Introduce iced_renderer subcrate featuring runtime renderer fallback

renderer/src/backend.rs

@@ -0,0 +1,94 @@
+use crate::{Font, Point, Size};
+
+use iced_graphics::backend;
+use iced_graphics::text;
+
+use std::borrow::Cow;
+
+pub enum Backend {
+    Wgpu(iced_wgpu::Backend),
+}
+
+impl iced_graphics::Backend for Backend {}
+
+impl backend::Text for Backend {
+    const ICON_FONT: Font = Font::Name("Iced-Icons");
+    const CHECKMARK_ICON: char = '\u{f00c}';
+    const ARROW_DOWN_ICON: char = '\u{e800}';
+
+    fn default_font(&self) -> Font {
+        match self {
+            Self::Wgpu(backend) => backend.default_font(),
+        }
+    }
+
+    fn default_size(&self) -> f32 {
+        match self {
+            Self::Wgpu(backend) => backend.default_size(),
+        }
+    }
+
+    fn measure(
+        &self,
+        contents: &str,
+        size: f32,
+        font: Font,
+        bounds: Size,
+    ) -> (f32, f32) {
+        match self {
+            Self::Wgpu(backend) => {
+                backend.measure(contents, size, font, bounds)
+            }
+        }
+    }
+
+    fn hit_test(
+        &self,
+        contents: &str,
+        size: f32,
+        font: Font,
+        bounds: Size,
+        position: Point,
+        nearest_only: bool,
+    ) -> Option<text::Hit> {
+        match self {
+            Self::Wgpu(backend) => backend.hit_test(
+                contents,
+                size,
+                font,
+                bounds,
+                position,
+                nearest_only,
+            ),
+        }
+    }
+
+    fn load_font(&mut self, font: Cow<'static, [u8]>) {
+        match self {
+            Self::Wgpu(backend) => {
+                backend.load_font(font);
+            }
+        }
+    }
+}
+
+#[cfg(feature = "image")]
+impl backend::Image for Backend {
+    fn dimensions(&self, handle: &iced_native::image::Handle) -> Size<u32> {
+        match self {
+            Self::Wgpu(backend) => backend.dimensions(handle),
+        }
+    }
+}
+
+#[cfg(feature = "svg")]
+impl backend::Svg for Backend {
+    fn viewport_dimensions(
+        &self,
+        handle: &iced_native::svg::Handle,
+    ) -> Size<u32> {
+        match self {
+            Self::Wgpu(backend) => backend.viewport_dimensions(handle),
+        }
+    }
+}