17 files changed, 215 insertions, 59 deletions
diff --git a/graphics/src/renderer.rs b/graphics/src/renderer.rs
new file mode 100644
index 00000000..836ed58d
--- /dev/null
+++ b/graphics/src/renderer.rs
@@ -0,0 +1,86 @@
+mod widget;
+
+use crate::{Backend, Defaults, Primitive};
+use iced_native::layout::{self, Layout};
+use iced_native::mouse;
+use iced_native::{Background, Color, Element, Point, Widget};
+
+pub struct Renderer<B> {
+    backend: B,
+}
+
+impl<B> Renderer<B> {
+    pub fn new(backend: B) -> Self {
+        Self { backend }
+    }
+
+    pub fn backend(&self) -> &B {
+        &self.backend
+    }
+
+    pub fn backend_mut(&mut self) -> &mut B {
+        &mut self.backend
+    }
+}
+
+impl<B> iced_native::Renderer for Renderer<B>
+where
+    B: Backend,
+{
+    type Output = (Primitive, mouse::Interaction);
+    type Defaults = Defaults;
+
+    fn layout<'a, Message>(
+        &mut self,
+        element: &Element<'a, Message, Self>,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        let layout = element.layout(self, limits);
+
+        self.backend.trim_measurements();
+
+        layout
+    }
+}
+
+impl<B> layout::Debugger for Renderer<B>
+where
+    B: Backend,
+{
+    fn explain<Message>(
+        &mut self,
+        defaults: &Defaults,
+        widget: &dyn Widget<Message, Self>,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        color: Color,
+    ) -> Self::Output {
+        let (primitive, cursor) =
+            widget.draw(self, defaults, layout, cursor_position);
+
+        let mut primitives = Vec::new();
+
+        explain_layout(layout, color, &mut primitives);
+        primitives.push(primitive);
+
+        (Primitive::Group { primitives }, cursor)
+    }
+}
+
+fn explain_layout(
+    layout: Layout<'_>,
+    color: Color,
+    primitives: &mut Vec<Primitive>,
+) {
+    primitives.push(Primitive::Quad {
+        bounds: layout.bounds(),
+        background: Background::Color(Color::TRANSPARENT),
+        border_radius: 0,
+        border_width: 1,
+        border_color: [0.6, 0.6, 0.6, 0.5].into(),
+    });
+
+    for child in layout.children() {
+        explain_layout(child, color, primitives);
+    }
+}
diff --git a/wgpu/src/renderer/widget.rs b/graphics/src/renderer/widget.rs
index 37421fbe..b652fdcf 100644
--- a/wgpu/src/renderer/widget.rs
+++ b/graphics/src/renderer/widget.rs
@@ -2,6 +2,7 @@ mod button;
 mod checkbox;
 mod column;
 mod container;
+mod image;
 mod pane_grid;
 mod progress_bar;
 mod radio;
@@ -9,11 +10,6 @@ mod row;
 mod scrollable;
 mod slider;
 mod space;
+mod svg;
 mod text;
 mod text_input;
-
-#[cfg(feature = "svg")]
-mod svg;
-
-#[cfg(feature = "image")]
-mod image;
diff --git a/wgpu/src/renderer/widget/button.rs b/graphics/src/renderer/widget/button.rs
index eb225038..6ee60df4 100644
--- a/wgpu/src/renderer/widget/button.rs
+++ b/graphics/src/renderer/widget/button.rs
@@ -1,9 +1,14 @@
-use crate::{button::StyleSheet, defaults, Defaults, Primitive, Renderer};
+use crate::{
+    button::StyleSheet, defaults, Backend, Defaults, Primitive, Renderer,
+};
 use iced_native::{
     mouse, Background, Color, Element, Layout, Point, Rectangle, Vector,
 };
 
-impl iced_native::button::Renderer for Renderer {
+impl<B> iced_native::button::Renderer for Renderer<B>
+where
+    B: Backend,
+{
     const DEFAULT_PADDING: u16 = 5;
 
     type Style = Box<dyn StyleSheet>;
diff --git a/wgpu/src/renderer/widget/checkbox.rs b/graphics/src/renderer/widget/checkbox.rs
index 0340bf62..75168629 100644
--- a/wgpu/src/renderer/widget/checkbox.rs
+++ b/graphics/src/renderer/widget/checkbox.rs
@@ -1,9 +1,14 @@
-use crate::{checkbox::StyleSheet, Primitive, Renderer};
+use crate::backend::{self, Backend};
+use crate::checkbox::StyleSheet;
+use crate::{Primitive, Renderer};
 use iced_native::{
     checkbox, mouse, HorizontalAlignment, Rectangle, VerticalAlignment,
 };
 
