+ virtual bool one_to_one_sampling() const { return true; }
+
+ // Actually, if _either_ image has blank alpha, our output will have
+ // blank alpha, too (this only tells the framework that having _both_
+ // images with blank alpha would result in blank alpha).
+ // However, understanding that would require changes
+ // to EffectChain, so postpone that optimization for later.
+ virtual AlphaHandling alpha_handling() const { return INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK; }
+
+private:
+ // If true, overlays input1 on top of input2 instead of vice versa.
+ // Must be set before finalize.
+ bool swap_inputs;