2 /* pngwrite.c - general routines to write a PNG file
4 * Copyright (c) 2018-2022 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_WRITE_APNG_SUPPORTED
132 if ((info_ptr
->valid
& PNG_INFO_acTL
) != 0)
133 png_write_acTL(png_ptr
, info_ptr
->num_frames
, info_ptr
->num_plays
);
135 #ifdef PNG_GAMMA_SUPPORTED
136 # ifdef PNG_WRITE_gAMA_SUPPORTED
137 if ((info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) == 0 &&
138 (info_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_gAMA
) != 0 &&
139 (info_ptr
->valid
& PNG_INFO_gAMA
) != 0)
140 png_write_gAMA_fixed(png_ptr
, info_ptr
->colorspace
.gamma
);
144 #ifdef PNG_COLORSPACE_SUPPORTED
145 /* Write only one of sRGB or an ICC profile. If a profile was supplied
146 * and it matches one of the known sRGB ones issue a warning.
148 # ifdef PNG_WRITE_iCCP_SUPPORTED
149 if ((info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) == 0 &&
150 (info_ptr
->valid
& PNG_INFO_iCCP
) != 0)
152 # ifdef PNG_WRITE_sRGB_SUPPORTED
153 if ((info_ptr
->valid
& PNG_INFO_sRGB
) != 0)
154 png_app_warning(png_ptr
,
155 "profile matches sRGB but writing iCCP instead");
158 png_write_iCCP(png_ptr
, info_ptr
->iccp_name
,
159 info_ptr
->iccp_profile
);
161 # ifdef PNG_WRITE_sRGB_SUPPORTED
166 # ifdef PNG_WRITE_sRGB_SUPPORTED
167 if ((info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) == 0 &&
168 (info_ptr
->valid
& PNG_INFO_sRGB
) != 0)
169 png_write_sRGB(png_ptr
, info_ptr
->colorspace
.rendering_intent
);
170 # endif /* WRITE_sRGB */
171 #endif /* COLORSPACE */
173 #ifdef PNG_WRITE_sBIT_SUPPORTED
174 if ((info_ptr
->valid
& PNG_INFO_sBIT
) != 0)
175 png_write_sBIT(png_ptr
, &(info_ptr
->sig_bit
), info_ptr
->color_type
);
178 #ifdef PNG_COLORSPACE_SUPPORTED
179 # ifdef PNG_WRITE_cHRM_SUPPORTED
180 if ((info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) == 0 &&
181 (info_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_cHRM
) != 0 &&
182 (info_ptr
->valid
& PNG_INFO_cHRM
) != 0)
183 png_write_cHRM_fixed(png_ptr
, &info_ptr
->colorspace
.end_points_xy
);
187 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
188 write_unknown_chunks(png_ptr
, info_ptr
, PNG_HAVE_IHDR
);
191 png_ptr
->mode
|= PNG_WROTE_INFO_BEFORE_PLTE
;
196 png_write_info(png_structrp png_ptr
, png_const_inforp info_ptr
)
198 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
202 png_debug(1, "in png_write_info");
204 if (png_ptr
== NULL
|| info_ptr
== NULL
)
207 png_write_info_before_PLTE(png_ptr
, info_ptr
);
209 if ((info_ptr
->valid
& PNG_INFO_PLTE
) != 0)
210 png_write_PLTE(png_ptr
, info_ptr
->palette
,
211 (png_uint_32
)info_ptr
->num_palette
);
213 else if (info_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
214 png_error(png_ptr
, "Valid palette required for paletted images");
216 #ifdef PNG_WRITE_tRNS_SUPPORTED
217 if ((info_ptr
->valid
& PNG_INFO_tRNS
) !=0)
219 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
220 /* Invert the alpha channel (in tRNS) */
221 if ((png_ptr
->transformations
& PNG_INVERT_ALPHA
) != 0 &&
222 info_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
226 jend
= info_ptr
->num_trans
;
227 if (jend
> PNG_MAX_PALETTE_LENGTH
)
228 jend
= PNG_MAX_PALETTE_LENGTH
;
230 for (j
= 0; j
<jend
; ++j
)
231 info_ptr
->trans_alpha
[j
] =
232 (png_byte
)(255 - info_ptr
->trans_alpha
[j
]);
235 png_write_tRNS(png_ptr
, info_ptr
->trans_alpha
, &(info_ptr
->trans_color
),
236 info_ptr
->num_trans
, info_ptr
->color_type
);
239 #ifdef PNG_WRITE_bKGD_SUPPORTED
240 if ((info_ptr
->valid
& PNG_INFO_bKGD
) != 0)
241 png_write_bKGD(png_ptr
, &(info_ptr
->background
), info_ptr
->color_type
);
244 #ifdef PNG_WRITE_eXIf_SUPPORTED
245 if ((info_ptr
->valid
& PNG_INFO_eXIf
) != 0)
246 png_write_eXIf(png_ptr
, info_ptr
->exif
, info_ptr
->num_exif
);
249 #ifdef PNG_WRITE_hIST_SUPPORTED
250 if ((info_ptr
->valid
& PNG_INFO_hIST
) != 0)
251 png_write_hIST(png_ptr
, info_ptr
->hist
, info_ptr
->num_palette
);
254 #ifdef PNG_WRITE_oFFs_SUPPORTED
255 if ((info_ptr
->valid
& PNG_INFO_oFFs
) != 0)
256 png_write_oFFs(png_ptr
, info_ptr
->x_offset
, info_ptr
->y_offset
,
257 info_ptr
->offset_unit_type
);
260 #ifdef PNG_WRITE_pCAL_SUPPORTED
261 if ((info_ptr
->valid
& PNG_INFO_pCAL
) != 0)
262 png_write_pCAL(png_ptr
, info_ptr
->pcal_purpose
, info_ptr
->pcal_X0
,
263 info_ptr
->pcal_X1
, info_ptr
->pcal_type
, info_ptr
->pcal_nparams
,
264 info_ptr
->pcal_units
, info_ptr
->pcal_params
);
267 #ifdef PNG_WRITE_sCAL_SUPPORTED
268 if ((info_ptr
->valid
& PNG_INFO_sCAL
) != 0)
269 png_write_sCAL_s(png_ptr
, (int)info_ptr
->scal_unit
,
270 info_ptr
->scal_s_width
, info_ptr
->scal_s_height
);
273 #ifdef PNG_WRITE_pHYs_SUPPORTED
274 if ((info_ptr
->valid
& PNG_INFO_pHYs
) != 0)
275 png_write_pHYs(png_ptr
, info_ptr
->x_pixels_per_unit
,
276 info_ptr
->y_pixels_per_unit
, info_ptr
->phys_unit_type
);
279 #ifdef PNG_WRITE_tIME_SUPPORTED
280 if ((info_ptr
->valid
& PNG_INFO_tIME
) != 0)
282 png_write_tIME(png_ptr
, &(info_ptr
->mod_time
));
283 png_ptr
->mode
|= PNG_WROTE_tIME
;
287 #ifdef PNG_WRITE_sPLT_SUPPORTED
288 if ((info_ptr
->valid
& PNG_INFO_sPLT
) != 0)
289 for (i
= 0; i
< (int)info_ptr
->splt_palettes_num
; i
++)
290 png_write_sPLT(png_ptr
, info_ptr
->splt_palettes
+ i
);
293 #ifdef PNG_WRITE_TEXT_SUPPORTED
294 /* Check to see if we need to write text chunks */
295 for (i
= 0; i
< info_ptr
->num_text
; i
++)
297 png_debug2(2, "Writing header text chunk %d, type %d", i
,
298 info_ptr
->text
[i
].compression
);
299 /* An internationalized chunk? */
300 if (info_ptr
->text
[i
].compression
> 0)
302 #ifdef PNG_WRITE_iTXt_SUPPORTED
303 /* Write international chunk */
304 png_write_iTXt(png_ptr
,
305 info_ptr
->text
[i
].compression
,
306 info_ptr
->text
[i
].key
,
307 info_ptr
->text
[i
].lang
,
308 info_ptr
->text
[i
].lang_key
,
309 info_ptr
->text
[i
].text
);
310 /* Mark this chunk as written */
311 if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
312 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
314 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
316 png_warning(png_ptr
, "Unable to write international text");
320 /* If we want a compressed text chunk */
321 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_zTXt
)
323 #ifdef PNG_WRITE_zTXt_SUPPORTED
324 /* Write compressed chunk */
325 png_write_zTXt(png_ptr
, info_ptr
->text
[i
].key
,
326 info_ptr
->text
[i
].text
, info_ptr
->text
[i
].compression
);
327 /* Mark this chunk as written */
328 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
330 png_warning(png_ptr
, "Unable to write compressed text");
334 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
336 #ifdef PNG_WRITE_tEXt_SUPPORTED
337 /* Write uncompressed chunk */
338 png_write_tEXt(png_ptr
, info_ptr
->text
[i
].key
,
339 info_ptr
->text
[i
].text
,
341 /* Mark this chunk as written */
342 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
345 png_warning(png_ptr
, "Unable to write uncompressed text");
351 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
352 write_unknown_chunks(png_ptr
, info_ptr
, PNG_HAVE_PLTE
);
356 /* Writes the end of the PNG file. If you don't want to write comments or
357 * time information, you can pass NULL for info. If you already wrote these
358 * in png_write_info(), do not write them again here. If you have long
359 * comments, I suggest writing them here, and compressing them.
