Struct PaintParts 

pub struct PaintParts { /* private fields */ }

A self-drawn widget’s draw, split into the parts of a PaintFrame as it paints: each part is drawn on its own, appended to the scene the widget paints in, and kept for the comparison with the last frame. A widget that paints its regions by hand (a timeline, a composer, a side panel) thereby reports the regions whose drawing changed, without tracking what each event touched.

Everything the widget paints must be in a part: ink added to the scene between parts is not compared, so the frame then proves nothing (Self::finish gives no frame).

Implementations

impl PaintParts

pub fn new(scene: &Scene) -> PaintParts

Start splitting the draw into scene, whatever it holds already.

pub fn draw<R>( &mut self, scene: &mut Scene, key: impl Into<Cow<'static, str>>, bounds: Rect, draw: impl FnOnce(&mut Scene) -> R, ) -> R

Draw the part key, whose bounds (logical, as the widget’s rect) cover every pixel draw paints, antialiasing and shadows included: a change inside it repaints where it was and is.

pub fn draw_bounded<R>( &mut self, scene: &mut Scene, key: impl Into<Cow<'static, str>>, draw: impl FnOnce(&mut Scene) -> (Rect, R), ) -> R

Self::draw for a part whose bounds its drawing decides (a bar that measures itself as it paints): draw returns them with its result.

pub fn finish( self, scene: &Scene, geometry: Vec<Rect>, transform: Affine, theme: &Theme, ) -> Option<PaintFrame>

The frame drawn, with the geometry, transform and theme it was drawn with; None when something was painted outside every part.