Support transforms for each widget

masonry/src/contexts.rs

@@ -10,7 +10,6 @@ use dpi::LogicalPosition;
 use parley::{FontContext, LayoutContext};
 use tracing::{trace, warn};
 use tree_arena::{ArenaMutChildren, ArenaRefChildren};
-use vello::kurbo::Vec2;
 use vello::peniko::Color;
 use winit::window::ResizeDirection;
 
@@ -19,8 +18,11 @@ use crate::passes::layout::run_layout_on;
 use crate::render_root::{MutateCallback, RenderRootSignal, RenderRootState};
 use crate::text::BrushIndex;
 use crate::theme::get_debug_color;
-use crate::widget::{WidgetMut, WidgetRef, WidgetState};
-use crate::{AllowRawMut, BoxConstraints, Insets, Point, Rect, Size, Widget, WidgetId, WidgetPod};
+use crate::widget::{CreatedWidget, WidgetMut, WidgetRef, WidgetState};
+use crate::{
+    Affine, AllowRawMut, BoxConstraints, Insets, Point, Rect, Size, Vec2, Widget, WidgetId,
+    WidgetPod,
+};
 
 // Note - Most methods defined in this file revolve around `WidgetState` fields.
 // Consider reading `WidgetState` documentation (especially the documented naming scheme)
@@ -258,8 +260,9 @@ impl_context_method!(
             self.widget_state.window_origin()
         }
 
-        pub fn window_layout_rect(&self) -> Rect {
-            self.widget_state.window_layout_rect()
+        /// The axis aligned bounding rect of this widget in window coordinates.
+        pub fn bounding_rect(&self) -> Rect {
+            self.widget_state.bounding_rect()
         }
 
         pub fn paint_rect(&self) -> Rect {
@@ -278,7 +281,7 @@ impl_context_method!(
         ///
         /// The returned point is relative to the content area; it excludes window chrome.
         pub fn to_window(&self, widget_point: Point) -> Point {
-            self.window_origin() + widget_point.to_vec2()
+            self.widget_state.window_transform * widget_point
         }
     }
 );
@@ -537,6 +540,12 @@ impl_context_method!(MutateCtx<'_>, EventCtx<'_>, UpdateCtx<'_>, {
         self.widget_state.request_compose = true;
     }
 
+    pub fn transform_changed(&mut self) {
+        trace!("transform_changed");
+        self.widget_state.transform_changed = true;
+        self.request_compose();
+    }
+
     /// Request an animation frame.
     pub fn request_anim_frame(&mut self) {
         trace!("request_anim_frame");
@@ -584,6 +593,11 @@ impl_context_method!(MutateCtx<'_>, EventCtx<'_>, UpdateCtx<'_>, {
         self.widget_state.needs_update_disabled = true;
         self.widget_state.is_explicitly_disabled = disabled;
     }
+
+    pub fn set_transform(&mut self, transform: Affine) {
+        self.widget_state.transform = transform;
+        self.transform_changed();
+    }
 });
 
 // --- MARK: OTHER METHODS ---
@@ -851,7 +865,7 @@ impl RegisterCtx<'_> {
     /// Container widgets should call this on all their children in
     /// their implementation of [`Widget::register_children`].
     pub fn register_child(&mut self, child: &mut WidgetPod<impl Widget>) {
-        let Some(widget) = child.take_inner() else {
+        let Some(CreatedWidget { widget, transform }) = child.take_inner() else {
             return;
         };
 