362 png_write_end(png_structrp png_ptr
, png_inforp info_ptr
)
364 png_debug(1, "in png_write_end");
369 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) == 0)
370 png_error(png_ptr
, "No IDATs written into file");
372 #ifdef PNG_WRITE_APNG_SUPPORTED
373 if (png_ptr
->num_frames_written
!= png_ptr
->num_frames_to_write
)
374 png_error(png_ptr
, "Not enough frames written");
377 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
378 if (png_ptr
->num_palette_max
> png_ptr
->num_palette
)
379 png_benign_error(png_ptr
, "Wrote palette index exceeding num_palette");
382 /* See if user wants us to write information chunks */
383 if (info_ptr
!= NULL
)
385 #ifdef PNG_WRITE_TEXT_SUPPORTED
386 int i
; /* local index variable */
388 #ifdef PNG_WRITE_tIME_SUPPORTED
389 /* Check to see if user has supplied a time chunk */
390 if ((info_ptr
->valid
& PNG_INFO_tIME
) != 0 &&
391 (png_ptr
->mode
& PNG_WROTE_tIME
) == 0)
392 png_write_tIME(png_ptr
, &(info_ptr
->mod_time
));
395 #ifdef PNG_WRITE_TEXT_SUPPORTED
396 /* Loop through comment chunks */
397 for (i
= 0; i
< info_ptr
->num_text
; i
++)
399 png_debug2(2, "Writing trailer text chunk %d, type %d", i
,
400 info_ptr
->text
[i
].compression
);
401 /* An internationalized chunk? */
402 if (info_ptr
->text
[i
].compression
> 0)
404 #ifdef PNG_WRITE_iTXt_SUPPORTED
405 /* Write international chunk */
406 png_write_iTXt(png_ptr
,
407 info_ptr
->text
[i
].compression
,
408 info_ptr
->text
[i
].key
,
409 info_ptr
->text
[i
].lang
,
410 info_ptr
->text
[i
].lang_key
,
411 info_ptr
->text
[i
].text
);
412 /* Mark this chunk as written */
413 if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
414 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
416 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
418 png_warning(png_ptr
, "Unable to write international text");
422 else if (info_ptr
->text
[i
].compression
>= PNG_TEXT_COMPRESSION_zTXt
)
424 #ifdef PNG_WRITE_zTXt_SUPPORTED
425 /* Write compressed chunk */
426 png_write_zTXt(png_ptr
, info_ptr
->text
[i
].key
,
427 info_ptr
->text
[i
].text
, info_ptr
->text
[i
].compression
);
428 /* Mark this chunk as written */
429 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
431 png_warning(png_ptr
, "Unable to write compressed text");
435 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
437 #ifdef PNG_WRITE_tEXt_SUPPORTED
438 /* Write uncompressed chunk */
439 png_write_tEXt(png_ptr
, info_ptr
->text
[i
].key
,
440 info_ptr
->text
[i
].text
, 0);
441 /* Mark this chunk as written */
442 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
444 png_warning(png_ptr
, "Unable to write uncompressed text");
450 #ifdef PNG_WRITE_eXIf_SUPPORTED
451 if ((info_ptr
->valid
& PNG_INFO_eXIf
) != 0)
452 png_write_eXIf(png_ptr
, info_ptr
->exif
, info_ptr
->num_exif
);
455 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
456 write_unknown_chunks(png_ptr
, info_ptr
, PNG_AFTER_IDAT
);
460 png_ptr
->mode
|= PNG_AFTER_IDAT
;
462 /* Write end of PNG file */
463 png_write_IEND(png_ptr
);
465 /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
466 * and restored again in libpng-1.2.30, may cause some applications that
467 * do not set png_ptr->output_flush_fn to crash. If your application
468 * experiences a problem, please try building libpng with
469 * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
470 * png-mng-implement at lists.sf.net .
472 #ifdef PNG_WRITE_FLUSH_SUPPORTED
473 # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
479 #ifdef PNG_CONVERT_tIME_SUPPORTED
481 png_convert_from_struct_tm(png_timep ptime
, const struct tm
* ttime
)
483 png_debug(1, "in png_convert_from_struct_tm");
485 ptime
->year
= (png_uint_16
)(1900 + ttime
->tm_year
);
486 ptime
->month
= (png_byte
)(ttime
->tm_mon
+ 1);
487 ptime
->day
= (png_byte
)ttime
->tm_mday
;
488 ptime
->hour
= (png_byte
)ttime
->tm_hour
;
489 ptime
->minute
= (png_byte
)ttime
->tm_min
;
490 ptime
->second
= (png_byte
)ttime
->tm_sec
;
494 png_convert_from_time_t(png_timep ptime
, time_t ttime
)
498 png_debug(1, "in png_convert_from_time_t");
500 tbuf
= gmtime(&ttime
);
503 /* TODO: add a safe function which takes a png_ptr argument and raises
504 * a png_error if the ttime argument is invalid and the call to gmtime
505 * fails as a consequence.
507 memset(ptime
, 0, sizeof(*ptime
));
511 png_convert_from_struct_tm(ptime
, tbuf
);
515 /* Initialize png_ptr structure, and allocate any memory needed */
516 PNG_FUNCTION(png_structp
,PNGAPI
517 png_create_write_struct
,(png_const_charp user_png_ver
, png_voidp error_ptr
,
518 png_error_ptr error_fn
, png_error_ptr warn_fn
),PNG_ALLOCATED
)
520 #ifndef PNG_USER_MEM_SUPPORTED
521 png_structrp png_ptr
= png_create_png_struct(user_png_ver
, error_ptr
,
522 error_fn
, warn_fn
, NULL
, NULL
, NULL
);
524 return png_create_write_struct_2(user_png_ver
, error_ptr
, error_fn
,
525 warn_fn
, NULL
, NULL
, NULL
);
528 /* Alternate initialize png_ptr structure, and allocate any memory needed */
529 PNG_FUNCTION(png_structp
,PNGAPI
530 png_create_write_struct_2
,(png_const_charp user_png_ver
, png_voidp error_ptr
,
531 png_error_ptr error_fn
, png_error_ptr warn_fn
, png_voidp mem_ptr
,
532 png_malloc_ptr malloc_fn
, png_free_ptr free_fn
),PNG_ALLOCATED
)
534 png_structrp png_ptr
= png_create_png_struct(user_png_ver
, error_ptr
,
535 error_fn
, warn_fn
, mem_ptr
, malloc_fn
, free_fn
);
536 #endif /* USER_MEM */
539 /* Set the zlib control values to defaults; they can be overridden by the
540 * application after the struct has been created.
542 png_ptr
->zbuffer_size
= PNG_ZBUF_SIZE
;
544 /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
545 * pngwutil.c defaults it according to whether or not filters will be
546 * used, and ignores this setting.
548 png_ptr
->zlib_strategy
= PNG_Z_DEFAULT_STRATEGY
;
549 png_ptr
->zlib_level
= PNG_Z_DEFAULT_COMPRESSION
;
550 png_ptr
->zlib_mem_level
= 8;
551 png_ptr
->zlib_window_bits
= 15;
552 png_ptr
->zlib_method
= 8;
554 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
555 png_ptr
->zlib_text_strategy
= PNG_TEXT_Z_DEFAULT_STRATEGY
;
556 png_ptr
->zlib_text_level
= PNG_TEXT_Z_DEFAULT_COMPRESSION
;
557 png_ptr
->zlib_text_mem_level
= 8;
558 png_ptr
->zlib_text_window_bits
= 15;
559 png_ptr
->zlib_text_method
= 8;
560 #endif /* WRITE_COMPRESSED_TEXT */
562 /* This is a highly dubious configuration option; by default it is off,
563 * but it may be appropriate for private builds that are testing
564 * extensions not conformant to the current specification, or of
565 * applications that must not fail to write at all costs!
567 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
568 /* In stable builds only warn if an application error can be completely
571 png_ptr
->flags
|= PNG_FLAG_BENIGN_ERRORS_WARN
;
574 /* App warnings are warnings in release (or release candidate) builds but
575 * are errors during development.
