zenilib: zenilib/jni/external/libpng/example.c Source File

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example.c
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1
2 #if 0 /* in case someone actually tries to compile this */
3
4 /* example.c - an example of using libpng
5 * Last changed in libpng 1.5.7 [December 15, 2011]
6 * Maintained 1998-2011 Glenn Randers-Pehrson
7 * Maintained 1996, 1997 Andreas Dilger
8 * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
9 */
10
11 /* This is an example of how to use libpng to read and write PNG files.
12 * The file libpng-manual.txt is much more verbose then this. If you have not
13 * read it, do so first. This was designed to be a starting point of an
14 * implementation. This is not officially part of libpng, is hereby placed
15 * in the public domain, and therefore does not require a copyright notice.
16 * To the extent possible under law, the authors have waived all copyright and
17 * related or neighboring rights to this file.
18 *
19 * This file does not currently compile, because it is missing certain
20 * parts, like allocating memory to hold an image. You will have to
21 * supply these parts to get it to compile. For an example of a minimal
22 * working PNG reader/writer, see pngtest.c, included in this distribution;
23 * see also the programs in the contrib directory.
24 */
25
26 #define _POSIX_SOURCE 1 /* libpng and zlib are POSIX-compliant. You may
27 * change this if your application uses non-POSIX
28 * extensions. */
29
30 #include "png.h"
31
32 /* The png_jmpbuf() macro, used in error handling, became available in
33 * libpng version 1.0.6. If you want to be able to run your code with older
34 * versions of libpng, you must define the macro yourself (but only if it
35 * is not already defined by libpng!).
36 */
37
38 #ifndef png_jmpbuf
39 # define png_jmpbuf(png_ptr) ((png_ptr)->png_jmpbuf)
40 #endif
41
42 /* Check to see if a file is a PNG file using png_sig_cmp(). png_sig_cmp()
43 * returns zero if the image is a PNG and nonzero if it isn't a PNG.
44 *
45 * The function check_if_png() shown here, but not used, returns nonzero (true)
46 * if the file can be opened and is a PNG, 0 (false) otherwise.
47 *
48 * If this call is successful, and you are going to keep the file open,
49 * you should call png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK); once
50 * you have created the png_ptr, so that libpng knows your application
51 * has read that many bytes from the start of the file. Make sure you
52 * don't call png_set_sig_bytes() with more than 8 bytes read or give it
53 * an incorrect number of bytes read, or you will either have read too
54 * many bytes (your fault), or you are telling libpng to read the wrong
55 * number of magic bytes (also your fault).
56 *
57 * Many applications already read the first 2 or 4 bytes from the start
58 * of the image to determine the file type, so it would be easiest just
59 * to pass the bytes to png_sig_cmp() or even skip that if you know
60 * you have a PNG file, and call png_set_sig_bytes().
61 */
62 #define PNG_BYTES_TO_CHECK 4
63 int check_if_png(char *file_name, FILE **fp)
64 {
65 char buf[PNG_BYTES_TO_CHECK];
66
67 /* Open the prospective PNG file. */
68 if ((*fp = fopen(file_name, "rb")) == NULL)
69 return 0;
70
71 /* Read in some of the signature bytes */
72 if (fread(buf, 1, PNG_BYTES_TO_CHECK, *fp) != PNG_BYTES_TO_CHECK)
73 return 0;
74
75 /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature.
76 Return nonzero (true) if they match */
77
78 return(!png_sig_cmp(buf, (png_size_t)0, PNG_BYTES_TO_CHECK));
79 }
80
81 /* Read a PNG file. You may want to return an error code if the read
82 * fails (depending upon the failure). There are two "prototypes" given
83 * here - one where we are given the filename, and we need to open the
84 * file, and the other where we are given an open file (possibly with
85 * some or all of the magic bytes read - see comments above).
86 */
87 #ifdef open_file /* prototype 1 */
88 void read_png(char *file_name) /* We need to open the file */
89 {
90 png_structp png_ptr;
91 png_infop info_ptr;
92 unsigned int sig_read = 0;
93 png_uint_32 width, height;
94 int bit_depth, color_type, interlace_type;
95 FILE *fp;
96
97 if ((fp = fopen(file_name, "rb")) == NULL)
98 return (ERROR);
99
100 #else no_open_file /* prototype 2 */
101 void read_png(FILE *fp, unsigned int sig_read) /* File is already open */
102 {
103 png_structp png_ptr;
104 png_infop info_ptr;
105 png_uint_32 width, height;
106 int bit_depth, color_type, interlace_type;
107 #endif no_open_file /* Only use one prototype! */
108
109 /* Create and initialize the png_struct with the desired error handler
110 * functions. If you want to use the default stderr and longjump method,
111 * you can supply NULL for the last three parameters. We also supply the
112 * the compiler header file version, so that we know if the application
113 * was compiled with a compatible version of the library. REQUIRED
114 */
115 png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
116 png_voidp user_error_ptr, user_error_fn, user_warning_fn);
117
118 if (png_ptr == NULL)
119 {
120 fclose(fp);
121 return (ERROR);
122 }
123
124 /* Allocate/initialize the memory for image information. REQUIRED. */
125 info_ptr = png_create_info_struct(png_ptr);
126 if (info_ptr == NULL)
127 {
128 fclose(fp);
129 png_destroy_read_struct(&png_ptr, NULL, NULL);
130 return (ERROR);
131 }
132
133 /* Set error handling if you are using the setjmp/longjmp method (this is
134 * the normal method of doing things with libpng). REQUIRED unless you
135 * set up your own error handlers in the png_create_read_struct() earlier.
