Module retained_present 

Drawing for a presenter that keeps the desktop between frames.

Such a presenter rasterizes a strip once into a canvas as wide as its content and shows the strip’s pan by reading that canvas at an offset. The strip is then drawn in canvas coordinates: where its windows sit with no pan, so the encoded scene does not change while the pan does, and a pan draws nothing.

Structs

RetainedScene

Restores the enclosing draw policy even on an early return or unwind.

Functions

begin_retained_scene

Start drawing one frame for such a presenter. unbake_scroll draws strip content in canvas coordinates. The flag is thread-local and cleared by end_retained_scene.

end_retained_scene

The frame is drawn.

unbake_scroll

Whether strip content should be drawn in canvas coordinates.