577 #if PNG_RELEASE_BUILD
578 png_ptr
->flags
|= PNG_FLAG_APP_WARNINGS_WARN
;
581 /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
582 * do it itself) avoiding setting the default function if it is not
585 png_set_write_fn(png_ptr
, NULL
, NULL
, NULL
);
592 /* Write a few rows of image data. If the image is interlaced,
593 * either you will have to write the 7 sub images, or, if you
594 * have called png_set_interlace_handling(), you will have to
595 * "write" the image seven times.
598 png_write_rows(png_structrp png_ptr
, png_bytepp row
,
599 png_uint_32 num_rows
)
601 png_uint_32 i
; /* row counter */
602 png_bytepp rp
; /* row pointer */
604 png_debug(1, "in png_write_rows");
609 /* Loop through the rows */
610 for (i
= 0, rp
= row
; i
< num_rows
; i
++, rp
++)
612 png_write_row(png_ptr
, *rp
);
616 /* Write the image. You only need to call this function once, even
617 * if you are writing an interlaced image.
620 png_write_image(png_structrp png_ptr
, png_bytepp image
)
622 png_uint_32 i
; /* row index */
623 int pass
, num_pass
; /* pass variables */
624 png_bytepp rp
; /* points to current row */
629 png_debug(1, "in png_write_image");
631 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
632 /* Initialize interlace handling. If image is not interlaced,
633 * this will set pass to 1
635 num_pass
= png_set_interlace_handling(png_ptr
);
639 /* Loop through passes */
640 for (pass
= 0; pass
< num_pass
; pass
++)
642 /* Loop through image */
643 for (i
= 0, rp
= image
; i
< png_ptr
->height
; i
++, rp
++)
645 png_write_row(png_ptr
, *rp
);
650 #ifdef PNG_MNG_FEATURES_SUPPORTED
651 /* Performs intrapixel differencing */
653 png_do_write_intrapixel(png_row_infop row_info
, png_bytep row
)
655 png_debug(1, "in png_do_write_intrapixel");
657 if ((row_info
->color_type
& PNG_COLOR_MASK_COLOR
) != 0)
660 png_uint_32 row_width
= row_info
->width
;
661 if (row_info
->bit_depth
== 8)
666 if (row_info
->color_type
== PNG_COLOR_TYPE_RGB
)
669 else if (row_info
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
675 for (i
= 0, rp
= row
; i
< row_width
; i
++, rp
+= bytes_per_pixel
)
677 *(rp
) = (png_byte
)(*rp
- *(rp
+ 1));
678 *(rp
+ 2) = (png_byte
)(*(rp
+ 2) - *(rp
+ 1));
682 #ifdef PNG_WRITE_16BIT_SUPPORTED
683 else if (row_info
->bit_depth
== 16)
688 if (row_info
->color_type
== PNG_COLOR_TYPE_RGB
)
691 else if (row_info
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
697 for (i
= 0, rp
= row
; i
< row_width
; i
++, rp
+= bytes_per_pixel
)
699 png_uint_32 s0
= (png_uint_32
)(*(rp
) << 8) | *(rp
+ 1);
700 png_uint_32 s1
= (png_uint_32
)(*(rp
+ 2) << 8) | *(rp
+ 3);
701 png_uint_32 s2
= (png_uint_32
)(*(rp
+ 4) << 8) | *(rp
+ 5);
702 png_uint_32 red
= (png_uint_32
)((s0
- s1
) & 0xffffL
);
703 png_uint_32 blue
= (png_uint_32
)((s2
- s1
) & 0xffffL
);
704 *(rp
) = (png_byte
)(red
>> 8);
705 *(rp
+ 1) = (png_byte
)red
;
706 *(rp
+ 4) = (png_byte
)(blue
>> 8);
707 *(rp
+ 5) = (png_byte
)blue
;
710 #endif /* WRITE_16BIT */
713 #endif /* MNG_FEATURES */
715 /* Called by user to write a row of image data */
717 png_write_row(png_structrp png_ptr
, png_const_bytep row
)
719 /* 1.5.6: moved from png_struct to be a local structure: */
720 png_row_info row_info
;
725 png_debug2(1, "in png_write_row (row %u, pass %d)",
726 png_ptr
->row_number
, png_ptr
->pass
);
728 /* Initialize transformations and other stuff if first time */
729 if (png_ptr
->row_number
== 0 && png_ptr
->pass
== 0)
731 /* Make sure we wrote the header info */
732 if ((png_ptr
->mode
& PNG_WROTE_INFO_BEFORE_PLTE
) == 0)
734 "png_write_info was never called before png_write_row");
736 /* Check for transforms that have been set but were defined out */
737 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
738 if ((png_ptr
->transformations
& PNG_INVERT_MONO
) != 0)
739 png_warning(png_ptr
, "PNG_WRITE_INVERT_SUPPORTED is not defined");
742 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
743 if ((png_ptr
->transformations
& PNG_FILLER
) != 0)
744 png_warning(png_ptr
, "PNG_WRITE_FILLER_SUPPORTED is not defined");
746 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
747 defined(PNG_READ_PACKSWAP_SUPPORTED)
748 if ((png_ptr
->transformations
& PNG_PACKSWAP
) != 0)
750 "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
753 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
754 if ((png_ptr
->transformations
& PNG_PACK
) != 0)
755 png_warning(png_ptr
, "PNG_WRITE_PACK_SUPPORTED is not defined");
758 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
759 if ((png_ptr
->transformations
& PNG_SHIFT
) != 0)
760 png_warning(png_ptr
, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
763 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
764 if ((png_ptr
->transformations
& PNG_BGR
) != 0)
765 png_warning(png_ptr
, "PNG_WRITE_BGR_SUPPORTED is not defined");
768 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
769 if ((png_ptr
->transformations
& PNG_SWAP_BYTES
) != 0)
770 png_warning(png_ptr
, "PNG_WRITE_SWAP_SUPPORTED is not defined");
773 png_write_start_row(png_ptr
);
776 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
777 /* If interlaced and not interested in row, return */
778 if (png_ptr
->interlaced
!= 0 &&
779 (png_ptr
->transformations
& PNG_INTERLACE
) != 0)
781 switch (png_ptr
->pass
)
784 if ((png_ptr
->row_number
& 0x07) != 0)
786 png_write_finish_row(png_ptr
);
792 if ((png_ptr
->row_number
& 0x07) != 0 || png_ptr
->width
< 5)
794 png_write_finish_row(png_ptr
);
800 if ((png_ptr
->row_number
& 0x07) != 4)
802 png_write_finish_row(png_ptr
);
808 if ((png_ptr
->row_number
& 0x03) != 0 || png_ptr
->width
< 3)
810 png_write_finish_row(png_ptr
);
816 if ((png_ptr
->row_number
& 0x03) != 2)
818 png_write_finish_row(png_ptr
);
824 if ((png_ptr
->row_number
& 0x01) != 0 || png_ptr
->width
< 2)
826 png_write_finish_row(png_ptr
);
832 if ((png_ptr
->row_number
& 0x01) == 0)
834 png_write_finish_row(png_ptr
);
839 default: /* error: ignore it */
845 /* Set up row info for transformations */
846 row_info
.color_type
= png_ptr
->color_type
;
847 row_info
.width
= png_ptr
->usr_width
;
848 row_info
.channels
= png_ptr
->usr_channels
;
849 row_info
.bit_depth
= png_ptr
->usr_bit_depth
;
850 row_info
.pixel_depth
= (png_byte
)(row_info
.bit_depth
* row_info
.channels
);
851 row_info
.rowbytes
= PNG_ROWBYTES(row_info
.pixel_depth
, row_info
.width
);
853 png_debug1(3, "row_info->color_type = %d", row_info
.color_type
);
854 png_debug1(3, "row_info->width = %u", row_info
.width
);
855 png_debug1(3, "row_info->channels = %d", row_info
.channels
);
856 png_debug1(3, "row_info->bit_depth = %d", row_info
.bit_depth
);
857 png_debug1(3, "row_info->pixel_depth = %d", row_info
.pixel_depth
);
858 png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info
.rowbytes
);
860 /* Copy user's row into buffer, leaving room for filter byte. */
861 memcpy(png_ptr
->row_buf
+ 1, row
, row_info
.rowbytes
);
863 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
864 /* Handle interlacing */
865 if (png_ptr
->interlaced
&& png_ptr
->pass
< 6 &&
866 (png_ptr
->transformations
& PNG_INTERLACE
) != 0)
868 png_do_write_interlace(&row_info
, png_ptr
->row_buf
+ 1, png_ptr
->pass
);
869 /* This should always get caught above, but still ... */
870 if (row_info
.width
== 0)
872 png_write_finish_row(png_ptr
);
878 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
879 /* Handle other transformations */
880 if (png_ptr
->transformations
!= 0)
881 png_do_write_transformations(png_ptr
, &row_info
);
884 /* At this point the row_info pixel depth must match the 'transformed' depth,
885 * which is also the output depth.
