Blends together two images with the given blend mode.
Until the first call to [method@Gtk.Snapshot.pop], the
bottom image for the blend operation will be recorded.
After that call, the top image to be blended will be
recorded until the second call to [method@Gtk.Snapshot.pop].
Calling this function requires two subsequent calls
to [method@Gtk.Snapshot.pop].
Blends together two images with the given blend mode.
Until the first call to [method@Gtk.Snapshot.pop], the bottom image for the blend operation will be recorded. After that call, the top image to be blended will be recorded until the second call to [method@Gtk.Snapshot.pop].
Calling this function requires two subsequent calls to [method@Gtk.Snapshot.pop].