invalidateContents

Called by implementations of GdkPaintable to invalidate their contents.

Unless the contents are invalidated, implementations must guarantee that multiple calls of method@Gdk.Paintable.snapshot produce the same output.

This function will emit the signal@Gdk.Paintable::invalidate-contents signal.

If a @paintable reports the %GDK_PAINTABLE_STATIC_CONTENTS flag, it must not call this function.