2 /* pngwrite.c - general routines to write a PNG file
4 * Copyright (c) 2018-2023 Cosmin Truta
5 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
6 * Copyright (c) 1996-1997 Andreas Dilger
7 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
9 * This code is released under the libpng license.
10 * For conditions of distribution and use, see the disclaimer
11 * and license in png.h
15 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
17 #endif /* SIMPLIFIED_WRITE_STDIO */
19 #ifdef PNG_WRITE_SUPPORTED
21 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
22 /* Write out all the unknown chunks for the current given location */
24 write_unknown_chunks(png_structrp png_ptr
, png_const_inforp info_ptr
,
27 if (info_ptr
->unknown_chunks_num
!= 0)
29 png_const_unknown_chunkp up
;
31 png_debug(5, "writing extra chunks");
33 for (up
= info_ptr
->unknown_chunks
;
34 up
< info_ptr
->unknown_chunks
+ info_ptr
->unknown_chunks_num
;
36 if ((up
->location
& where
) != 0)
38 /* If per-chunk unknown chunk handling is enabled use it, otherwise
39 * just write the chunks the application has set.
41 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
42 int keep
= png_handle_as_unknown(png_ptr
, up
->name
);
44 /* NOTE: this code is radically different from the read side in the
45 * matter of handling an ancillary unknown chunk. In the read side
46 * the default behavior is to discard it, in the code below the default
47 * behavior is to write it. Critical chunks are, however, only
48 * written if explicitly listed or if the default is set to write all
51 * The default handling is also slightly weird - it is not possible to
52 * stop the writing of all unsafe-to-copy chunks!
54 * TODO: REVIEW: this would seem to be a bug.
56 if (keep
!= PNG_HANDLE_CHUNK_NEVER
&&
57 ((up
->name
[3] & 0x20) /* safe-to-copy overrides everything */ ||
58 keep
== PNG_HANDLE_CHUNK_ALWAYS
||
59 (keep
== PNG_HANDLE_CHUNK_AS_DEFAULT
&&
60 png_ptr
->unknown_default
== PNG_HANDLE_CHUNK_ALWAYS
)))
63 /* TODO: review, what is wrong with a zero length unknown chunk? */
65 png_warning(png_ptr
, "Writing zero-length unknown chunk");
67 png_write_chunk(png_ptr
, up
->name
, up
->data
, up
->size
);
72 #endif /* WRITE_UNKNOWN_CHUNKS */
74 /* Writes all the PNG information. This is the suggested way to use the
75 * library. If you have a new chunk to add, make a function to write it,
76 * and put it in the correct location here. If you want the chunk written
77 * after the image data, put it in png_write_end(). I strongly encourage
78 * you to supply a PNG_INFO_<chunk> flag, and check info_ptr->valid before
79 * writing the chunk, as that will keep the code from breaking if you want
80 * to just write a plain PNG file. If you have long comments, I suggest
81 * writing them in png_write_end(), and compressing them.
84 png_write_info_before_PLTE(png_structrp png_ptr
, png_const_inforp info_ptr
)
86 png_debug(1, "in png_write_info_before_PLTE");
88 if (png_ptr
== NULL
|| info_ptr
== NULL
)
91 if ((png_ptr
->mode
& PNG_WROTE_INFO_BEFORE_PLTE
) == 0)
93 /* Write PNG signature */
94 png_write_sig(png_ptr
);
96 #ifdef PNG_MNG_FEATURES_SUPPORTED
97 if ((png_ptr
->mode
& PNG_HAVE_PNG_SIGNATURE
) != 0 && \
98 png_ptr
->mng_features_permitted
!= 0)
101 "MNG features are not allowed in a PNG datastream");
102 png_ptr
->mng_features_permitted
= 0;
106 /* Write IHDR information. */
107 png_write_IHDR(png_ptr
, info_ptr
->width
, info_ptr
->height
,
108 info_ptr
->bit_depth
, info_ptr
->color_type
, info_ptr
->compression_type
,
109 info_ptr
->filter_type
,
110 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
111 info_ptr
->interlace_type
117 /* The rest of these check to see if the valid field has the appropriate
118 * flag set, and if it does, writes the chunk.
120 * 1.6.0: COLORSPACE support controls the writing of these chunks too, and
121 * the chunks will be written if the WRITE routine is there and
122 * information * is available in the COLORSPACE. (See
123 * png_colorspace_sync_info in png.c for where the valid flags get set.)
125 * Under certain circumstances the colorspace can be invalidated without
126 * syncing the info_struct 'valid' flags; this happens if libpng detects
127 * an error and calls png_error while the color space is being set, yet
128 * the application continues writing the PNG. So check the 'invalid'
131 #ifdef PNG_GAMMA_SUPPORTED
132 # ifdef PNG_WRITE_gAMA_SUPPORTED
133 if ((info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) == 0 &&
134 (info_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_gAMA
) != 0 &&
135 (info_ptr
->valid
& PNG_INFO_gAMA
) != 0)
136 png_write_gAMA_fixed(png_ptr
, info_ptr
->colorspace
.gamma
);
140 #ifdef PNG_COLORSPACE_SUPPORTED
141 /* Write only one of sRGB or an ICC profile. If a profile was supplied
142 * and it matches one of the known sRGB ones issue a warning.
144 # ifdef PNG_WRITE_iCCP_SUPPORTED
145 if ((info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) == 0 &&
146 (info_ptr
->valid
& PNG_INFO_iCCP
) != 0)
148 # ifdef PNG_WRITE_sRGB_SUPPORTED
149 if ((info_ptr
->valid
& PNG_INFO_sRGB
) != 0)
150 png_app_warning(png_ptr
,
151 "profile matches sRGB but writing iCCP instead");
154 png_write_iCCP(png_ptr
, info_ptr
->iccp_name
,
155 info_ptr
->iccp_profile
);
157 # ifdef PNG_WRITE_sRGB_SUPPORTED
162 # ifdef PNG_WRITE_sRGB_SUPPORTED
163 if ((info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) == 0 &&
164 (info_ptr
->valid
& PNG_INFO_sRGB
) != 0)
165 png_write_sRGB(png_ptr
, info_ptr
->colorspace
.rendering_intent
);
166 # endif /* WRITE_sRGB */
167 #endif /* COLORSPACE */
169 #ifdef PNG_WRITE_sBIT_SUPPORTED
170 if ((info_ptr
->valid
& PNG_INFO_sBIT
) != 0)
171 png_write_sBIT(png_ptr
, &(info_ptr
->sig_bit
), info_ptr
->color_type
);
174 #ifdef PNG_COLORSPACE_SUPPORTED
175 # ifdef PNG_WRITE_cHRM_SUPPORTED
176 if ((info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) == 0 &&
177 (info_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_cHRM
) != 0 &&
178 (info_ptr
->valid
& PNG_INFO_cHRM
) != 0)
179 png_write_cHRM_fixed(png_ptr
, &info_ptr
->colorspace
.end_points_xy
);
183 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
184 write_unknown_chunks(png_ptr
, info_ptr
, PNG_HAVE_IHDR
);
187 png_ptr
->mode
|= PNG_WROTE_INFO_BEFORE_PLTE
;
192 png_write_info(png_structrp png_ptr
, png_const_inforp info_ptr
)
194 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
198 png_debug(1, "in png_write_info");
200 if (png_ptr
== NULL
|| info_ptr
== NULL
)
203 png_write_info_before_PLTE(png_ptr
, info_ptr
);
205 if ((info_ptr
->valid
& PNG_INFO_PLTE
) != 0)
206 png_write_PLTE(png_ptr
, info_ptr
->palette
,
207 (png_uint_32
)info_ptr
->num_palette
);
209 else if (info_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
210 png_error(png_ptr
, "Valid palette required for paletted images");
212 #ifdef PNG_WRITE_tRNS_SUPPORTED
213 if ((info_ptr
->valid
& PNG_INFO_tRNS
) !=0)
215 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
216 /* Invert the alpha channel (in tRNS) */
217 if ((png_ptr
->transformations
& PNG_INVERT_ALPHA
) != 0 &&
218 info_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
222 jend
= info_ptr
->num_trans
;
223 if (jend
> PNG_MAX_PALETTE_LENGTH
)
224 jend
= PNG_MAX_PALETTE_LENGTH
;
226 for (j
= 0; j
<jend
; ++j
)
227 info_ptr
->trans_alpha
[j
] =
228 (png_byte
)(255 - info_ptr
->trans_alpha
[j
]);
231 png_write_tRNS(png_ptr
, info_ptr
->trans_alpha
, &(info_ptr
->trans_color
),
232 info_ptr
->num_trans
, info_ptr
->color_type
);
235 #ifdef PNG_WRITE_bKGD_SUPPORTED
236 if ((info_ptr
->valid
& PNG_INFO_bKGD
) != 0)
237 png_write_bKGD(png_ptr
, &(info_ptr
->background
), info_ptr
->color_type
);
240 #ifdef PNG_WRITE_eXIf_SUPPORTED
241 if ((info_ptr
->valid
& PNG_INFO_eXIf
) != 0)
243 png_write_eXIf(png_ptr
, info_ptr
->exif
, info_ptr
->num_exif
);
244 png_ptr
->mode
|= PNG_WROTE_eXIf
;
248 #ifdef PNG_WRITE_hIST_SUPPORTED
249 if ((info_ptr
->valid
& PNG_INFO_hIST
) != 0)
250 png_write_hIST(png_ptr
, info_ptr
->hist
, info_ptr
->num_palette
);
253 #ifdef PNG_WRITE_oFFs_SUPPORTED
254 if ((info_ptr
->valid
& PNG_INFO_oFFs
) != 0)
255 png_write_oFFs(png_ptr
, info_ptr
->x_offset
, info_ptr
->y_offset
,
256 info_ptr
->offset_unit_type
);
259 #ifdef PNG_WRITE_pCAL_SUPPORTED
260 if ((info_ptr
->valid
& PNG_INFO_pCAL
) != 0)
261 png_write_pCAL(png_ptr
, info_ptr
->pcal_purpose
, info_ptr
->pcal_X0
,
262 info_ptr
->pcal_X1
, info_ptr
