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 signalGdk.Paintable::invalidate-contents signal.

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