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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 5131 | clevermous | 1 | /* |
| 2 | IMGLIB: An example image loading library for use with SDL |
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| 3 | Copyright (C) 1999 Sam Lantinga |
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| 4 | |||
| 5 | This library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Library General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2 of the License, or (at your option) any later version. |
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| 9 | |||
| 10 | This library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Library General Public License for more details. |
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| 14 | |||
| 15 | You should have received a copy of the GNU Library General Public |
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| 16 | License along with this library; if not, write to the Free |
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| 17 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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| 18 | |||
| 19 | Sam Lantinga |
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| 20 | 5635-34 Springhouse Dr. |
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| 21 | Pleasanton, CA 94588 (USA) |
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| 22 | slouken@devolution.com |
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| 23 | */ |
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| 24 | |||
| 25 | /* |
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| 26 | * PNM (portable anymap) image loader: |
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| 27 | * |
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| 28 | * Supports: PBM, PGM and PPM, ASCII and binary formats |
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| 29 | * (PBM and PGM are loaded as 8bpp surfaces) |
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| 30 | * Does not support: maximum component value > 255 |
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| 31 | */ |
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| 32 | |||
| 33 | #include |
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| 34 | #include |
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| 35 | #include |
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| 36 | #include |
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| 37 | |||
| 38 | #include "SDL_image.h" |
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| 39 | |||
| 40 | #ifdef LOAD_PNM |
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| 41 | |||
| 42 | /* See if an image is contained in a data source */ |
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| 43 | int IMG_isPNM(SDL_RWops *src) |
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| 44 | { |
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| 45 | char magic[2]; |
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| 46 | |||
| 47 | /* |
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| 48 | * PNM magic signatures: |
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| 49 | * P1 PBM, ascii format |
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| 50 | * P2 PGM, ascii format |
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| 51 | * P3 PPM, ascii format |
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| 52 | * P4 PBM, binary format |
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| 53 | * P5 PGM, binary format |
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| 54 | * P6 PPM, binary format |
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| 55 | */ |
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| 56 | return (SDL_RWread(src, magic, 2, 1) |
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| 57 | && magic[0] == 'P' && magic[1] >= '1' && magic[1] <= '6'); |
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| 58 | } |
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| 59 | |||
| 60 | /* read a non-negative integer from the source. return -1 upon error */ |
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| 61 | static int ReadNumber(SDL_RWops *src) |
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| 62 | { |
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| 63 | int number; |
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| 64 | unsigned char ch; |
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| 65 | |||
| 66 | /* Initialize return value */ |
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| 67 | number = 0; |
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| 68 | |||
| 69 | /* Skip leading whitespace */ |
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| 70 | do { |
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| 71 | if ( ! SDL_RWread(src, &ch, 1, 1) ) { |
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| 72 | return(0); |
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| 73 | } |
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| 74 | /* Eat comments as whitespace */ |
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| 75 | if ( ch == '#' ) { /* Comment is '#' to end of line */ |
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| 76 | do { |
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| 77 | if ( ! SDL_RWread(src, &ch, 1, 1) ) { |
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| 78 | return -1; |
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| 79 | } |
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| 80 | } while ( (ch != '\r') && (ch != '\n') ); |
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| 81 | } |
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| 82 | } while ( isspace(ch) ); |
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| 83 | |||
| 84 | /* Add up the number */ |
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| 85 | do { |
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| 86 | number *= 10; |
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| 87 | number += ch-'0'; |
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| 88 | |||
| 89 | if ( !SDL_RWread(src, &ch, 1, 1) ) { |
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| 90 | return -1; |
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| 91 | } |
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| 92 | } while ( isdigit(ch) ); |
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| 93 | |||
| 94 | return(number); |
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| 95 | } |
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| 96 | |||
| 97 | SDL_Surface *IMG_LoadPNM_RW(SDL_RWops *src) |
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| 98 | { |
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| 99 | SDL_Surface *surface = NULL; |
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| 100 | int width, height; |
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| 101 | int maxval, y, bpl; |
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| 102 | Uint8 *row; |
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| 103 | Uint8 *buf = NULL; |
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| 104 | char *error = NULL; |
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| 105 | Uint8 magic[2]; |
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| 106 | int ascii; |
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| 107 | enum { PBM, PGM, PPM } kind; |
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| 108 | |||
| 109 | #define ERROR(s) do { error = (s); goto done; } while(0) |
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| 110 | |||
| 111 | if(!src) |
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| 112 | return NULL; |
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| 113 | |||
| 114 | SDL_RWread(src, magic, 2, 1); |
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| 115 | kind = magic[1] - '1'; |
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| 116 | ascii = 1; |
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| 117 | if(kind >= 3) { |
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| 118 | ascii = 0; |
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| 119 | kind -= 3; |
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| 120 | } |
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| 121 | |||
| 122 | width = ReadNumber(src); |
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| 123 | height = ReadNumber(src); |
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| 124 | if(width <= 0 || height <= 0) |
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| 125 | ERROR("Unable to read image width and height"); |
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| 126 | |||
| 127 | if(kind != PBM) { |
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| 128 | maxval = ReadNumber(src); |
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| 129 | if(maxval <= 0 || maxval > 255) |