887 if (row_info
.pixel_depth
!= png_ptr
->pixel_depth
||
888 row_info
.pixel_depth
!= png_ptr
->transformed_pixel_depth
)
889 png_error(png_ptr
, "internal write transform logic error");
891 #ifdef PNG_MNG_FEATURES_SUPPORTED
892 /* Write filter_method 64 (intrapixel differencing) only if
893 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
894 * 2. Libpng did not write a PNG signature (this filter_method is only
895 * used in PNG datastreams that are embedded in MNG datastreams) and
896 * 3. The application called png_permit_mng_features with a mask that
897 * included PNG_FLAG_MNG_FILTER_64 and
898 * 4. The filter_method is 64 and
899 * 5. The color_type is RGB or RGBA
901 if ((png_ptr
->mng_features_permitted
& PNG_FLAG_MNG_FILTER_64
) != 0 &&
902 (png_ptr
->filter_type
== PNG_INTRAPIXEL_DIFFERENCING
))
904 /* Intrapixel differencing */
905 png_do_write_intrapixel(&row_info
, png_ptr
->row_buf
+ 1);
909 /* Added at libpng-1.5.10 */
910 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
911 /* Check for out-of-range palette index */
912 if (row_info
.color_type
== PNG_COLOR_TYPE_PALETTE
&&
913 png_ptr
->num_palette_max
>= 0)
914 png_do_check_palette_indexes(png_ptr
, &row_info
);
917 /* Find a filter if necessary, filter the row and write it out. */
918 png_write_find_filter(png_ptr
, &row_info
);
920 if (png_ptr
->write_row_fn
!= NULL
)
921 (*(png_ptr
->write_row_fn
))(png_ptr
, png_ptr
->row_number
, png_ptr
->pass
);
924 #ifdef PNG_WRITE_FLUSH_SUPPORTED
925 /* Set the automatic flush interval or 0 to turn flushing off */
927 png_set_flush(png_structrp png_ptr
, int nrows
)
929 png_debug(1, "in png_set_flush");
934 png_ptr
->flush_dist
= (nrows
< 0 ? 0 : (png_uint_32
)nrows
);
937 /* Flush the current output buffers now */
939 png_write_flush(png_structrp png_ptr
)
941 png_debug(1, "in png_write_flush");
946 /* We have already written out all of the data */
947 if (png_ptr
->row_number
>= png_ptr
->num_rows
)
950 png_compress_IDAT(png_ptr
, NULL
, 0, Z_SYNC_FLUSH
);
951 png_ptr
->flush_rows
= 0;
954 #endif /* WRITE_FLUSH */
956 /* Free any memory used in png_ptr struct without freeing the struct itself. */
958 png_write_destroy(png_structrp png_ptr
)
960 png_debug(1, "in png_write_destroy");
962 /* Free any memory zlib uses */
963 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_INITIALIZED
) != 0)
964 deflateEnd(&png_ptr
->zstream
);
966 /* Free our memory. png_free checks NULL for us. */
967 png_free_buffer_list(png_ptr
, &png_ptr
->zbuffer_list
);
968 png_free(png_ptr
, png_ptr
->row_buf
);
969 png_ptr
->row_buf
= NULL
;
970 #ifdef PNG_WRITE_FILTER_SUPPORTED
971 png_free(png_ptr
, png_ptr
->prev_row
);
972 png_free(png_ptr
, png_ptr
->try_row
);
973 png_free(png_ptr
, png_ptr
->tst_row
);
974 png_ptr
->prev_row
= NULL
;
975 png_ptr
->try_row
= NULL
;
976 png_ptr
->tst_row
= NULL
;
979 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
980 png_free(png_ptr
, png_ptr
->chunk_list
);
981 png_ptr
->chunk_list
= NULL
;
984 /* The error handling and memory handling information is left intact at this
985 * point: the jmp_buf may still have to be freed. See png_destroy_png_struct
986 * for how this happens.
990 /* Free all memory used by the write.
991 * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
992 * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
993 * the passed in info_structs but it would quietly fail to free any of the data
994 * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
998 png_destroy_write_struct(png_structpp png_ptr_ptr
, png_infopp info_ptr_ptr
)
1000 png_debug(1, "in png_destroy_write_struct");
1002 if (png_ptr_ptr
!= NULL
)
1004 png_structrp png_ptr
= *png_ptr_ptr
;
1006 if (png_ptr
!= NULL
) /* added in libpng 1.6.0 */
1008 png_destroy_info_struct(png_ptr
, info_ptr_ptr
);
1010 *png_ptr_ptr
= NULL
;
1011 png_write_destroy(png_ptr
);
1012 png_destroy_png_struct(png_ptr
);
1017 /* Allow the application to select one or more row filters to use. */
1019 png_set_filter(png_structrp png_ptr
, int method
, int filters
)
1021 png_debug(1, "in png_set_filter");
1023 if (png_ptr
== NULL
)
1026 #ifdef PNG_MNG_FEATURES_SUPPORTED
1027 if ((png_ptr
->mng_features_permitted
& PNG_FLAG_MNG_FILTER_64
) != 0 &&
1028 (method
== PNG_INTRAPIXEL_DIFFERENCING
))
1029 method
= PNG_FILTER_TYPE_BASE
;
1032 if (method
== PNG_FILTER_TYPE_BASE
)
1034 switch (filters
& (PNG_ALL_FILTERS
| 0x07))
1036 #ifdef PNG_WRITE_FILTER_SUPPORTED
1039 case 7: png_app_error(png_ptr
, "Unknown row filter for method 0");
1040 #endif /* WRITE_FILTER */
1042 case PNG_FILTER_VALUE_NONE
:
1043 png_ptr
->do_filter
= PNG_FILTER_NONE
; break;
1045 #ifdef PNG_WRITE_FILTER_SUPPORTED
1046 case PNG_FILTER_VALUE_SUB
:
1047 png_ptr
->do_filter
= PNG_FILTER_SUB
; break;
1049 case PNG_FILTER_VALUE_UP
:
1050 png_ptr
->do_filter
= PNG_FILTER_UP
; break;
1052 case PNG_FILTER_VALUE_AVG
:
1053 png_ptr
->do_filter
= PNG_FILTER_AVG
; break;
1055 case PNG_FILTER_VALUE_PAETH
:
1056 png_ptr
->do_filter
= PNG_FILTER_PAETH
; break;
1059 png_ptr
->do_filter
= (png_byte
)filters
; break;
1062 png_app_error(png_ptr
, "Unknown row filter for method 0");
1063 #endif /* WRITE_FILTER */
1066 #ifdef PNG_WRITE_FILTER_SUPPORTED
1067 /* If we have allocated the row_buf, this means we have already started
1068 * with the image and we should have allocated all of the filter buffers
1069 * that have been selected. If prev_row isn't already allocated, then
1070 * it is too late to start using the filters that need it, since we
1071 * will be missing the data in the previous row. If an application
1072 * wants to start and stop using particular filters during compression,
1073 * it should start out with all of the filters, and then remove them
1074 * or add them back after the start of compression.
1076 * NOTE: this is a nasty constraint on the code, because it means that the
1077 * prev_row buffer must be maintained even if there are currently no
1078 * 'prev_row' requiring filters active.
1080 if (png_ptr
->row_buf
!= NULL
)
1083 png_alloc_size_t buf_size
;
1085 /* Repeat the checks in png_write_start_row; 1 pixel high or wide
1086 * images cannot benefit from certain filters. If this isn't done here
1087 * the check below will fire on 1 pixel high images.
1089 if (png_ptr
->height
== 1)
1090 filters
&= ~(PNG_FILTER_UP
|PNG_FILTER_AVG
|PNG_FILTER_PAETH
);
1092 if (png_ptr
->width
== 1)
1093 filters
&= ~(PNG_FILTER_SUB
|PNG_FILTER_AVG
|PNG_FILTER_PAETH
);
1095 if ((filters
& (PNG_FILTER_UP
|PNG_FILTER_AVG
|PNG_FILTER_PAETH
)) != 0
1096 && png_ptr
->prev_row
== NULL
)
1098 /* This is the error case, however it is benign - the previous row
1099 * is not available so the filter can't be used. Just warn here.
