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1
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2 /* Bring up a window and manipulate the gamma on it */
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3
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4 #include <stdlib.h>
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5 #include <stdio.h>
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6 #include <string.h>
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7 #include <math.h>
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8
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9 #include "SDL.h"
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10
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11 /* Turn a normal gamma value into an appropriate gamma ramp */
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12 void CalculateGamma(double gamma, Uint16 *ramp)
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13 {
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14 int i, value;
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15
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16 gamma = 1.0 / gamma;
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17 for ( i=0; i<256; ++i ) {
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18 value = (int)(pow((double)i/256.0, gamma)*65535.0 + 0.5);
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19 if ( value > 65535 ) {
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20 value = 65535;
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21 }
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22 ramp[i] = (Uint16)value;
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23 }
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24 }
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25
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26 /* This can be used as a general routine for all of the test programs */
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27 int get_video_args(char *argv[], int *w, int *h, int *bpp, Uint32 *flags)
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28 {
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29 int i;
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30
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31 *w = 640;
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32 *h = 480;
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33 *bpp = 0;
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34 *flags = SDL_SWSURFACE;
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35
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36 for ( i=1; argv[i]; ++i ) {
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37 if ( strcmp(argv[i], "-width") == 0 ) {
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38 if ( argv[i+1] ) {
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39 *w = atoi(argv[++i]);
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40 }
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41 } else
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42 if ( strcmp(argv[i], "-height") == 0 ) {
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43 if ( argv[i+1] ) {
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44 *h = atoi(argv[++i]);
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45 }
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46 } else
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47 if ( strcmp(argv[i], "-bpp") == 0 ) {
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48 if ( argv[i+1] ) {
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49 *bpp = atoi(argv[++i]);
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50 }
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51 } else
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52 if ( strcmp(argv[i], "-fullscreen") == 0 ) {
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53 *flags |= SDL_FULLSCREEN;
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54 } else
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55 if ( strcmp(argv[i], "-hw") == 0 ) {
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56 *flags |= SDL_HWSURFACE;
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57 } else
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58 if ( strcmp(argv[i], "-hwpalette") == 0 ) {
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59 *flags |= SDL_HWPALETTE;
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60 } else
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61 break;
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62 }
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63 return i;
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64 }
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65
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66 int main(int argc, char *argv[])
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67 {
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68 SDL_Surface *screen;
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69 SDL_Surface *image;
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70 float gamma;
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71 int i;
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72 int w, h, bpp;
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73 Uint32 flags;
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74 Uint16 ramp[256];
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75 Uint16 red_ramp[256];
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76 Uint32 then, timeout;
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77
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78 /* Check command line arguments */
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79 argv += get_video_args(argv, &w, &h, &bpp, &flags);
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80
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81 /* Initialize SDL */
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82 if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
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83 fprintf(stderr,
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84 "Couldn't initialize SDL: %s\n", SDL_GetError());
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85 exit(1);
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86 }
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87 atexit(SDL_Quit);
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88
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89 /* Initialize the display, always use hardware palette */
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90 screen = SDL_SetVideoMode(w, h, bpp, flags | SDL_HWPALETTE);
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91 if ( screen == NULL ) {
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92 fprintf(stderr, "Couldn't set %dx%d video mode: %s\n",
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93 w, h, SDL_GetError());
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94 exit(1);
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95 }
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96
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97 /* Set the window manager title bar */
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98 SDL_WM_SetCaption("SDL gamma test", "testgamma");
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99
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100 /* Set the desired gamma, if any */
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101 gamma = 1.0f;
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102 if ( *argv ) {
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103 gamma = (float)atof(*argv);
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104 }
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105 if ( SDL_SetGamma(gamma, gamma, gamma) < 0 ) {
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106 fprintf(stderr, "Unable to set gamma: %s\n", SDL_GetError());
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107 exit(1);
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108 }
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109
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110 #if 0 /* This isn't supported. Integrating the gamma ramps isn't exact */
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111 /* See what gamma was actually set */
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112 float real[3];
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113 if ( SDL_GetGamma(&real[0], &real[1], &real[2]) < 0 ) {
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114 printf("Couldn't get gamma: %s\n", SDL_GetError());
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115 } else {
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116 printf("Set gamma values: R=%2.2f, G=%2.2f, B=%2.2f\n",
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117 real[0], real[1], real[2]);
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118 }
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119 #endif
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120
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121 /* Do all the drawing work */
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122 image = SDL_LoadBMP("sample.bmp");
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123 if ( image ) {
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124 SDL_Rect dst;
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125
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126 dst.x = (screen->w - image->w)/2;
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127 dst.y = (screen->h - image->h)/2;
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128 dst.w = image->w;
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129 dst.h = image->h;
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130 SDL_BlitSurface(image, NULL, screen, &dst);
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131 SDL_UpdateRects(screen, 1, &dst);
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132 }
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133
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134 /* Wait a bit, handling events */
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135 then = SDL_GetTicks();
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136 timeout = (5*1000);
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137 while ( (SDL_GetTicks()-then) < timeout ) {
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138 SDL_Event event;
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139
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140 while ( SDL_PollEvent(&event) ) {
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141 switch (event.type) {
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142 case SDL_QUIT: /* Quit now */
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143 timeout = 0;
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144 break;
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145 case SDL_KEYDOWN:
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146 switch (event.key.keysym.sym) {
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147 case SDLK_SPACE: /* Go longer.. */
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148 timeout += (5*1000);
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149 break;
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150 case SDLK_UP:
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151 gamma += 0.2f;
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152 SDL_SetGamma(gamma, gamma, gamma);
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153 break;
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154 case SDLK_DOWN:
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155 gamma -= 0.2f;
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156 SDL_SetGamma(gamma, gamma, gamma);
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157 break;
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158 case SDLK_ESCAPE:
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159 timeout = 0;
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160 break;
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161 default:
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162 break;
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163 }
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164 break;
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165 }
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166 }
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167 }
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168
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169 /* Perform a gamma flash to red using color ramps */
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170 while ( gamma < 10.0 ) {
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171 /* Increase the red gamma and decrease everything else... */
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172 gamma += 0.1f;
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173 CalculateGamma(gamma, red_ramp);
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174 CalculateGamma(1.0/gamma, ramp);
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175 SDL_SetGammaRamp(red_ramp, ramp, ramp);
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176 }
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177 /* Finish completely red */
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178 memset(red_ramp, 255, sizeof(red_ramp));
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179 memset(ramp, 0, sizeof(ramp));
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180 SDL_SetGammaRamp(red_ramp, ramp, ramp);
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181
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182 /* Now fade out to black */
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183 for ( i=(red_ramp[0] >> 8); i >= 0; --i ) {
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184 memset(red_ramp, i, sizeof(red_ramp));
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185 SDL_SetGammaRamp(red_ramp, NULL, NULL);
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186 }
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187 SDL_Delay(1*1000);
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188
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189 return(0);
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190 }
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