-impl checkbox::Renderer for Renderer {
+impl<B> checkbox::Renderer for Renderer<B>
+where
+    B: Backend + backend::Text,
+{
     type Style = Box<dyn StyleSheet>;
 
     const DEFAULT_SIZE: u16 = 20;
@@ -35,8 +40,8 @@ impl checkbox::Renderer for Renderer {
             Primitive::Group {
                 primitives: if is_checked {
                     let check = Primitive::Text {
-                        content: crate::text::CHECKMARK_ICON.to_string(),
-                        font: crate::text::BUILTIN_ICONS,
+                        content: B::CHECKMARK_ICON.to_string(),
+                        font: B::ICON_FONT,
                         size: bounds.height * 0.7,
                         bounds: Rectangle {
                             x: bounds.center_x(),
diff --git a/glow/src/renderer/widget/column.rs b/graphics/src/renderer/widget/column.rs
index b853276d..b70d2338 100644
--- a/glow/src/renderer/widget/column.rs
+++ b/graphics/src/renderer/widget/column.rs
@@ -1,7 +1,12 @@
-use crate::{Primitive, Renderer};
-use iced_native::{column, mouse, Element, Layout, Point};
+use crate::{Backend, Primitive, Renderer};
+use iced_native::column;
+use iced_native::mouse;
+use iced_native::{Element, Layout, Point};
 
-impl column::Renderer for Renderer {
+impl<B> column::Renderer for Renderer<B>
+where
+    B: Backend,
+{
     fn draw<Message>(
         &mut self,
         defaults: &Self::Defaults,
diff --git a/glow/src/renderer/widget/container.rs b/graphics/src/renderer/widget/container.rs
index 30cc3f07..a1f6a211 100644
--- a/glow/src/renderer/widget/container.rs
+++ b/graphics/src/renderer/widget/container.rs
@@ -1,7 +1,12 @@
-use crate::{container, defaults, Defaults, Primitive, Renderer};
+use crate::container;
+use crate::defaults::{self, Defaults};
+use crate::{Backend, Primitive, Renderer};
 use iced_native::{Background, Color, Element, Layout, Point, Rectangle};
 
-impl iced_native::container::Renderer for Renderer {
+impl<B> iced_native::container::Renderer for Renderer<B>
+where
+    B: Backend,
+{
     type Style = Box<dyn container::StyleSheet>;
 
     fn draw<Message>(
diff --git a/wgpu/src/renderer/widget/image.rs b/graphics/src/renderer/widget/image.rs
index c4c04984..3092237f 100644
--- a/wgpu/src/renderer/widget/image.rs
+++ b/graphics/src/renderer/widget/image.rs
@@ -1,9 +1,15 @@
+use crate::backend::{self, Backend};
 use crate::{Primitive, Renderer};
-use iced_native::{image, mouse, Layout};
+use iced_native::image;
+use iced_native::mouse;
+use iced_native::Layout;
 
-impl image::Renderer for Renderer {
+impl<B> image::Renderer for Renderer<B>
+where
+    B: Backend + backend::Image,
+{
     fn dimensions(&self, handle: &image::Handle) -> (u32, u32) {
-        self.image_pipeline.dimensions(handle)
+        self.backend().dimensions(handle)
     }
 
     fn draw(
diff --git a/glow/src/renderer/widget/pane_grid.rs b/graphics/src/renderer/widget/pane_grid.rs
index 2253e4af..3fa171f5 100644
--- a/glow/src/renderer/widget/pane_grid.rs
+++ b/graphics/src/renderer/widget/pane_grid.rs
@@ -1,11 +1,12 @@
-use crate::{Primitive, Renderer};
-use iced_native::{
-    mouse,
-    pane_grid::{self, Axis, Pane},
-    Element, Layout, Point, Rectangle, Vector,
-};
+use crate::{Backend, Primitive, Renderer};
+use iced_native::mouse;
+use iced_native::pane_grid::{self, Axis, Pane};
+use iced_native::{Element, Layout, Point, Rectangle, Vector};
 
-impl pane_grid::Renderer for Renderer {
+impl<B> pane_grid::Renderer for Renderer<B>
+where
+    B: Backend,
+{
     fn draw<Message>(
         &mut self,
         defaults: &Self::Defaults,
diff --git a/glow/src/renderer/widget/progress_bar.rs b/graphics/src/renderer/widget/progress_bar.rs
index 2baeeb14..d8a145a4 100644
--- a/glow/src/renderer/widget/progress_bar.rs
+++ b/graphics/src/renderer/widget/progress_bar.rs
@@ -1,7 +1,11 @@
-use crate::{progress_bar::StyleSheet, Primitive, Renderer};
+use crate::progress_bar::StyleSheet;
+use crate::{Backend, Primitive, Renderer};
 use iced_native::{mouse, progress_bar, Color, Rectangle};
 
