• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  *  png2pnm.c --- conversion from PNG-file to PGM/PPM-file
3  *  copyright (C) 1999 by Willem van Schaik <willem@schaik.com>
4  *
5  *  version 1.0 - 1999.10.15 - First version.
6  *
7  *  Permission to use, copy, modify, and distribute this software and
8  *  its documentation for any purpose and without fee is hereby granted,
9  *  provided that the above copyright notice appear in all copies and
10  *  that both that copyright notice and this permission notice appear in
11  *  supporting documentation. This software is provided "as is" without
12  *  express or implied warranty.
13  */
14 
15 #include <stdio.h>
16 #include <stdlib.h>
17 #ifdef __TURBOC__
18 #include <mem.h>
19 #include <fcntl.h>
20 #endif
21 #include <zlib.h>
22 
23 #ifndef BOOL
24 #define BOOL unsigned char
25 #endif
26 #ifndef TRUE
27 #define TRUE (BOOL) 1
28 #endif
29 #ifndef FALSE
30 #define FALSE (BOOL) 0
31 #endif
32 
33 #ifdef __TURBOC__
34 #define STDIN  0
35 #define STDOUT 1
36 #define STDERR 2
37 #endif
38 
39 /* to make png2pnm verbose so we can find problems (needs to be before png.h) */
40 #ifndef PNG_DEBUG
41 #define PNG_DEBUG 0
42 #endif
43 
44 #include "png.h"
45 
46 /* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */
47 #ifndef png_jmpbuf
48 #  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
49 #endif
50 
51 /* function prototypes */
52 
53 int  main (int argc, char *argv[]);
54 void usage ();
55 BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw,
56    BOOL alpha);
57 
58 /*
59  *  main
60  */
61 
main(int argc,char * argv[])62 int main(int argc, char *argv[])
63 {
64   FILE *fp_rd = stdin;
65   FILE *fp_wr = stdout;
66   FILE *fp_al = NULL;
67   BOOL raw = TRUE;
68   BOOL alpha = FALSE;
69   int argi;
70 
71   for (argi = 1; argi < argc; argi++)
72   {
73     if (argv[argi][0] == '-')
74     {
75       switch (argv[argi][1])
76       {
77         case 'n':
78           raw = FALSE;
79           break;
80         case 'r':
81           raw = TRUE;
82           break;
83         case 'a':
84           alpha = TRUE;
85           argi++;
86           if ((fp_al = fopen (argv[argi], "wb")) == NULL)
87           {
88             fprintf (stderr, "PNM2PNG\n");
89             fprintf (stderr, "Error:  can not create alpha-channel file %s\n",
90                argv[argi]);
91             exit (1);
92           }
93           break;
94         case 'h':
95         case '?':
96           usage();
97           exit(0);
98           break;
99         default:
100           fprintf (stderr, "PNG2PNM\n");
101           fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
102           usage();
103           exit(1);
104           break;
105       } /* end switch */
106     }
107     else if (fp_rd == stdin)
108     {
109       if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
110       {
111              fprintf (stderr, "PNG2PNM\n");
112             fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
113             exit (1);
114       }
115     }
116     else if (fp_wr == stdout)
117     {
118       if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
119       {
120         fprintf (stderr, "PNG2PNM\n");
121         fprintf (stderr, "Error:  can not create file %s\n", argv[argi]);
122         exit (1);
123       }
124     }
125     else
126     {
127       fprintf (stderr, "PNG2PNM\n");
128       fprintf (stderr, "Error:  too many parameters\n");
129       usage();
130       exit(1);
131     }
132   } /* end for */
133 
134 #ifdef __TURBOC__
135   /* set stdin/stdout if required to binary */
136   if (fp_rd == stdin)
137   {
138     setmode (STDIN, O_BINARY);
139   }
140   if ((raw) && (fp_wr == stdout))
141   {
142     setmode (STDOUT, O_BINARY);
143   }
144 #endif
145 
146   /* call the conversion program itself */
147   if (png2pnm (fp_rd, fp_wr, fp_al, raw, alpha) == FALSE)
148   {
149     fprintf (stderr, "PNG2PNM\n");
150     fprintf (stderr, "Error:  unsuccessful conversion of PNG-image\n");
151     exit(1);
152   }
153 
154   /* close input file */
155   fclose (fp_rd);
156   /* close output file */
157   fclose (fp_wr);
158   /* close alpha file */
159   if (alpha)
160     fclose (fp_al);
161 
162   return 0;
163 }
164 
165 /*
166  *  usage
167  */
168 
usage()169 void usage()
170 {
171   fprintf (stderr, "PNG2PNM\n");
172   fprintf (stderr, "   by Willem van Schaik, 1999\n");
173 #ifdef __TURBOC__
174   fprintf (stderr, "   for Turbo-C and Borland-C compilers\n");
