// Put one image on top of another, using alpha where appropriate.
// (If both images are the same aspect and the top image has alpha=1.0
// Put one image on top of another, using alpha where appropriate.
// (If both images are the same aspect and the top image has alpha=1.0
virtual bool needs_srgb_primaries() const { return false; }
virtual unsigned num_inputs() const { return 2; }
virtual bool needs_srgb_primaries() const { return false; }
virtual unsigned num_inputs() const { return 2; }
// Actually, if _either_ image has blank alpha, our output will have
// blank alpha, too (this only tells the framework that having _both_
// Actually, if _either_ image has blank alpha, our output will have
// blank alpha, too (this only tells the framework that having _both_