ui: feed computed image size into bevy_ui flex

crates/bevy_ui/src/entity.rs

@@ -1,7 +1,7 @@
 use super::Node;
 use crate::{
     render::UI_PIPELINE_HANDLE,
-    widget::{Button, Text},
+    widget::{Button, Text, Image},
     Click, FocusPolicy, Hover, Style, CalculatedSize,
 };
 use bevy_asset::Handle;
@@ -62,6 +62,55 @@ impl Default for NodeComponents {
     }
 }
 
+#[derive(Bundle)]
+pub struct ImageComponents {
+    pub node: Node,
+    pub style: Style,
+    pub image: Image,
+    pub calculated_size: CalculatedSize,
+    pub mesh: Handle<Mesh>, // TODO: maybe abstract this out
+    pub material: Handle<ColorMaterial>,
+    pub draw: Draw,
+    pub render_pipelines: RenderPipelines,
+    pub transform: Transform,
+    pub local_transform: LocalTransform,
+}
+
+impl Default for ImageComponents {
+    fn default() -> Self {
+        ImageComponents {
+            mesh: QUAD_HANDLE,
+            render_pipelines: RenderPipelines::from_pipelines(vec![RenderPipeline::specialized(
+                UI_PIPELINE_HANDLE,
+                PipelineSpecialization {
+                    dynamic_bindings: vec![
+                        // Transform
+                        DynamicBinding {
+                            bind_group: 1,
+                            binding: 0,
+                        },
+                        // Node_size
+                        DynamicBinding {
+                            bind_group: 1,
+                            binding: 1,
+                        },
+                    ],
+                    ..Default::default()
+                },
+            )]),
+            node: Default::default(),
+            image: Default::default(),
+            calculated_size: Default::default(),
+            style: Default::default(),
+            material: Default::default(),
+            draw: Default::default(),
+            transform: Default::default(),
+            local_transform: Default::default(),
+        }
+    }
+}
+
+
 #[derive(Bundle)]
 pub struct TextComponents {
     pub node: Node,

crates/bevy_ui/src/flex/mod.rs

@@ -6,7 +6,7 @@ use bevy_math::Vec2;
 use bevy_transform::prelude::{Children, LocalTransform, Parent};
 use bevy_window::{Window, WindowId, Windows};
 use std::collections::HashMap;
-use stretch::Stretch;
+use stretch::{number::Number, Stretch};
 
 pub struct FlexSurface {
     entity_to_stretch: HashMap<Entity, stretch::node::Node>,
@@ -43,40 +43,41 @@ impl FlexSurface {
     }
 
     pub fn upsert_leaf(&mut self, entity: Entity, style: &Style, calculated_size: CalculatedSize) {
-        let mut added = false;
         let stretch = &mut self.stretch;
         let stretch_style = style.into();
-        let stretch_node = self.entity_to_stretch.entry(entity).or_insert_with(|| {
-            added = true;
-            let stretch_node = stretch
-                .new_leaf(
-                    stretch_style,
-                    Box::new(move |_| {
-                        Ok(stretch::geometry::Size {
-                            width: calculated_size.size.width,
-                            height: calculated_size.size.height,
-                        })
-                    }),
-                )
-                .unwrap();
-            stretch_node
+        let measure = Box::new(move |constraints: stretch::geometry::Size<Number>| {
+            let mut size = stretch::geometry::Size {
+                width: calculated_size.size.width,
+                height: calculated_size.size.height,
+            };
+            match (constraints.width, constraints.height) {
+                (Number::Undefined, Number::Undefined) => {}
+                (Number::Defined(width), Number::Undefined) => {
+                    size.height = width * size.height / size.width;
+                    size.width = width;
+                }
+                (Number::Undefined, Number::Defined(height)) => {
+                    size.width = height * size.width / size.height;
+                    size.height = height;
+                }
+                (Number::Defined(width), Number::Defined(height)) => {
+                    size.width = width;
+                    size.height = height;
+                }
+            }
+            Ok(size)
         });
 
