In ResampleEffect, precompute the Lanczos function into a table.

[movit] / overlay_effect.h

diff --git a/overlay_effect.h b/overlay_effect.h
index 06ff7939128257e9ccc006e3076b3e91b29aaeb5..c11569f4eec6c34e0eea4e169ee51b6142fef637 100644 (file)
--- a/overlay_effect.h
+++ b/overlay_effect.h
@@ -1,17 +1,21 @@
-#ifndef _OVERLAY_EFFECT_H
-#define _OVERLAY_EFFECT_H 1
+#ifndef _MOVIT_OVERLAY_EFFECT_H
+#define _MOVIT_OVERLAY_EFFECT_H 1
 
 // 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
 // for all pixels, you will not see anything of the one on the bottom.)
 //
-// This is the “atop” operation from Porter-Duff blending, also used
+// This is the “over” operation from Porter-Duff blending, also used
 // when merging layers in e.g. GIMP or Photoshop.
 //
 // The first input is the bottom, and the second is the top.
 
+#include <string>
+
 #include "effect.h"
 
+namespace movit {
+
 class OverlayEffect : public Effect {
 public:
        OverlayEffect();
@@ -20,6 +24,16 @@ public:
 
        virtual bool needs_srgb_primaries() const { return false; }
        virtual unsigned num_inputs() const { return 2; }
+       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; }
 };
 
-#endif // !defined(_OVERLAY_EFFECT_H)
+}  // namespace movit
+
+#endif // !defined(_MOVIT_OVERLAY_EFFECT_H)