->pcal_type
, info_ptr
->pcal_nparams
,
263 info_ptr
->pcal_units
, info_ptr
->pcal_params
);
266 #ifdef PNG_WRITE_sCAL_SUPPORTED
267 if ((info_ptr
->valid
& PNG_INFO_sCAL
) != 0)
268 png_write_sCAL_s(png_ptr
, (int)info_ptr
->scal_unit
,
269 info_ptr
->scal_s_width
, info_ptr
->scal_s_height
);
272 #ifdef PNG_WRITE_pHYs_SUPPORTED
273 if ((info_ptr
->valid
& PNG_INFO_pHYs
) != 0)
274 png_write_pHYs(png_ptr
, info_ptr
->x_pixels_per_unit
,
275 info_ptr
->y_pixels_per_unit
, info_ptr
->phys_unit_type
);
278 #ifdef PNG_WRITE_tIME_SUPPORTED
279 if ((info_ptr
->valid
& PNG_INFO_tIME
) != 0)
281 png_write_tIME(png_ptr
, &(info_ptr
->mod_time
));
282 png_ptr
->mode
|= PNG_WROTE_tIME
;
286 #ifdef PNG_WRITE_sPLT_SUPPORTED
287 if ((info_ptr
->valid
& PNG_INFO_sPLT
) != 0)
288 for (i
= 0; i
< (int)info_ptr
->splt_palettes_num
; i
++)
289 png_write_sPLT(png_ptr
, info_ptr
->splt_palettes
+ i
);
292 #ifdef PNG_WRITE_TEXT_SUPPORTED
293 /* Check to see if we need to write text chunks */
294 for (i
= 0; i
< info_ptr
->num_text
; i
++)
296 png_debug2(2, "Writing header text chunk %d, type %d", i
,
297 info_ptr
->text
[i
].compression
);
298 /* An internationalized chunk? */
299 if (info_ptr
->text
[i
].compression
> 0)
301 #ifdef PNG_WRITE_iTXt_SUPPORTED
302 /* Write international chunk */
303 png_write_iTXt(png_ptr
,
304 info_ptr
->text
[i
].compression
,
305 info_ptr
->text
[i
].key
,
306 info_ptr
->text
[i
].lang
,
307 info_ptr
->text
[i
].lang_key
,
308 info_ptr
->text
[i
].text
);
309 /* Mark this chunk as written */
310 if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
311 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
313 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
315 png_warning(png_ptr
, "Unable to write international text");
319 /* If we want a compressed text chunk */
320 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_zTXt
)
322 #ifdef PNG_WRITE_zTXt_SUPPORTED
323 /* Write compressed chunk */
324 png_write_zTXt(png_ptr
, info_ptr
->text
[i
].key
,
325 info_ptr
->text
[i
].text
, info_ptr
->text
[i
].compression
);
326 /* Mark this chunk as written */
327 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
329 png_warning(png_ptr
, "Unable to write compressed text");
333 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
335 #ifdef PNG_WRITE_tEXt_SUPPORTED
336 /* Write uncompressed chunk */
337 png_write_tEXt(png_ptr
, info_ptr
->text
[i
].key
,
338 info_ptr
->text
[i
].text
,
340 /* Mark this chunk as written */
341 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
344 png_warning(png_ptr
, "Unable to write uncompressed text");
350 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
351 write_unknown_chunks(png_ptr
, info_ptr
, PNG_HAVE_PLTE
);
355 /* Writes the end of the PNG file. If you don't want to write comments or
356 * time information, you can pass NULL for info. If you already wrote these
357 * in png_write_info(), do not write them again here. If you have long
358 * comments, I suggest writing them here, and compressing them.
361 png_write_end(png_structrp png_ptr
, png_inforp info_ptr
)
363 png_debug(1, "in png_write_end");
368 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) == 0)
369 png_error(png_ptr
, "No IDATs written into file");
371 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
372 if (png_ptr
->num_palette_max
> png_ptr
->num_palette
)
373 png_benign_error(png_ptr
, "Wrote palette index exceeding num_palette");
376 /* See if user wants us to write information chunks */
377 if (info_ptr
!= NULL
)
379 #ifdef PNG_WRITE_TEXT_SUPPORTED
380 int i
; /* local index variable */
382 #ifdef PNG_WRITE_tIME_SUPPORTED
383 /* Check to see if user has supplied a time chunk */
384 if ((info_ptr
->valid
& PNG_INFO_tIME
) != 0 &&
385 (png_ptr
->mode
& PNG_WROTE_tIME
) == 0)
386 png_write_tIME(png_ptr
, &(info_ptr
->mod_time
));
389 #ifdef PNG_WRITE_TEXT_SUPPORTED
390 /* Loop through comment chunks */
391 for (i
= 0; i
< info_ptr
->num_text
; i
++)
393 png_debug2(2, "Writing trailer text chunk %d, type %d", i
,
394 info_ptr
->text
[i
].compression
);
395 /* An internationalized chunk? */
396 if (info_ptr
->text
[i
].compression
> 0)
398 #ifdef PNG_WRITE_iTXt_SUPPORTED
399 /* Write international chunk */
400 png_write_iTXt(png_ptr
,
401 info_ptr
->text
[i
].compression
,
402 info_ptr
->text
[i
].key
,
403 info_ptr
->text
[i
].lang
,
404 info_ptr
->text
[i
].lang_key
,
405 info_ptr
->text
[i
].text
);
406 /* Mark this chunk as written */
407 if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
408 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
410 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
412 png_warning(png_ptr
, "Unable to write international text");
416 else if (info_ptr
->text
[i
].compression
>= PNG_TEXT_COMPRESSION_zTXt
)
418 #ifdef PNG_WRITE_zTXt_SUPPORTED
419 /* Write compressed chunk */
420 png_write_zTXt(png_ptr
, info_ptr
->text
[i
].key
,
421 info_ptr
->text
[i
].text
, info_ptr
->text
[i
].compression
);
422 /* Mark this chunk as written */
423 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
425 png_warning(png_ptr
, "Unable to write compressed text");
429 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
431 #ifdef PNG_WRITE_tEXt_SUPPORTED
432 /* Write uncompressed chunk */
433 png_write_tEXt(png_ptr
, info_ptr
->text
[i
].key
,
434 info_ptr
->text
[i
].text
, 0);
435 /* Mark this chunk as written */
436 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
438 png_warning(png_ptr
, "Unable to write uncompressed text");
444 #ifdef PNG_WRITE_eXIf_SUPPORTED
445 if ((info_ptr
->valid
& PNG_INFO_eXIf
) != 0 &&
446 (png_ptr
->mode
& PNG_WROTE_eXIf
) == 0)
447 png_write_eXIf(png_ptr
, info_ptr
->exif
, info_ptr
->num_exif
);
450 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
451 write_unknown_chunks(png_ptr
, info_ptr
, PNG_AFTER_IDAT
);
455 png_ptr
->mode
|= PNG_AFTER_IDAT
;
457 /* Write end of PNG file */
458 png_write_IEND(png_ptr
);
460 /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
461 * and restored again in libpng-1.2.30, may cause some applications that
462 * do not set png_ptr->output_flush_fn to crash. If your application
463 * experiences a problem, please try building libpng with
464 * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
465 * png-mng-implement at lists.sf.net .
467 #ifdef PNG_WRITE_FLUSH_SUPPORTED
468 # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
474 #ifdef PNG_CONVERT_tIME_SUPPORTED
476 png_convert_from_struct_tm(png_timep ptime
, const struct tm
* ttime
)
478 png_debug(1, "in png_convert_from_struct_tm");
480 ptime
->year
= (png_uint_16
)(1900 + ttime
->tm_year
);
481 ptime
->month
= (png_byte
)(ttime
->tm_mon
+ 1);
482 ptime
->day
= (png_byte
)ttime
->tm_mday
;
483 ptime
->hour
= (png_byte
)ttime
->tm_hour
;
484 ptime
->minute
= (png_byte
)ttime
->tm_min
;
485 ptime
->second
= (png_byte
)ttime
->tm_sec
;
489 png_convert_from_time_t(png_timep ptime
, time_t ttime
)
493 png_debug(1, "in png_convert_from_time_t");
495 tbuf
= gmtime(&ttime
);
498 /* TODO: add a safe function which takes a png_ptr argument and raises
499 * a png_error if the ttime argument is invalid and the call to gmtime
500 * fails as a consequence.
502 memset(ptime
, 0, sizeof(*ptime
));
506 png_convert_from_struct_tm(ptime
, tbuf
);
510 /* Initialize png_ptr structure, and allocate any memory needed */
511 PNG_FUNCTION(png_structp
,PNGAPI
512 png_create_write_struct
,(png_const_charp user_png_ver
, png_voidp error_ptr
,
513 png_error_ptr error_fn
, png_error_ptr warn_fn
),PNG_ALLOCATED
)
515 #ifndef PNG_USER_MEM_SUPPORTED
516 png_structrp png_ptr
= png_create_png_struct(user_png_ver
, error_ptr
,
517 error_fn
, warn_fn
, NULL
, NULL
, NULL
);
519 return png_create_write_struct_2(user_png_ver
, error_ptr
, error_fn
,
520 warn_fn
, NULL
, NULL
, NULL
);
523 /* Alternate initialize png_ptr structure, and allocate any memory needed */
524 PNG_FUNCTION(png_structp
,PNGAPI
525 png_create_write_struct_2
,(png_const_charp user_png_ver
, png_voidp error_ptr
,
526 png_error_ptr error_fn
, png_error_ptr warn_fn
, png_voidp mem_ptr
,
527 png_malloc_ptr malloc_fn
, png_free_ptr free_fn
),PNG_ALLOCATED
)
529 png_structrp png_ptr
= png_create_png_struct(user_png_ver
, error_ptr
,
530 error_fn
, warn_fn
, mem_ptr
, malloc_fn
, free_fn
);
531 #endif /* USER_MEM */
534 /* Set the zlib control values to defaults; they can be overridden by the
535 * application after the struct has been created.
