Add background_color support to TaffyLayout

src/view/taffy_layout.rs

@@ -14,6 +14,8 @@
 
 use std::{any::Any, marker::PhantomData};
 
+use vello::peniko::Color;
+
 use crate::view::{Id, VecSplice, ViewMarker, ViewSequence};
 use crate::widget::{self, ChangeFlags};
 use crate::MessageResult;
@@ -28,6 +30,7 @@ use super::{Cx, View};
 pub struct TaffyLayout<T, A, VT: ViewSequence<T, A>> {
     children: VT,
     style: taffy::Style,
+    background_color: Option<Color>,
     phantom: PhantomData<fn() -> (T, A)>,
 }
 
@@ -55,6 +58,7 @@ impl<T, A, VT: ViewSequence<T, A>> TaffyLayout<T, A, VT> {
                 display,
                 ..Default::default()
             },
+            background_color: None,
             phantom,
         }
     }
@@ -69,6 +73,7 @@ impl<T, A, VT: ViewSequence<T, A>> TaffyLayout<T, A, VT> {
                 flex_direction,
                 ..Default::default()
             },
+            background_color: None,
             phantom,
         }
     }
@@ -77,6 +82,11 @@ impl<T, A, VT: ViewSequence<T, A>> TaffyLayout<T, A, VT> {
         style_modifier(&mut self.style);
         self
     }
+
+    pub fn with_background_color(mut self, color: impl Into<Color>) -> Self {
+        self.background_color = Some(color.into());
+        self
+    }
 }
 
 impl<T, A, VT: ViewSequence<T, A>> ViewMarker for TaffyLayout<T, A, VT> {}
@@ -89,7 +99,7 @@ impl<T, A, VT: ViewSequence<T, A>> View<T, A> for TaffyLayout<T, A, VT> {
     fn build(&self, cx: &mut Cx) -> (Id, Self::State, Self::Element) {
         let mut elements = vec![];
         let (id, state) = cx.with_new_id(|cx| self.children.build(cx, &mut elements));
-        let column = widget::TaffyLayout::new(elements, self.style.clone());
+        let column = widget::TaffyLayout::new(elements, self.style.clone(), self.background_color);
         (id, state, column)
     }
 
@@ -109,10 +119,10 @@ impl<T, A, VT: ViewSequence<T, A>> View<T, A> for TaffyLayout<T, A, VT> {
                 .rebuild(cx, &prev.children, state, &mut splice)
         });
 
-        // if self.background_color != prev.background_color {
-        //     element.background_color = self.background_color;
-        //     flags |= ChangeFlags::PAINT
-        // }
+        if self.background_color != prev.background_color {
+            element.background_color = self.background_color;
+            flags |= ChangeFlags::PAINT
+        }
 
         if self.style != prev.style {
             element.style = self.style.clone();

src/widget/taffy_layout.rs

@@ -15,7 +15,9 @@
 use crate::geometry::Axis;
 use crate::widget::{AccessCx, BoxConstraints, Event};
 use accesskit::NodeId;
+use glazier::kurbo::Affine;
 use vello::kurbo::{Point, Size};
+use vello::peniko::{Brush, Color, Fill};
 use vello::SceneBuilder;
 
 use super::{contexts::LifeCycleCx, EventCx, LayoutCx, LifeCycle, PaintCx, Pod, UpdateCx, Widget};
@@ -35,14 +37,19 @@ pub struct TaffyLayout {
     pub children: Vec<Pod>,
     pub cache: taffy::Cache,
     pub style: taffy::Style,
+    pub background_color: Option<Color>,
 }
 
 impl TaffyLayout {
-    pub fn new(children: Vec<Pod>, style: taffy::Style) -> Self {
+    pub fn new(children: Vec<Pod>, style: taffy::Style, background_color: Option<Color>) -> Self {
+        let len = children.len();
+        let mut caches = Vec::new();
+        caches.resize_with(len, taffy::Cache::new);
         TaffyLayout {
             children,
             cache: taffy::Cache::new(),
             style,
+            background_color,
         }
     }
 }
@@ -433,8 +440,16 @@ impl Widget for TaffyLayout {
     }
 
     fn paint(&mut self, cx: &mut PaintCx, builder: &mut SceneBuilder) {
+        if let Some(color) = self.background_color {
+            builder.fill(
+                Fill::NonZero,
+                Affine::IDENTITY,
+                &Brush::Solid(color),
+                None,
+                &cx.size().to_rect(),
+            );
+        }
         for child in &mut self.children {
-            println!("paint child!");
             child.paint(cx, builder);
         }
     }