1 | /* |
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2 | * paypal.c: decode Paypal captchas |
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3 | * $Id: paypal.c 457 2005-01-12 16:33:03Z sam $ |
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4 | * |
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5 | * Copyright: (c) 2005 Sam Hocevar <sam@zoy.org> |
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6 | * This program is free software; you can redistribute it and/or |
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7 | * modify it under the terms of the Do What The Fuck You Want To |
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8 | * Public License as published by Banlu Kemiyatorn. See |
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9 | * http://sam.zoy.org/projects/COPYING.WTFPL for more details. |
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10 | */ |
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11 | |
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12 | #include <stdio.h> |
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13 | #include <stdlib.h> |
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14 | #include <string.h> |
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15 | #include <limits.h> |
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16 | |
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17 | #include "config.h" |
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18 | #include "common.h" |
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19 | |
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20 | static void find_glyphs(struct image *img); |
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21 | |
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22 | /* Our macros */ |
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23 | char *result; |
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24 | |
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25 | /* Main function */ |
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26 | char *decode_paypal(struct image *img) |
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27 | { |
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28 | struct image *tmp; |
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29 | |
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30 | /* paypal captchas have 8 characters */ |
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31 | result = malloc(9 * sizeof(char)); |
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32 | strcpy(result, " "); |
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33 | |
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34 | tmp = image_dup(img); |
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35 | find_glyphs(tmp); |
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36 | |
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37 | image_free(tmp); |
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38 | |
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39 | return result; |
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40 | } |
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41 | |
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42 | static void find_glyphs(struct image *img) |
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43 | { |
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44 | #define DELTA 2 |
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45 | #define FONTS 2 |
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46 | static struct font *fonts[FONTS]; |
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47 | static char *files[] = |
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48 | { |
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49 | "font_stencil_23_AZ.bmp", "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ", |
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50 | "font_stencil_24_AZ.bmp", "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ", |
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51 | }; |
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52 | int x, y, i = 0, f; |
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53 | int r, g, b; |
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54 | int xmin, xmax, ymin, ymax, startx = 0, cur = 0; |
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55 | int bestdist, bestfont, bestx, besty, bestch; |
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56 | |
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57 | for(f = 0; f < FONTS; f++) |
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58 | { |
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59 | if(!fonts[f]) |
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60 | { |
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61 | fonts[f] = font_load_variable(files[f * 2], files[f * 2 + 1]); |
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62 | if(!fonts[f]) |
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63 | exit(1); |
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64 | } |
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65 | } |
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66 | |
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67 | while(cur < 8) |
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68 | { |
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69 | /* Try to find 1st letter */ |
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70 | bestdist = INT_MAX; |
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71 | for(f = 0; f < FONTS; f++) for(i = 0; i < fonts[f]->size; i++) |
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72 | { |
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73 | int localmin = INT_MAX, localx, localy; |
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74 | xmin = fonts[f]->glyphs[i].xmin - DELTA; |
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75 | ymin = fonts[f]->glyphs[i].ymin; |
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76 | xmax = fonts[f]->glyphs[i].xmax + DELTA; |
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77 | ymax = fonts[f]->glyphs[i].ymax; |
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78 | for(y = -3; y < 1; y++) |
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79 | { |
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80 | for(x = startx; x < startx + 15; x++) |
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81 | { |
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82 | int z, t, dist; |
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83 | dist = 0; |
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84 | for(t = 0; t < ymax - ymin; t++) |
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85 | for(z = 0; z < xmax - xmin; z++) |
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86 | { |
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87 | int r2; |
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88 | getgray(fonts[f]->img, xmin + z, ymin + t, &r); |
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89 | getgray(img, x + z, y + t, &r2); |
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90 | if(r < r2) |
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91 | dist += (r - r2) * (r - r2); |
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92 | else |
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93 | dist += (r - r2) * (r - r2) / 2; |
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94 | } |
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95 | //dist = dist * 128 / fonts[f]->glyphs[i].count; |
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96 | dist = dist / (xmax - xmin - 2 * DELTA) / (xmax - xmin - 2 * DELTA); |
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97 | if(dist < localmin) |
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98 | { |
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99 | localmin = dist; |
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100 | localx = x; |
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101 | localy = y; |
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102 | } |
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103 | } |
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104 | } |
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105 | if(localmin < bestdist) |
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106 | { |
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107 | bestdist = localmin; |
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108 | bestfont = f; |
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109 | bestx = localx; |
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110 | besty = localy; |
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111 | bestch = i; |
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112 | } |
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113 | } |
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114 | |
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115 | /* Print min glyph */ |
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116 | #if 0 |
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117 | xmin = fonts[bestfont]->glyphs[bestch].xmin - DELTA; |
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118 | ymin = fonts[bestfont]->glyphs[bestch].ymin; |
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119 | xmax = fonts[bestfont]->glyphs[bestch].xmax + DELTA; |
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120 | ymax = fonts[bestfont]->glyphs[bestch].ymax; |
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121 | for(y = 0; y < ymax - ymin; y++) |
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122 | for(x = 0; x < xmax - xmin; x++) |
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123 | { |
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124 | getpixel(fonts[bestfont]->img, xmin + x, ymin + y, &r, &g, &b); |
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125 | if(r > 128) |
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126 | { |
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127 | getpixel(img, bestx + x, besty + y, &r, &g, &b); |
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128 | r = 255; |
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129 | } |
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130 | setpixel(img, bestx + x, besty + y, r, g, b); |
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131 | } |
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132 | #endif |
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133 | |
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134 | startx = bestx + fonts[bestfont]->glyphs[bestch].xmax - fonts[bestfont]->glyphs[bestch].xmin; |
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135 | result[cur++] = fonts[bestfont]->glyphs[bestch].c; |
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136 | } |
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137 | } |
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138 | |
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