537 png_ptr
->zbuffer_size
= PNG_ZBUF_SIZE
;
539 /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
540 * pngwutil.c defaults it according to whether or not filters will be
541 * used, and ignores this setting.
543 png_ptr
->zlib_strategy
= PNG_Z_DEFAULT_STRATEGY
;
544 png_ptr
->zlib_level
= PNG_Z_DEFAULT_COMPRESSION
;
545 png_ptr
->zlib_mem_level
= 8;
546 png_ptr
->zlib_window_bits
= 15;
547 png_ptr
->zlib_method
= 8;
549 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
550 png_ptr
->zlib_text_strategy
= PNG_TEXT_Z_DEFAULT_STRATEGY
;
551 png_ptr
->zlib_text_level
= PNG_TEXT_Z_DEFAULT_COMPRESSION
;
552 png_ptr
->zlib_text_mem_level
= 8;
553 png_ptr
->zlib_text_window_bits
= 15;
554 png_ptr
->zlib_text_method
= 8;
555 #endif /* WRITE_COMPRESSED_TEXT */
557 /* This is a highly dubious configuration option; by default it is off,
558 * but it may be appropriate for private builds that are testing
559 * extensions not conformant to the current specification, or of
560 * applications that must not fail to write at all costs!
562 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
563 /* In stable builds only warn if an application error can be completely
566 png_ptr
->flags
|= PNG_FLAG_BENIGN_ERRORS_WARN
;
569 /* App warnings are warnings in release (or release candidate) builds but
570 * are errors during development.
572 #if PNG_RELEASE_BUILD
573 png_ptr
->flags
|= PNG_FLAG_APP_WARNINGS_WARN
;
576 /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
577 * do it itself) avoiding setting the default function if it is not
580 png_set_write_fn(png_ptr
, NULL
, NULL
, NULL
);
587 /* Write a few rows of image data. If the image is interlaced,
588 * either you will have to write the 7 sub images, or, if you
589 * have called png_set_interlace_handling(), you will have to
590 * "write" the image seven times.
593 png_write_rows(png_structrp png_ptr
, png_bytepp row
,
594 png_uint_32 num_rows
)
596 png_uint_32 i
; /* row counter */
597 png_bytepp rp
; /* row pointer */
599 png_debug(1, "in png_write_rows");
604 /* Loop through the rows */
605 for (i
= 0, rp
= row
; i
< num_rows
; i
++, rp
++)
607 png_write_row(png_ptr
, *rp
);
611 /* Write the image. You only need to call this function once, even
612 * if you are writing an interlaced image.
615 png_write_image(png_structrp png_ptr
, png_bytepp image
)
617 png_uint_32 i
; /* row index */
618 int pass
, num_pass
; /* pass variables */
619 png_bytepp rp
; /* points to current row */
624 png_debug(1, "in png_write_image");
626 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
627 /* Initialize interlace handling. If image is not interlaced,
628 * this will set pass to 1
630 num_pass
= png_set_interlace_handling(png_ptr
);
634 /* Loop through passes */
635 for (pass
= 0; pass
< num_pass
; pass
++)
637 /* Loop through image */
638 for (i
= 0, rp
= image
; i
< png_ptr
->height
; i
++, rp
++)
640 png_write_row(png_ptr
, *rp
);
645 #ifdef PNG_MNG_FEATURES_SUPPORTED
646 /* Performs intrapixel differencing */
648 png_do_write_intrapixel(png_row_infop row_info
, png_bytep row
)
650 png_debug(1, "in png_do_write_intrapixel");
652 if ((row_info
->color_type
& PNG_COLOR_MASK_COLOR
) != 0)
655 png_uint_32 row_width
= row_info
->width
;
656 if (row_info
->bit_depth
== 8)
661 if (row_info
->color_type
== PNG_COLOR_TYPE_RGB
)
664 else if (row_info
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
670 for (i
= 0, rp
= row
; i
< row_width
; i
++, rp
+= bytes_per_pixel
)
672 *(rp
) = (png_byte
)(*rp
- *(rp
+ 1));
673 *(rp
+ 2) = (png_byte
)(*(rp
+ 2) - *(rp
+ 1));
677 #ifdef PNG_WRITE_16BIT_SUPPORTED
678 else if (row_info
->bit_depth
== 16)
683 if (row_info
->color_type
== PNG_COLOR_TYPE_RGB
)
686 else if (row_info
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
692 for (i
= 0, rp
= row
; i
< row_width
; i
++, rp
+= bytes_per_pixel
)
694 png_uint_32 s0
= (png_uint_32
)(*(rp
) << 8) | *(rp
+ 1);
695 png_uint_32 s1
= (png_uint_32
)(*(rp
+ 2) << 8) | *(rp
+ 3);
696 png_uint_32 s2
= (png_uint_32
)(*(rp
+ 4) << 8) | *(rp
+ 5);
697 png_uint_32 red
= (png_uint_32
)((s0
- s1
) & 0xffffL
);
698 png_uint_32 blue
= (png_uint_32
)((s2
- s1
) & 0xffffL
);
699 *(rp
) = (png_byte
)(red
>> 8);
700 *(rp
+ 1) = (png_byte
)red
;
701 *(rp
+ 4) = (png_byte
)(blue
>> 8);
702 *(rp
+ 5) = (png_byte
)blue
;
705 #endif /* WRITE_16BIT */
708 #endif /* MNG_FEATURES */
710 /* Called by user to write a row of image data */
712 png_write_row(png_structrp png_ptr
, png_const_bytep row
)
714 /* 1.5.6: moved from png_struct to be a local structure: */
715 png_row_info row_info
;
720 png_debug2(1, "in png_write_row (row %u, pass %d)",
721 png_ptr
->row_number
, png_ptr
->pass
);
723 /* Initialize transformations and other stuff if first time */
724 if (png_ptr
->row_number
== 0 && png_ptr
->pass
== 0)
726 /* Make sure we wrote the header info */
727 if ((png_ptr
->mode
& PNG_WROTE_INFO_BEFORE_PLTE
) == 0)
729 "png_write_info was never called before png_write_row");
731 /* Check for transforms that have been set but were defined out */
732 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
733 if ((png_ptr
->transformations
& PNG_INVERT_MONO
) != 0)
734 png_warning(png_ptr
, "PNG_WRITE_INVERT_SUPPORTED is not defined");
737 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
738 if ((png_ptr
->transformations
& PNG_FILLER
) != 0)
739 png_warning(png_ptr
, "PNG_WRITE_FILLER_SUPPORTED is not defined");
741 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
742 defined(PNG_READ_PACKSWAP_SUPPORTED)
743 if ((png_ptr
->transformations
& PNG_PACKSWAP
) != 0)
745 "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
748 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
749 if ((png_ptr
->transformations
& PNG_PACK
) != 0)
750 png_warning(png_ptr
, "PNG_WRITE_PACK_SUPPORTED is not defined");
753 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
754 if ((png_ptr
->transformations
& PNG_SHIFT
) != 0)
755 png_warning(png_ptr
, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
758 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
759 if ((png_ptr
->transformations
& PNG_BGR
) != 0)
760 png_warning(png_ptr
, "PNG_WRITE_BGR_SUPPORTED is not defined");
763 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
764 if ((png_ptr
->transformations
& PNG_SWAP_BYTES
) != 0)
765 png_warning(png_ptr
, "PNG_WRITE_SWAP_SUPPORTED is not defined");
768 png_write_start_row(png_ptr
);
771 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
772 /* If interlaced and not interested in row, return */
773 if (png_ptr
->interlaced
!= 0 &&
774 (png_ptr
->transformations
& PNG_INTERLACE
) != 0)
776 switch (png_ptr
->pass
)
779 if ((png_ptr
->row_number
& 0x07) != 0)
781 png_write_finish_row(png_ptr
);
787 if ((png_ptr
->row_number
& 0x07) != 0 || png_ptr
->width
< 5)
789 png_write_finish_row(png_ptr
);
795 if ((png_ptr
->row_number
& 0x07) != 4)
797 png_write_finish_row(png_ptr
);
803 if ((png_ptr
->row_number
& 0x03) != 0 || png_ptr
->width
< 3)
805 png_write_finish_row(png_ptr
);
811 if ((png_ptr
->row_number
& 0x03) != 2)
813 png_write_finish_row(png_ptr
);
819 if ((png_ptr
->row_number
& 0x01) != 0 || png_ptr
->width
< 2)
821 png_write_finish_row(png_ptr
);
827 if ((png_ptr
->row_number
& 0x01) == 0)
829 png_write_finish_row(png_ptr
);
834 default: /* error: ignore it */
840 /* Set up row info for transformations */
841 row_info
.color_type
= png_ptr
->color_type
;
842 row_info
.width
= png_ptr
->usr_width
;
843 row_info
.channels
= png_ptr
->usr_channels
;
844 row_info
.bit_depth
= png_ptr
->usr_bit_depth
;
845 row_info
.pixel_depth
= (png_byte
)(row_info
.bit_depth
* row_info
.channels
);
846 row_info
.rowbytes
= PNG_ROWBYTES(row_info
.pixel_depth
, row_info
.width
);
848 png_debug1(3, "row_info->color_type = %d", row_info
.color_type
);
849 png_debug1(3, "row_info->width = %u", row_info
.width
);
850 png_debug1(3, "row_info->channels = %d", row_info
.channels
);
851 png_debug1(3, "row_info->bit_depth = %d", row_info
.bit_depth
);
852 png_debug1(3, "row_info->pixel_depth = %d", row_info
.pixel_depth
);
853 png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info
.rowbytes
);
855 /* Copy user's row into buffer, leaving room for filter byte. */
856 memcpy(png_ptr
->row_buf
+ 1, row
, row_info
.rowbytes
);
858 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
859 /* Handle interlacing */
860 if (png_ptr
->interlaced
&& png_ptr
->pass
< 6 &&
861 (png_ptr
->transformations
& PNG_INTERLACE
) != 0)
863 png_do_write_interlace(&row_info
, png_ptr
->row_buf
+ 1, png_ptr
->pass
);
864 /* This should always get caught above, but still ... */
865 if (row_info
.width
== 0)
867 png_write_finish_row(png_ptr
);
873 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
874 /* Handle other transformations */
875 if (png_ptr
->transformations
!= 0)
876 png_do_write_transformations(png_ptr
, &row_info
);
879 /* At this point the row_info pixel depth must match the 'transformed' depth,
880 * which is also the output depth.
