Paintable.invalidateContents

Called by implementations of gdk.paintable.Paintable to invalidate their contents.

Unless the contents are invalidated, implementations must guarantee that multiple calls of gdk.paintable.Paintable.snapshot produce the same output.

This function will emit the gdk.paintable.Paintable.invalidateContents signal.

If a paintable reports the gdk.types.PaintableFlags.Contents flag, it must not call this function.