1101 png_app_warning(png_ptr
,
1102 "png_set_filter: UP/AVG/PAETH cannot be added after start");
1103 filters
&= ~(PNG_FILTER_UP
|PNG_FILTER_AVG
|PNG_FILTER_PAETH
);
1108 if (filters
& PNG_FILTER_SUB
)
1111 if (filters
& PNG_FILTER_UP
)
1114 if (filters
& PNG_FILTER_AVG
)
1117 if (filters
& PNG_FILTER_PAETH
)
1120 /* Allocate needed row buffers if they have not already been
1123 buf_size
= PNG_ROWBYTES(png_ptr
->usr_channels
* png_ptr
->usr_bit_depth
,
1124 png_ptr
->width
) + 1;
1126 if (png_ptr
->try_row
== NULL
)
1127 png_ptr
->try_row
= png_voidcast(png_bytep
,
1128 png_malloc(png_ptr
, buf_size
));
1130 if (num_filters
> 1)
1132 if (png_ptr
->tst_row
== NULL
)
1133 png_ptr
->tst_row
= png_voidcast(png_bytep
,
1134 png_malloc(png_ptr
, buf_size
));
1137 png_ptr
->do_filter
= (png_byte
)filters
;
1141 png_error(png_ptr
, "Unknown custom filter method");
1144 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
1145 /* Provide floating and fixed point APIs */
1146 #ifdef PNG_FLOATING_POINT_SUPPORTED
1148 png_set_filter_heuristics(png_structrp png_ptr
, int heuristic_method
,
1149 int num_weights
, png_const_doublep filter_weights
,
1150 png_const_doublep filter_costs
)
1153 PNG_UNUSED(heuristic_method
)
1154 PNG_UNUSED(num_weights
)
1155 PNG_UNUSED(filter_weights
)
1156 PNG_UNUSED(filter_costs
)
1158 #endif /* FLOATING_POINT */
1160 #ifdef PNG_FIXED_POINT_SUPPORTED
1162 png_set_filter_heuristics_fixed(png_structrp png_ptr
, int heuristic_method
,
1163 int num_weights
, png_const_fixed_point_p filter_weights
,
1164 png_const_fixed_point_p filter_costs
)
1167 PNG_UNUSED(heuristic_method
)
1168 PNG_UNUSED(num_weights
)
1169 PNG_UNUSED(filter_weights
)
1170 PNG_UNUSED(filter_costs
)
1172 #endif /* FIXED_POINT */
1173 #endif /* WRITE_WEIGHTED_FILTER */
1175 #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
1177 png_set_compression_level(png_structrp png_ptr
, int level
)
1179 png_debug(1, "in png_set_compression_level");
1181 if (png_ptr
== NULL
)
1184 png_ptr
->zlib_level
= level
;
1188 png_set_compression_mem_level(png_structrp png_ptr
, int mem_level
)
1190 png_debug(1, "in png_set_compression_mem_level");
1192 if (png_ptr
== NULL
)
1195 png_ptr
->zlib_mem_level
= mem_level
;
1199 png_set_compression_strategy(png_structrp png_ptr
, int strategy
)
1201 png_debug(1, "in png_set_compression_strategy");
1203 if (png_ptr
== NULL
)
1206 /* The flag setting here prevents the libpng dynamic selection of strategy.
1208 png_ptr
->flags
|= PNG_FLAG_ZLIB_CUSTOM_STRATEGY
;
1209 png_ptr
->zlib_strategy
= strategy
;
1212 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1213 * smaller value of window_bits if it can do so safely.
1216 png_set_compression_window_bits(png_structrp png_ptr
, int window_bits
)
1218 if (png_ptr
== NULL
)
1221 /* Prior to 1.6.0 this would warn but then set the window_bits value. This
1222 * meant that negative window bits values could be selected that would cause
1223 * libpng to write a non-standard PNG file with raw deflate or gzip
1224 * compressed IDAT or ancillary chunks. Such files can be read and there is
1225 * no warning on read, so this seems like a very bad idea.
1227 if (window_bits
> 15)
1229 png_warning(png_ptr
, "Only compression windows <= 32k supported by PNG");
1233 else if (window_bits
< 8)
1235 png_warning(png_ptr
, "Only compression windows >= 256 supported by PNG");
1239 png_ptr
->zlib_window_bits
= window_bits
;
1243 png_set_compression_method(png_structrp png_ptr
, int method
)
1245 png_debug(1, "in png_set_compression_method");
1247 if (png_ptr
== NULL
)
1250 /* This would produce an invalid PNG file if it worked, but it doesn't and
1251 * deflate will fault it, so it is harmless to just warn here.
1254 png_warning(png_ptr
, "Only compression method 8 is supported by PNG");
1256 png_ptr
->zlib_method
= method
;
1258 #endif /* WRITE_CUSTOMIZE_COMPRESSION */
1260 /* The following were added to libpng-1.5.4 */
1261 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1263 png_set_text_compression_level(png_structrp png_ptr
, int level
)
1265 png_debug(1, "in png_set_text_compression_level");
1267 if (png_ptr
== NULL
)
1270 png_ptr
->zlib_text_level
= level
;
1274 png_set_text_compression_mem_level(png_structrp png_ptr
, int mem_level
)
1276 png_debug(1, "in png_set_text_compression_mem_level");
1278 if (png_ptr
== NULL
)
1281 png_ptr
->zlib_text_mem_level
= mem_level
;
1285 png_set_text_compression_strategy(png_structrp png_ptr
, int strategy
)
1287 png_debug(1, "in png_set_text_compression_strategy");
1289 if (png_ptr
== NULL
)
1292 png_ptr
->zlib_text_strategy
= strategy
;
1295 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1296 * smaller value of window_bits if it can do so safely.
1299 png_set_text_compression_window_bits(png_structrp png_ptr
, int window_bits
)
1301 if (png_ptr
== NULL
)
1304 if (window_bits
> 15)
1306 png_warning(png_ptr
, "Only compression windows <= 32k supported by PNG");
1310 else if (window_bits
< 8)
1312 png_warning(png_ptr
, "Only compression windows >= 256 supported by PNG");
1316 png_ptr
->zlib_text_window_bits
= window_bits
;
1320 png_set_text_compression_method(png_structrp png_ptr
, int method
)
1322 png_debug(1, "in png_set_text_compression_method");
1324 if (png_ptr
== NULL
)
1328 png_warning(png_ptr
, "Only compression method 8 is supported by PNG");
1330 png_ptr
->zlib_text_method
= method
;
1332 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1333 /* end of API added to libpng-1.5.4 */
1336 png_set_write_status_fn(png_structrp png_ptr
, png_write_status_ptr write_row_fn
)
1338 if (png_ptr
== NULL
)
1341 png_ptr
->write_row_fn
= write_row_fn
;
1344 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1346 png_set_write_user_transform_fn(png_structrp png_ptr
, png_user_transform_ptr
1347 write_user_transform_fn
)
1349 png_debug(1, "in png_set_write_user_transform_fn");
1351 if (png_ptr
== NULL
)
1354 png_ptr
->transformations
|= PNG_USER_TRANSFORM
;
1355 png_ptr
->write_user_transform_fn
= write_user_transform_fn
;
1360 #ifdef PNG_INFO_IMAGE_SUPPORTED
1362 png_write_png(png_structrp png_ptr
, png_inforp info_ptr
,
1363 int transforms
, voidp params
)
1365 if (png_ptr
== NULL
|| info_ptr
== NULL
)
1368 if ((info_ptr
->valid
& PNG_INFO_IDAT
) == 0)
1370 png_app_error(png_ptr
, "no rows for png_write_image to write");
1374 /* Write the file header information. */
1375 png_write_info(png_ptr
, info_ptr
);
1377 /* ------ these transformations don't touch the info structure ------- */
1379 /* Invert monochrome pixels */
1380 if ((transforms
& PNG_TRANSFORM_INVERT_MONO
) != 0)
1381 #ifdef PNG_WRITE_INVERT_SUPPORTED
1382 png_set_invert_mono(png_ptr
);
1384 png_app_error(png_ptr
, "PNG_TRANSFORM_INVERT_MONO not supported");
1387 /* Shift the pixels up to a legal bit depth and fill in
1388 * as appropriate to correctly scale the image.
