source/libs/libpng/libpng-src/contrib/gregbook/writepng.c

   1 /*---------------------------------------------------------------------------
   2
   3    wpng - simple PNG-writing program                             writepng.c
   4
   5   ---------------------------------------------------------------------------
   6
   7       Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
   8
   9       This software is provided "as is," without warranty of any kind,
  10       express or implied.  In no event shall the author or contributors
  11       be held liable for any damages arising in any way from the use of
  12       this software.
  13
  14       The contents of this file are DUAL-LICENSED.  You may modify and/or
  15       redistribute this software according to the terms of one of the
  16       following two licenses (at your option):
  17
  18
  19       LICENSE 1 ("BSD-like with advertising clause"):
  20
  21       Permission is granted to anyone to use this software for any purpose,
  22       including commercial applications, and to alter it and redistribute
  23       it freely, subject to the following restrictions:
  24
  25       1. Redistributions of source code must retain the above copyright
  26          notice, disclaimer, and this list of conditions.
  27       2. Redistributions in binary form must reproduce the above copyright
  28          notice, disclaimer, and this list of conditions in the documenta-
  29          tion and/or other materials provided with the distribution.
  30       3. All advertising materials mentioning features or use of this
  31          software must display the following acknowledgment:
  32
  33             This product includes software developed by Greg Roelofs
  34             and contributors for the book, "PNG: The Definitive Guide,"
  35             published by O'Reilly and Associates.
  36
  37
  38       LICENSE 2 (GNU GPL v2 or later):
  39
  40       This program is free software; you can redistribute it and/or modify
  41       it under the terms of the GNU General Public License as published by
  42       the Free Software Foundation; either version 2 of the License, or
  43       (at your option) any later version.
  44
  45       This program is distributed in the hope that it will be useful,
  46       but WITHOUT ANY WARRANTY; without even the implied warranty of
  47       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  48       GNU General Public License for more details.
  49
  50       You should have received a copy of the GNU General Public License
  51       along with this program; if not, write to the Free Software Foundation,
  52       Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  53
  54   ---------------------------------------------------------------------------*/
  55
  56
  57 #include <stdlib.h>     /* for exit() prototype */
  58 #include <zlib.h>
  59
  60 #include "png.h"        /* libpng header, includes setjmp.h */
  61 #include "writepng.h"   /* typedefs, common macros, public prototypes */
  62
  63
  64 /* local prototype */
  65
  66 static void writepng_error_handler(png_structp png_ptr, png_const_charp msg);
  67
  68
  69
  70 void writepng_version_info(void)
  71 {
  72   fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
  73     PNG_LIBPNG_VER_STRING, png_libpng_ver);
  74   fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
  75     ZLIB_VERSION, zlib_version);
  76 }
  77
  78
  79
  80
  81 /* returns 0 for success, 2 for libpng problem, 4 for out of memory, 11 for
  82  *  unexpected pnmtype; note that outfile might be stdout */
  83
  84 int writepng_init(mainprog_info *mainprog_ptr)
  85 {
  86     png_structp  png_ptr;       /* note:  temporary variables! */
  87     png_infop  info_ptr;
  88     int color_type, interlace_type;
  89
  90
  91     /* could also replace libpng warning-handler (final NULL), but no need: */
  92
  93     png_ptr = png_create_write_struct(png_get_libpng_ver(NULL), mainprog_ptr,
  94       writepng_error_handler, NULL);
  95     if (!png_ptr)
  96         return 4;   /* out of memory */
  97
  98     info_ptr = png_create_info_struct(png_ptr);
  99     if (!info_ptr) {
 100         png_destroy_write_struct(&png_ptr, NULL);
 101         return 4;   /* out of memory */
 102     }
 103
 104
 105     /* setjmp() must be called in every function that calls a PNG-writing
 106      * libpng function, unless an alternate error handler was installed--
 107      * but compatible error handlers must either use longjmp() themselves
 108      * (as in this program) or some other method to return control to
 109      * application code, so here we go: */
 110
 111     if (setjmp(mainprog_ptr->jmpbuf)) {
 112         png_destroy_write_struct(&png_ptr, &info_ptr);
 113         return 2;
 114     }
 115
 116
 117     /* make sure outfile is (re)opened in BINARY mode */
 118
 119     png_init_io(png_ptr, mainprog_ptr->outfile);
 120
 121
 122     /* set the compression levels--in general, always want to leave filtering