882 if (row_info
.pixel_depth
!= png_ptr
->pixel_depth
||
883 row_info
.pixel_depth
!= png_ptr
->transformed_pixel_depth
)
884 png_error(png_ptr
, "internal write transform logic error");
886 #ifdef PNG_MNG_FEATURES_SUPPORTED
887 /* Write filter_method 64 (intrapixel differencing) only if
888 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
889 * 2. Libpng did not write a PNG signature (this filter_method is only
890 * used in PNG datastreams that are embedded in MNG datastreams) and
891 * 3. The application called png_permit_mng_features with a mask that
892 * included PNG_FLAG_MNG_FILTER_64 and
893 * 4. The filter_method is 64 and
894 * 5. The color_type is RGB or RGBA
896 if ((png_ptr
->mng_features_permitted
& PNG_FLAG_MNG_FILTER_64
) != 0 &&
897 (png_ptr
->filter_type
== PNG_INTRAPIXEL_DIFFERENCING
))
899 /* Intrapixel differencing */
900 png_do_write_intrapixel(&row_info
, png_ptr
->row_buf
+ 1);
904 /* Added at libpng-1.5.10 */
905 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
906 /* Check for out-of-range palette index */
907 if (row_info
.color_type
== PNG_COLOR_TYPE_PALETTE
&&
908 png_ptr
->num_palette_max
>= 0)
909 png_do_check_palette_indexes(png_ptr
, &row_info
);
912 /* Find a filter if necessary, filter the row and write it out. */
913 png_write_find_filter(png_ptr
, &row_info
);
915 if (png_ptr
->write_row_fn
!= NULL
)
916 (*(png_ptr
->write_row_fn
))(png_ptr
, png_ptr
->row_number
, png_ptr
->pass
);
919 #ifdef PNG_WRITE_FLUSH_SUPPORTED
920 /* Set the automatic flush interval or 0 to turn flushing off */
922 png_set_flush(png_structrp png_ptr
, int nrows
)
924 png_debug(1, "in png_set_flush");
929 png_ptr
->flush_dist
= (nrows
< 0 ? 0 : (png_uint_32
)nrows
);
932 /* Flush the current output buffers now */
934 png_write_flush(png_structrp png_ptr
)
936 png_debug(1, "in png_write_flush");
941 /* We have already written out all of the data */
942 if (png_ptr
->row_number
>= png_ptr
->num_rows
)
945 png_compress_IDAT(png_ptr
, NULL
, 0, Z_SYNC_FLUSH
);
946 png_ptr
->flush_rows
= 0;
949 #endif /* WRITE_FLUSH */
951 /* Free any memory used in png_ptr struct without freeing the struct itself. */
953 png_write_destroy(png_structrp png_ptr
)
955 png_debug(1, "in png_write_destroy");
957 /* Free any memory zlib uses */
958 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_INITIALIZED
) != 0)
959 deflateEnd(&png_ptr
->zstream
);
961 /* Free our memory. png_free checks NULL for us. */
962 png_free_buffer_list(png_ptr
, &png_ptr
->zbuffer_list
);
963 png_free(png_ptr
, png_ptr
->row_buf
);
964 png_ptr
->row_buf
= NULL
;
965 #ifdef PNG_WRITE_FILTER_SUPPORTED
966 png_free(png_ptr
, png_ptr
->prev_row
);
967 png_free(png_ptr
, png_ptr
->try_row
);
968 png_free(png_ptr
, png_ptr
->tst_row
);
969 png_ptr
->prev_row
= NULL
;
970 png_ptr
->try_row
= NULL
;
971 png_ptr
->tst_row
= NULL
;
974 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
975 png_free(png_ptr
, png_ptr
->chunk_list
);
976 png_ptr
->chunk_list
= NULL
;
979 /* The error handling and memory handling information is left intact at this
980 * point: the jmp_buf may still have to be freed. See png_destroy_png_struct
981 * for how this happens.
985 /* Free all memory used by the write.
986 * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
987 * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
988 * the passed in info_structs but it would quietly fail to free any of the data
989 * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
993 png_destroy_write_struct(png_structpp png_ptr_ptr
, png_infopp info_ptr_ptr
)
995 png_debug(1, "in png_destroy_write_struct");
997 if (png_ptr_ptr
!= NULL
)
999 png_structrp png_ptr
= *png_ptr_ptr
;
1001 if (png_ptr
!= NULL
) /* added in libpng 1.6.0 */
1003 png_destroy_info_struct(png_ptr
, info_ptr_ptr
);
1005 *png_ptr_ptr
= NULL
;
1006 png_write_destroy(png_ptr
);
1007 png_destroy_png_struct(png_ptr
);
1012 /* Allow the application to select one or more row filters to use. */
1014 png_set_filter(png_structrp png_ptr
, int method
, int filters
)
1016 png_debug(1, "in png_set_filter");
1018 if (png_ptr
== NULL
)
1021 #ifdef PNG_MNG_FEATURES_SUPPORTED
1022 if ((png_ptr
->mng_features_permitted
& PNG_FLAG_MNG_FILTER_64
) != 0 &&
1023 (method
== PNG_INTRAPIXEL_DIFFERENCING
))
1024 method
= PNG_FILTER_TYPE_BASE
;
1027 if (method
== PNG_FILTER_TYPE_BASE
)
1029 switch (filters
& (PNG_ALL_FILTERS
| 0x07))
1031 #ifdef PNG_WRITE_FILTER_SUPPORTED
1034 case 7: png_app_error(png_ptr
, "Unknown row filter for method 0");
1035 #endif /* WRITE_FILTER */
1037 case PNG_FILTER_VALUE_NONE
:
1038 png_ptr
->do_filter
= PNG_FILTER_NONE
; break;
1040 #ifdef PNG_WRITE_FILTER_SUPPORTED
1041 case PNG_FILTER_VALUE_SUB
:
1042 png_ptr
->do_filter
= PNG_FILTER_SUB
; break;
1044 case PNG_FILTER_VALUE_UP
:
1045 png_ptr
->do_filter
= PNG_FILTER_UP
; break;
1047 case PNG_FILTER_VALUE_AVG
:
1048 png_ptr
->do_filter
= PNG_FILTER_AVG
; break;
1050 case PNG_FILTER_VALUE_PAETH
:
1051 png_ptr
->do_filter
= PNG_FILTER_PAETH
; break;
1054 png_ptr
->do_filter
= (png_byte
)filters
; break;
1057 png_app_error(png_ptr
, "Unknown row filter for method 0");
1058 #endif /* WRITE_FILTER */
1061 #ifdef PNG_WRITE_FILTER_SUPPORTED
1062 /* If we have allocated the row_buf, this means we have already started
1063 * with the image and we should have allocated all of the filter buffers
1064 * that have been selected. If prev_row isn't already allocated, then
1065 * it is too late to start using the filters that need it, since we
1066 * will be missing the data in the previous row. If an application
1067 * wants to start and stop using particular filters during compression,
1068 * it should start out with all of the filters, and then remove them
1069 * or add them back after the start of compression.
1071 * NOTE: this is a nasty constraint on the code, because it means that the
1072 * prev_row buffer must be maintained even if there are currently no
1073 * 'prev_row' requiring filters active.
1075 if (png_ptr
->row_buf
!= NULL
)
1078 png_alloc_size_t buf_size
;
1080 /* Repeat the checks in png_write_start_row; 1 pixel high or wide
1081 * images cannot benefit from certain filters. If this isn't done here
1082 * the check below will fire on 1 pixel high images.
1084 if (png_ptr
->height
== 1)
1085 filters
&= ~(PNG_FILTER_UP
|PNG_FILTER_AVG
|PNG_FILTER_PAETH
);
1087 if (png_ptr
->width
== 1)
1088 filters
&= ~(PNG_FILTER_SUB
|PNG_FILTER_AVG
|PNG_FILTER_PAETH
);
1090 if ((filters
& (PNG_FILTER_UP
|PNG_FILTER_AVG
|PNG_FILTER_PAETH
)) != 0
1091 && png_ptr
->prev_row
== NULL
)
1093 /* This is the error case, however it is benign - the previous row
1094 * is not available so the filter can't be used. Just warn here.