-impl progress_bar::Renderer for Renderer {
+impl<B> progress_bar::Renderer for Renderer<B>
+where
+    B: Backend,
+{
     type Style = Box<dyn StyleSheet>;
 
     const DEFAULT_HEIGHT: u16 = 30;
diff --git a/glow/src/renderer/widget/radio.rs b/graphics/src/renderer/widget/radio.rs
index cee0deb6..4da2b60a 100644
--- a/glow/src/renderer/widget/radio.rs
+++ b/graphics/src/renderer/widget/radio.rs
@@ -1,10 +1,13 @@
-use crate::{radio::StyleSheet, Primitive, Renderer};
+use crate::{radio::StyleSheet, Backend, Primitive, Renderer};
 use iced_native::{mouse, radio, Background, Color, Rectangle};
 
 const SIZE: f32 = 28.0;
 const DOT_SIZE: f32 = SIZE / 2.0;
 
-impl radio::Renderer for Renderer {
+impl<B> radio::Renderer for Renderer<B>
+where
+    B: Backend,
+{
     type Style = Box<dyn StyleSheet>;
 
     const DEFAULT_SIZE: u16 = SIZE as u16;
diff --git a/wgpu/src/renderer/widget/row.rs b/graphics/src/renderer/widget/row.rs
index d0b7ef09..b0bb0d2e 100644
--- a/wgpu/src/renderer/widget/row.rs
+++ b/graphics/src/renderer/widget/row.rs
@@ -1,7 +1,12 @@
-use crate::{Primitive, Renderer};
-use iced_native::{mouse, row, Element, Layout, Point};
+use crate::{Backend, Primitive, Renderer};
+use iced_native::mouse;
+use iced_native::row;
+use iced_native::{Element, Layout, Point};
 
-impl row::Renderer for Renderer {
+impl<B> row::Renderer for Renderer<B>
+where
+    B: Backend,
+{
     fn draw<Message>(
         &mut self,
         defaults: &Self::Defaults,
diff --git a/glow/src/renderer/widget/scrollable.rs b/graphics/src/renderer/widget/scrollable.rs
index 8a400b82..8db17bec 100644
--- a/glow/src/renderer/widget/scrollable.rs
+++ b/graphics/src/renderer/widget/scrollable.rs
@@ -1,10 +1,15 @@
-use crate::{Primitive, Renderer};
-use iced_native::{mouse, scrollable, Background, Color, Rectangle, Vector};
+use crate::{Backend, Primitive, Renderer};
+use iced_native::mouse;
+use iced_native::scrollable;
+use iced_native::{Background, Color, Rectangle, Vector};
 
 const SCROLLBAR_WIDTH: u16 = 10;
 const SCROLLBAR_MARGIN: u16 = 2;
 
-impl scrollable::Renderer for Renderer {
+impl<B> scrollable::Renderer for Renderer<B>
+where
+    B: Backend,
+{
     type Style = Box<dyn iced_style::scrollable::StyleSheet>;
 
     fn scrollbar(
diff --git a/wgpu/src/renderer/widget/slider.rs b/graphics/src/renderer/widget/slider.rs
index 220feace..95c843d0 100644
--- a/wgpu/src/renderer/widget/slider.rs
+++ b/graphics/src/renderer/widget/slider.rs
@@ -1,12 +1,15 @@
-use crate::{
-    slider::{HandleShape, StyleSheet},
-    Primitive, Renderer,
-};
-use iced_native::{mouse, slider, Background, Color, Point, Rectangle};
+use crate::slider::{HandleShape, StyleSheet};
+use crate::{Backend, Primitive, Renderer};
+use iced_native::mouse;
+use iced_native::slider;
+use iced_native::{Background, Color, Point, Rectangle};
 
 const HANDLE_HEIGHT: f32 = 22.0;
 