175 #else
176   fprintf (stderr, "   for Linux (and Unix) compilers\n");
177 #endif
178   fprintf (stderr, "Usage:  png2pnm [options] <file>.png [<file>.pnm]\n");
179   fprintf (stderr, "   or:  ... | png2pnm [options]\n");
180   fprintf (stderr, "Options:\n");
181   fprintf (stderr,
182      "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
183   fprintf (stderr, "   -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n");
184   fprintf (stderr,
185      "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
186   fprintf (stderr, "   -h | -?  print this help-information\n");
187 }
188 
189 /*
190  *  png2pnm
191  */
192 
png2pnm(FILE * png_file,FILE * pnm_file,FILE * alpha_file,volatile BOOL raw,BOOL alpha)193 BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
194     volatile BOOL raw, BOOL alpha)
195 {
196   png_struct    *png_ptr = NULL;
197   png_info        *info_ptr = NULL;
198   png_byte      buf[8];
199   png_byte      *png_pixels = NULL;
200   png_byte      **row_pointers = NULL;
201   png_byte      *pix_ptr = NULL;
202   png_uint_32   row_bytes;
203 
204   png_uint_32   width;
205   png_uint_32   height;
206   int           bit_depth;
207   int           channels;
208   int           color_type;
209   int           alpha_present;
210   int           row, col;
211   int           ret;
212   int           i;
213   long          dep_16;
214 
215   /* read and check signature in PNG file */
216   ret = fread (buf, 1, 8, png_file);
217   if (ret != 8)
218     return FALSE;
219 
220   ret = png_sig_cmp (buf, 0, 8);
221   if (ret)
222     return FALSE;
223 
224   /* create png and info structures */
225 
226   png_ptr = png_create_read_struct (png_get_libpng_ver(NULL),
227     NULL, NULL, NULL);
228   if (!png_ptr)
229     return FALSE;   /* out of memory */
230 
231   info_ptr = png_create_info_struct (png_ptr);
232   if (!info_ptr)
233   {
234     png_destroy_read_struct (&png_ptr, NULL, NULL);
235     return FALSE;   /* out of memory */
236   }
237 
238   if (setjmp (png_jmpbuf(png_ptr)))
239   {
240     png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
241     return FALSE;
242   }
243 
244   /* set up the input control for C streams */
245   png_init_io (png_ptr, png_file);
246   png_set_sig_bytes (png_ptr, 8);  /* we already read the 8 signature bytes */
247 
248   /* read the file information */
249   png_read_info (png_ptr, info_ptr);
250 
251   /* get size and bit-depth of the PNG-image */
252   png_get_IHDR (png_ptr, info_ptr,
253     &width, &height, &bit_depth, &color_type,
254     NULL, NULL, NULL);
255 
256   /* set-up the transformations */
257 
258   /* transform paletted images into full-color rgb */
259   if (color_type == PNG_COLOR_TYPE_PALETTE)
260     png_set_expand (png_ptr);
261   /* expand images to bit-depth 8 (only applicable for grayscale images) */
262   if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
263     png_set_expand (png_ptr);
264   /* transform transparency maps into full alpha-channel */
265   if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS))
266     png_set_expand (png_ptr);
267 
268 #ifdef NJET
269   /* downgrade 16-bit images to 8-bit */
270   if (bit_depth == 16)
271     png_set_strip_16 (png_ptr);
272   /* transform grayscale images into full-color */
273   if (color_type == PNG_COLOR_TYPE_GRAY ||
274     color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
275     png_set_gray_to_rgb (png_ptr);
276   /* only if file has a file gamma, we do a correction */
277   if (png_get_gAMA (png_ptr, info_ptr, &file_gamma))
278     png_set_gamma (png_ptr, (double) 2.2, file_gamma);
279 #endif
280 
281   /* all transformations have been registered; now update info_ptr data,
282    * get rowbytes and channels, and allocate image memory */
283 
284   png_read_update_info (png_ptr, info_ptr);
285 
286   /* get the new color-type and bit-depth (after expansion/stripping) */
287   png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
288     NULL, NULL, NULL);
289 
290   /* check for 16-bit files */
291   if (bit_depth == 16)
292   {
293     raw = FALSE;
294 #ifdef __TURBOC__
295     pnm_file->flags &= ~((unsigned) _F_BIN);
296 #endif
297   }
298 
299   /* calculate new number of channels and store alpha-presence */
300   if (color_type == PNG_COLOR_TYPE_GRAY)
301     channels = 1;
302   else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
303     channels = 2;
304   else if (color_type == PNG_COLOR_TYPE_RGB)