1096 png_app_warning(png_ptr
,
1097 "png_set_filter: UP/AVG/PAETH cannot be added after start");
1098 filters
&= ~(PNG_FILTER_UP
|PNG_FILTER_AVG
|PNG_FILTER_PAETH
);
1103 if (filters
& PNG_FILTER_SUB
)
1106 if (filters
& PNG_FILTER_UP
)
1109 if (filters
& PNG_FILTER_AVG
)
1112 if (filters
& PNG_FILTER_PAETH
)
1115 /* Allocate needed row buffers if they have not already been
1118 buf_size
= PNG_ROWBYTES(png_ptr
->usr_channels
* png_ptr
->usr_bit_depth
,
1119 png_ptr
->width
) + 1;
1121 if (png_ptr
->try_row
== NULL
)
1122 png_ptr
->try_row
= png_voidcast(png_bytep
,
1123 png_malloc(png_ptr
, buf_size
));
1125 if (num_filters
> 1)
1127 if (png_ptr
->tst_row
== NULL
)
1128 png_ptr
->tst_row
= png_voidcast(png_bytep
,
1129 png_malloc(png_ptr
, buf_size
));
1132 png_ptr
->do_filter
= (png_byte
)filters
;
1136 png_error(png_ptr
, "Unknown custom filter method");
1139 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1140 /* Provide floating and fixed point APIs */
1141 #ifdef PNG_FLOATING_POINT_SUPPORTED
1143 png_set_filter_heuristics(png_structrp png_ptr
, int heuristic_method
,
1144 int num_weights
, png_const_doublep filter_weights
,
1145 png_const_doublep filter_costs
)
1148 PNG_UNUSED(heuristic_method
)
1149 PNG_UNUSED(num_weights
)
1150 PNG_UNUSED(filter_weights
)
1151 PNG_UNUSED(filter_costs
)
1153 #endif /* FLOATING_POINT */
1155 #ifdef PNG_FIXED_POINT_SUPPORTED
1157 png_set_filter_heuristics_fixed(png_structrp png_ptr
, int heuristic_method
,
1158 int num_weights
, png_const_fixed_point_p filter_weights
,
1159 png_const_fixed_point_p filter_costs
)
1162 PNG_UNUSED(heuristic_method
)
1163 PNG_UNUSED(num_weights
)
1164 PNG_UNUSED(filter_weights
)
1165 PNG_UNUSED(filter_costs
)
1167 #endif /* FIXED_POINT */
1168 #endif /* WRITE_WEIGHTED_FILTER */
1170 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1172 png_set_compression_level(png_structrp png_ptr
, int level
)
1174 png_debug(1, "in png_set_compression_level");
1176 if (png_ptr
== NULL
)
1179 png_ptr
->zlib_level
= level
;
1183 png_set_compression_mem_level(png_structrp png_ptr
, int mem_level
)
1185 png_debug(1, "in png_set_compression_mem_level");
1187 if (png_ptr
== NULL
)
1190 png_ptr
->zlib_mem_level
= mem_level
;
1194 png_set_compression_strategy(png_structrp png_ptr
, int strategy
)
1196 png_debug(1, "in png_set_compression_strategy");
1198 if (png_ptr
== NULL
)
1201 /* The flag setting here prevents the libpng dynamic selection of strategy.
1203 png_ptr
->flags
|= PNG_FLAG_ZLIB_CUSTOM_STRATEGY
;
1204 png_ptr
->zlib_strategy
= strategy
;
1207 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1208 * smaller value of window_bits if it can do so safely.
1211 png_set_compression_window_bits(png_structrp png_ptr
, int window_bits
)
1213 if (png_ptr
== NULL
)
1216 /* Prior to 1.6.0 this would warn but then set the window_bits value. This
1217 * meant that negative window bits values could be selected that would cause
1218 * libpng to write a non-standard PNG file with raw deflate or gzip
1219 * compressed IDAT or ancillary chunks. Such files can be read and there is
1220 * no warning on read, so this seems like a very bad idea.
1222 if (window_bits
> 15)
1224 png_warning(png_ptr
, "Only compression windows <= 32k supported by PNG");
1228 else if (window_bits
< 8)
1230 png_warning(png_ptr
, "Only compression windows >= 256 supported by PNG");
1234 png_ptr
->zlib_window_bits
= window_bits
;
1238 png_set_compression_method(png_structrp png_ptr
, int method
)
1240 png_debug(1, "in png_set_compression_method");
1242 if (png_ptr
== NULL
)
1245 /* This would produce an invalid PNG file if it worked, but it doesn't and
1246 * deflate will fault it, so it is harmless to just warn here.
1249 png_warning(png_ptr
, "Only compression method 8 is supported by PNG");
1251 png_ptr
->zlib_method
= method
;
1253 #endif /* WRITE_CUSTOMIZE_COMPRESSION */
1255 /* The following were added to libpng-1.5.4 */
1256 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1258 png_set_text_compression_level(png_structrp png_ptr
, int level
)
1260 png_debug(1, "in png_set_text_compression_level");
1262 if (png_ptr
== NULL
)
1265 png_ptr
->zlib_text_level
= level
;
1269 png_set_text_compression_mem_level(png_structrp png_ptr
, int mem_level
)
1271 png_debug(1, "in png_set_text_compression_mem_level");
1273 if (png_ptr
== NULL
)
1276 png_ptr
->zlib_text_mem_level
= mem_level
;
1280 png_set_text_compression_strategy(png_structrp png_ptr
, int strategy
)
1282 png_debug(1, "in png_set_text_compression_strategy");
1284 if (png_ptr
== NULL
)
1287 png_ptr
->zlib_text_strategy
= strategy
;
1290 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1291 * smaller value of window_bits if it can do so safely.
1294 png_set_text_compression_window_bits(png_structrp png_ptr
, int window_bits
)
1296 if (png_ptr
== NULL
)
1299 if (window_bits
> 15)
1301 png_warning(png_ptr
, "Only compression windows <= 32k supported by PNG");
1305 else if (window_bits
< 8)
1307 png_warning(png_ptr
, "Only compression windows >= 256 supported by PNG");
1311 png_ptr
->zlib_text_window_bits
= window_bits
;
1315 png_set_text_compression_method(png_structrp png_ptr
, int method
)
1317 png_debug(1, "in png_set_text_compression_method");
1319 if (png_ptr
== NULL
)
1323 png_warning(png_ptr
, "Only compression method 8 is supported by PNG");
1325 png_ptr
->zlib_text_method
= method
;
1327 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1328 /* end of API added to libpng-1.5.4 */
1331 png_set_write_status_fn(png_structrp png_ptr
, png_write_status_ptr write_row_fn
)
1333 if (png_ptr
== NULL
)
1336 png_ptr
->write_row_fn
= write_row_fn
;
1339 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1341 png_set_write_user_transform_fn(png_structrp png_ptr
, png_user_transform_ptr
1342 write_user_transform_fn
)
1344 png_debug(1, "in png_set_write_user_transform_fn");
1346 if (png_ptr
== NULL
)
1349 png_ptr
->transformations
|= PNG_USER_TRANSFORM
;
1350 png_ptr
->write_user_transform_fn
= write_user_transform_fn
;
1355 #ifdef PNG_INFO_IMAGE_SUPPORTED
1357 png_write_png(png_structrp png_ptr
, png_inforp info_ptr
,
1358 int transforms
, voidp params
)
1360 if (png_ptr
== NULL
|| info_ptr
== NULL
)
1363 if ((info_ptr
->valid
& PNG_INFO_IDAT
) == 0)
1365 png_app_error(png_ptr
, "no rows for png_write_image to write");
1369 /* Write the file header information. */
1370 png_write_info(png_ptr
, info_ptr
);
1372 /* ------ these transformations don't touch the info structure ------- */
1374 /* Invert monochrome pixels */
1375 if ((transforms
& PNG_TRANSFORM_INVERT_MONO
) != 0)
1376 #ifdef PNG_WRITE_INVERT_SUPPORTED
1377 png_set_invert_mono(png_ptr
);
1379 png_app_error(png_ptr
, "PNG_TRANSFORM_INVERT_MONO not supported");
1382 /* Shift the pixels up to a legal bit depth and fill in
1383 * as appropriate to correctly scale the image.