1390 if ((transforms
& PNG_TRANSFORM_SHIFT
) != 0)
1391 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1392 if ((info_ptr
->valid
& PNG_INFO_sBIT
) != 0)
1393 png_set_shift(png_ptr
, &info_ptr
->sig_bit
);
1395 png_app_error(png_ptr
, "PNG_TRANSFORM_SHIFT not supported");
1398 /* Pack pixels into bytes */
1399 if ((transforms
& PNG_TRANSFORM_PACKING
) != 0)
1400 #ifdef PNG_WRITE_PACK_SUPPORTED
1401 png_set_packing(png_ptr
);
1403 png_app_error(png_ptr
, "PNG_TRANSFORM_PACKING not supported");
1406 /* Swap location of alpha bytes from ARGB to RGBA */
1407 if ((transforms
& PNG_TRANSFORM_SWAP_ALPHA
) != 0)
1408 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1409 png_set_swap_alpha(png_ptr
);
1411 png_app_error(png_ptr
, "PNG_TRANSFORM_SWAP_ALPHA not supported");
1414 /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
1415 * RGB, note that the code expects the input color type to be G or RGB; no
1418 if ((transforms
& (PNG_TRANSFORM_STRIP_FILLER_AFTER
|
1419 PNG_TRANSFORM_STRIP_FILLER_BEFORE
)) != 0)
1421 #ifdef PNG_WRITE_FILLER_SUPPORTED
1422 if ((transforms
& PNG_TRANSFORM_STRIP_FILLER_AFTER
) != 0)
1424 if ((transforms
& PNG_TRANSFORM_STRIP_FILLER_BEFORE
) != 0)
1425 png_app_error(png_ptr
,
1426 "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
1428 /* Continue if ignored - this is the pre-1.6.10 behavior */
1429 png_set_filler(png_ptr
, 0, PNG_FILLER_AFTER
);
1432 else if ((transforms
& PNG_TRANSFORM_STRIP_FILLER_BEFORE
) != 0)
1433 png_set_filler(png_ptr
, 0, PNG_FILLER_BEFORE
);
1435 png_app_error(png_ptr
, "PNG_TRANSFORM_STRIP_FILLER not supported");
1439 /* Flip BGR pixels to RGB */
1440 if ((transforms
& PNG_TRANSFORM_BGR
) != 0)
1441 #ifdef PNG_WRITE_BGR_SUPPORTED
1442 png_set_bgr(png_ptr
);
1444 png_app_error(png_ptr
, "PNG_TRANSFORM_BGR not supported");
1447 /* Swap bytes of 16-bit files to most significant byte first */
1448 if ((transforms
& PNG_TRANSFORM_SWAP_ENDIAN
) != 0)
1449 #ifdef PNG_WRITE_SWAP_SUPPORTED
1450 png_set_swap(png_ptr
);
1452 png_app_error(png_ptr
, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
1455 /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
1456 if ((transforms
& PNG_TRANSFORM_PACKSWAP
) != 0)
1457 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1458 png_set_packswap(png_ptr
);
1460 png_app_error(png_ptr
, "PNG_TRANSFORM_PACKSWAP not supported");
1463 /* Invert the alpha channel from opacity to transparency */
1464 if ((transforms
& PNG_TRANSFORM_INVERT_ALPHA
) != 0)
1465 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1466 png_set_invert_alpha(png_ptr
);
1468 png_app_error(png_ptr
, "PNG_TRANSFORM_INVERT_ALPHA not supported");
1471 /* ----------------------- end of transformations ------------------- */
1473 /* Write the bits */
1474 png_write_image(png_ptr
, info_ptr
->row_pointers
);
1476 /* It is REQUIRED to call this to finish writing the rest of the file */
1477 png_write_end(png_ptr
, info_ptr
);
1484 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
1485 /* Initialize the write structure - general purpose utility. */
1487 png_image_write_init(png_imagep image
)
1489 png_structp png_ptr
= png_create_write_struct(PNG_LIBPNG_VER_STRING
, image
,
1490 png_safe_error
, png_safe_warning
);
1492 if (png_ptr
!= NULL
)
1494 png_infop info_ptr
= png_create_info_struct(png_ptr
);
1496 if (info_ptr
!= NULL
)
1498 png_controlp control
= png_voidcast(png_controlp
,
1499 png_malloc_warn(png_ptr
, (sizeof *control
)));
1501 if (control
!= NULL
)
1503 memset(control
, 0, (sizeof *control
));
1505 control
->png_ptr
= png_ptr
;
1506 control
->info_ptr
= info_ptr
;
1507 control
->for_write
= 1;
1509 image
->opaque
= control
;
1513 /* Error clean up */
1514 png_destroy_info_struct(png_ptr
, &info_ptr
);
1517 png_destroy_write_struct(&png_ptr
, NULL
);
1520 return png_image_error(image
, "png_image_write_: out of memory");
1523 /* Arguments to png_image_write_main: */
1528 png_const_voidp buffer
;
1529 png_int_32 row_stride
;
1530 png_const_voidp colormap
;
1531 int convert_to_8bit
;
1532 /* Local variables: */
1533 png_const_voidp first_row
;
1534 ptrdiff_t row_bytes
;
1535 png_voidp local_row
;
1536 /* Byte count for memory writing */
1538 png_alloc_size_t memory_bytes
; /* not used for STDIO */
1539 png_alloc_size_t output_bytes
; /* running total */
1540 } png_image_write_control
;
1542 /* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
1543 * do any necessary byte swapping. The component order is defined by the
1544 * png_image format value.
1547 png_write_image_16bit(png_voidp argument
)
1549 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
1551 png_imagep image
= display
->image
;
1552 png_structrp png_ptr
= image
->opaque
->png_ptr
;
1554 png_const_uint_16p input_row
= png_voidcast(png_const_uint_16p
,
1555 display
->first_row
);
1556 png_uint_16p output_row
= png_voidcast(png_uint_16p
, display
->local_row
);
1557 png_uint_16p row_end
;
1558 unsigned int channels
= (image
->format
& PNG_FORMAT_FLAG_COLOR
) != 0 ?
1561 png_uint_32 y
= image
->height
;
1563 if ((image
->format
& PNG_FORMAT_FLAG_ALPHA
) != 0)
1565 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1566 if ((image
->format
& PNG_FORMAT_FLAG_AFIRST
) != 0)
1569 ++input_row
; /* To point to the first component */
1573 aindex
= (int)channels
;
1575 aindex
= (int)channels
;
1580 png_error(png_ptr
, "png_write_image: internal call error");
1582 /* Work out the output row end and count over this, note that the increment
1583 * above to 'row' means that row_end can actually be beyond the end of the
1584 * row; this is correct.
1586 row_end
= output_row
+ image
->width
* (channels
+1);
1590 png_const_uint_16p in_ptr
= input_row
;
1591 png_uint_16p out_ptr
= output_row
;
1593 while (out_ptr
< row_end
)
1595 png_uint_16 alpha
= in_ptr
[aindex
];
1596 png_uint_32 reciprocal
= 0;
1599 out_ptr
[aindex
] = alpha
;
1601 /* Calculate a reciprocal. The correct calculation is simply
1602 * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
1603 * allows correct rounding by adding .5 before the shift. 'reciprocal'
1604 * is only initialized when required.
1606 if (alpha
> 0 && alpha
< 65535)
1607 reciprocal
= ((0xffff<<15)+(alpha
>>1))/alpha
;
1610 do /* always at least one channel */
1612 png_uint_16 component
= *in_ptr
++;
1614 /* The following gives 65535 for an alpha of 0, which is fine,
1615 * otherwise if 0/0 is represented as some other value there is more
1616 * likely to be a discontinuity which will probably damage
1617 * compression when moving from a fully transparent area to a
1618 * nearly transparent one. (The assumption here is that opaque
1619 * areas tend not to be 0 intensity.)
1621 if (component
>= alpha
)
1624 /* component<alpha, so component/alpha is less than one and
1625 * component*reciprocal is less than 2^31.
1627 else if (component
> 0 && alpha
< 65535)
1629 png_uint_32 calc
= component
* reciprocal
;
1630 calc
+= 16384; /* round to nearest */
1631 component
= (png_uint_16
)(calc
>> 15);
1634 *out_ptr
++ = component
;
1638 /* Skip to next component (skip the intervening alpha channel) */
1643 png_write_row(png_ptr
, png_voidcast(png_const_bytep
, display
->local_row
));
1644 input_row
+= (png_uint_16
)display
->row_bytes
/(sizeof (png_uint_16
));
1650 /* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
1651 * is present it must be removed from the components, the components are then
1652 * written in sRGB encoding. No components are added or removed.
1654 * Calculate an alpha reciprocal to reverse pre-multiplication. As above the
1655 * calculation can be done to 15 bits of accuracy; however, the output needs to
1656 * be scaled in the range 0..255*65535, so include that scaling here.
1658 # define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+((alpha)>>1))/(alpha))
1661 png_unpremultiply(png_uint_32 component
, png_uint_32 alpha
,
1662 png_uint_32 reciprocal
/*from the above macro*/)
1664 /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
1665 * is represented as some other value there is more likely to be a
1666 * discontinuity which will probably damage compression when moving from a
1667 * fully transparent area to a nearly transparent one. (The assumption here
1668 * is that opaque areas tend not to be 0 intensity.)
1670 * There is a rounding problem here; if alpha is less than 128 it will end up
1671 * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
1672 * output change for this too.
1674 if (component
>= alpha
|| alpha
< 128)
1677 /* component<alpha, so component/alpha is less than one and
1678 * component*reciprocal is less than 2^31.
1680 else if (component
> 0)
1682 /* The test is that alpha/257 (rounded) is less than 255, the first value
1683 * that becomes 255 is 65407.
