Draft custom layout engine based on `druid`

9 files changed, 107 insertions, 66 deletions

diff --git a/wgpu/src/renderer/widget/button.rs b/wgpu/src/renderer/widget/button.rs
index e8a97385..3d5e42ba 100644
--- a/wgpu/src/renderer/widget/button.rs
+++ b/wgpu/src/renderer/widget/button.rs
@@ -1,6 +1,7 @@
 use crate::{Primitive, Renderer};
 use iced_native::{
-    button, layout, Background, Button, Layout, MouseCursor, Point, Rectangle,
+    button, layout, Background, Button, Layout, Length, MouseCursor, Point,
+    Rectangle,
 };
 
 impl button::Renderer for Renderer {
@@ -8,20 +9,28 @@ impl button::Renderer for Renderer {
         &self,
         button: &Button<Message, Self>,
         limits: &layout::Limits,
-    ) -> Layout {
-        // TODO
-        Layout::new(Rectangle {
-            x: 0.0,
-            y: 0.0,
-            width: 0.0,
-            height: 0.0,
-        })
+    ) -> layout::Node {
+        let padding = f32::from(button.padding);
+        let limits = limits
+            .min_width(100)
+            .width(button.width)
+            .height(Length::Shrink)
+            .pad(padding);
+
+        let mut content = button.content.layout(self, &limits);
+
+        content.bounds.x = padding;
+        content.bounds.y = padding;
+
+        let size = limits.resolve(content.size()).pad(padding);
+
+        layout::Node::with_children(size, vec![content])
     }
 
     fn draw<Message>(
         &mut self,
         button: &Button<Message, Self>,
-        layout: &Layout,
+        layout: Layout<'_>,
         cursor_position: Point,
     ) -> Self::Output {
         let bounds = layout.bounds();
diff --git a/wgpu/src/renderer/widget/checkbox.rs b/wgpu/src/renderer/widget/checkbox.rs
index de921e6b..c2d7911c 100644
--- a/wgpu/src/renderer/widget/checkbox.rs
+++ b/wgpu/src/renderer/widget/checkbox.rs
@@ -1,7 +1,8 @@
 use crate::{Primitive, Renderer};
 use iced_native::{
     checkbox, layout, text, text::HorizontalAlignment, text::VerticalAlignment,
-    Background, Checkbox, Layout, MouseCursor, Point, Rectangle, Text,
+    Align, Background, Checkbox, Column, Layout, Length, MouseCursor, Point,
+    Rectangle, Row, Text, Widget,
 };
 
 const SIZE: f32 = 28.0;
@@ -11,20 +12,23 @@ impl checkbox::Renderer for Renderer {
         &self,
         checkbox: &Checkbox<Message>,
         limits: &layout::Limits,
-    ) -> Layout {
-        // TODO
-        Layout::new(Rectangle {
-            x: 0.0,
-            y: 0.0,
-            width: 0.0,
-            height: 0.0,
-        })
+    ) -> layout::Node {
+        Row::<(), Self>::new()
+            .spacing(15)
+            .align_items(Align::Center)
+            .push(
+                Column::new()
+                    .width(Length::Units(SIZE as u16))
+                    .height(Length::Units(SIZE as u16)),
+            )
+            .push(Text::new(&checkbox.label))
+            .layout(self, limits)
     }
 
     fn draw<Message>(
         &mut self,
         checkbox: &Checkbox<Message>,
-        layout: &Layout,
+        layout: Layout<'_>,
         cursor_position: Point,
     ) -> Self::Output {
         let bounds = layout.bounds();
diff --git a/wgpu/src/renderer/widget/column.rs b/wgpu/src/renderer/widget/column.rs
index 6355f000..cac6da77 100644
--- a/wgpu/src/renderer/widget/column.rs
+++ b/wgpu/src/renderer/widget/column.rs
@@ -5,7 +5,7 @@ impl column::Renderer for Renderer {
     fn draw<Message>(
         &mut self,
         column: &Column<'_, Message, Self>,
-        layout: &Layout,
+        layout: Layout<'_>,
         cursor_position: Point,
     ) -> Self::Output {
         let mut mouse_cursor = MouseCursor::OutOfBounds;
diff --git a/wgpu/src/renderer/widget/image.rs b/wgpu/src/renderer/widget/image.rs
index ea9d19c7..0afb11e3 100644
--- a/wgpu/src/renderer/widget/image.rs
+++ b/wgpu/src/renderer/widget/image.rs
@@ -1,18 +1,31 @@
 use crate::{Primitive, Renderer};
-use iced_native::{image, layout, Image, Layout, MouseCursor, Rectangle};
+use iced_native::{image, layout, Image, Layout, Length, MouseCursor, Size};
 
