Support pad/crop from bottom, not just from the top.

[movit] / padding_effect.cpp

diff --git a/padding_effect.cpp b/padding_effect.cpp
index 15381a32567e7bdd6ffed157c8aea6b52cdf4aff..a70025d015475f885a9841d96e40c08fe3ac762e 100644 (file)
--- a/padding_effect.cpp
+++ b/padding_effect.cpp
@@ -14,13 +14,15 @@ PaddingEffect::PaddingEffect()
          output_width(1280),
          output_height(720),
          top(0),
-         left(0)
+         left(0),
+         pad_from_bottom(0)
 {
        register_vec4("border_color", (float *)&border_color);
        register_int("width", &output_width);
        register_int("height", &output_height);
        register_float("top", &top);
        register_float("left", &left);
+       register_int("pad_from_bottom", &pad_from_bottom);
 }
 
 string PaddingEffect::output_fragment_shader()
@@ -32,10 +34,13 @@ void PaddingEffect::set_gl_state(GLuint glsl_program_num, const string &prefix,
 {
        Effect::set_gl_state(glsl_program_num, prefix, sampler_num);
 
-       float offset[2] = {
-               left / output_width,
-               (output_height - input_height - top) / output_height
-       };
+       float offset[2];
+       offset[0] = left / output_width;
+       if (pad_from_bottom) {
+               offset[1] = top / output_height;
+       } else {
+               offset[1] = (output_height - input_height - top) / output_height;
+       }
        set_uniform_vec2(glsl_program_num, prefix, "offset", offset);
 
        float scale[2] = {