1684 * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
1685 * be exact!) [Could also test reciprocal != 0]
1689 component
*= reciprocal
;
1690 component
+= 64; /* round to nearest */
1697 /* Convert the component to sRGB. */
1698 return (png_byte
)PNG_sRGB_FROM_LINEAR(component
);
1706 png_write_image_8bit(png_voidp argument
)
1708 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
1710 png_imagep image
= display
->image
;
1711 png_structrp png_ptr
= image
->opaque
->png_ptr
;
1713 png_const_uint_16p input_row
= png_voidcast(png_const_uint_16p
,
1714 display
->first_row
);
1715 png_bytep output_row
= png_voidcast(png_bytep
, display
->local_row
);
1716 png_uint_32 y
= image
->height
;
1717 unsigned int channels
= (image
->format
& PNG_FORMAT_FLAG_COLOR
) != 0 ?
1720 if ((image
->format
& PNG_FORMAT_FLAG_ALPHA
) != 0)
1725 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1726 if ((image
->format
& PNG_FORMAT_FLAG_AFIRST
) != 0)
1729 ++input_row
; /* To point to the first component */
1735 aindex
= (int)channels
;
1737 /* Use row_end in place of a loop counter: */
1738 row_end
= output_row
+ image
->width
* (channels
+1);
1742 png_const_uint_16p in_ptr
= input_row
;
1743 png_bytep out_ptr
= output_row
;
1745 while (out_ptr
< row_end
)
1747 png_uint_16 alpha
= in_ptr
[aindex
];
1748 png_byte alphabyte
= (png_byte
)PNG_DIV257(alpha
);
1749 png_uint_32 reciprocal
= 0;
1752 /* Scale and write the alpha channel. */
1753 out_ptr
[aindex
] = alphabyte
;
1755 if (alphabyte
> 0 && alphabyte
< 255)
1756 reciprocal
= UNP_RECIPROCAL(alpha
);
1759 do /* always at least one channel */
1760 *out_ptr
++ = png_unpremultiply(*in_ptr
++, alpha
, reciprocal
);
1763 /* Skip to next component (skip the intervening alpha channel) */
1766 } /* while out_ptr < row_end */
1768 png_write_row(png_ptr
, png_voidcast(png_const_bytep
,
1769 display
->local_row
));
1770 input_row
+= (png_uint_16
)display
->row_bytes
/(sizeof (png_uint_16
));
1776 /* No alpha channel, so the row_end really is the end of the row and it
1777 * is sufficient to loop over the components one by one.
1779 png_bytep row_end
= output_row
+ image
->width
* channels
;
1783 png_const_uint_16p in_ptr
= input_row
;
1784 png_bytep out_ptr
= output_row
;
1786 while (out_ptr
< row_end
)
1788 png_uint_32 component
= *in_ptr
++;
1791 *out_ptr
++ = (png_byte
)PNG_sRGB_FROM_LINEAR(component
);
1794 png_write_row(png_ptr
, output_row
);
1795 input_row
+= (png_uint_16
)display
->row_bytes
/(sizeof (png_uint_16
));
1803 png_image_set_PLTE(png_image_write_control
*display
)
1805 png_imagep image
= display
->image
;
1806 const void *cmap
= display
->colormap
;
1807 int entries
= image
->colormap_entries
> 256 ? 256 :
1808 (int)image
->colormap_entries
;
1810 /* NOTE: the caller must check for cmap != NULL and entries != 0 */
1811 png_uint_32 format
= image
->format
;
1812 unsigned int channels
= PNG_IMAGE_SAMPLE_CHANNELS(format
);
1814 # if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
1815 defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
1816 int afirst
= (format
& PNG_FORMAT_FLAG_AFIRST
) != 0 &&
1817 (format
& PNG_FORMAT_FLAG_ALPHA
) != 0;
1822 # ifdef PNG_FORMAT_BGR_SUPPORTED
1823 int bgr
= (format
& PNG_FORMAT_FLAG_BGR
) != 0 ? 2 : 0;
1829 png_color palette
[256];
1832 memset(tRNS
, 255, (sizeof tRNS
));
1833 memset(palette
, 0, (sizeof palette
));
1835 for (i
=num_trans
=0; i
<entries
; ++i
)
1837 /* This gets automatically converted to sRGB with reversal of the
1838 * pre-multiplication if the color-map has an alpha channel.
1840 if ((format
& PNG_FORMAT_FLAG_LINEAR
) != 0)
1842 png_const_uint_16p entry
= png_voidcast(png_const_uint_16p
, cmap
);
1844 entry
+= (unsigned int)i
* channels
;
1846 if ((channels
& 1) != 0) /* no alpha */
1848 if (channels
>= 3) /* RGB */
1850 palette
[i
].blue
= (png_byte
)PNG_sRGB_FROM_LINEAR(255 *
1852 palette
[i
].green
= (png_byte
)PNG_sRGB_FROM_LINEAR(255 *
1854 palette
[i
].red
= (png_byte
)PNG_sRGB_FROM_LINEAR(255 *
1859 palette
[i
].blue
= palette
[i
].red
= palette
[i
].green
=
1860 (png_byte
)PNG_sRGB_FROM_LINEAR(255 * *entry
);
1865 png_uint_16 alpha
= entry
[afirst
? 0 : channels
-1];
1866 png_byte alphabyte
= (png_byte
)PNG_DIV257(alpha
);
1867 png_uint_32 reciprocal
= 0;
1869 /* Calculate a reciprocal, as in the png_write_image_8bit code above
1870 * this is designed to produce a value scaled to 255*65535 when
1871 * divided by 128 (i.e. asr 7).
1873 if (alphabyte
> 0 && alphabyte
< 255)
1874 reciprocal
= (((0xffff*0xff)<<7)+(alpha
>>1))/alpha
;
1876 tRNS
[i
] = alphabyte
;
1877 if (alphabyte
< 255)
1880 if (channels
>= 3) /* RGB */
1882 palette
[i
].blue
= png_unpremultiply(entry
[afirst
+ (2 ^ bgr
)],
1884 palette
[i
].green
= png_unpremultiply(entry
[afirst
+ 1], alpha
,
1886 palette
[i
].red
= png_unpremultiply(entry
[afirst
+ bgr
], alpha
,
1891 palette
[i
].blue
= palette
[i
].red
= palette
[i
].green
=
1892 png_unpremultiply(entry
[afirst
], alpha
, reciprocal
);
1896 else /* Color-map has sRGB values */
1898 png_const_bytep entry
= png_voidcast(png_const_bytep
, cmap
);
1900 entry
+= (unsigned int)i
* channels
;
1905 tRNS
[i
] = entry
[afirst
? 0 : 3];
1910 palette
[i
].blue
= entry
[afirst
+ (2 ^ bgr
)];
1911 palette
[i
].green
= entry
[afirst
+ 1];
1912 palette
[i
].red
= entry
[afirst
+ bgr
];
1916 tRNS
[i
] = entry
[1 ^ afirst
];
1921 palette
[i
].blue
= palette
[i
].red
= palette
[i
].green
=
1938 png_set_PLTE(image
->opaque
->png_ptr
, image
->opaque
->info_ptr
, palette
,
1942 png_set_tRNS(image
->opaque
->png_ptr
, image
->opaque
->info_ptr
, tRNS
,
1945 image
->colormap_entries
= (png_uint_32
)entries
;
1949 png_image_write_main(png_voidp argument
)
1951 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
1953 png_imagep image
= display
->image
;
1954 png_structrp png_ptr
= image
->opaque
->png_ptr
;
1955 png_inforp info_ptr
= image
->opaque
->info_ptr
;
1956 png_uint_32 format
= image
->format
;
1958 /* The following four ints are actually booleans */
1959 int colormap
= (format
& PNG_FORMAT_FLAG_COLORMAP
);
1960 int linear
= !colormap
&& (format
& PNG_FORMAT_FLAG_LINEAR
); /* input */
1961 int alpha
= !colormap
&& (format
& PNG_FORMAT_FLAG_ALPHA
);
1962 int write_16bit
= linear
&& (display
->convert_to_8bit
== 0);
1964 # ifdef PNG_BENIGN_ERRORS_SUPPORTED
1965 /* Make sure we error out on any bad situation */
1966 png_set_benign_errors(png_ptr
, 0/*error*/);
1969 /* Default the 'row_stride' parameter if required, also check the row stride
1970 * and total image size to ensure that they are within the system limits.