1385 if ((transforms
& PNG_TRANSFORM_SHIFT
) != 0)
1386 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1387 if ((info_ptr
->valid
& PNG_INFO_sBIT
) != 0)
1388 png_set_shift(png_ptr
, &info_ptr
->sig_bit
);
1390 png_app_error(png_ptr
, "PNG_TRANSFORM_SHIFT not supported");
1393 /* Pack pixels into bytes */
1394 if ((transforms
& PNG_TRANSFORM_PACKING
) != 0)
1395 #ifdef PNG_WRITE_PACK_SUPPORTED
1396 png_set_packing(png_ptr
);
1398 png_app_error(png_ptr
, "PNG_TRANSFORM_PACKING not supported");
1401 /* Swap location of alpha bytes from ARGB to RGBA */
1402 if ((transforms
& PNG_TRANSFORM_SWAP_ALPHA
) != 0)
1403 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1404 png_set_swap_alpha(png_ptr
);
1406 png_app_error(png_ptr
, "PNG_TRANSFORM_SWAP_ALPHA not supported");
1409 /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
1410 * RGB, note that the code expects the input color type to be G or RGB; no
1413 if ((transforms
& (PNG_TRANSFORM_STRIP_FILLER_AFTER
|
1414 PNG_TRANSFORM_STRIP_FILLER_BEFORE
)) != 0)
1416 #ifdef PNG_WRITE_FILLER_SUPPORTED
1417 if ((transforms
& PNG_TRANSFORM_STRIP_FILLER_AFTER
) != 0)
1419 if ((transforms
& PNG_TRANSFORM_STRIP_FILLER_BEFORE
) != 0)
1420 png_app_error(png_ptr
,
1421 "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
1423 /* Continue if ignored - this is the pre-1.6.10 behavior */
1424 png_set_filler(png_ptr
, 0, PNG_FILLER_AFTER
);
1427 else if ((transforms
& PNG_TRANSFORM_STRIP_FILLER_BEFORE
) != 0)
1428 png_set_filler(png_ptr
, 0, PNG_FILLER_BEFORE
);
1430 png_app_error(png_ptr
, "PNG_TRANSFORM_STRIP_FILLER not supported");
1434 /* Flip BGR pixels to RGB */
1435 if ((transforms
& PNG_TRANSFORM_BGR
) != 0)
1436 #ifdef PNG_WRITE_BGR_SUPPORTED
1437 png_set_bgr(png_ptr
);
1439 png_app_error(png_ptr
, "PNG_TRANSFORM_BGR not supported");
1442 /* Swap bytes of 16-bit files to most significant byte first */
1443 if ((transforms
& PNG_TRANSFORM_SWAP_ENDIAN
) != 0)
1444 #ifdef PNG_WRITE_SWAP_SUPPORTED
1445 png_set_swap(png_ptr
);
1447 png_app_error(png_ptr
, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
1450 /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
1451 if ((transforms
& PNG_TRANSFORM_PACKSWAP
) != 0)
1452 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1453 png_set_packswap(png_ptr
);
1455 png_app_error(png_ptr
, "PNG_TRANSFORM_PACKSWAP not supported");
1458 /* Invert the alpha channel from opacity to transparency */
1459 if ((transforms
& PNG_TRANSFORM_INVERT_ALPHA
) != 0)
1460 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1461 png_set_invert_alpha(png_ptr
);
1463 png_app_error(png_ptr
, "PNG_TRANSFORM_INVERT_ALPHA not supported");
1466 /* ----------------------- end of transformations ------------------- */
1468 /* Write the bits */
1469 png_write_image(png_ptr
, info_ptr
->row_pointers
);
1471 /* It is REQUIRED to call this to finish writing the rest of the file */
1472 png_write_end(png_ptr
, info_ptr
);
1479 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
1480 /* Initialize the write structure - general purpose utility. */
1482 png_image_write_init(png_imagep image
)
1484 png_structp png_ptr
= png_create_write_struct(PNG_LIBPNG_VER_STRING
, image
,
1485 png_safe_error
, png_safe_warning
);
1487 if (png_ptr
!= NULL
)
1489 png_infop info_ptr
= png_create_info_struct(png_ptr
);
1491 if (info_ptr
!= NULL
)
1493 png_controlp control
= png_voidcast(png_controlp
,
1494 png_malloc_warn(png_ptr
, (sizeof *control
)));
1496 if (control
!= NULL
)
1498 memset(control
, 0, (sizeof *control
));
1500 control
->png_ptr
= png_ptr
;
1501 control
->info_ptr
= info_ptr
;
1502 control
->for_write
= 1;
1504 image
->opaque
= control
;
1508 /* Error clean up */
1509 png_destroy_info_struct(png_ptr
, &info_ptr
);
1512 png_destroy_write_struct(&png_ptr
, NULL
);
1515 return png_image_error(image
, "png_image_write_: out of memory");
1518 /* Arguments to png_image_write_main: */
1523 png_const_voidp buffer
;
1524 png_int_32 row_stride
;
1525 png_const_voidp colormap
;
1526 int convert_to_8bit
;
1527 /* Local variables: */
1528 png_const_voidp first_row
;
1529 ptrdiff_t row_bytes
;
1530 png_voidp local_row
;
1531 /* Byte count for memory writing */
1533 png_alloc_size_t memory_bytes
; /* not used for STDIO */
1534 png_alloc_size_t output_bytes
; /* running total */
1535 } png_image_write_control
;
1537 /* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
1538 * do any necessary byte swapping. The component order is defined by the
1539 * png_image format value.
1542 png_write_image_16bit(png_voidp argument
)
1544 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
1546 png_imagep image
= display
->image
;
1547 png_structrp png_ptr
= image
->opaque
->png_ptr
;
1549 png_const_uint_16p input_row
= png_voidcast(png_const_uint_16p
,
1550 display
->first_row
);
1551 png_uint_16p output_row
= png_voidcast(png_uint_16p
, display
->local_row
);
1552 png_uint_16p row_end
;
1553 unsigned int channels
= (image
->format
& PNG_FORMAT_FLAG_COLOR
) != 0 ?
1556 png_uint_32 y
= image
->height
;
1558 if ((image
->format
& PNG_FORMAT_FLAG_ALPHA
) != 0)
1560 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1561 if ((image
->format
& PNG_FORMAT_FLAG_AFIRST
) != 0)
1564 ++input_row
; /* To point to the first component */
1568 aindex
= (int)channels
;
1570 aindex
= (int)channels
;
1575 png_error(png_ptr
, "png_write_image: internal call error");
1577 /* Work out the output row end and count over this, note that the increment
1578 * above to 'row' means that row_end can actually be beyond the end of the
1579 * row; this is correct.
1581 row_end
= output_row
+ image
->width
* (channels
+1);
1585 png_const_uint_16p in_ptr
= input_row
;
1586 png_uint_16p out_ptr
= output_row
;
1588 while (out_ptr
< row_end
)
1590 png_uint_16 alpha
= in_ptr
[aindex
];
1591 png_uint_32 reciprocal
= 0;
1594 out_ptr
[aindex
] = alpha
;
1596 /* Calculate a reciprocal. The correct calculation is simply
1597 * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
1598 * allows correct rounding by adding .5 before the shift. 'reciprocal'
1599 * is only initialized when required.
1601 if (alpha
> 0 && alpha
< 65535)
1602 reciprocal
= ((0xffff<<15)+(alpha
>>1))/alpha
;
1605 do /* always at least one channel */
1607 png_uint_16 component
= *in_ptr
++;
1609 /* The following gives 65535 for an alpha of 0, which is fine,
1610 * otherwise if 0/0 is represented as some other value there is more
1611 * likely to be a discontinuity which will probably damage
1612 * compression when moving from a fully transparent area to a
1613 * nearly transparent one. (The assumption here is that opaque
1614 * areas tend not to be 0 intensity.)
1616 if (component
>= alpha
)
1619 /* component<alpha, so component/alpha is less than one and
1620 * component*reciprocal is less than 2^31.
1622 else if (component
> 0 && alpha
< 65535)
1624 png_uint_32 calc
= component
* reciprocal
;
1625 calc
+= 16384; /* round to nearest */
1626 component
= (png_uint_16
)(calc
>> 15);
1629 *out_ptr
++ = component
;
1633 /* Skip to next component (skip the intervening alpha channel) */
1638 png_write_row(png_ptr
, png_voidcast(png_const_bytep
, display
->local_row
));
1639 input_row
+= (png_uint_16
)display
->row_bytes
/(sizeof (png_uint_16
));
1645 /* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
1646 * is present it must be removed from the components, the components are then
1647 * written in sRGB encoding. No components are added or removed.
1649 * Calculate an alpha reciprocal to reverse pre-multiplication. As above the
1650 * calculation can be done to 15 bits of accuracy; however, the output needs to
1651 * be scaled in the range 0..255*65535, so include that scaling here.
1653 # define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+((alpha)>>1))/(alpha))
1656 png_unpremultiply(png_uint_32 component
, png_uint_32 alpha
,
1657 png_uint_32 reciprocal
/*from the above macro*/)
1659 /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
1660 * is represented as some other value there is more likely to be a
1661 * discontinuity which will probably damage compression when moving from a
1662 * fully transparent area to a nearly transparent one. (The assumption here
1663 * is that opaque areas tend not to be 0 intensity.)
1665 * There is a rounding problem here; if alpha is less than 128 it will end up
1666 * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
1667 * output change for this too.
1669 if (component
>= alpha
|| alpha
< 128)
1672 /* component<alpha, so component/alpha is less than one and
1673 * component*reciprocal is less than 2^31.
1675 else if (component
> 0)
1677 /* The test is that alpha/257 (rounded) is less than 255, the first value
1678 * that becomes 255 is 65407.
1679 * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
1680 * be exact!) [Could also test reciprocal != 0]
1684 component
*= reciprocal
;
1685 component
+= 64; /* round to nearest */
1692 /* Convert the component to sRGB. */
1693 return (png_byte
)PNG_sRGB_FROM_LINEAR(component
);
1701 png_write_image_8bit(png_voidp argument
)
1703 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
1705 png_imagep image
= display
->image
;
1706 png_structrp png_ptr
= image
->opaque
->png_ptr
;
1708 png_const_uint_16p input_row
= png_voidcast(png_const_uint_16p
,
1709 display
->first_row
);
1710 png_bytep output_row
= png_voidcast(png_bytep
, display
->local_row
);
1711 png_uint_32 y
= image
->height
;
1712 unsigned int channels
= (image
->format
& PNG_FORMAT_FLAG_COLOR
) != 0 ?
1715 if ((image
->format
& PNG_FORMAT_FLAG_ALPHA
) != 0)
1720 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1721 if ((image
->format
& PNG_FORMAT_FLAG_AFIRST
) != 0)
1724 ++input_row
; /* To point to the first component */
1730 aindex
= (int)channels
;
1732 /* Use row_end in place of a loop counter: */
1733 row_end
= output_row
+ image
->width
* (channels
+1);
1737 png_const_uint_16p in_ptr
= input_row
;
1738 png_bytep out_ptr
= output_row
;
1740 while (out_ptr
< row_end
)
1742 png_uint_16 alpha
= in_ptr
[aindex
];
1743 png_byte alphabyte
= (png_byte
)PNG_DIV257(alpha
);
1744 png_uint_32 reciprocal
= 0;
1747 /* Scale and write the alpha channel. */
1748 out_ptr
[aindex
] = alphabyte
;
1750 if (alphabyte
> 0 && alphabyte
< 255)
1751 reciprocal
= UNP_RECIPROCAL(alpha
);
1754 do /* always at least one channel */
1755 *out_ptr
++ = png_unpremultiply(*in_ptr
++, alpha
, reciprocal
);
1758 /* Skip to next component (skip the intervening alpha channel) */
1761 } /* while out_ptr < row_end */
1763 png_write_row(png_ptr
, png_voidcast(png_const_bytep
,
1764 display
->local_row
));
1765 input_row
+= (png_uint_16
)display
->row_bytes
/(sizeof (png_uint_16
));
1771 /* No alpha channel, so the row_end really is the end of the row and it
1772 * is sufficient to loop over the components one by one.
