Merge branch 'master' into improvement/update-wgpu_glyph

1 files changed, 50 insertions, 0 deletions

diff --git a/graphics/src/backend.rs b/graphics/src/backend.rs
new file mode 100644
index 00000000..83510311
--- /dev/null
+++ b/graphics/src/backend.rs
@@ -0,0 +1,50 @@
+//! Write a graphics backend.
+use iced_native::image;
+use iced_native::svg;
+use iced_native::{Font, Size};
+
+/// The graphics backend of a [`Renderer`].
+///
+/// [`Renderer`]: ../struct.Renderer.html
+pub trait Backend {
+    /// Trims the measurements cache.
+    ///
+    /// This method is currently necessary to properly trim the text cache in
+    /// `iced_wgpu` and `iced_glow` because of limitations in the text rendering
+    /// pipeline. It will be removed in the future.
+    fn trim_measurements(&mut self) {}
+}
+
+/// A graphics backend that supports text rendering.
+pub trait Text {
+    /// The icon font of the backend.
+    const ICON_FONT: Font;
+
+    /// The `char` representing a ✔ icon in the [`ICON_FONT`].
+    ///
+    /// [`ICON_FONT`]: #associatedconst.ICON_FONt
+    const CHECKMARK_ICON: char;
+
+    /// Measures the text contents with the given size and font,
+    /// returning the size of a laid out paragraph that fits in the provided
+    /// bounds.
+    fn measure(
+        &self,
+        contents: &str,
+        size: f32,
+        font: Font,
+        bounds: Size,
+    ) -> (f32, f32);
+}
+
+/// A graphics backend that supports image rendering.
+pub trait Image {
+    /// Returns the dimensions of the provided image.
+    fn dimensions(&self, handle: &image::Handle) -> (u32, u32);
+}
+
+/// A graphics backend that supports SVG rendering.
+pub trait Svg {
+    /// Returns the viewport dimensions of the provided SVG.
+    fn viewport_dimensions(&self, handle: &svg::Handle) -> (u32, u32);
+}