@@ -861,7 +875,8 @@ impl RegisterCtx<'_> {
         }
 
         let id = child.id();
-        let state = WidgetState::new(child.id(), widget.short_type_name());
+        let mut state = WidgetState::new(child.id(), widget.short_type_name());
+        state.transform = transform;
 
         self.widget_children.insert_child(id, Box::new(widget));
         self.widget_state_children.insert_child(id, state);
@@ -944,7 +959,7 @@ impl LayoutCtx<'_> {
     ) -> Insets {
         self.assert_layout_done(child, "compute_insets_from_child");
         self.assert_placed(child, "compute_insets_from_child");
-        let parent_bounds = Rect::ZERO.with_size(my_size);
+        let parent_bounds = my_size.to_rect();
         let union_paint_rect = self
             .get_child_state(child)
             .paint_rect()
@@ -1092,7 +1107,7 @@ impl LayoutCtx<'_> {
         }
         if origin != self.get_child_state_mut(child).origin {
             self.get_child_state_mut(child).origin = origin;
-            self.get_child_state_mut(child).translation_changed = true;
+            self.get_child_state_mut(child).transform_changed = true;
         }
         self.get_child_state_mut(child)
             .is_expecting_place_child_call = false;
@@ -1133,7 +1148,7 @@ impl ComposeCtx<'_> {
         let child = self.get_child_state_mut(child);
         if translation != child.translation {
             child.translation = translation;
-            child.translation_changed = true;
+            child.transform_changed = true;
         }
     }
 }

masonry/src/event.rs

@@ -5,6 +5,7 @@
 
 use std::path::PathBuf;
 
+use vello::kurbo::Point;
 use winit::event::{Force, Ime, KeyEvent, Modifiers};
 use winit::keyboard::ModifiersState;
 
@@ -379,6 +380,12 @@ impl PointerEvent {
             PointerEvent::Pinch(_, _) => true,
         }
     }
+
+    // TODO Logical/PhysicalPosition as return type instead?
+    pub fn local_position(&self, ctx: &crate::EventCtx) -> Point {
+        let position = self.pointer_state().position;
+        ctx.widget_state.window_transform.inverse() * Point::new(position.x, position.y)
+    }
 }
 
 impl TextEvent {

masonry/src/passes/accessibility.rs

@@ -91,7 +91,7 @@ fn build_accessibility_tree(
 // --- MARK: BUILD NODE ---
 fn build_access_node(widget: &mut dyn Widget, ctx: &mut AccessCtx) -> Node {
     let mut node = Node::new(widget.accessibility_role());
-    node.set_bounds(to_accesskit_rect(ctx.widget_state.window_layout_rect()));
+    node.set_bounds(to_accesskit_rect(ctx.widget_state.bounding_rect()));
 
     node.set_children(
         widget

masonry/src/passes/compose.rs

@@ -3,7 +3,7 @@
 
 use tracing::info_span;
 use tree_arena::ArenaMut;
-use vello::kurbo::Vec2;
+use vello::kurbo::Affine;
 
 use crate::passes::{enter_span_if, recurse_on_children};
 use crate::render_root::{RenderRoot, RenderRootSignal, RenderRootState};
@@ -14,8 +14,8 @@ fn compose_widget(
     global_state: &mut RenderRootState,
     mut widget: ArenaMut<'_, Box<dyn Widget>>,
     mut state: ArenaMut<'_, WidgetState>,
-    parent_moved: bool,
-    parent_translation: Vec2,
+    parent_transformed: bool,
+    parent_window_transform: Affine,
 ) {
     let _span = enter_span_if(
         global_state.trace.compose,
@@ -24,14 +24,21 @@ fn compose_widget(
         state.reborrow(),
     );
 
-    let moved = parent_moved || state.item.translation_changed;
-    let translation = parent_translation + state.item.translation + state.item.origin.to_vec2();
-    state.item.window_origin = translation.to_point();
+    let transformed = parent_transformed || state.item.transform_changed;
 
-    if !parent_moved && !state.item.translation_changed && !state.item.needs_compose {
+    if !transformed && !state.item.needs_compose {
         return;
     }
 