136 */
137
138 if (setjmp(png_jmpbuf(png_ptr)))
139 {
140 /* Free all of the memory associated with the png_ptr and info_ptr */
141 png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
142 fclose(fp);
143 /* If we get here, we had a problem reading the file */
144 return (ERROR);
145 }
146
147 /* One of the following I/O initialization methods is REQUIRED */
148 #ifdef streams /* PNG file I/O method 1 */
149 /* Set up the input control if you are using standard C streams */
150 png_init_io(png_ptr, fp);
151
152 #else no_streams /* PNG file I/O method 2 */
153 /* If you are using replacement read functions, instead of calling
154 * png_init_io() here you would call:
155 */
156 png_set_read_fn(png_ptr, (void *)user_io_ptr, user_read_fn);
157 /* where user_io_ptr is a structure you want available to the callbacks */
158 #endif no_streams /* Use only one I/O method! */
159
160 /* If we have already read some of the signature */
161 png_set_sig_bytes(png_ptr, sig_read);
162
163 #ifdef hilevel
164 /*
165 * If you have enough memory to read in the entire image at once,
166 * and you need to specify only transforms that can be controlled
167 * with one of the PNG_TRANSFORM_* bits (this presently excludes
168 * quantizing, filling, setting background, and doing gamma
169 * adjustment), then you can read the entire image (including
170 * pixels) into the info structure with this call:
171 */
172 png_read_png(png_ptr, info_ptr, png_transforms, NULL);
173
174 #else
175 /* OK, you're doing it the hard way, with the lower-level functions */
176
177 /* The call to png_read_info() gives us all of the information from the
178 * PNG file before the first IDAT (image data chunk). REQUIRED
179 */
180 png_read_info(png_ptr, info_ptr);
181
182 png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
183 &interlace_type, NULL, NULL);
184
185 /* Set up the data transformations you want. Note that these are all
186 * optional. Only call them if you want/need them. Many of the
187 * transformations only work on specific types of images, and many
188 * are mutually exclusive.
189 */
190
191 /* Tell libpng to strip 16 bit/color files down to 8 bits/color.
192 * Use accurate scaling if it's available, otherwise just chop off the
193 * low byte.
194 */
195 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
196 png_set_scale_16(png_ptr);
197 #else
198 png_set_strip_16(png_ptr);
199 #endif
200
201 /* Strip alpha bytes from the input data without combining with the
202 * background (not recommended).
203 */
204 png_set_strip_alpha(png_ptr);
205
206 /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
207 * byte into separate bytes (useful for paletted and grayscale images).
208 */
209 png_set_packing(png_ptr);
210
211 /* Change the order of packed pixels to least significant bit first
212 * (not useful if you are using png_set_packing). */
213 png_set_packswap(png_ptr);
214
215 /* Expand paletted colors into true RGB triplets */
216 if (color_type == PNG_COLOR_TYPE_PALETTE)
217 png_set_palette_to_rgb(png_ptr);
218
219 /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
220 if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
221 png_set_expand_gray_1_2_4_to_8(png_ptr);
222
223 /* Expand paletted or RGB images with transparency to full alpha channels
224 * so the data will be available as RGBA quartets.
225 */
226 if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
227 png_set_tRNS_to_alpha(png_ptr);
228
229 /* Set the background color to draw transparent and alpha images over.
230 * It is possible to set the red, green, and blue components directly
231 * for paletted images instead of supplying a palette index. Note that
232 * even if the PNG file supplies a background, you are not required to
233 * use it - you should use the (solid) application background if it has one.
234 */
235
236 png_color_16 my_background, *image_background;
237
238 if (png_get_bKGD(png_ptr, info_ptr, &image_background))
239 png_set_background(png_ptr, image_background,
240 PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
241 else
242 png_set_background(png_ptr, &my_background,
243 PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
244
245 /* Some suggestions as to how to get a screen gamma value
246 *
247 * Note that screen gamma is the display_exponent, which includes
248 * the CRT_exponent and any correction for viewing conditions
249 */
250 if (/* We have a user-defined screen gamma value */)
251 {
252 screen_gamma = user-defined screen_gamma;
253 }
254 /* This is one way that applications share the same screen gamma value */
255 else if ((gamma_str = getenv("SCREEN_GAMMA")) != NULL)
256 {
257 screen_gamma = atof(gamma_str);
258 }
259 /* If we don't have another value */
260 else
261 {
262 screen_gamma = 2.2; /* A good guess for a PC monitor in a dimly
263 lit room */
264 screen_gamma = 1.7 or 1.0; /* A good guess for Mac systems */
265 }
266
267 /* Tell libpng to handle the gamma conversion for you. The final call
268 * is a good guess for PC generated images, but it should be configurable
269 * by the user at run time by the user. It is strongly suggested that
270 * your application support gamma correction.
271 */
272
273 int intent;
274
275 if (png_get_sRGB(png_ptr, info_ptr, &intent))
276 png_set_gamma(png_ptr, screen_gamma, 0.45455);
277 else
278 {
279 double image_gamma;
280 if (png_get_gAMA(png_ptr, info_ptr, &image_gamma))
281 png_set_gamma(png_ptr, screen_gamma, image_gamma);
282 else
283 png_set_gamma(png_ptr, screen_gamma, 0.45455);
284 }
285
286 #ifdef PNG_READ_QUANTIZE_SUPPORTED
287 /* Quantize RGB files down to 8 bit palette or reduce palettes
288 * to the number of colors available on your screen.