-impl slider::Renderer for Renderer {
+impl<B> slider::Renderer for Renderer<B>
+where
+    B: Backend,
+{
     type Style = Box<dyn StyleSheet>;
 
     fn height(&self) -> u32 {
diff --git a/graphics/src/renderer/widget/space.rs b/graphics/src/renderer/widget/space.rs
new file mode 100644
index 00000000..d0e82f8d
--- /dev/null
+++ b/graphics/src/renderer/widget/space.rs
@@ -0,0 +1,13 @@
+use crate::{Backend, Primitive, Renderer};
+use iced_native::mouse;
+use iced_native::space;
+use iced_native::Rectangle;
+
+impl<B> space::Renderer for Renderer<B>
+where
+    B: Backend,
+{
+    fn draw(&mut self, _bounds: Rectangle) -> Self::Output {
+        (Primitive::None, mouse::Interaction::default())
+    }
+}
diff --git a/wgpu/src/renderer/widget/svg.rs b/graphics/src/renderer/widget/svg.rs
index f6d6d0ba..4d80869e 100644
--- a/wgpu/src/renderer/widget/svg.rs
+++ b/graphics/src/renderer/widget/svg.rs
@@ -1,9 +1,13 @@
+use crate::backend::{self, Backend};
 use crate::{Primitive, Renderer};
 use iced_native::{mouse, svg, Layout};
 
-impl svg::Renderer for Renderer {
+impl<B> svg::Renderer for Renderer<B>
+where
+    B: Backend + backend::Svg,
+{
     fn dimensions(&self, handle: &svg::Handle) -> (u32, u32) {
-        self.image_pipeline.viewport_dimensions(handle)
+        self.backend().viewport_dimensions(handle)
     }
 
     fn draw(
diff --git a/glow/src/renderer/widget/text.rs b/graphics/src/renderer/widget/text.rs
index 4605ed06..45cb1be2 100644
--- a/glow/src/renderer/widget/text.rs
+++ b/graphics/src/renderer/widget/text.rs
@@ -1,3 +1,4 @@
+use crate::backend::{self, Backend};
 use crate::{Primitive, Renderer};
 use iced_native::{
     mouse, text, Color, Font, HorizontalAlignment, Rectangle, Size,
@@ -6,7 +7,10 @@ use iced_native::{
 
 use std::f32;
 
-impl text::Renderer for Renderer {
+impl<B> text::Renderer for Renderer<B>
+where
+    B: Backend + backend::Text,
+{
     type Font = Font;
 
     const DEFAULT_SIZE: u16 = 20;
@@ -18,7 +22,7 @@ impl text::Renderer for Renderer {
         font: Font,
         bounds: Size,
     ) -> (f32, f32) {
-        self.text_pipeline
+        self.backend()
             .measure(content, f32::from(size), font, bounds)
     }
 
diff --git a/wgpu/src/renderer/widget/text_input.rs b/graphics/src/renderer/widget/text_input.rs
index 57be6692..33807b0f 100644
--- a/wgpu/src/renderer/widget/text_input.rs
+++ b/graphics/src/renderer/widget/text_input.rs
@@ -1,4 +1,6 @@
-use crate::{text_input::StyleSheet, Primitive, Renderer};
+use crate::backend::{self, Backend};
+use crate::text_input::StyleSheet;
+use crate::{Primitive, Renderer};
 
 use iced_native::{
     mouse,
@@ -8,7 +10,10 @@ use iced_native::{
 };
 use std::f32;
 
-impl text_input::Renderer for Renderer {
+impl<B> text_input::Renderer for Renderer<B>
+where
+    B: Backend + backend::Text,
+{
     type Style = Box<dyn StyleSheet>;
 
     fn default_size(&self) -> u16 {
@@ -17,17 +22,15 @@ impl text_input::Renderer for Renderer {
     }
 
     fn measure_value(&self, value: &str, size: u16, font: Font) -> f32 {
-        let (mut width, _) = self.text_pipeline.measure(
-            value,
-            f32::from(size),
-            font,
-            Size::INFINITY,
-        );
+        let backend = self.backend();
+
+        let (mut width, _) =
+            backend.measure(value, f32::from(size), font, Size::INFINITY);
 
         let spaces_around = value.len() - value.trim().len();
 
         if spaces_around > 0 {
-            let space_width = self.text_pipeline.space_width(size as f32);
+            let space_width = backend.space_width(size as f32);
             width += spaces_around as f32 * space_width;
         }
 
@@ -241,14 +244,17 @@ impl text_input::Renderer for Renderer {
     }
 }
 
-fn measure_cursor_and_scroll_offset(
-    renderer: &Renderer,
+fn measure_cursor_and_scroll_offset<B>(
+    renderer: &Renderer<B>,
     text_bounds: Rectangle,
     value: &text_input::Value,
     size: u16,
     cursor_index: usize,
     font: Font,
-) -> (f32, f32) {
+) -> (f32, f32)
+where
+    B: Backend + backend::Text,
+{
     use iced_native::text_input::Renderer;
 
     let text_before_cursor = value.until(cursor_index).to_string();