Initial dirty hack to get transforms per widget working

masonry/src/contexts.rs

@@ -538,6 +538,12 @@ 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");
@@ -1093,7 +1099,7 @@ 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;
@@ -1134,7 +1140,7 @@ 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/passes/compose.rs

@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 use tracing::info_span;
-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 +24,17 @@ 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;
     }
 
+    state.item.window_transform = parent_window_transform
+        .then_translate(state.item.translation + state.item.origin.to_vec2())
+        * widget.item.transform();
+    state.item.window_origin = state.item.window_transform.translation().to_point();
+
     let mut ctx = ComposeCtx {
         global_state,
         widget_state: state.item,
@@ -43,7 +46,7 @@ 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 +58,10 @@ 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,
@@ -68,8 +72,8 @@ fn compose_widget(
                 global_state,
                 widget,
                 state.reborrow_mut(),
-                moved,
-                translation,
+                transformed,
+                parent_transform,
             );
             parent_state.merge_up(state.item);
         },
@@ -92,6 +96,6 @@ pub(crate) fn run_compose_pass(root: &mut RenderRoot) {
         root_widget,
         root_state,
         false,
-        Vec2::ZERO,
+        Affine::IDENTITY,
     );
 }

masonry/src/passes/paint.rs

@@ -4,7 +4,7 @@
 use std::collections::HashMap;
 
 use tracing::{info_span, trace};
-use vello::kurbo::{Affine, Stroke};
+use vello::kurbo::Stroke;
 use vello::peniko::Mix;
 use vello::Scene;
 
@@ -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 {

masonry/src/testing/helper_widgets.rs

@@ -413,6 +413,10 @@ impl<S: 'static> Widget for ModularWidget<S> {
     fn as_mut_any(&mut self) -> &mut dyn std::any::Any {
         self.as_mut_dyn_any()
     }
+
+    fn transform(&self) -> Affine {
+        Affine::IDENTITY
+    }
 }
 
 impl ReplaceChild {
@@ -613,4 +617,8 @@ impl<W: Widget> Widget for Recorder<W> {
     fn as_mut_any(&mut self) -> &mut dyn std::any::Any {
         self.child.as_mut_any()
     }
+
+    fn transform(&self) -> Affine {
+        self.child.transform()
+    }
 }

masonry/src/widget/button.rs

@@ -6,6 +6,7 @@
 use accesskit::{Node, Role};
 use smallvec::{smallvec, SmallVec};
 use tracing::{trace, trace_span, Span};
+use vello::kurbo::Affine;
 use vello::Scene;
 
 use crate::action::Action;
@@ -28,6 +29,7 @@ const LABEL_INSETS: Insets = Insets::uniform_xy(8., 2.);
 /// Emits [`Action::ButtonPressed`] when pressed.
 pub struct Button {
     label: WidgetPod<Label>,
+    transform: Affine,
 }
 
 // --- MARK: BUILDERS ---
@@ -41,7 +43,7 @@ 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))
     }
 
@@ -56,11 +58,17 @@ 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),
+            transform: Affine::IDENTITY,
         }
     }
+
+    pub fn with_transform(mut self, transform: Affine) -> Self {
+        self.transform = transform;
+        self
+    }
 }
 
 // --- MARK: WIDGETMUT ---
@@ -73,6 +81,11 @@ impl Button {
     pub fn label_mut<'t>(this: &'t mut WidgetMut<'_, Self>) -> WidgetMut<'t, Label> {
         this.ctx.get_mut(&mut this.widget.label)
     }
+
+    pub fn set_transform(this: &mut WidgetMut<'_, Self>, transform: Affine) {
+        this.widget.transform = transform;
+        this.ctx.transform_changed();
+    }
 }
 
 // --- MARK: IMPL WIDGET ---
@@ -213,6 +226,10 @@ impl Widget for Button {
     fn get_debug_text(&self) -> Option<String> {
         Some(self.label.as_ref().text().as_ref().to_string())
     }
+
+    fn transform(&self) -> Affine {
+        self.transform
+    }
 }
 
 // --- MARK: TESTS ---

masonry/src/widget/flex.rs

@@ -21,6 +21,7 @@ use crate::{
 /// This widget is the foundation of most layouts, and is highly configurable.
 pub struct Flex {
     direction: Axis,
+    transform: Affine,
     cross_alignment: CrossAxisAlignment,
     main_alignment: MainAxisAlignment,
     fill_major_axis: bool,
@@ -128,6 +129,7 @@ impl Flex {
             fill_major_axis: false,
             old_bc: BoxConstraints::tight(Size::ZERO),
             gap: None,
+            transform: Affine::IDENTITY,
         }
     }
 
@@ -165,6 +167,11 @@ impl Flex {
         self
     }
 
+    pub fn with_transform(mut self, transform: Affine) -> Self {
+        self.transform = transform;
+        self
+    }
+
     /// Builder-style method for setting the spacing along the
     /// major axis between any two elements in logical pixels.
     ///
@@ -328,6 +335,12 @@ impl Flex {
         this.ctx.request_layout();
     }
 