 impl image::Renderer for Renderer {
-    fn layout(&self, image: &Image, limits: &layout::Limits) -> Layout {
-        // TODO
-        Layout::new(Rectangle {
-            x: 0.0,
-            y: 0.0,
-            width: 0.0,
-            height: 0.0,
-        })
+    fn layout(&self, image: &Image, limits: &layout::Limits) -> layout::Node {
+        let (width, height) = self.image_pipeline.dimensions(&image.path);
+
+        let aspect_ratio = width as f32 / height as f32;
+
+        // TODO: Deal with additional cases
+        let (width, height) = match (image.width, image.height) {
+            (Length::Units(width), _) => (
+                image.width,
+                Length::Units((width as f32 / aspect_ratio).round() as u16),
+            ),
+            (_, _) => {
+                (Length::Units(width as u16), Length::Units(height as u16))
+            }
+        };
+
+        let mut size = limits.width(width).height(height).resolve(Size::ZERO);
+
+        size.height = size.width / aspect_ratio;
+
+        layout::Node::new(size)
     }
 
-    fn draw(&mut self, image: &Image, layout: &Layout) -> Self::Output {
+    fn draw(&mut self, image: &Image, layout: Layout<'_>) -> Self::Output {
         (
             Primitive::Image {
                 path: image.path.clone(),
diff --git a/wgpu/src/renderer/widget/radio.rs b/wgpu/src/renderer/widget/radio.rs
index 9f3c528f..1f17ba28 100644
--- a/wgpu/src/renderer/widget/radio.rs
+++ b/wgpu/src/renderer/widget/radio.rs
@@ -1,7 +1,7 @@
 use crate::{Primitive, Renderer};
 use iced_native::{
-    layout, radio, text, Background, Layout, MouseCursor, Point, Radio,
-    Rectangle, Text,
+    layout, radio, text, Align, Background, Column, Layout, Length,
+    MouseCursor, Point, Radio, Rectangle, Row, Text, Widget,
 };
 
 const SIZE: f32 = 28.0;
@@ -12,20 +12,23 @@ impl radio::Renderer for Renderer {
         &self,
         radio: &Radio<Message>,
         limits: &layout::Limits,
-    ) -> Layout {
-        // TODO
-        Layout::new(Rectangle {
-            x: 0.0,
-            y: 0.0,
-            width: 0.0,
-            height: 0.0,
-        })
+    ) -> layout::Node {
+        Row::<(), Self>::new()
+            .spacing(15)
+            .align_items(Align::Center)
+            .push(
+                Column::new()
+                    .width(Length::Units(SIZE as u16))
+                    .height(Length::Units(SIZE as u16)),
+            )
+            .push(Text::new(&radio.label))
+            .layout(self, limits)
     }
 
