| 0,0 → 1,242 |
|---|
| /* |
| IMGLIB: An example image loading library for use with SDL |
| Copyright (C) 1999 Sam Lantinga |
| |
| This library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Library General Public |
| License as published by the Free Software Foundation; either |
| version 2 of the License, or (at your option) any later version. |
| |
| This library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Library General Public License for more details. |
| |
| You should have received a copy of the GNU Library General Public |
| License along with this library; if not, write to the Free |
| Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| |
| Sam Lantinga |
| 5635-34 Springhouse Dr. |
| Pleasanton, CA 94588 (USA) |
| slouken@devolution.com |
| */ |
| |
| /* |
| * PNM (portable anymap) image loader: |
| * |
| * Supports: PBM, PGM and PPM, ASCII and binary formats |
| * (PBM and PGM are loaded as 8bpp surfaces) |
| * Does not support: maximum component value > 255 |
| */ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <ctype.h> |
| #include <string.h> |
| |
| #include "SDL_image.h" |
| |
| #ifdef LOAD_PNM |
| |
| /* See if an image is contained in a data source */ |
| int IMG_isPNM(SDL_RWops *src) |
| { |
| char magic[2]; |
| |
| /* |
| * PNM magic signatures: |
| * P1 PBM, ascii format |
| * P2 PGM, ascii format |
| * P3 PPM, ascii format |
| * P4 PBM, binary format |
| * P5 PGM, binary format |
| * P6 PPM, binary format |
| */ |
| return (SDL_RWread(src, magic, 2, 1) |
| && magic[0] == 'P' && magic[1] >= '1' && magic[1] <= '6'); |
| } |
| |
| /* read a non-negative integer from the source. return -1 upon error */ |
| static int ReadNumber(SDL_RWops *src) |
| { |
| int number; |
| unsigned char ch; |
| |
| /* Initialize return value */ |
| number = 0; |
| |
| /* Skip leading whitespace */ |
| do { |
| if ( ! SDL_RWread(src, &ch, 1, 1) ) { |
| return(0); |
| } |
| /* Eat comments as whitespace */ |
| if ( ch == '#' ) { /* Comment is '#' to end of line */ |
| do { |
| if ( ! SDL_RWread(src, &ch, 1, 1) ) { |
| return -1; |
| } |
| } while ( (ch != '\r') && (ch != '\n') ); |
| } |
| } while ( isspace(ch) ); |
| |
| /* Add up the number */ |
| do { |
| number *= 10; |
| number += ch-'0'; |
| |
| if ( !SDL_RWread(src, &ch, 1, 1) ) { |
| return -1; |
| } |
| } while ( isdigit(ch) ); |
| |
| return(number); |
| } |
| |
| SDL_Surface *IMG_LoadPNM_RW(SDL_RWops *src) |
| { |
| SDL_Surface *surface = NULL; |
| int width, height; |
| int maxval, y, bpl; |
| Uint8 *row; |
| Uint8 *buf = NULL; |
| char *error = NULL; |
| Uint8 magic[2]; |
| int ascii; |
| enum { PBM, PGM, PPM } kind; |
| |
| #define ERROR(s) do { error = (s); goto done; } while(0) |
| |
| if(!src) |
| return NULL; |
| |
| SDL_RWread(src, magic, 2, 1); |
| kind = magic[1] - '1'; |
| ascii = 1; |
| if(kind >= 3) { |
| ascii = 0; |
| kind -= 3; |
| } |
| |
| width = ReadNumber(src); |
| height = ReadNumber(src); |
| if(width <= 0 || height <= 0) |
| ERROR("Unable to read image width and height"); |
| |
| if(kind != PBM) { |
| maxval = ReadNumber(src); |
| if(maxval <= 0 || maxval > 255) |
| ERROR("unsupported PNM format"); |
| } else |
| maxval = 255; /* never scale PBMs */ |
| |
| /* binary PNM allows just a single character of whitespace after |
| the last parameter, and we've already consumed it */ |
| |
| if(kind == PPM) { |
| /* 24-bit surface in R,G,B byte order */ |
| surface = SDL_AllocSurface(SDL_SWSURFACE, width, height, 24, |
| #if SDL_BYTEORDER == SDL_LIL_ENDIAN |
| 0x000000ff, 0x0000ff00, 0x00ff0000, |
| #else |
| 0x00ff0000, 0x0000ff00, 0x000000ff, |
| #endif |
| 0); |
| } else { |
| /* load PBM/PGM as 8-bit indexed images */ |
| surface = SDL_AllocSurface(SDL_SWSURFACE, width, height, 8, |
| 0, 0, 0, 0); |
| } |
| if ( surface == NULL ) |
| ERROR("Out of memory"); |
| bpl = width * surface->format->BytesPerPixel; |
| if(kind == PGM) { |
| SDL_Color *c = surface->format->palette->colors; |
| int i; |
| for(i = 0; i < 256; i++) |
| c[i].r = c[i].g = c[i].b = i; |
| surface->format->palette->ncolors = 256; |
| } else if(kind == PBM) { |
| /* for some reason PBM has 1=black, 0=white */ |
| SDL_Color *c = surface->format->palette->colors; |
| c[0].r = c[0].g = c[0].b = 255; |
| c[1].r = c[1].g = c[1].b = 0; |
| surface->format->palette->ncolors = 2; |
| bpl = (width + 7) >> 3; |
| buf = malloc(bpl); |
| if(buf == NULL) |
| ERROR("Out of memory"); |
| } |
| |
| /* Read the image into the surface */ |
| row = surface->pixels; |
| for(y = 0; y < height; y++) { |
| if(ascii) { |
| int i; |
| if(kind == PBM) { |
| for(i = 0; i < width; i++) { |
| Uint8 ch; |
| do { |
| if(!SDL_RWread(src, &ch, |
| 1, 1)) |
| ERROR("file truncated"); |
| ch -= '0'; |
| } while(ch > 1); |
| row[i] = ch; |
| } |
| } else { |
| for(i = 0; i < bpl; i++) { |
| int c; |
| c = ReadNumber(src); |
| if(c < 0) |
| ERROR("file truncated"); |
| row[i] = c; |
| } |
| } |
| } else { |
| Uint8 *dst = (kind == PBM) ? buf : row; |
| if(!SDL_RWread(src, dst, bpl, 1)) |
| ERROR("file truncated"); |
| if(kind == PBM) { |
| /* expand bitmap to 8bpp */ |
| int i; |
| for(i = 0; i < width; i++) { |
| int bit = 7 - (i & 7); |
| row[i] = (buf[i >> 3] >> bit) & 1; |
| } |
| } |
| } |
| if(maxval < 255) { |
| /* scale up to full dynamic range (slow) */ |
| int i; |
| for(i = 0; i < bpl; i++) |
| row[i] = row[i] * 255 / maxval; |
| } |
| row += surface->pitch; |
| } |
| done: |
| free(buf); |
| if(error) { |
| SDL_FreeSurface(surface); |
| IMG_SetError(error); |
| surface = NULL; |
| } |
| return(surface); |
| } |
| |
| #else |
| |
| /* See if an image is contained in a data source */ |
| int IMG_isPNM(SDL_RWops *src) |
| { |
| return(0); |
| } |
| |
| /* Load a PNM type image from an SDL datasource */ |
| SDL_Surface *IMG_LoadPNM_RW(SDL_RWops *src) |
| { |
| return(NULL); |
| } |
| |
| #endif /* LOAD_PNM */ |