289 */
290 if (color_type & PNG_COLOR_MASK_COLOR)
291 {
292 int num_palette;
293 png_colorp palette;
294
295 /* This reduces the image to the application supplied palette */
296 if (/* We have our own palette */)
297 {
298 /* An array of colors to which the image should be quantized */
299 png_color std_color_cube[MAX_SCREEN_COLORS];
300
301 png_set_quantize(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
302 MAX_SCREEN_COLORS, NULL, 0);
303 }
304 /* This reduces the image to the palette supplied in the file */
305 else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette))
306 {
307 png_uint_16p histogram = NULL;
308
309 png_get_hIST(png_ptr, info_ptr, &histogram);
310
311 png_set_quantize(png_ptr, palette, num_palette,
312 max_screen_colors, histogram, 0);
313 }
314 }
315 #endif /* PNG_READ_QUANTIZE_SUPPORTED */
316
317 /* Invert monochrome files to have 0 as white and 1 as black */
318 png_set_invert_mono(png_ptr);
319
320 /* If you want to shift the pixel values from the range [0,255] or
321 * [0,65535] to the original [0,7] or [0,31], or whatever range the
322 * colors were originally in:
323 */
324 if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
325 {
326 png_color_8p sig_bit_p;
327
328 png_get_sBIT(png_ptr, info_ptr, &sig_bit_p);
329 png_set_shift(png_ptr, sig_bit_p);
330 }
331
332 /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
333 if (color_type & PNG_COLOR_MASK_COLOR)
334 png_set_bgr(png_ptr);
335
336 /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
337 png_set_swap_alpha(png_ptr);
338
339 /* Swap bytes of 16 bit files to least significant byte first */
340 png_set_swap(png_ptr);
341
342 /* Add filler (or alpha) byte (before/after each RGB triplet) */
343 png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
344
345 #ifdef PNG_READ_INTERLACING_SUPPORTED
346 /* Turn on interlace handling. REQUIRED if you are not using
347 * png_read_image(). To see how to handle interlacing passes,
348 * see the png_read_row() method below:
349 */
350 number_passes = png_set_interlace_handling(png_ptr);
351 #else
352 number_passes = 1;
353 #endif /* PNG_READ_INTERLACING_SUPPORTED */
354
355
356 /* Optional call to gamma correct and add the background to the palette
357 * and update info structure. REQUIRED if you are expecting libpng to
358 * update the palette for you (ie you selected such a transform above).
359 */
360 png_read_update_info(png_ptr, info_ptr);
361
362 /* Allocate the memory to hold the image using the fields of info_ptr. */
363
364 /* The easiest way to read the image: */
365 png_bytep row_pointers[height];
366
367 /* Clear the pointer array */
368 for (row = 0; row < height; row++)
369 row_pointers[row] = NULL;
370
371 for (row = 0; row < height; row++)
372 row_pointers[row] = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
373 info_ptr));
374
375 /* Now it's time to read the image. One of these methods is REQUIRED */
376 #ifdef entire /* Read the entire image in one go */
377 png_read_image(png_ptr, row_pointers);
378
379 #else no_entire /* Read the image one or more scanlines at a time */
380 /* The other way to read images - deal with interlacing: */
381
382 for (pass = 0; pass < number_passes; pass++)
383 {
384 #ifdef single /* Read the image a single row at a time */
385 for (y = 0; y < height; y++)
386 {
387 png_read_rows(png_ptr, &row_pointers[y], NULL, 1);
388 }
389
390 #else no_single /* Read the image several rows at a time */
391 for (y = 0; y < height; y += number_of_rows)
392 {
393 #ifdef sparkle /* Read the image using the "sparkle" effect. */
394 png_read_rows(png_ptr, &row_pointers[y], NULL,
395 number_of_rows);
396 #else no_sparkle /* Read the image using the "rectangle" effect */
397 png_read_rows(png_ptr, NULL, &row_pointers[y],
398 number_of_rows);
399 #endif no_sparkle /* Use only one of these two methods */
400 }
401
402 /* If you want to display the image after every pass, do so here */
403 #endif no_single /* Use only one of these two methods */
404 }
405 #endif no_entire /* Use only one of these two methods */
406
407 /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
408 png_read_end(png_ptr, info_ptr);
409 #endif hilevel
410
411 /* At this point you have read the entire image */
412
413 /* Clean up after the read, and free any memory allocated - REQUIRED */
414 png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
415
416 /* Close the file */
417 fclose(fp);
418
419 /* That's it */
420 return (OK);
421 }
422
423 /* Progressively read a file */
424
425 int
426 initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr)
427 {
428 /* Create and initialize the png_struct with the desired error handler
429 * functions. If you want to use the default stderr and longjump method,
430 * you can supply NULL for the last three parameters. We also check that
431 * the library version is compatible in case we are using dynamically
432 * linked libraries.
433 */
434 *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
435 png_voidp user_error_ptr, user_error_fn, user_warning_fn);
436
437 if (*png_ptr == NULL)
438 {
439 *info_ptr = NULL;
440 return (ERROR);
441 }
442
443 *info_ptr = png_create_info_struct(png_ptr);
444
445 if (*info_ptr == NULL)
446 {
447 png_destroy_read_struct(png_ptr, info_ptr, NULL);
448 return (ERROR);
449 }
450
451 if (setjmp(png_jmpbuf((*png_ptr))))
452 {
453 png_destroy_read_struct(png_ptr, info_ptr, NULL);
454 return (ERROR);
455 }
456
457 /* This one's new. You will need to provide all three
458 * function callbacks, even if you aren't using them all.