+    /// Set the transform (see [`Affine`]).
+    pub fn set_transform(this: &mut WidgetMut<'_, Self>, transform: Affine) {
+        this.widget.transform = transform;
+        this.ctx.transform_changed();
+    }
+
     /// Set the spacing along the major axis between any two elements in logical pixels.
     ///
     /// Equivalent to the css [gap] property.
@@ -1204,6 +1217,10 @@ impl Widget for Flex {
     fn make_trace_span(&self, ctx: &QueryCtx<'_>) -> Span {
         trace_span!("Flex", id = ctx.widget_id().trace())
     }
+
+    fn transform(&self) -> Affine {
+        self.transform
+    }
 }
 
 // --- MARK: TESTS ---

masonry/src/widget/widget.rs

@@ -12,6 +12,7 @@ use cursor_icon::CursorIcon;
 use smallvec::SmallVec;
 use tracing::field::DisplayValue;
 use tracing::{trace_span, Span};
+use vello::kurbo::Affine;
 use vello::Scene;
 
 use crate::contexts::ComposeCtx;
@@ -178,6 +179,10 @@ pub trait Widget: AsAny {
     /// responsible for visiting all their children during `layout` and `register_children`.
     fn children_ids(&self) -> SmallVec<[WidgetId; 16]>;
 
+    fn transform(&self) -> Affine {
+        Affine::IDENTITY
+    }
+
     /// Whether this widget gets pointer events and hovered status. True by default.
     ///
     /// If false, the widget will be treated as "transparent" for the pointer, meaning
@@ -308,10 +313,10 @@ pub(crate) fn get_child_at_pos<'c>(
     ctx: QueryCtx<'c>,
     pos: Point,
 ) -> Option<WidgetRef<'c, dyn Widget>> {
-    let relative_pos = pos - ctx.window_origin().to_vec2();
+    let local_pos = ctx.widget_state.window_transform.inverse() * pos;
     if !ctx
         .clip_path()
-        .map_or(true, |clip| clip.contains(relative_pos))
+        .map_or(true, |clip| clip.contains(local_pos))
     {
         return None;
     }
@@ -320,12 +325,13 @@ pub(crate) fn get_child_at_pos<'c>(
     // of overlapping children.
     for child_id in widget.children_ids().iter().rev() {
         let child = ctx.get(*child_id);
+        let local_pos = child.ctx().widget_state.window_transform.inverse() * pos;
 
         // The position must be inside the child's layout and inside the child's clip path (if
         // any).
         if !child.ctx().is_stashed()
             && child.ctx().accepts_pointer_interaction()
-            && child.ctx().window_layout_rect().contains(pos)
+            && child.ctx().size().to_rect().contains(local_pos)
         {
             return Some(child);
         }
@@ -507,4 +513,8 @@ impl Widget for Box<dyn Widget> {
     fn as_mut_any(&mut self) -> &mut dyn Any {
         self.deref_mut().as_mut_any()
     }
+
+    fn transform(&self) -> Affine {
+        self.deref().transform()
+    }
 }

masonry/src/widget/widget_ref.rs

@@ -165,9 +165,10 @@ impl<'w> WidgetRef<'w, dyn Widget> {
     /// **pos** - the position in global coordinates (e.g. `(0,0)` is the top-left corner of the
     /// window).
     pub fn find_widget_at_pos(&self, pos: Point) -> Option<WidgetRef<'_, dyn Widget>> {
+        let local_pos = self.ctx.widget_state.window_transform.inverse() * pos;
         let mut innermost_widget = *self;
 
-        if !self.ctx.window_layout_rect().contains(pos) {
+        if !self.ctx.size().to_rect().contains(local_pos) {
             return None;
         }
 

masonry/src/widget/widget_state.rs

@@ -3,7 +3,7 @@
 
 #![cfg(not(tarpaulin_include))]
 
-use vello::kurbo::{Insets, Point, Rect, Size, Vec2};
+use vello::kurbo::{Affine, Insets, Point, Rect, Size, Vec2};
 
 use crate::WidgetId;
 
@@ -79,9 +79,11 @@ pub(crate) struct WidgetState {
     // efficiently hold an arbitrary shape.
     pub(crate) clip_path: Option<Rect>,
 
-    // TODO - Handle matrix transforms
+    /// This is being computed out of the descendant transforms and `translation`
+    pub(crate) window_transform: Affine,
+    // TODO - Handle matrix transforms correctly
     pub(crate) translation: Vec2,
-    pub(crate) translation_changed: bool,
+    pub(crate) transform_changed: bool,
 
     // --- PASSES ---
     /// `WidgetAdded` hasn't been sent to this widget yet.
@@ -166,7 +168,7 @@ impl WidgetState {
             ime_area: None,
             clip_path: Default::default(),
             translation: Vec2::ZERO,
-            translation_changed: false,
+            transform_changed: false,
             is_explicitly_disabled: false,
             is_explicitly_stashed: false,
             is_disabled: false,
@@ -192,6 +194,7 @@ impl WidgetState {
             update_focus_chain: true,
             #[cfg(debug_assertions)]
             widget_name,
+            window_transform: Affine::IDENTITY,
         }
     }
 
@@ -265,6 +268,7 @@ impl WidgetState {
     ///
     /// By default, returns the same as [`Self::window_layout_rect`].
     pub(crate) fn get_ime_area(&self) -> Rect {
+        // TODO correctly calculate IME area based on transform
         self.ime_area.unwrap_or_else(|| self.size.to_rect()) + self.window_origin.to_vec2()
     }