+    let local_translation = state.item.translation + state.item.origin.to_vec2();
+
+    state.item.window_transform =
+        parent_window_transform * state.item.transform.then_translate(local_translation);
+    state.item.window_origin = state.item.window_transform.translation().to_point();
+
+    let local_rect = state.item.size.to_rect();
+    state.item.bounding_rect = state.item.window_transform.transform_rect_bbox(local_rect);
+
     let mut ctx = ComposeCtx {
         global_state,
         widget_state: state.item,
@@ -43,7 +50,7 @@ fn compose_widget(
     }
 
     // TODO - Add unit tests for this.
-    if moved && state.item.accepts_text_input && global_state.is_focused(state.item.id) {
+    if transformed && state.item.accepts_text_input && global_state.is_focused(state.item.id) {
         let ime_area = state.item.get_ime_area();
         global_state.emit_signal(RenderRootSignal::new_ime_moved_signal(ime_area));
     }
@@ -55,9 +62,10 @@ fn compose_widget(
 
     state.item.needs_compose = false;
     state.item.request_compose = false;
-    state.item.translation_changed = false;
+    state.item.transform_changed = false;
 
     let id = state.item.id;
+    let parent_transform = state.item.window_transform;
     let parent_state = state.item;
     recurse_on_children(
         id,
@@ -68,9 +76,10 @@ fn compose_widget(
                 global_state,
                 widget,
                 state.reborrow_mut(),
-                moved,
-                translation,
+                transformed,
+                parent_transform,
             );
+            parent_state.bounding_rect = parent_state.bounding_rect.union(state.item.bounding_rect);
             parent_state.merge_up(state.item);
         },
     );
@@ -92,6 +101,6 @@ pub(crate) fn run_compose_pass(root: &mut RenderRoot) {
         root_widget,
         root_state,
         false,
-        Vec2::ZERO,
+        Affine::IDENTITY,
     );
 }

masonry/src/passes/paint.rs

@@ -5,10 +5,10 @@ use std::collections::HashMap;
 
 use tracing::{info_span, trace};
 use tree_arena::ArenaMut;
-use vello::kurbo::{Affine, Stroke};
 use vello::peniko::Mix;
 use vello::Scene;
 
+use crate::paint_scene_helpers::stroke;
 use crate::passes::{enter_span_if, recurse_on_children};
 use crate::render_root::{RenderRoot, RenderRootState};
 use crate::theme::get_debug_color;
@@ -53,7 +53,7 @@ fn paint_widget(
 
     let clip = state.item.clip_path;
     let has_clip = clip.is_some();
-    let transform = Affine::translate(state.item.window_origin.to_vec2());
+    let transform = state.item.window_transform;
     let scene = scenes.get(&id).unwrap();
 
     if let Some(clip) = clip {
@@ -63,7 +63,7 @@ fn paint_widget(
     complete_scene.append(scene, Some(transform));
 
     let id = state.item.id;
-    let size = state.item.size;
+    let bounding_rect = state.item.bounding_rect;
     let parent_state = state.item;
     recurse_on_children(
         id,
@@ -93,9 +93,9 @@ fn paint_widget(
 
     if debug_paint {
         const BORDER_WIDTH: f64 = 1.0;
-        let rect = size.to_rect().inset(BORDER_WIDTH / -2.0);
         let color = get_debug_color(id.to_raw());
-        complete_scene.stroke(&Stroke::new(BORDER_WIDTH), transform, color, None, &rect);
+        let rect = bounding_rect.inset(BORDER_WIDTH / -2.0);
+        stroke(complete_scene, &rect, color, BORDER_WIDTH);
     }
 
     if has_clip {

masonry/src/testing/harness.rs

@@ -418,7 +418,7 @@ impl TestHarness {
     ///
     /// Combines [`mouse_move`](Self::mouse_move), [`mouse_button_press`](Self::mouse_button_press), and [`mouse_button_release`](Self::mouse_button_release).
     pub fn mouse_click_on(&mut self, id: WidgetId) {
-        let widget_rect = self.get_widget(id).ctx().window_layout_rect();
+        let widget_rect = self.get_widget(id).ctx().bounding_rect();
         let widget_center = widget_rect.center();
 
