X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=overlay_effect.h;h=4c6d37a4fea6d9a95715031426eb7332fcf73346;hp=121027a9f891aef043a735be1a7ff004097ee1e3;hb=7af4d1b54ba141fdb74cd13ddc6110708855d157;hpb=105717071781cb6ce338760937e43af29dcb228a

diff --git a/overlay_effect.h b/overlay_effect.h
index 121027a..4c6d37a 100644
--- a/overlay_effect.h
+++ b/overlay_effect.h
@@ -20,6 +20,13 @@ public:
 
 	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_
+	// 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; }
 };
 
 #endif // !defined(_OVERLAY_EFFECT_H)