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gpui/src/elements/canvas.rs

@@ -0,0 +1,73 @@
+use super::Element;
+use crate::PaintContext;
+use pathfinder_geometry::{
+    rect::RectF,
+    vector::{vec2f, Vector2F},
+};
+
+pub struct Canvas<F>(F)
+where
+    F: FnMut(RectF, &mut PaintContext);
+
+impl<F> Canvas<F>
+where
+    F: FnMut(RectF, &mut PaintContext),
+{
+    pub fn new(f: F) -> Self {
+        Self(f)
+    }
+}
+
+impl<F> Element for Canvas<F>
+where
+    F: FnMut(RectF, &mut PaintContext),
+{
+    type LayoutState = ();
+    type PaintState = ();
+
+    fn layout(
+        &mut self,
+        constraint: crate::SizeConstraint,
+        _: &mut crate::LayoutContext,
+    ) -> (Vector2F, Self::LayoutState) {
+        let x = if constraint.max.x().is_finite() {
+            constraint.max.x()
+        } else {
+            constraint.min.x()
+        };
+        let y = if constraint.max.y().is_finite() {
+            constraint.max.y()
+        } else {
+            constraint.min.y()
+        };
+        (vec2f(x, y), ())
+    }
+
+    fn paint(
+        &mut self,
+        bounds: RectF,
+        _: &mut Self::LayoutState,
+        ctx: &mut PaintContext,
+    ) -> Self::PaintState {
+        self.0(bounds, ctx)
+    }
+
+    fn after_layout(
+        &mut self,
+        _: Vector2F,
+        _: &mut Self::LayoutState,
+        _: &mut crate::AfterLayoutContext,
+    ) {
+    }
+
+    fn dispatch_event(
+        &mut self,
+        _: &crate::Event,
+        _: RectF,
+        _: &mut Self::LayoutState,
+        _: &mut Self::PaintState,
+        _: &mut crate::EventContext,
+    ) -> bool {
+        false
+    }
+}

gpui/src/elements/mod.rs

@@ -1,4 +1,5 @@
 mod align;
+mod canvas;
 mod constrained_box;
 mod container;
 mod empty;
@@ -13,6 +14,7 @@ mod uniform_list;
 
 pub use crate::presenter::ChildView;
 pub use align::*;
+pub use canvas::*;
 pub use constrained_box::*;
 pub use container::*;
 pub use empty::*;