-        if !added {
+        if let Some(stretch_node) = self.entity_to_stretch.get(&entity) {
             self.stretch
                 .set_style(*stretch_node, stretch_style)
                 .unwrap();
             self.stretch
-                .set_measure(
-                    *stretch_node,
-                    Some(Box::new(move |_| {
-                        Ok(stretch::geometry::Size {
-                            width: calculated_size.size.width,
-                            height: calculated_size.size.height,
-                        })
-                    })),
-                )
+                .set_measure(*stretch_node, Some(measure))
                 .unwrap();
+        } else {
+            let stretch_node = stretch.new_leaf(stretch_style, measure).unwrap();
+            self.entity_to_stretch.insert(entity, stretch_node);
         }
     }
 

crates/bevy_ui/src/lib.rs

@@ -40,6 +40,7 @@ impl AppPlugin for UiPlugin {
             .add_system_to_stage_front(stage::POST_UPDATE, flex_node_system.system())
             .add_system_to_stage_front(stage::POST_UPDATE, ui_z_system.system())
             .add_system_to_stage_front(stage::POST_UPDATE, widget::text_system.system())
+            .add_system_to_stage_front(stage::POST_UPDATE, widget::image_node_system.system())
             .add_system_to_stage(bevy_render::stage::DRAW, widget::draw_text_system.system());
 
         let resources = app.resources();

crates/bevy_ui/src/widget/image.rs

@@ -0,0 +1,35 @@
+use crate::CalculatedSize;
+use bevy_asset::{Assets, Handle};
+use bevy_ecs::{Query, Res};
+use bevy_math::Size;
+use bevy_render::texture::Texture;
+use bevy_sprite::ColorMaterial;
+
+pub enum Image {
+    KeepAspect,
+}
+
+impl Default for Image {
+    fn default() -> Self {
+        Image::KeepAspect
+    }
+}
+
+pub fn image_node_system(
+    materials: Res<Assets<ColorMaterial>>,
+    textures: Res<Assets<Texture>>,
+    mut query: Query<(&Image, &mut CalculatedSize, &Handle<ColorMaterial>)>,
+) {
+    for (_image, mut calculated_size, material_handle) in &mut query.iter() {
+        materials
+            .get(material_handle)
+            .and_then(|material| material.texture)
+            .and_then(|texture_handle| textures.get(&texture_handle))
+            .map(|texture| {
+                calculated_size.size = Size {
+                    width: texture.size.x(),
+                    height: texture.size.y(),
+                };
+            });
+    }
+}

crates/bevy_ui/src/widget/mod.rs

@@ -1,5 +1,7 @@
 mod button;
 mod text;
+mod image;
 
 pub use button::*;
 pub use text::*;
+pub use image::*;

examples/ui/ui.rs

@@ -10,16 +10,8 @@ fn main() {
 fn setup(
     mut commands: Commands,
     asset_server: Res<AssetServer>,
-    mut textures: ResMut<Assets<Texture>>,
     mut materials: ResMut<Assets<ColorMaterial>>,
 ) {
-    let texture_handle = asset_server
-        .load_sync(&mut textures, "assets/branding/bevy_logo_dark_big.png")
-        .unwrap();
-
-    let texture = textures.get(&texture_handle).unwrap();
-    let aspect = texture.aspect();
-
     commands
         // ui camera
         .spawn(UiCameraComponents::default())
@@ -87,7 +79,7 @@ fn setup(
                     material: materials.add(Color::rgb(0.02, 0.02, 0.02).into()),
                     ..Default::default()
                 })
-                // Absolute positioning
+                // absolute positioning
                 .spawn(NodeComponents {
                     style: Style {
                         size: Size::new(Val::Px(200.0), Val::Px(200.0)),
@@ -222,12 +214,17 @@ fn setup(
                 })
                 .with_children(|parent| {
                     // bevy logo (image)
-                    parent.spawn(NodeComponents {
+                    parent.spawn(ImageComponents {
                         style: Style {
-                            min_size: Size::new(Val::Px(500.0), Val::Px(500.0 * aspect)),
+                            size: Size::new(Val::Px(500.0), Val::Auto),
                             ..Default::default()
                         },
-                        material: materials.add(ColorMaterial::texture(texture_handle)),
+                        material: materials.add(
+                            asset_server
+                                .load("assets/branding/bevy_logo_dark_big.png")
+                                .unwrap()
+                                .into(),
+                        ),
                         draw: Draw {
                             is_transparent: true,
                             ..Default::default()