     fn draw<Message>(
         &mut self,
         radio: &Radio<Message>,
-        layout: &Layout,
+        layout: Layout<'_>,
         cursor_position: Point,
     ) -> Self::Output {
         let bounds = layout.bounds();
diff --git a/wgpu/src/renderer/widget/row.rs b/wgpu/src/renderer/widget/row.rs
index 4f7cb10e..bbfef9a1 100644
--- a/wgpu/src/renderer/widget/row.rs
+++ b/wgpu/src/renderer/widget/row.rs
@@ -5,7 +5,7 @@ impl row::Renderer for Renderer {
     fn draw<Message>(
         &mut self,
         row: &Row<'_, Message, Self>,
-        layout: &Layout,
+        layout: Layout<'_>,
         cursor_position: Point,
     ) -> Self::Output {
         let mut mouse_cursor = MouseCursor::OutOfBounds;
diff --git a/wgpu/src/renderer/widget/scrollable.rs b/wgpu/src/renderer/widget/scrollable.rs
index 4b318d6d..dd6ebcc1 100644
--- a/wgpu/src/renderer/widget/scrollable.rs
+++ b/wgpu/src/renderer/widget/scrollable.rs
@@ -32,7 +32,7 @@ impl scrollable::Renderer for Renderer {
         &mut self,
         scrollable: &Scrollable<'_, Message, Self>,
         bounds: Rectangle,
-        content: &Layout,
+        content: Layout<'_>,
         cursor_position: Point,
     ) -> Self::Output {
         let is_mouse_over = bounds.contains(cursor_position);
diff --git a/wgpu/src/renderer/widget/slider.rs b/wgpu/src/renderer/widget/slider.rs
index a3423785..98065bc9 100644
--- a/wgpu/src/renderer/widget/slider.rs
+++ b/wgpu/src/renderer/widget/slider.rs
@@ -1,7 +1,7 @@
 use crate::{Primitive, Renderer};
 use iced_native::{
-    layout, slider, Background, Color, Layout, MouseCursor, Point, Rectangle,
-    Slider,
+    layout, slider, Background, Color, Layout, Length, MouseCursor, Point,
+    Rectangle, Size, Slider,
 };
 
 const HANDLE_WIDTH: f32 = 8.0;
@@ -12,20 +12,17 @@ impl slider::Renderer for Renderer {
         &self,
         slider: &Slider<Message>,
         limits: &layout::Limits,
-    ) -> Layout {
-        // TODO
-        Layout::new(Rectangle {
-            x: 0.0,
-            y: 0.0,
-            width: 0.0,
-            height: 0.0,
-        })
+    ) -> layout::Node {
+        let limits = limits.width(slider.width).height(Length::Units(30));
+        let size = limits.resolve(Size::ZERO);
+
+        layout::Node::new(size)
     }
 
     fn draw<Message>(
         &mut self,
         slider: &Slider<Message>,
-        layout: &Layout,
+        layout: Layout<'_>,
         cursor_position: Point,
     ) -> Self::Output {
         let bounds = layout.bounds();
diff --git a/wgpu/src/renderer/widget/text.rs b/wgpu/src/renderer/widget/text.rs
index d824c07c..713b514f 100644
--- a/wgpu/src/renderer/widget/text.rs
+++ b/wgpu/src/renderer/widget/text.rs
@@ -1,7 +1,7 @@
 use crate::{Primitive, Renderer};
-use iced_native::{layout, text, Color, Layout, MouseCursor, Rectangle, Text};
+use iced_native::{layout, text, Color, Layout, MouseCursor, Size, Text};
 
-//use wgpu_glyph::{GlyphCruncher, Section};
+use wgpu_glyph::{GlyphCruncher, Section};
 
 use std::f32;
 
@@ -9,17 +9,32 @@ use std::f32;
 const DEFAULT_TEXT_SIZE: f32 = 20.0;
 
 impl text::Renderer for Renderer {
-    fn layout(&self, text: &Text, limits: &layout::Limits) -> Layout {
-        // TODO
-        Layout::new(Rectangle {
-            x: 0.0,
-            y: 0.0,
-            width: 0.0,
-            height: 0.0,
-        })
+    fn layout(&self, text: &Text, limits: &layout::Limits) -> layout::Node {
+        let limits = limits.width(text.width).height(text.height);
+        let size = text.size.map(f32::from).unwrap_or(DEFAULT_TEXT_SIZE);
+        let bounds = limits.max();
+
+        let section = Section {
+            text: &text.content,
+            scale: wgpu_glyph::Scale { x: size, y: size },
+            bounds: (bounds.width, bounds.height),
+            ..Default::default()
+        };
+
+        let (width, height) = if let Some(bounds) =
+            self.glyph_brush.borrow_mut().glyph_bounds(&section)
+        {
+            (bounds.width().ceil(), bounds.height().ceil())
+        } else {
+            (0.0, 0.0)
+        };
+
+        let size = limits.resolve(Size::new(width, height));
+
+        layout::Node::new(size)
     }
 
-    fn draw(&mut self, text: &Text, layout: &Layout) -> Self::Output {
+    fn draw(&mut self, text: &Text, layout: Layout<'_>) -> Self::Output {
         (
             Primitive::Text {
                 content: text.content.clone(),