459 * If you aren't using all functions, you can specify NULL
460 * parameters. Even when all three functions are NULL,
461 * you need to call png_set_progressive_read_fn().
462 * These functions shouldn't be dependent on global or
463 * static variables if you are decoding several images
464 * simultaneously. You should store stream specific data
465 * in a separate struct, given as the second parameter,
466 * and retrieve the pointer from inside the callbacks using
467 * the function png_get_progressive_ptr(png_ptr).
468 */
469 png_set_progressive_read_fn(*png_ptr, (void *)stream_data,
470 info_callback, row_callback, end_callback);
471
472 return (OK);
473 }
474
475 int
476 process_data(png_structp *png_ptr, png_infop *info_ptr,
477 png_bytep buffer, png_uint_32 length)
478 {
479 if (setjmp(png_jmpbuf((*png_ptr))))
480 {
481 /* Free the png_ptr and info_ptr memory on error */
482 png_destroy_read_struct(png_ptr, info_ptr, NULL);
483 return (ERROR);
484 }
485
486 /* This one's new also. Simply give it chunks of data as
487 * they arrive from the data stream (in order, of course).
488 * On segmented machines, don't give it any more than 64K.
489 * The library seems to run fine with sizes of 4K, although
490 * you can give it much less if necessary (I assume you can
491 * give it chunks of 1 byte, but I haven't tried with less
492 * than 256 bytes yet). When this function returns, you may
493 * want to display any rows that were generated in the row
494 * callback, if you aren't already displaying them there.
495 */
496 png_process_data(*png_ptr, *info_ptr, buffer, length);
497 return (OK);
498 }
499
500 info_callback(png_structp png_ptr, png_infop info)
501 {
502 /* Do any setup here, including setting any of the transformations
503 * mentioned in the Reading PNG files section. For now, you _must_
504 * call either png_start_read_image() or png_read_update_info()
505 * after all the transformations are set (even if you don't set
506 * any). You may start getting rows before png_process_data()
507 * returns, so this is your last chance to prepare for that.
508 */
509 }
510
511 row_callback(png_structp png_ptr, png_bytep new_row,
512 png_uint_32 row_num, int pass)
513 {
514 /*
515 * This function is called for every row in the image. If the
516 * image is interlaced, and you turned on the interlace handler,
517 * this function will be called for every row in every pass.
518 *
519 * In this function you will receive a pointer to new row data from
520 * libpng called new_row that is to replace a corresponding row (of
521 * the same data format) in a buffer allocated by your application.
522 *
523 * The new row data pointer "new_row" may be NULL, indicating there is
524 * no new data to be replaced (in cases of interlace loading).
525 *
526 * If new_row is not NULL then you need to call
527 * png_progressive_combine_row() to replace the corresponding row as
528 * shown below:
529 */
530
531 /* Get pointer to corresponding row in our
532 * PNG read buffer.
533 */
534 png_bytep old_row = ((png_bytep *)our_data)[row_num];
535
536 #ifdef PNG_READ_INTERLACING_SUPPORTED
537 /* If both rows are allocated then copy the new row
538 * data to the corresponding row data.
539 */
540 if ((old_row != NULL) && (new_row != NULL))
541 png_progressive_combine_row(png_ptr, old_row, new_row);
542
543 /*
544 * The rows and passes are called in order, so you don't really
545 * need the row_num and pass, but I'm supplying them because it
546 * may make your life easier.
547 *
548 * For the non-NULL rows of interlaced images, you must call
549 * png_progressive_combine_row() passing in the new row and the
550 * old row, as demonstrated above. You can call this function for
551 * NULL rows (it will just return) and for non-interlaced images
552 * (it just does the png_memcpy for you) if it will make the code
553 * easier. Thus, you can just do this for all cases:
554 */
555
556 png_progressive_combine_row(png_ptr, old_row, new_row);
557
558 /* where old_row is what was displayed for previous rows. Note
559 * that the first pass (pass == 0 really) will completely cover
560 * the old row, so the rows do not have to be initialized. After
561 * the first pass (and only for interlaced images), you will have
562 * to pass the current row as new_row, and the function will combine
563 * the old row and the new row.
564 */
565 #endif /* PNG_READ_INTERLACING_SUPPORTED */
566 }
567
568 end_callback(png_structp png_ptr, png_infop info)
569 {
570 /* This function is called when the whole image has been read,
571 * including any chunks after the image (up to and including
572 * the IEND). You will usually have the same info chunk as you
573 * had in the header, although some data may have been added
574 * to the comments and time fields.
575 *
576 * Most people won't do much here, perhaps setting a flag that
577 * marks the image as finished.
578 */
579 }
580
581 /* Write a png file */
582 void write_png(char *file_name /* , ... other image information ... */)
583 {
584 FILE *fp;
585 png_structp png_ptr;
586 png_infop info_ptr;
587 png_colorp palette;
588
589 /* Open the file */
590 fp = fopen(file_name, "wb");
591 if (fp == NULL)
592 return (ERROR);
593
594 /* Create and initialize the png_struct with the desired error handler
595 * functions. If you want to use the default stderr and longjump method,
596 * you can supply NULL for the last three parameters. We also check that
597 * the library version is compatible with the one used at compile time,
598 * in case we are using dynamically linked libraries. REQUIRED.