305     channels = 3;
306   else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
307     channels = 4;
308   else
309     channels = 0; /* should never happen */
310   alpha_present = (channels - 1) % 2;
311 
312   /* check if alpha is expected to be present in file */
313   if (alpha && !alpha_present)
314   {
315     fprintf (stderr, "PNG2PNM\n");
316     fprintf (stderr, "Error:  PNG-file doesn't contain alpha channel\n");
317     exit (1);
318   }
319 
320   /* row_bytes is the width x number of channels x (bit-depth / 8) */
321   row_bytes = png_get_rowbytes (png_ptr, info_ptr);
322 
323   if ((png_pixels = (png_byte *)
324      malloc (row_bytes * height * sizeof (png_byte))) == NULL) {
325     png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
326     return FALSE;
327   }
328 
329   if ((row_pointers = (png_byte **)
330      malloc (height * sizeof (png_bytep))) == NULL)
331   {
332     png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
333     free (png_pixels);
334     png_pixels = NULL;
335     return FALSE;
336   }
337 
338   /* set the individual row_pointers to point at the correct offsets */
339   for (i = 0; i < ((int) height); i++)
340     row_pointers[i] = png_pixels + i * row_bytes;
341 
342   /* now we can go ahead and just read the whole image */
343   png_read_image (png_ptr, row_pointers);
344 
345   /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
346   png_read_end (png_ptr, info_ptr);
347 
348   /* clean up after the read, and free any memory allocated - REQUIRED */
349   png_destroy_read_struct (&png_ptr, &info_ptr, (png_infopp) NULL);
350 
351   /* write header of PNM file */
352 
353   if ((color_type == PNG_COLOR_TYPE_GRAY) ||
354       (color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
355   {
356     fprintf (pnm_file, "%s\n", (raw) ? "P5" : "P2");
357     fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
358     fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
359   }
360   else if ((color_type == PNG_COLOR_TYPE_RGB) ||
361            (color_type == PNG_COLOR_TYPE_RGB_ALPHA))
362   {
363     fprintf (pnm_file, "%s\n", (raw) ? "P6" : "P3");
364     fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
365     fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
366   }
367 
368   /* write header of PGM file with alpha channel */
369 
370   if ((alpha) &&
371       ((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) ||
372        (color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
373   {
374     fprintf (alpha_file, "%s\n", (raw) ? "P5" : "P2");
375     fprintf (alpha_file, "%d %d\n", (int) width, (int) height);
376     fprintf (alpha_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
377   }
378 
379   /* write data to PNM file */
380   pix_ptr = png_pixels;
381 
382   for (row = 0; row < (int) height; row++)
383   {
384     for (col = 0; col < (int) width; col++)
385     {
386       for (i = 0; i < (channels - alpha_present); i++)
387       {
388         if (raw)
389           fputc ((int) *pix_ptr++ , pnm_file);
390         else
391           if (bit_depth == 16){
392             dep_16 = (long) *pix_ptr++;
393             fprintf (pnm_file, "%ld ", (dep_16 << 8) + ((long) *pix_ptr++));
394           }
395           else
396             fprintf (pnm_file, "%ld ", (long) *pix_ptr++);
397       }
398       if (alpha_present)
399       {
400         if (!alpha)
401         {
402           pix_ptr++; /* alpha */
403           if (bit_depth == 16)
404             pix_ptr++;
405         }
406         else /* output alpha-channel as pgm file */
407         {
408           if (raw)
409             fputc ((int) *pix_ptr++ , alpha_file);
410           else
411             if (bit_depth == 16){
412               dep_16 = (long) *pix_ptr++;
413               fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++);
414             }
415             else
416               fprintf (alpha_file, "%ld ", (long) *pix_ptr++);
417         }
418       } /* if alpha_present */
419 
420       if (!raw)
421         if (col % 4 == 3)
422           fprintf (pnm_file, "\n");
423     } /* end for col */
424 
425     if (!raw)
426       if (col % 4 != 0)
427         fprintf (pnm_file, "\n");
428   } /* end for row */
429 
430   if (row_pointers != (unsigned char**) NULL)
431     free (row_pointers);
432   if (png_pixels != (unsigned char*) NULL)
433     free (png_pixels);
434 
435   return TRUE;
436 
437 } /* end of source */
438 
439