1774 png_bytep row_end
= output_row
+ image
->width
* channels
;
1778 png_const_uint_16p in_ptr
= input_row
;
1779 png_bytep out_ptr
= output_row
;
1781 while (out_ptr
< row_end
)
1783 png_uint_32 component
= *in_ptr
++;
1786 *out_ptr
++ = (png_byte
)PNG_sRGB_FROM_LINEAR(component
);
1789 png_write_row(png_ptr
, output_row
);
1790 input_row
+= (png_uint_16
)display
->row_bytes
/(sizeof (png_uint_16
));
1798 png_image_set_PLTE(png_image_write_control
*display
)
1800 png_imagep image
= display
->image
;
1801 const void *cmap
= display
->colormap
;
1802 int entries
= image
->colormap_entries
> 256 ? 256 :
1803 (int)image
->colormap_entries
;
1805 /* NOTE: the caller must check for cmap != NULL and entries != 0 */
1806 png_uint_32 format
= image
->format
;
1807 unsigned int channels
= PNG_IMAGE_SAMPLE_CHANNELS(format
);
1809 # if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
1810 defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
1811 int afirst
= (format
& PNG_FORMAT_FLAG_AFIRST
) != 0 &&
1812 (format
& PNG_FORMAT_FLAG_ALPHA
) != 0;
1817 # ifdef PNG_FORMAT_BGR_SUPPORTED
1818 int bgr
= (format
& PNG_FORMAT_FLAG_BGR
) != 0 ? 2 : 0;
1824 png_color palette
[256];
1827 memset(tRNS
, 255, (sizeof tRNS
));
1828 memset(palette
, 0, (sizeof palette
));
1830 for (i
=num_trans
=0; i
<entries
; ++i
)
1832 /* This gets automatically converted to sRGB with reversal of the
1833 * pre-multiplication if the color-map has an alpha channel.
1835 if ((format
& PNG_FORMAT_FLAG_LINEAR
) != 0)
1837 png_const_uint_16p entry
= png_voidcast(png_const_uint_16p
, cmap
);
1839 entry
+= (unsigned int)i
* channels
;
1841 if ((channels
& 1) != 0) /* no alpha */
1843 if (channels
>= 3) /* RGB */
1845 palette
[i
].blue
= (png_byte
)PNG_sRGB_FROM_LINEAR(255 *
1847 palette
[i
].green
= (png_byte
)PNG_sRGB_FROM_LINEAR(255 *
1849 palette
[i
].red
= (png_byte
)PNG_sRGB_FROM_LINEAR(255 *
1854 palette
[i
].blue
= palette
[i
].red
= palette
[i
].green
=
1855 (png_byte
)PNG_sRGB_FROM_LINEAR(255 * *entry
);
1860 png_uint_16 alpha
= entry
[afirst
? 0 : channels
-1];
1861 png_byte alphabyte
= (png_byte
)PNG_DIV257(alpha
);
1862 png_uint_32 reciprocal
= 0;
1864 /* Calculate a reciprocal, as in the png_write_image_8bit code above
1865 * this is designed to produce a value scaled to 255*65535 when
1866 * divided by 128 (i.e. asr 7).
1868 if (alphabyte
> 0 && alphabyte
< 255)
1869 reciprocal
= (((0xffff*0xff)<<7)+(alpha
>>1))/alpha
;
1871 tRNS
[i
] = alphabyte
;
1872 if (alphabyte
< 255)
1875 if (channels
>= 3) /* RGB */
1877 palette
[i
].blue
= png_unpremultiply(entry
[afirst
+ (2 ^ bgr
)],
1879 palette
[i
].green
= png_unpremultiply(entry
[afirst
+ 1], alpha
,
1881 palette
[i
].red
= png_unpremultiply(entry
[afirst
+ bgr
], alpha
,
1886 palette
[i
].blue
= palette
[i
].red
= palette
[i
].green
=
1887 png_unpremultiply(entry
[afirst
], alpha
, reciprocal
);
1891 else /* Color-map has sRGB values */
1893 png_const_bytep entry
= png_voidcast(png_const_bytep
, cmap
);
1895 entry
+= (unsigned int)i
* channels
;
1900 tRNS
[i
] = entry
[afirst
? 0 : 3];
1905 palette
[i
].blue
= entry
[afirst
+ (2 ^ bgr
)];
1906 palette
[i
].green
= entry
[afirst
+ 1];
1907 palette
[i
].red
= entry
[afirst
+ bgr
];
1911 tRNS
[i
] = entry
[1 ^ afirst
];
1916 palette
[i
].blue
= palette
[i
].red
= palette
[i
].green
=
1933 png_set_PLTE(image
->opaque
->png_ptr
, image
->opaque
->info_ptr
, palette
,
1937 png_set_tRNS(image
->opaque
->png_ptr
, image
->opaque
->info_ptr
, tRNS
,
1940 image
->colormap_entries
= (png_uint_32
)entries
;
1944 png_image_write_main(png_voidp argument
)
1946 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
1948 png_imagep image
= display
->image
;
1949 png_structrp png_ptr
= image
->opaque
->png_ptr
;
1950 png_inforp info_ptr
= image
->opaque
->info_ptr
;
1951 png_uint_32 format
= image
->format
;
1953 /* The following four ints are actually booleans */
1954 int colormap
= (format
& PNG_FORMAT_FLAG_COLORMAP
);
1955 int linear
= !colormap
&& (format
& PNG_FORMAT_FLAG_LINEAR
); /* input */
1956 int alpha
= !colormap
&& (format
& PNG_FORMAT_FLAG_ALPHA
);
1957 int write_16bit
= linear
&& (display
->convert_to_8bit
== 0);
1959 # ifdef PNG_BENIGN_ERRORS_SUPPORTED
1960 /* Make sure we error out on any bad situation */
1961 png_set_benign_errors(png_ptr
, 0/*error*/);
1964 /* Default the 'row_stride' parameter if required, also check the row stride
1965 * and total image size to ensure that they are within the system limits.
1968 unsigned int channels
= PNG_IMAGE_PIXEL_CHANNELS(image
->format
);
1970 if (image
->width
<= 0x7fffffffU
/channels
) /* no overflow */
1973 png_uint_32 png_row_stride
= image
->width
* channels
;
1975 if (display
->row_stride
== 0)
1976 display
->row_stride
= (png_int_32
)/*SAFE*/png_row_stride
;
1978 if (display
->row_stride
< 0)
1979 check
= (png_uint_32
)(-display
->row_stride
);
1982 check
= (png_uint_32
)display
->row_stride
;
1984 if (check
>= png_row_stride
)
1986 /* Now check for overflow of the image buffer calculation; this
1987 * limits the whole image size to 32 bits for API compatibility with
1988 * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
1990 if (image
->height
> 0xffffffffU
/png_row_stride
)
1991 png_error(image
->opaque
->png_ptr
, "memory image too large");
1995 png_error(image
->opaque
->png_ptr
, "supplied row stride too small");
1999 png_error(image
->opaque
->png_ptr
, "image row stride too large");
2002 /* Set the required transforms then write the rows in the correct order. */
2003 if ((format
& PNG_FORMAT_FLAG_COLORMAP
) != 0)
2005 if (display
->colormap
!= NULL
&& image
->colormap_entries
> 0)
2007 png_uint_32 entries
= image
->colormap_entries
;
2009 png_set_IHDR(png_ptr
, info_ptr
, image
->width
, image
->height
,
2010 entries
> 16 ? 8 : (entries
> 4 ? 4 : (entries
> 2 ? 2 : 1)),
2011 PNG_COLOR_TYPE_PALETTE
, PNG_INTERLACE_NONE
,
2012 PNG_COMPRESSION_TYPE_BASE
, PNG_FILTER_TYPE_BASE
);
2014 png_image_set_PLTE(display
);
2018 png_error(image
->opaque
->png_ptr
,
2019 "no color-map for color-mapped image");
2023 png_set_IHDR(png_ptr
, info_ptr
, image
->width
, image
->height
,
2024 write_16bit
? 16 : 8,
2025 ((format
& PNG_FORMAT_FLAG_COLOR
) ? PNG_COLOR_MASK_COLOR
: 0) +
2026 ((format
& PNG_FORMAT_FLAG_ALPHA
) ? PNG_COLOR_MASK_ALPHA
: 0),
2027 PNG_INTERLACE_NONE
, PNG_COMPRESSION_TYPE_BASE
, PNG_FILTER_TYPE_BASE
);
2029 /* Counter-intuitively the data transformations must be called *after*
2030 * png_write_info, not before as in the read code, but the 'set' functions
2031 * must still be called before. Just set the color space information, never
2032 * write an interlaced image.
2035 if (write_16bit
!= 0)
2037 /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
2038 png_set_gAMA_fixed(png_ptr
, info_ptr
, PNG_GAMMA_LINEAR
);
2040 if ((image
->flags
& PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB
) == 0)
2041 png_set_cHRM_fixed(png_ptr
, info_ptr
,
2043 /* white */ 31270, 32900,
2044 /* red */ 64000, 33000,
2045 /* green */ 30000, 60000,
2046 /* blue */ 15000, 6000
2050 else if ((image
->flags
& PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB
) == 0)
2051 png_set_sRGB(png_ptr
, info_ptr
, PNG_sRGB_INTENT_PERCEPTUAL
);
2053 /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
2054 * space must still be gamma encoded.
2057 png_set_gAMA_fixed(png_ptr
, info_ptr
, PNG_GAMMA_sRGB_INVERSE
);
2059 /* Write the file header. */
2060 png_write_info(png_ptr
, info_ptr
);
2062 /* Now set up the data transformations (*after* the header is written),
2063 * remove the handled transformations from the 'format' flags for checking.
2065 * First check for a little endian system if writing 16-bit files.
