/usr/lib/libreoffice/program/opengl/areaScaleFragmentShader.glsl is in libreoffice-common 1:5.1.2-0ubuntu1.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 | /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#version 120
#if __VERSION__ < 130
int min( int a, int b ) { return a < b ? a : b; }
float min( float a, float b ) { return a < b ? a : b; }
#endif
/* TODO Use textureOffset for newest version of GLSL */
uniform sampler2D sampler;
uniform int swidth;
uniform int sheight;
uniform float xscale;
uniform float yscale;
uniform float xsrcconvert;
uniform float ysrcconvert;
uniform float xdestconvert;
uniform float ydestconvert;
varying vec2 tex_coord;
// This mode makes the scaling work like maskedTextureFragmentShader.glsl
// (instead of like plain textureVertexShader.glsl).
#ifdef MASKED
varying vec2 mask_coord;
uniform sampler2D mask;
#endif
void main(void)
{
// Convert to pixel coordinates again.
int dx = int( tex_coord.s * xdestconvert );
int dy = int( tex_coord.t * ydestconvert );
// Note: These values are always the same for the same X (or Y),
// so they could be precalculated in C++ and passed to the shader,
// but GLSL has limits on the size of uniforms passed to it,
// so it'd need something like texture buffer objects from newer
// GLSL versions, and it seems the hassle is not really worth it.
// How much each column/row will contribute to the resulting pixel.
// assert( xscale <= 100 ); assert( yscale <= 100 );
float xratio[ 100 + 2 ];
float yratio[ 100 + 2 ];
// For finding the first and last source pixel.
int xpixel[ 100 + 2 ];
int ypixel[ 100 + 2 ];
int xpos = 0;
int ypos = 0;
// Compute the range of source pixels which will make up this destination pixel.
float fsx1 = dx * xscale;
float fsx2 = fsx1 + xscale;
// To whole pixel coordinates.
int sx1 = int( ceil( fsx1 ) );
int sx2 = int( floor( fsx2 ) );
// Range checking.
sx2 = min( sx2, swidth - 1 );
sx1 = min( sx1, sx2 );
// How much one full column contributes to the resulting pixel.
float width = min( xscale, swidth - fsx1 );
if( sx1 - fsx1 > 0.001 )
{ // The first column contributes only partially.
xpixel[ xpos ] = sx1 - 1;
xratio[ xpos ] = ( sx1 - fsx1 ) / width;
++xpos;
}
for( int sx = sx1; sx < sx2; ++sx )
{ // Columns that fully contribute to the resulting pixel.
xpixel[ xpos ] = sx;
xratio[ xpos ] = 1.0 / width;
++xpos;
}
if( fsx2 - sx2 > 0.001 )
{ // The last column contributes only partially.
xpixel[ xpos ] = sx2;
xratio[ xpos ] = min( min( fsx2 - sx2, 1.0 ) / width, 1.0 );
++xpos;
}
// The same for Y.
float fsy1 = dy * yscale;
float fsy2 = fsy1 + yscale;
int sy1 = int( ceil( fsy1 ) );
int sy2 = int( floor( fsy2 ) );
sy2 = min( sy2, sheight - 1 );
sy1 = min( sy1, sy2 );
float height = min( yscale, sheight - fsy1 );
if( sy1 - fsy1 > 0.001 )
{
ypixel[ ypos ] = sy1 - 1;
yratio[ ypos ] = ( sy1 - fsy1 ) / height;
++ypos;
}
for( int sy = sy1; sy < sy2; ++sy )
{
ypixel[ ypos ] = sy;
yratio[ ypos ] = 1.0 / height;
++ypos;
}
if( fsy2 - sy2 > 0.001 )
{
ypixel[ ypos ] = sy2;
yratio[ ypos ] = min( min( fsy2 - sy2, 1.0 ) / height, 1.0 );
++ypos;
}
int xstart = xpixel[ 0 ];
int xend = xpixel[ xpos - 1 ];
int ystart = ypixel[ 0 ];
int yend = ypixel[ ypos - 1 ];
vec4 sum = vec4( 0.0, 0.0, 0.0, 0.0 );
ypos = 0;
for( int y = ystart; y <= yend; ++y, ++ypos )
{
vec4 tmp = vec4( 0.0, 0.0, 0.0, 0.0 );
xpos = 0;
for( int x = xstart; x <= xend; ++x, ++xpos )
{
vec2 offset = vec2( x * xsrcconvert, y * ysrcconvert );
#ifndef MASKED
tmp += texture2D( sampler, offset ) * xratio[ xpos ];
#else
vec4 texel;
texel = texture2D( sampler, offset );
texel.a = 1.0 - texture2D( mask, offset ).r;
tmp += texel * xratio[ xpos ];
#endif
}
sum += tmp * yratio[ ypos ];
}
gl_FragColor = sum;
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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