599 */
600 png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
601 png_voidp user_error_ptr, user_error_fn, user_warning_fn);
602
603 if (png_ptr == NULL)
604 {
605 fclose(fp);
606 return (ERROR);
607 }
608
609 /* Allocate/initialize the image information data. REQUIRED */
610 info_ptr = png_create_info_struct(png_ptr);
611 if (info_ptr == NULL)
612 {
613 fclose(fp);
614 png_destroy_write_struct(&png_ptr, NULL);
615 return (ERROR);
616 }
617
618 /* Set error handling. REQUIRED if you aren't supplying your own
619 * error handling functions in the png_create_write_struct() call.
620 */
621 if (setjmp(png_jmpbuf(png_ptr)))
622 {
623 /* If we get here, we had a problem writing the file */
624 fclose(fp);
625 png_destroy_write_struct(&png_ptr, &info_ptr);
626 return (ERROR);
627 }
628
629 /* One of the following I/O initialization functions is REQUIRED */
630
631 #ifdef streams /* I/O initialization method 1 */
632 /* Set up the output control if you are using standard C streams */
633 png_init_io(png_ptr, fp);
634
635 #else no_streams /* I/O initialization method 2 */
636 /* If you are using replacement write functions, instead of calling
637 * png_init_io() here you would call
638 */
639 png_set_write_fn(png_ptr, (void *)user_io_ptr, user_write_fn,
640 user_IO_flush_function);
641 /* where user_io_ptr is a structure you want available to the callbacks */
642 #endif no_streams /* Only use one initialization method */
643
644 #ifdef hilevel
645 /* This is the easy way. Use it if you already have all the
646 * image info living in the structure. You could "|" many
647 * PNG_TRANSFORM flags into the png_transforms integer here.
648 */
649 png_write_png(png_ptr, info_ptr, png_transforms, NULL);
650
651 #else
652 /* This is the hard way */
653
654 /* Set the image information here. Width and height are up to 2^31,
655 * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on
656 * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY,
657 * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB,
658 * or PNG_COLOR_TYPE_RGB_ALPHA. interlace is either PNG_INTERLACE_NONE or
659 * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST
660 * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE. REQUIRED
661 */
662 png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, PNG_COLOR_TYPE_???,
663 PNG_INTERLACE_????, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
664
665 /* Set the palette if there is one. REQUIRED for indexed-color images */
666 palette = (png_colorp)png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH
667 * png_sizeof(png_color));
668 /* ... Set palette colors ... */
669 png_set_PLTE(png_ptr, info_ptr, palette, PNG_MAX_PALETTE_LENGTH);
670 /* You must not free palette here, because png_set_PLTE only makes a link to
671 * the palette that you malloced. Wait until you are about to destroy
672 * the png structure.
673 */
674
675 /* Optional significant bit (sBIT) chunk */
676 png_color_8 sig_bit;
677
678 /* If we are dealing with a grayscale image then */
679 sig_bit.gray = true_bit_depth;
680
681 /* Otherwise, if we are dealing with a color image then */
682 sig_bit.red = true_red_bit_depth;
683 sig_bit.green = true_green_bit_depth;
684 sig_bit.blue = true_blue_bit_depth;
685
686 /* If the image has an alpha channel then */
687 sig_bit.alpha = true_alpha_bit_depth;
688
689 png_set_sBIT(png_ptr, info_ptr, &sig_bit);
690
691
692 /* Optional gamma chunk is strongly suggested if you have any guess
693 * as to the correct gamma of the image.
694 */
695 png_set_gAMA(png_ptr, info_ptr, gamma);
696
697 /* Optionally write comments into the image */
698 text_ptr[0].key = "Title";
699 text_ptr[0].text = "Mona Lisa";
700 text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
701 text_ptr[0].itxt_length = 0;
702 text_ptr[0].lang = NULL;
703 text_ptr[0].lang_key = NULL;
704 text_ptr[1].key = "Author";
705 text_ptr[1].text = "Leonardo DaVinci";
706 text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE;
707 text_ptr[1].itxt_length = 0;
708 text_ptr[1].lang = NULL;
709 text_ptr[1].lang_key = NULL;
710 text_ptr[2].key = "Description";
711 text_ptr[2].text = "<long text>";
712 text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
713 text_ptr[2].itxt_length = 0;
714 text_ptr[2].lang = NULL;
715 text_ptr[2].lang_key = NULL;
716 png_set_text(png_ptr, info_ptr, text_ptr, 3);
717
718 /* Other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs */
719
720 /* Note that if sRGB is present the gAMA and cHRM chunks must be ignored
721 * on read and, if your application chooses to write them, they must
722 * be written in accordance with the sRGB profile
723 */
724
725 /* Write the file header information. REQUIRED */
726 png_write_info(png_ptr, info_ptr);
727
728 /* If you want, you can write the info in two steps, in case you need to
729 * write your private chunk ahead of PLTE:
730 *
731 * png_write_info_before_PLTE(write_ptr, write_info_ptr);
732 * write_my_chunk();
733 * png_write_info(png_ptr, info_ptr);
734 *
735 * However, given the level of known- and unknown-chunk support in 1.2.0
736 * and up, this should no longer be necessary.
737 */
738
739 /* Once we write out the header, the compression type on the text
740 * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
741 * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
742 * at the end.
743 */
744
745 /* Set up the transformations you want. Note that these are
746 * all optional. Only call them if you want them.
747 */
748
749 /* Invert monochrome pixels */
750 png_set_invert_mono(png_ptr);
751
752 /* Shift the pixels up to a legal bit depth and fill in
753 * as appropriate to correctly scale the image.