2067 if (write_16bit
!= 0)
2069 png_uint_16 le
= 0x0001;
2071 if ((*(png_const_bytep
) & le
) != 0)
2072 png_set_swap(png_ptr
);
2075 # ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
2076 if ((format
& PNG_FORMAT_FLAG_BGR
) != 0)
2078 if (colormap
== 0 && (format
& PNG_FORMAT_FLAG_COLOR
) != 0)
2079 png_set_bgr(png_ptr
);
2080 format
&= ~PNG_FORMAT_FLAG_BGR
;
2084 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
2085 if ((format
& PNG_FORMAT_FLAG_AFIRST
) != 0)
2087 if (colormap
== 0 && (format
& PNG_FORMAT_FLAG_ALPHA
) != 0)
2088 png_set_swap_alpha(png_ptr
);
2089 format
&= ~PNG_FORMAT_FLAG_AFIRST
;
2093 /* If there are 16 or fewer color-map entries we wrote a lower bit depth
2094 * above, but the application data is still byte packed.
2096 if (colormap
!= 0 && image
->colormap_entries
<= 16)
2097 png_set_packing(png_ptr
);
2099 /* That should have handled all (both) the transforms. */
2100 if ((format
& ~(png_uint_32
)(PNG_FORMAT_FLAG_COLOR
| PNG_FORMAT_FLAG_LINEAR
|
2101 PNG_FORMAT_FLAG_ALPHA
| PNG_FORMAT_FLAG_COLORMAP
)) != 0)
2102 png_error(png_ptr
, "png_write_image: unsupported transformation");
2105 png_const_bytep row
= png_voidcast(png_const_bytep
, display
->buffer
);
2106 ptrdiff_t row_bytes
= display
->row_stride
;
2109 row_bytes
*= (sizeof (png_uint_16
));
2112 row
+= (image
->height
-1) * (-row_bytes
);
2114 display
->first_row
= row
;
2115 display
->row_bytes
= row_bytes
;
2118 /* Apply 'fast' options if the flag is set. */
2119 if ((image
->flags
& PNG_IMAGE_FLAG_FAST
) != 0)
2121 png_set_filter(png_ptr
, PNG_FILTER_TYPE_BASE
, PNG_NO_FILTERS
);
2122 /* NOTE: determined by experiment using pngstest, this reflects some
2123 * balance between the time to write the image once and the time to read
2124 * it about 50 times. The speed-up in pngstest was about 10-20% of the
2125 * total (user) time on a heavily loaded system.
2127 # ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
2128 png_set_compression_level(png_ptr
, 3);
2132 /* Check for the cases that currently require a pre-transform on the row
2133 * before it is written. This only applies when the input is 16-bit and
2134 * either there is an alpha channel or it is converted to 8-bit.
2136 if ((linear
!= 0 && alpha
!= 0 ) ||
2137 (colormap
== 0 && display
->convert_to_8bit
!= 0))
2139 png_bytep row
= png_voidcast(png_bytep
, png_malloc(png_ptr
,
2140 png_get_rowbytes(png_ptr
, info_ptr
)));
2143 display
->local_row
= row
;
2144 if (write_16bit
!= 0)
2145 result
= png_safe_execute(image
, png_write_image_16bit
, display
);
2147 result
= png_safe_execute(image
, png_write_image_8bit
, display
);
2148 display
->local_row
= NULL
;
2150 png_free(png_ptr
, row
);
2152 /* Skip the 'write_end' on error: */
2157 /* Otherwise this is the case where the input is in a format currently
2158 * supported by the rest of the libpng write code; call it directly.
2162 png_const_bytep row
= png_voidcast(png_const_bytep
, display
->first_row
);
2163 ptrdiff_t row_bytes
= display
->row_bytes
;
2164 png_uint_32 y
= image
->height
;
2168 png_write_row(png_ptr
, row
);
2173 png_write_end(png_ptr
, info_ptr
);
2178 static void (PNGCBAPI
2179 image_memory_write
)(png_structp png_ptr
, png_bytep
/*const*/ data
, size_t size
)
2181 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
2182 png_ptr
->io_ptr
/*backdoor: png_get_io_ptr(png_ptr)*/);
2183 png_alloc_size_t ob
= display
->output_bytes
;
2185 /* Check for overflow; this should never happen: */
2186 if (size
<= ((png_alloc_size_t
)-1) - ob
)
2188 /* I don't think libpng ever does this, but just in case: */
2191 if (display
->memory_bytes
>= ob
+size
) /* writing */
2192 memcpy(display
->memory
+ob
, data
, size
);
2194 /* Always update the size: */
2195 display
->output_bytes
= ob
+size
;
2200 png_error(png_ptr
, "png_image_write_to_memory: PNG too big");
2203 static void (PNGCBAPI
2204 image_memory_flush
)(png_structp png_ptr
)
2210 png_image_write_memory(png_voidp argument
)
2212 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
2215 /* The rest of the memory-specific init and write_main in an error protected
2216 * environment. This case needs to use callbacks for the write operations
2217 * since libpng has no built in support for writing to memory.
2219 png_set_write_fn(display
->image
->opaque
->png_ptr
, display
/*io_ptr*/,
2220 image_memory_write
, image_memory_flush
);
2222 return png_image_write_main(display
);
2226 png_image_write_to_memory(png_imagep image
, void *memory
,
2227 png_alloc_size_t
* PNG_RESTRICT memory_bytes
, int convert_to_8bit
,
2228 const void *buffer
, png_int_32 row_stride
, const void *colormap
)
2230 /* Write the image to the given buffer, or count the bytes if it is NULL */
2231 if (image
!= NULL
&& image
->version
== PNG_IMAGE_VERSION
)
2233 if (memory_bytes
!= NULL
&& buffer
!= NULL
)
2235 /* This is to give the caller an easier error detection in the NULL
2236 * case and guard against uninitialized variable problems:
2241 if (png_image_write_init(image
) != 0)
2243 png_image_write_control display
;
2246 memset(&display
, 0, (sizeof display
));
2247 display
.image
= image
;
2248 display
.buffer
= buffer
;
2249 display
.row_stride
= row_stride
;
2250 display
.colormap
= colormap
;
2251 display
.convert_to_8bit
= convert_to_8bit
;
2252 display
.memory
= png_voidcast(png_bytep
, memory
);
2253 display
.memory_bytes
= *memory_bytes
;
2254 display
.output_bytes
= 0;
2256 result
= png_safe_execute(image
, png_image_write_memory
, &display
);
2257 png_image_free(image
);
2259 /* write_memory returns true even if we ran out of buffer. */
2262 /* On out-of-buffer this function returns '0' but still updates
2265 if (memory
!= NULL
&& display
.output_bytes
> *memory_bytes
)
2268 *memory_bytes
= display
.output_bytes
;
2279 return png_image_error(image
,
2280 "png_image_write_to_memory: invalid argument");
2283 else if (image
!= NULL
)
2284 return png_image_error(image
,
2285 "png_image_write_to_memory: incorrect PNG_IMAGE_VERSION");
2291 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
2293 png_image_write_to_stdio(png_imagep image
, FILE *file
, int convert_to_8bit
,
2294 const void *buffer
, png_int_32 row_stride
, const void *colormap
)
2296 /* Write the image to the given (FILE*). */
2297 if (image
!= NULL
&& image
->version
== PNG_IMAGE_VERSION
)
2299 if (file
!= NULL
&& buffer
!= NULL
)
2301 if (png_image_write_init(image
) != 0)
2303 png_image_write_control display
;
2306 /* This is slightly evil, but png_init_io doesn't do anything other
2307 * than this and we haven't changed the standard IO functions so
2308 * this saves a 'safe' function.
2310 image
->opaque
->png_ptr
->io_ptr
= file
;
2312 memset(&display
, 0, (sizeof display
));
2313 display
.image
= image
;
2314 display
.buffer
= buffer
;
2315 display
.row_stride
= row_stride
;
2316 display
.colormap
= colormap
;
2317 display
.convert_to_8bit
= convert_to_8bit
;
2319 result
= png_safe_execute(image
, png_image_write_main
, &display
);
2320 png_image_free(image
);
2329 return png_image_error(image
,
2330 "png_image_write_to_stdio: invalid argument");
2333 else if (image
!= NULL
)
2334 return png_image_error(image
,
2335 "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
2342 png_image_write_to_file(png_imagep image
, const char *file_name
,
2343 int convert_to_8bit
, const void *buffer
, png_int_32 row_stride
,
2344 const void *colormap
)
2346 /* Write the image to the named file. */
2347 if (image
!= NULL
&& image
->version
== PNG_IMAGE_VERSION
)
2349 if (file_name
!= NULL
&& buffer
!= NULL
)
2351 FILE *fp
= fopen(file_name
, "wb");
2355 if (png_image_write_to_stdio(image
, fp
, convert_to_8bit
, buffer
,
2356 row_stride
, colormap
) != 0)
2358 int error
; /* from fflush/fclose */
2360 /* Make sure the file is flushed correctly. */
2361 if (fflush(fp
) == 0 && ferror(fp
) == 0)
2363 if (fclose(fp
) == 0)
2366 error
= errno
; /* from fclose */
2371 error
= errno
; /* from fflush or ferror */
2375 (void)remove(file_name
);
2376 /* The image has already been cleaned up; this is just used to
2377 * set the error (because the original write succeeded).
2379 return png_image_error(image
, strerror(error
));
2384 /* Clean up: just the opened file. */
2386 (void)remove(file_name
);
2392 return png_image_error(image
, strerror(errno
));
2396 return png_image_error(image
,
2397 "png_image_write_to_file: invalid argument");
2400 else if (image
!= NULL
)
2401 return png_image_error(image
,
2402 "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
2407 #endif /* SIMPLIFIED_WRITE_STDIO */
2408 #endif /* SIMPLIFIED_WRITE */