};
 
 mod state;
@@ -8,7 +9,7 @@ pub use state::State;
 /// The core of a user interface application following The Elm Architecture.
 pub trait Program: Sized {
     /// The graphics backend to use to draw the [`Program`].
-    type Renderer: Renderer;
+    type Renderer: Renderer + text::Renderer;
 
     /// The type of __messages__ your [`Program`] will produce.
     type Message: std::fmt::Debug + Send;

native/src/renderer/null.rs

@@ -2,6 +2,8 @@ use crate::renderer::{self, Renderer};
 use crate::text::{self, Text};
 use crate::{Background, Font, Point, Rectangle, Size, Theme, Vector};
 
+use std::borrow::Cow;
+
 /// A renderer that does nothing.
 ///
 /// It can be useful if you are writing tests!
@@ -52,6 +54,8 @@ impl text::Renderer for Null {
         16.0
     }
 
+    fn load_font(&mut self, _font: Cow<'static, [u8]>) {}
+
     fn measure(
         &self,
         _content: &str,

native/src/text.rs

@@ -2,6 +2,8 @@
 use crate::alignment;
 use crate::{Color, Point, Rectangle, Size, Vector};
 
+use std::borrow::Cow;
+
 /// A paragraph.
 #[derive(Debug, Clone, Copy)]
 pub struct Text<'a, Font> {
@@ -72,7 +74,7 @@ pub trait Renderer: crate::Renderer {
     /// [`ICON_FONT`]: Self::ICON_FONT
     const ARROW_DOWN_ICON: char;
 
-    /// Returns the default [`Font`].
+    /// Returns the default [`Self::Font`].
     fn default_font(&self) -> Self::Font;
 
     /// Returns the default size of [`Text`].
@@ -112,6 +114,9 @@ pub trait Renderer: crate::Renderer {
         nearest_only: bool,
     ) -> Option<Hit>;
 
+    /// Loads a [`Self::Font`] from its bytes.
+    fn load_font(&mut self, font: Cow<'static, [u8]>);
+
     /// Draws the given [`Text`].
     fn fill_text(&mut self, text: Text<'_, Self::Font>);
 }