754 */
755 png_set_shift(png_ptr, &sig_bit);
756
757 /* Pack pixels into bytes */
758 png_set_packing(png_ptr);
759
760 /* Swap location of alpha bytes from ARGB to RGBA */
761 png_set_swap_alpha(png_ptr);
762
763 /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into
764 * RGB (4 channels -> 3 channels). The second parameter is not used.
765 */
766 png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
767
768 /* Flip BGR pixels to RGB */
769 png_set_bgr(png_ptr);
770
771 /* Swap bytes of 16-bit files to most significant byte first */
772 png_set_swap(png_ptr);
773
774 /* Swap bits of 1, 2, 4 bit packed pixel formats */
775 png_set_packswap(png_ptr);
776
777 /* Turn on interlace handling if you are not using png_write_image() */
778 if (interlacing)
779 number_passes = png_set_interlace_handling(png_ptr);
780
781 else
782 number_passes = 1;
783
784 /* The easiest way to write the image (you may have a different memory
785 * layout, however, so choose what fits your needs best). You need to
786 * use the first method if you aren't handling interlacing yourself.
787 */
788 png_uint_32 k, height, width;
789 png_byte image[height][width*bytes_per_pixel];
790 png_bytep row_pointers[height];
791
792 if (height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
793 png_error (png_ptr, "Image is too tall to process in memory");
794
795 for (k = 0; k < height; k++)
796 row_pointers[k] = image + k*width*bytes_per_pixel;
797
798 /* One of the following output methods is REQUIRED */
799
800 #ifdef entire /* Write out the entire image data in one call */
801 png_write_image(png_ptr, row_pointers);
802
803 /* The other way to write the image - deal with interlacing */
804
805 #else no_entire /* Write out the image data by one or more scanlines */
806
807 /* The number of passes is either 1 for non-interlaced images,
808 * or 7 for interlaced images.
809 */
810 for (pass = 0; pass < number_passes; pass++)
811 {
812 /* Write a few rows at a time. */
813 png_write_rows(png_ptr, &row_pointers[first_row], number_of_rows);
814
815 /* If you are only writing one row at a time, this works */
816 for (y = 0; y < height; y++)
817 png_write_rows(png_ptr, &row_pointers[y], 1);
818 }
819 #endif no_entire /* Use only one output method */
820
821 /* You can write optional chunks like tEXt, zTXt, and tIME at the end
822 * as well. Shouldn't be necessary in 1.2.0 and up as all the public
823 * chunks are supported and you can use png_set_unknown_chunks() to
824 * register unknown chunks into the info structure to be written out.
825 */
826
827 /* It is REQUIRED to call this to finish writing the rest of the file */
828 png_write_end(png_ptr, info_ptr);
829 #endif hilevel
830
831 /* If you png_malloced a palette, free it here (don't free info_ptr->palette,
832 * as recommended in versions 1.0.5m and earlier of this example; if
833 * libpng mallocs info_ptr->palette, libpng will free it). If you
834 * allocated it with malloc() instead of png_malloc(), use free() instead
835 * of png_free().
836 */
837 png_free(png_ptr, palette);
838 palette = NULL;
839
840 /* Similarly, if you png_malloced any data that you passed in with
841 * png_set_something(), such as a hist or trans array, free it here,
842 * when you can be sure that libpng is through with it.
843 */
844 png_free(png_ptr, trans);
845 trans = NULL;
846 /* Whenever you use png_free() it is a good idea to set the pointer to
847 * NULL in case your application inadvertently tries to png_free() it
848 * again. When png_free() sees a NULL it returns without action, thus
849 * avoiding the double-free security problem.
850 */
851
852 /* Clean up after the write, and free any memory allocated */
853 png_destroy_write_struct(&png_ptr, &info_ptr);
854
855 /* Close the file */
856 fclose(fp);
857
858 /* That's it */
859 return (OK);
860 }
861
862 #endif /* if 0 */
png_set_packing
void PNGAPI png_set_packing(png_structp png_ptr)
Definition: pngtrans.c:50
png_set_IHDR
void PNGAPI png_set_IHDR(png_structp png_ptr, png_infop info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth, int color_type, int interlace_type, int compression_type, int filter_type)
Definition: pngset.c:219
png_color_8_struct::blue
png_byte blue
Definition: png.h:577
png_get_rowbytes
png_size_t PNGAPI png_get_rowbytes(png_const_structp png_ptr, png_const_infop info_ptr)
Definition: pngget.c:30
png_write_image
void PNGAPI png_write_image(png_structp png_ptr, png_bytepp image)
Definition: pngwrite.c:578
png_write_png
void PNGAPI png_write_png(png_structp png_ptr, png_infop info_ptr, int transforms, voidp params)
Definition: pngwrite.c:1571
