Add an effect for padding.

[movit] / padding_effect.h

diff --git a/padding_effect.h b/padding_effect.h
new file mode 100644 (file)
index 0000000..e9d4ce7
--- /dev/null
+++ b/padding_effect.h
@@ -0,0 +1,39 @@
+#ifndef _PADDING_EFFECT_H
+#define _PADDING_EFFECT_H 1
+
+// Takes an image and pads it to fit a larger image, or crops it to fit a smaller one
+// (although the latter is implemented slightly less efficiently, and you cannot both
+// pad and crop in the same effect).
+//
+// The source image is cut off at the texel borders (so there is no interpolation
+// outside them), and then given a user-specific color; by default, full transparent.
+//
+// The border color is taken to be in linear gamma, sRGB, with premultiplied alpha.
+// You may not change it after calling finalize(), since that could change the
+// graph (need_linear_light() etc. depend on the border color you choose).
+
+#include "effect.h"
+
+class PaddingEffect : public Effect {
+public:
+       PaddingEffect();
+       virtual std::string effect_type_id() const { return "PaddingEffect"; }
+       std::string output_fragment_shader();
+       void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);
+
+       virtual bool needs_linear_light() const;
+       virtual bool needs_srgb_primaries() const;
+       virtual AlphaHandling alpha_handling() const;
+       
+       virtual bool changes_output_size() const { return true; }
+       virtual void get_output_size(unsigned *width, unsigned *height) const;
+       virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height);
+
+private:
+       RGBATriplet border_color;
+       int input_width, input_height;
+       int output_width, output_height;
+       float top, left;
+};
+
+#endif // !defined(_PADDING_EFFECT_H)