 123      * turned on (except for palette images) and allow all of the filters,
 124      * which is the default; want 32K zlib window, unless entire image buffer
 125      * is 16K or smaller (unknown here)--also the default; usually want max
 126      * compression (NOT the default); and remaining compression flags should
 127      * be left alone */
 128
 129     png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
 130 /*
 131     >> this is default for no filtering; Z_FILTERED is default otherwise:
 132     png_set_compression_strategy(png_ptr, Z_DEFAULT_STRATEGY);
 133     >> these are all defaults:
 134     png_set_compression_mem_level(png_ptr, 8);
 135     png_set_compression_window_bits(png_ptr, 15);
 136     png_set_compression_method(png_ptr, 8);
 137  */
 138
 139
 140     /* set the image parameters appropriately */
 141
 142     if (mainprog_ptr->pnmtype == 5)
 143         color_type = PNG_COLOR_TYPE_GRAY;
 144     else if (mainprog_ptr->pnmtype == 6)
 145         color_type = PNG_COLOR_TYPE_RGB;
 146     else if (mainprog_ptr->pnmtype == 8)
 147         color_type = PNG_COLOR_TYPE_RGB_ALPHA;
 148     else {
 149         png_destroy_write_struct(&png_ptr, &info_ptr);
 150         return 11;
 151     }
 152
 153     interlace_type = mainprog_ptr->interlaced? PNG_INTERLACE_ADAM7 :
 154                                                PNG_INTERLACE_NONE;
 155
 156     png_set_IHDR(png_ptr, info_ptr, mainprog_ptr->width, mainprog_ptr->height,
 157       mainprog_ptr->sample_depth, color_type, interlace_type,
 158       PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
 159
 160     if (mainprog_ptr->gamma > 0.0)
 161         png_set_gAMA(png_ptr, info_ptr, mainprog_ptr->gamma);
 162
 163     if (mainprog_ptr->have_bg) {   /* we know it's RGBA, not gray+alpha */
 164         png_color_16  background;
 165
 166         background.red = mainprog_ptr->bg_red;
 167         background.green = mainprog_ptr->bg_green;
 168         background.blue = mainprog_ptr->bg_blue;
 169         png_set_bKGD(png_ptr, info_ptr, &background);
 170     }
 171
 172     if (mainprog_ptr->have_time) {
 173         png_time  modtime;
 174
 175         png_convert_from_time_t(&modtime, mainprog_ptr->modtime);
 176         png_set_tIME(png_ptr, info_ptr, &modtime);
 177     }
 178
 179     if (mainprog_ptr->have_text) {
 180         png_text  text[6];
 181         int  num_text = 0;
 182
 183         if (mainprog_ptr->have_text & TEXT_TITLE) {
 184             text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
 185             text[num_text].key = "Title";
 186             text[num_text].text = mainprog_ptr->title;
 187             ++num_text;
 188         }
 189         if (mainprog_ptr->have_text & TEXT_AUTHOR) {
 190             text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
 191             text[num_text].key = "Author";
 192             text[num_text].text = mainprog_ptr->author;
 193             ++num_text;
 194         }
 195         if (mainprog_ptr->have_text & TEXT_DESC) {
 196             text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
 197             text[num_text].key = "Description";
 198             text[num_text].text = mainprog_ptr->desc;
 199             ++num_text;
 200         }
 201         if (mainprog_ptr->have_text & TEXT_COPY) {
 202             text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
 203             text[num_text].key = "Copyright";
 204             text[num_text].text = mainprog_ptr->copyright;
 205             ++num_text;
 206         }
 207         if (mainprog_ptr->have_text & TEXT_EMAIL) {
 208             text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
 209             text[num_text].key = "E-mail";
 210             text[num_text].text = mainprog_ptr->email;
 211             ++num_text;
 212         }
 213         if (mainprog_ptr->have_text & TEXT_URL) {
 214             text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
 215             text[num_text].key = "URL";
 216             text[num_text].text = mainprog_ptr->url;
 217             ++num_text;
 218         }
 219         png_set_text(png_ptr, info_ptr, text, num_text);
 220     }
 221
 222
 223     /* write all chunks up to (but not including) first IDAT */
 224
 225     png_write_info(png_ptr, info_ptr);
 226
 227
 228     /* if we wanted to write any more text info *after* the image data, we
 229      * would set up text struct(s) here and call png_set_text() again, with
 230      * just the new data; png_set_tIME() could also go here, but it would
 231      * have no effect since we already called it above (only one tIME chunk
 232      * allowed) */
 233
 234
 235     /* set up the transformations:  for now, just pack low-bit-depth pixels
 236      * into bytes (one, two or four pixels per byte) */
 237
 238     png_set_packing(png_ptr);
 239 /*  png_set_shift(png_ptr, &sig_bit);  to scale low-bit-depth values */
 240
 241
 242     /* make sure we save our pointers for use in writepng_encode_image() */
 243