png_set_expand_gray_1_2_4_to_8
void PNGAPI png_set_expand_gray_1_2_4_to_8(png_structp png_ptr)
Definition: pngrtran.c:867
PNG_FILLER_BEFORE
#define PNG_FILLER_BEFORE
Definition: png.h:1395
png_get_PLTE
png_uint_32 PNGAPI png_get_PLTE(png_const_structp png_ptr, png_const_infop info_ptr, png_colorp *palette, int *num_palette)
Definition: pngget.c:912
png_process_data
void PNGAPI png_process_data(png_structp png_ptr, png_infop info_ptr, png_bytep buffer, png_size_t buffer_size)
Definition: pngpread.c:30
png_progressive_combine_row
void PNGAPI png_progressive_combine_row(png_structp png_ptr, png_bytep old_row, png_const_bytep new_row)
Definition: pngpread.c:1805
png_color_8_struct::red
png_byte red
Definition: png.h:575
png.h
png_get_sRGB
png_uint_32 PNGAPI png_get_sRGB(png_const_structp png_ptr, png_const_infop info_ptr, int *file_srgb_intent)
Definition: pngget.c:660
NULL
#define NULL
Definition: ftobjs.h:61
PNG_BACKGROUND_GAMMA_SCREEN
#define PNG_BACKGROUND_GAMMA_SCREEN
Definition: png.h:1456
PNG_MAX_PALETTE_LENGTH
#define PNG_MAX_PALETTE_LENGTH
Definition: png.h:802
png_set_background
void PNGAPI png_set_background(png_structp png_ptr, png_const_color_16p background_color, int background_gamma_code, int need_expand, double background_gamma)
Definition: pngrtran.c:125
png_set_palette_to_rgb
void PNGAPI png_set_palette_to_rgb(png_structp png_ptr)
Definition: pngrtran.c:854
k
int32_t k
Definition: e_log.c:102
png_write_rows
void PNGAPI png_write_rows(png_structp png_ptr, png_bytepp row, png_uint_32 num_rows)
Definition: pngwrite.c:556
PNG_COLOR_TYPE_PALETTE
#define PNG_COLOR_TYPE_PALETTE
Definition: png.h:746
png_read_rows
void PNGAPI png_read_rows(png_structp png_ptr, png_bytepp row, png_bytepp display_row, png_uint_32 num_rows)
Definition: pngread.c:679
PNG_LIBPNG_VER_STRING
#define PNG_LIBPNG_VER_STRING
Definition: png.h:382
png_error
png_error(png_ptr,"Missing IHDR before iCCP")
png_set_quantize
void PNGAPI png_set_quantize(png_structp png_ptr, png_colorp palette, int num_palette, int maximum_colors, png_const_uint_16p histogram, int full_quantize)
Definition: pngrtran.c:381
png_color_8_struct::green
png_byte green
Definition: png.h:576
png_set_sig_bytes
void PNGAPI png_set_sig_bytes(png_structp png_ptr, int num_bytes)
Definition: png.c:27
height
EGLSurface EGLint EGLint EGLint EGLint height
Definition: eglext.h:293
png_uint_32
unsigned int png_uint_32
Definition: pngconf.h:441
png_get_hIST
png_uint_32 PNGAPI png_get_hIST(png_const_structp png_ptr, png_const_infop info_ptr, png_uint_16p *hist)
Definition: pngget.c:719
png_get_gAMA
png_uint_32 PNGAPI png_get_gAMA(png_const_structp png_ptr, png_const_infop info_ptr, double *file_gamma)
Definition: pngget.c:643
png_set_strip_16
void PNGAPI png_set_strip_16(png_structp png_ptr)
Definition: pngrtran.c:155
png_set_write_fn
void PNGAPI png_set_write_fn(png_structp png_ptr, png_voidp io_ptr, png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
Definition: pngwio.c:180
PNG_BACKGROUND_GAMMA_FILE
#define PNG_BACKGROUND_GAMMA_FILE
Definition: png.h:1457
png_jmpbuf
#define png_jmpbuf(png_ptr)
Definition: png.h:1035
png_set_gAMA
void PNGAPI png_set_gAMA(png_structp png_ptr, png_infop info_ptr, double file_gamma)
Definition: pngset.c:167
image
EGLImageKHR image
Definition: eglext.h:88
png_set_bgr
void PNGAPI png_set_bgr(png_structp png_ptr)
Definition: pngtrans.c:21
png_get_sBIT
png_uint_32 PNGAPI png_get_sBIT(png_const_structp png_ptr, png_infop info_ptr, png_color_8p *sig_bit)
Definition: pngget.c:931
PNG_TEXT_COMPRESSION_zTXt
#define PNG_TEXT_COMPRESSION_zTXt
Definition: png.h:662
buffer
EGLContext EGLenum EGLClientBuffer buffer
Definition: eglext.h:87
PNG_TEXT_COMPRESSION_NONE
#define PNG_TEXT_COMPRESSION_NONE
Definition: png.h:661
row
GLenum GLenum GLvoid * row
Definition: glew.h:4447
png_set_sBIT
void PNGAPI png_set_sBIT(png_structp png_ptr, png_infop info_ptr, png_const_color_8p sig_bit)
Definition: pngset.c:561
png_structp
png_struct FAR * png_structp
Definition: png.h:849
png_write_info
void PNGAPI png_write_info(png_structp png_ptr, png_infop info_ptr)
Definition: pngwrite.c:122
png_read_end
void PNGAPI png_read_end(png_structp png_ptr, png_infop info_ptr)
Definition: pngread.c:799
png_set_filler
void PNGAPI png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
Definition: pngtrans.c:118
png_set_PLTE
void PNGAPI png_set_PLTE(png_structp png_ptr, png_infop info_ptr, png_const_colorp palette, int num_palette)
Definition: pngset.c:516
PNG_COLOR_MASK_COLOR
#define PNG_COLOR_MASK_COLOR
Definition: png.h:741
png_set_packswap
void PNGAPI png_set_packswap(png_structp png_ptr)
