/usr/include/movit/resample_effect.h is in libmovit-dev 1.1.2-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 | #ifndef _MOVIT_RESAMPLE_EFFECT_H
#define _MOVIT_RESAMPLE_EFFECT_H 1
// High-quality image resizing, either up or down.
//
// The default scaling offered by the GPU (and as used in ResizeEffect)
// is bilinear (optionally mipmapped), which is not the highest-quality
// choice, especially for upscaling. ResampleEffect offers the three-lobed
// Lanczos kernel, which is among the most popular choices in image
// processing. While it does have its weaknesses, in particular a certain
// ringing/sharpening effect with artifacts that accumulate over several
// consecutive resizings, it is generally regarded as the best tradeoff.
//
// Works in two passes; first horizontal, then vertical (ResampleEffect,
// which is what the user is intended to use, instantiates two copies of
// SingleResamplePassEffect behind the scenes).
#include <epoxy/gl.h>
#include <assert.h>
#include <stddef.h>
#include <string>
#include "effect.h"
namespace movit {
class EffectChain;
class Node;
class SingleResamplePassEffect;
class ResampleEffect : public Effect {
public:
ResampleEffect();
virtual std::string effect_type_id() const { return "ResampleEffect"; }
// We want this for the same reason as ResizeEffect; we could end up scaling
// down quite a lot.
virtual bool needs_texture_bounce() const { return true; }
virtual bool needs_srgb_primaries() const { return false; }
virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height);
virtual std::string output_fragment_shader() {
assert(false);
}
virtual void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num) {
assert(false);
}
virtual void rewrite_graph(EffectChain *graph, Node *self);
virtual bool set_float(const std::string &key, float value);
private:
void update_size();
void update_offset_and_zoom();
SingleResamplePassEffect *hpass, *vpass;
int input_width, input_height, output_width, output_height;
float offset_x, offset_y;
float zoom_x, zoom_y;
float zoom_center_x, zoom_center_y;
};
class SingleResamplePassEffect : public Effect {
public:
// If parent is non-NULL, calls to inform_input_size will be forwarded,
// so that it can inform both passes about the right input and output
// resolutions.
SingleResamplePassEffect(ResampleEffect *parent);
~SingleResamplePassEffect();
virtual std::string effect_type_id() const { return "SingleResamplePassEffect"; }
std::string output_fragment_shader();
virtual bool needs_texture_bounce() const { return true; }
virtual bool needs_srgb_primaries() const { return false; }
virtual AlphaHandling alpha_handling() const { return INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK; }
virtual void inform_added(EffectChain *chain) { this->chain = chain; }
virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height) {
if (parent != NULL) {
parent->inform_input_size(input_num, width, height);
}
}
virtual bool changes_output_size() const { return true; }
virtual void get_output_size(unsigned *width, unsigned *height, unsigned *virtual_width, unsigned *virtual_height) const {
*virtual_width = *width = this->output_width;
*virtual_height = *height = this->output_height;
}
void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);
enum Direction { HORIZONTAL = 0, VERTICAL = 1 };
private:
void update_texture(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);
ResampleEffect *parent;
EffectChain *chain;
Direction direction;
GLuint texnum;
int input_width, input_height, output_width, output_height;
float offset, zoom;
int last_input_width, last_input_height, last_output_width, last_output_height;
float last_offset, last_zoom;
int src_bilinear_samples, num_loops;
float slice_height;
};
} // namespace movit
#endif // !defined(_MOVIT_RESAMPLE_EFFECT_H)
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