 244     mainprog_ptr->png_ptr = png_ptr;
 245     mainprog_ptr->info_ptr = info_ptr;
 246
 247
 248     /* OK, that's all we need to do for now; return happy */
 249
 250     return 0;
 251 }
 252
 253
 254
 255
 256
 257 /* returns 0 for success, 2 for libpng (longjmp) problem */
 258
 259 int writepng_encode_image(mainprog_info *mainprog_ptr)
 260 {
 261     png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
 262     png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
 263
 264
 265     /* as always, setjmp() must be called in every function that calls a
 266      * PNG-writing libpng function */
 267
 268     if (setjmp(mainprog_ptr->jmpbuf)) {
 269         png_destroy_write_struct(&png_ptr, &info_ptr);
 270         mainprog_ptr->png_ptr = NULL;
 271         mainprog_ptr->info_ptr = NULL;
 272         return 2;
 273     }
 274
 275
 276     /* and now we just write the whole image; libpng takes care of interlacing
 277      * for us */
 278
 279     png_write_image(png_ptr, mainprog_ptr->row_pointers);
 280
 281
 282     /* since that's it, we also close out the end of the PNG file now--if we
 283      * had any text or time info to write after the IDATs, second argument
 284      * would be info_ptr, but we optimize slightly by sending NULL pointer: */
 285
 286     png_write_end(png_ptr, NULL);
 287
 288     return 0;
 289 }
 290
 291
 292
 293
 294
 295 /* returns 0 if succeeds, 2 if libpng problem */
 296
 297 int writepng_encode_row(mainprog_info *mainprog_ptr)  /* NON-interlaced only! */
 298 {
 299     png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
 300     png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
 301
 302
 303     /* as always, setjmp() must be called in every function that calls a
 304      * PNG-writing libpng function */
 305
 306     if (setjmp(mainprog_ptr->jmpbuf)) {
 307         png_destroy_write_struct(&png_ptr, &info_ptr);
 308         mainprog_ptr->png_ptr = NULL;
 309         mainprog_ptr->info_ptr = NULL;
 310         return 2;
 311     }
 312
 313
 314     /* image_data points at our one row of image data */
 315
 316     png_write_row(png_ptr, mainprog_ptr->image_data);
 317
 318     return 0;
 319 }
 320
 321
 322
 323
 324
 325 /* returns 0 if succeeds, 2 if libpng problem */
 326
 327 int writepng_encode_finish(mainprog_info *mainprog_ptr)   /* NON-interlaced! */
 328 {
 329     png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
 330     png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
 331
 332
 333     /* as always, setjmp() must be called in every function that calls a
 334      * PNG-writing libpng function */
 335
 336     if (setjmp(mainprog_ptr->jmpbuf)) {
 337         png_destroy_write_struct(&png_ptr, &info_ptr);
 338         mainprog_ptr->png_ptr = NULL;
 339         mainprog_ptr->info_ptr = NULL;
 340         return 2;
 341     }
 342
 343
 344     /* close out PNG file; if we had any text or time info to write after
 345      * the IDATs, second argument would be info_ptr: */
 346
 347     png_write_end(png_ptr, NULL);
 348
 349     return 0;
 350 }
 351
 352
 353
 354
 355
 356 void writepng_cleanup(mainprog_info *mainprog_ptr)
 357 {
 358     png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
 359     png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
 360
 361     if (png_ptr && info_ptr)
 362         png_destroy_write_struct(&png_ptr, &info_ptr);
 363 }
 364
 365
 366
 367
 368
 369 static void writepng_error_handler(png_structp png_ptr, png_const_charp msg)
 370 {
 371     mainprog_info  *mainprog_ptr;
 372
 373     /* This function, aside from the extra step of retrieving the "error
 374      * pointer" (below) and the fact that it exists within the application
 375      * rather than within libpng, is essentially identical to libpng's
 376      * default error handler.  The second point is critical:  since both
 377      * setjmp() and longjmp() are called from the same code, they are
 378      * guaranteed to have compatible notions of how big a jmp_buf is,
 379      * regardless of whether _BSD_SOURCE or anything else has (or has not)
 380      * been defined. */
 381
 382     fprintf(stderr, "writepng libpng error: %s\n", msg);
 383     fflush(stderr);
 384
 385     mainprog_ptr = png_get_error_ptr(png_ptr);
 386     if (mainprog_ptr == NULL) {         /* we are completely hosed now */
 387         fprintf(stderr,
 388           "writepng severe error:  jmpbuf not recoverable; terminating.\n");
 389         fflush(stderr);
 390         exit(99);
 391     }
 392
 393     /* Now we have our data structure we can use the information in it
 394      * to return control to our own higher level code (all the points
 395      * where 'setjmp' is called in this file.)  This will work with other
 396      * error handling mechanisms as well - libpng always calls png_error
 397      * when it can proceed no further, thus, so long as the error handler
 398      * is intercepted, application code can do its own error recovery.
 399      */
 400     longjmp(mainprog_ptr->jmpbuf, 1);
 401 }