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| 130 | ERROR("unsupported PNM format"); |
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| 131 | } else |
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| 132 | maxval = 255; /* never scale PBMs */ |
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| 133 | |||
| 134 | /* binary PNM allows just a single character of whitespace after |
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| 135 | the last parameter, and we've already consumed it */ |
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| 136 | |||
| 137 | if(kind == PPM) { |
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| 138 | /* 24-bit surface in R,G,B byte order */ |
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| 139 | surface = SDL_AllocSurface(SDL_SWSURFACE, width, height, 24, |
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| 140 | #if SDL_BYTEORDER == SDL_LIL_ENDIAN |
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| 141 | 0x000000ff, 0x0000ff00, 0x00ff0000, |
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| 142 | #else |
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| 143 | 0x00ff0000, 0x0000ff00, 0x000000ff, |
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| 144 | #endif |
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| 145 | 0); |
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| 146 | } else { |
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| 147 | /* load PBM/PGM as 8-bit indexed images */ |
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| 148 | surface = SDL_AllocSurface(SDL_SWSURFACE, width, height, 8, |
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| 149 | 0, 0, 0, 0); |
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| 150 | } |
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| 151 | if ( surface == NULL ) |
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| 152 | ERROR("Out of memory"); |
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| 153 | bpl = width * surface->format->BytesPerPixel; |
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| 154 | if(kind == PGM) { |
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| 155 | SDL_Color *c = surface->format->palette->colors; |
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| 156 | int i; |
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| 157 | for(i = 0; i < 256; i++) |
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| 158 | c[i].r = c[i].g = c[i].b = i; |
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| 159 | surface->format->palette->ncolors = 256; |
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| 160 | } else if(kind == PBM) { |
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| 161 | /* for some reason PBM has 1=black, 0=white */ |
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| 162 | SDL_Color *c = surface->format->palette->colors; |
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| 163 | c[0].r = c[0].g = c[0].b = 255; |
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| 164 | c[1].r = c[1].g = c[1].b = 0; |
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| 165 | surface->format->palette->ncolors = 2; |
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| 166 | bpl = (width + 7) >> 3; |
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| 167 | buf = malloc(bpl); |
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| 168 | if(buf == NULL) |
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| 169 | ERROR("Out of memory"); |
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| 170 | } |
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| 171 | |||
| 172 | /* Read the image into the surface */ |
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| 173 | row = surface->pixels; |
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| 174 | for(y = 0; y < height; y++) { |
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| 175 | if(ascii) { |
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| 176 | int i; |
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| 177 | if(kind == PBM) { |
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| 178 | for(i = 0; i < width; i++) { |
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| 179 | Uint8 ch; |
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| 180 | do { |
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| 181 | if(!SDL_RWread(src, &ch, |
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| 182 | 1, 1)) |
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| 183 | ERROR("file truncated"); |
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| 184 | ch -= '0'; |
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| 185 | } while(ch > 1); |
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| 186 | row[i] = ch; |
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| 187 | } |
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| 188 | } else { |
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| 189 | for(i = 0; i < bpl; i++) { |
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| 190 | int c; |
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| 191 | c = ReadNumber(src); |
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| 192 | if(c < 0) |
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| 193 | ERROR("file truncated"); |
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| 194 | row[i] = c; |
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| 195 | } |
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| 196 | } |
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| 197 | } else { |
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| 198 | Uint8 *dst = (kind == PBM) ? buf : row; |
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| 199 | if(!SDL_RWread(src, dst, bpl, 1)) |
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| 200 | ERROR("file truncated"); |
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| 201 | if(kind == PBM) { |
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| 202 | /* expand bitmap to 8bpp */ |
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| 203 | int i; |
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| 204 | for(i = 0; i < width; i++) { |
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| 205 | int bit = 7 - (i & 7); |
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| 206 | row[i] = (buf[i >> 3] >> bit) & 1; |
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| 207 | } |
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| 208 | } |
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| 209 | } |
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| 210 | if(maxval < 255) { |
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| 211 | /* scale up to full dynamic range (slow) */ |
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| 212 | int i; |
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| 213 | for(i = 0; i < bpl; i++) |
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| 214 | row[i] = row[i] * 255 / maxval; |
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| 215 | } |
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| 216 | row += surface->pitch; |
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| 217 | } |
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| 218 | done: |
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| 219 | free(buf); |
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| 220 | if(error) { |
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| 221 | SDL_FreeSurface(surface); |
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| 222 | IMG_SetError(error); |
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| 223 | surface = NULL; |
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| 224 | } |
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| 225 | return(surface); |
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| 226 | } |
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| 227 | |||
| 228 | #else |
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| 229 | |||
| 230 | /* See if an image is contained in a data source */ |
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| 231 | int IMG_isPNM(SDL_RWops *src) |
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| 232 | { |
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| 233 | return(0); |
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| 234 | } |
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| 235 | |||
| 236 | /* Load a PNM type image from an SDL datasource */ |
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| 237 | SDL_Surface *IMG_LoadPNM_RW(SDL_RWops *src) |
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| 238 | { |
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| 239 | return(NULL); |
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| 240 | } |
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| 241 | |||
| 242 | #endif /* LOAD_PNM */ |