Definition: pngtrans.c:68
png_infop
png_info FAR * png_infop
Definition: png.h:721
length
GLsizei GLsizei * length
Definition: gl2ext.h:792
png_get_IHDR
png_uint_32 PNGAPI png_get_IHDR(png_structp png_ptr, png_infop info_ptr, png_uint_32 *width, png_uint_32 *height, int *bit_depth, int *color_type, int *interlace_type, int *compression_type, int *filter_type)
Definition: pngget.c:736
png_set_swap
void PNGAPI png_set_swap(png_structp png_ptr)
Definition: pngtrans.c:35
width
EGLSurface EGLint EGLint EGLint width
Definition: eglext.h:293
png_byte
unsigned char png_byte
Definition: pngconf.h:449
png_set_text
void PNGAPI png_set_text(png_structp png_ptr, png_infop info_ptr, png_const_textp text_ptr, int num_text)
Definition: pngset.c:668
PNG_COLOR_TYPE_GRAY
#define PNG_COLOR_TYPE_GRAY
Definition: png.h:745
png_set_scale_16
void PNGAPI png_set_scale_16(png_structp png_ptr)
Definition: pngrtran.c:141
png_uint_16p
png_uint_16 FAR * png_uint_16p
Definition: pngconf.h:532
PNG_UINT_32_MAX
#define PNG_UINT_32_MAX
Definition: png.h:727
png_write_end
void PNGAPI png_write_end(png_structp png_ptr, png_infop info_ptr)
Definition: pngwrite.c:298
png_set_shift
void PNGAPI png_set_shift(png_structp png_ptr, png_const_color_8p true_bits)
Definition: pngtrans.c:82
png_set_gamma
void PNGAPI png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
Definition: pngrtran.c:809
png_color_struct
Definition: png.h:551
png_get_valid
png_uint_32 PNGAPI png_get_valid(png_const_structp png_ptr, png_const_infop info_ptr, png_uint_32 flag)
Definition: pngget.c:20
PNG_INFO_sBIT
#define PNG_INFO_sBIT
Definition: png.h:810
png_set_strip_alpha
void PNGAPI png_set_strip_alpha(png_structp png_ptr)
Definition: pngrtran.c:168
png_read_info
void PNGAPI png_read_info(png_structp png_ptr, png_infop info_ptr)
Definition: pngread.c:182
png_set_read_fn
void PNGAPI png_set_read_fn(png_structp png_ptr, png_voidp io_ptr, png_rw_ptr read_data_fn)
Definition: pngrio.c:145
png_set_invert_mono
void PNGAPI png_set_invert_mono(png_structp png_ptr)
Definition: pngtrans.c:198
png_color_8_struct
Definition: png.h:573
y
EGLSurface EGLint EGLint y
Definition: eglext.h:293
png_bytep
png_byte FAR * png_bytep
Definition: pngconf.h:526
PNG_FILTER_TYPE_BASE
#define PNG_FILTER_TYPE_BASE
Definition: png.h:759
PNG_COMPRESSION_TYPE_BASE
#define PNG_COMPRESSION_TYPE_BASE
Definition: png.h:755
buf
GLenum GLuint GLsizei const GLchar * buf
Definition: glew.h:2539
PNG_INFO_tRNS
#define PNG_INFO_tRNS
Definition: png.h:813
png_destroy_write_struct
void PNGAPI png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
Definition: pngwrite.c:876
png_color_8p
png_color_8 FAR * png_color_8p
Definition: png.h:581
png_set_interlace_handling
int PNGAPI png_set_interlace_handling(png_structp png_ptr)
Definition: pngtrans.c:97
png_voidp
void FAR * png_voidp
Definition: pngconf.h:524
png_set_tRNS_to_alpha
void PNGAPI png_set_tRNS_to_alpha(png_structp png_ptr)
Definition: pngrtran.c:882
png_read_png
void PNGAPI png_read_png(png_structp png_ptr, png_infop info_ptr, int transforms, voidp params)
Definition: pngread.c:1125
png_read_image
void PNGAPI png_read_image(png_structp png_ptr, png_bytepp image)
Definition: pngread.c:734
PNG_FILLER_AFTER
#define PNG_FILLER_AFTER
Definition: png.h:1396
png_size_t
size_t png_size_t
Definition: pngconf.h:454
png_color_8_struct::alpha
png_byte alpha
Definition: png.h:579
png_set_progressive_read_fn
void PNGAPI png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr, png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn)
Definition: pngpread.c:1821
png_get_bKGD
png_uint_32 PNGAPI png_get_bKGD(png_const_structp png_ptr, png_infop info_ptr, png_color_16p *background)
Definition: pngget.c:445
histogram
float ** histogram
Definition: metrics.c:44
png_free
void PNGAPI png_free(png_structp png_ptr, png_voidp ptr)
Definition: pngmem.c:578
png_color_16_struct
Definition: png.h:561
png_set_swap_alpha
void PNGAPI png_set_swap_alpha(png_structp png_ptr)
Definition: pngtrans.c:171
png_destroy_read_struct
void PNGAPI png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr)
Definition: pngread.c:940
png_color_8_struct::gray
png_byte gray
Definition: png.h:578
png_read_update_info
void PNGAPI png_read_update_info(png_structp png_ptr, png_infop info_ptr)
Definition: pngread.c:345
png_init_io
void PNGAPI png_init_io(png_structp png_ptr, png_FILE_p fp)
Definition: png.c:577
png_sig_cmp
int PNGAPI png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check)
Definition: png.c:49
png_sizeof
#define png_sizeof(x)
Definition: pngconf.h:456
png_colorp
png_color FAR * png_colorp
Definition: png.h:557