Function transform_clip_rect 

pub fn transform_clip_rect(m: [f32; 6], r: Rect) -> Rect

Maps clip rect r (in the currently-active transform’s local space) to window space — the axis-aligned bounds of its four mapped corners. Widgets emit clip rects in their own local space, but the renderer clips in window space, so a clip must be mapped through the active cumulative matrix (scroll/layout translations) to compose correctly.