         self.mouse_move(widget_center);
@@ -430,7 +430,7 @@ impl TestHarness {
     pub fn mouse_move_to(&mut self, id: WidgetId) {
         // FIXME - handle case where the widget isn't visible
         // FIXME - assert that the widget correctly receives the event otherwise?
-        let widget_rect = self.get_widget(id).ctx().window_layout_rect();
+        let widget_rect = self.get_widget(id).ctx().bounding_rect();
         let widget_center = widget_rect.center();
 
         self.mouse_move(widget_center);

masonry/src/testing/helper_widgets.rs

@@ -16,7 +16,7 @@ use accesskit::{Node, Role};
 use smallvec::SmallVec;
 use tracing::trace_span;
 use vello::Scene;
-use widget::widget::get_child_at_pos;
+use widget::widget::{find_widget_at_pos, AsDynWidget as _};
 use widget::WidgetRef;
 
 use crate::event::{PointerEvent, TextEvent};
@@ -390,12 +390,18 @@ impl<S: 'static> Widget for ModularWidget<S> {
         CursorIcon::Default
     }
 
-    fn get_child_at_pos<'c>(
-        &self,
+    fn find_widget_at_pos<'c>(
+        &'c self,
         ctx: QueryCtx<'c>,
         pos: Point,
     ) -> Option<WidgetRef<'c, dyn Widget>> {
-        get_child_at_pos(self, ctx, pos)
+        find_widget_at_pos(
+            &WidgetRef {
+                widget: self.as_dyn(),
+                ctx,
+            },
+            pos,
+        )
     }
 
     fn type_name(&self) -> &'static str {
@@ -590,12 +596,12 @@ impl<W: Widget> Widget for Recorder<W> {
         self.child.get_cursor(ctx, pos)
     }
 
-    fn get_child_at_pos<'c>(
-        &self,
+    fn find_widget_at_pos<'c>(
+        &'c self,
         ctx: QueryCtx<'c>,
         pos: Point,
     ) -> Option<WidgetRef<'c, dyn Widget>> {
-        self.child.get_child_at_pos(ctx, pos)
+        self.child.find_widget_at_pos(ctx, pos)
     }
 
     fn type_name(&self) -> &'static str {

masonry/src/widget/button.rs

@@ -41,7 +41,7 @@ impl Button {
     ///
     /// let button = Button::new("Increment");
     /// ```
-    pub fn new(text: impl Into<ArcStr>) -> Button {
+    pub fn new(text: impl Into<ArcStr>) -> Self {
         Button::from_label(Label::new(text))
     }
 
@@ -56,7 +56,7 @@ impl Button {
     /// let label = Label::new("Increment").with_brush(Color::rgb(0.5, 0.5, 0.5));
     /// let button = Button::from_label(label);
     /// ```
-    pub fn from_label(label: Label) -> Button {
+    pub fn from_label(label: Label) -> Self {
         Button {
             label: WidgetPod::new(label),
         }

masonry/src/widget/flex.rs

@@ -1148,7 +1148,7 @@ impl Widget for Flex {
         // or be clipped (e.g. if its parent is a Portal).
         let my_size: Size = self.direction.pack(major, minor_dim).into();
 
-        let my_bounds = Rect::ZERO.with_size(my_size);
+        let my_bounds = my_size.to_rect();
         let insets = child_paint_rect - my_bounds;
         ctx.set_paint_insets(insets);
 

masonry/src/widget/mod.rs

@@ -56,6 +56,7 @@ pub use widget_pod::WidgetPod;
 pub use widget_ref::WidgetRef;
 
 pub(crate) use widget_arena::WidgetArena;
+pub(crate) use widget_pod::CreatedWidget;
 pub(crate) use widget_state::WidgetState;
 
 use crate::{Affine, Size};