1973 unsigned int channels
= PNG_IMAGE_PIXEL_CHANNELS(image
->format
);
1975 if (image
->width
<= 0x7fffffffU
/channels
) /* no overflow */
1978 png_uint_32 png_row_stride
= image
->width
* channels
;
1980 if (display
->row_stride
== 0)
1981 display
->row_stride
= (png_int_32
)/*SAFE*/png_row_stride
;
1983 if (display
->row_stride
< 0)
1984 check
= (png_uint_32
)(-display
->row_stride
);
1987 check
= (png_uint_32
)display
->row_stride
;
1989 if (check
>= png_row_stride
)
1991 /* Now check for overflow of the image buffer calculation; this
1992 * limits the whole image size to 32 bits for API compatibility with
1993 * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
1995 if (image
->height
> 0xffffffffU
/png_row_stride
)
1996 png_error(image
->opaque
->png_ptr
, "memory image too large");
2000 png_error(image
->opaque
->png_ptr
, "supplied row stride too small");
2004 png_error(image
->opaque
->png_ptr
, "image row stride too large");
2007 /* Set the required transforms then write the rows in the correct order. */
2008 if ((format
& PNG_FORMAT_FLAG_COLORMAP
) != 0)
2010 if (display
->colormap
!= NULL
&& image
->colormap_entries
> 0)
2012 png_uint_32 entries
= image
->colormap_entries
;
2014 png_set_IHDR(png_ptr
, info_ptr
, image
->width
, image
->height
,
2015 entries
> 16 ? 8 : (entries
> 4 ? 4 : (entries
> 2 ? 2 : 1)),
2016 PNG_COLOR_TYPE_PALETTE
, PNG_INTERLACE_NONE
,
2017 PNG_COMPRESSION_TYPE_BASE
, PNG_FILTER_TYPE_BASE
);
2019 png_image_set_PLTE(display
);
2023 png_error(image
->opaque
->png_ptr
,
2024 "no color-map for color-mapped image");
2028 png_set_IHDR(png_ptr
, info_ptr
, image
->width
, image
->height
,
2029 write_16bit
? 16 : 8,
2030 ((format
& PNG_FORMAT_FLAG_COLOR
) ? PNG_COLOR_MASK_COLOR
: 0) +
2031 ((format
& PNG_FORMAT_FLAG_ALPHA
) ? PNG_COLOR_MASK_ALPHA
: 0),
2032 PNG_INTERLACE_NONE
, PNG_COMPRESSION_TYPE_BASE
, PNG_FILTER_TYPE_BASE
);
2034 /* Counter-intuitively the data transformations must be called *after*
2035 * png_write_info, not before as in the read code, but the 'set' functions
2036 * must still be called before. Just set the color space information, never
2037 * write an interlaced image.
2040 if (write_16bit
!= 0)
2042 /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
2043 png_set_gAMA_fixed(png_ptr
, info_ptr
, PNG_GAMMA_LINEAR
);
2045 if ((image
->flags
& PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB
) == 0)
2046 png_set_cHRM_fixed(png_ptr
, info_ptr
,
2048 /* white */ 31270, 32900,
2049 /* red */ 64000, 33000,
2050 /* green */ 30000, 60000,
2051 /* blue */ 15000, 6000
2055 else if ((image
->flags
& PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB
) == 0)
2056 png_set_sRGB(png_ptr
, info_ptr
, PNG_sRGB_INTENT_PERCEPTUAL
);
2058 /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
2059 * space must still be gamma encoded.
2062 png_set_gAMA_fixed(png_ptr
, info_ptr
, PNG_GAMMA_sRGB_INVERSE
);
2064 /* Write the file header. */
2065 png_write_info(png_ptr
, info_ptr
);
2067 /* Now set up the data transformations (*after* the header is written),
2068 * remove the handled transformations from the 'format' flags for checking.
2070 * First check for a little endian system if writing 16-bit files.
2072 if (write_16bit
!= 0)
2074 png_uint_16 le
= 0x0001;
2076 if ((*(png_const_bytep
) & le
) != 0)
2077 png_set_swap(png_ptr
);
2080 # ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
2081 if ((format
& PNG_FORMAT_FLAG_BGR
) != 0)
2083 if (colormap
== 0 && (format
& PNG_FORMAT_FLAG_COLOR
) != 0)
2084 png_set_bgr(png_ptr
);
2085 format
&= ~PNG_FORMAT_FLAG_BGR
;
2089 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
2090 if ((format
& PNG_FORMAT_FLAG_AFIRST
) != 0)
2092 if (colormap
== 0 && (format
& PNG_FORMAT_FLAG_ALPHA
) != 0)
2093 png_set_swap_alpha(png_ptr
);
2094 format
&= ~PNG_FORMAT_FLAG_AFIRST
;
2098 /* If there are 16 or fewer color-map entries we wrote a lower bit depth
2099 * above, but the application data is still byte packed.
2101 if (colormap
!= 0 && image
->colormap_entries
<= 16)
2102 png_set_packing(png_ptr
);
2104 /* That should have handled all (both) the transforms. */
2105 if ((format
& ~(png_uint_32
)(PNG_FORMAT_FLAG_COLOR
| PNG_FORMAT_FLAG_LINEAR
|
2106 PNG_FORMAT_FLAG_ALPHA
| PNG_FORMAT_FLAG_COLORMAP
)) != 0)
2107 png_error(png_ptr
, "png_write_image: unsupported transformation");
2110 png_const_bytep row
= png_voidcast(png_const_bytep
, display
->buffer
);
2111 ptrdiff_t row_bytes
= display
->row_stride
;
2114 row_bytes
*= (sizeof (png_uint_16
));
2117 row
+= (image
->height
-1) * (-row_bytes
);
2119 display
->first_row
= row
;
2120 display
->row_bytes
= row_bytes
;
2123 /* Apply 'fast' options if the flag is set. */
2124 if ((image
->flags
& PNG_IMAGE_FLAG_FAST
) != 0)
2126 png_set_filter(png_ptr
, PNG_FILTER_TYPE_BASE
, PNG_NO_FILTERS
);
2127 /* NOTE: determined by experiment using pngstest, this reflects some
2128 * balance between the time to write the image once and the time to read
2129 * it about 50 times. The speed-up in pngstest was about 10-20% of the
2130 * total (user) time on a heavily loaded system.
2132 # ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
2133 png_set_compression_level(png_ptr
, 3);
2137 /* Check for the cases that currently require a pre-transform on the row
2138 * before it is written. This only applies when the input is 16-bit and
2139 * either there is an alpha channel or it is converted to 8-bit.
2141 if ((linear
!= 0 && alpha
!= 0 ) ||
2142 (colormap
== 0 && display
->convert_to_8bit
!= 0))
2144 png_bytep row
= png_voidcast(png_bytep
, png_malloc(png_ptr
,
2145 png_get_rowbytes(png_ptr
, info_ptr
)));
2148 display
->local_row
= row
;
2149 if (write_16bit
!= 0)
2150 result
= png_safe_execute(image
, png_write_image_16bit
, display
);
2152 result
= png_safe_execute(image
, png_write_image_8bit
, display
);
2153 display
->local_row
= NULL
;
2155 png_free(png_ptr
, row
);
2157 /* Skip the 'write_end' on error: */
2162 /* Otherwise this is the case where the input is in a format currently
2163 * supported by the rest of the libpng write code; call it directly.
2167 png_const_bytep row
= png_voidcast(png_const_bytep
, display
->first_row
);
2168 ptrdiff_t row_bytes
= display
->row_bytes
;
2169 png_uint_32 y
= image
->height
;
2173 png_write_row(png_ptr
, row
);
2178 png_write_end(png_ptr
, info_ptr
);
2183 static void (PNGCBAPI
2184 image_memory_write
)(png_structp png_ptr
, png_bytep
/*const*/ data
, size_t size
)
2186 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
2187 png_ptr
->io_ptr
/*backdoor: png_get_io_ptr(png_ptr)*/);
2188 png_alloc_size_t ob
= display
->output_bytes
;
2190 /* Check for overflow; this should never happen: */
2191 if (size
<= ((png_alloc_size_t
)-1) - ob
)
2193 /* I don't think libpng ever does this, but just in case: */
2196 if (display
->memory_bytes
>= ob
+size
) /* writing */
2197 memcpy(display
->memory
+ob
, data
, size
);
2199 /* Always update the size: */
2200 display
->output_bytes
= ob
+size
;
2205 png_error(png_ptr
, "png_image_write_to_memory: PNG too big");
2208 static void (PNGCBAPI
2209 image_memory_flush
)(png_structp png_ptr
)
2215 png_image_write_memory(png_voidp argument
)
2217 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
2220 /* The rest of the memory-specific init and write_main in an error protected
2221 * environment. This case needs to use callbacks for the write operations
2222 * since libpng has no built in support for writing to memory.
2224 png_set_write_fn(display
->image
->opaque
->png_ptr
, display
/*io_ptr*/,
2225 image_memory_write
, image_memory_flush
);
2227 return png_image_write_main(display
);
2231 png_image_write_to_memory(png_imagep image
, void *memory
,
2232 png_alloc_size_t
* PNG_RESTRICT memory_bytes
, int convert_to_8bit
,
2233 const void *buffer
, png_int_32 row_stride
, const void *colormap
)
2235 /* Write the image to the given buffer, or count the bytes if it is NULL */
2236 if (image
!= NULL
&& image
->version
== PNG_IMAGE_VERSION
)
2238 if (memory_bytes
!= NULL
&& buffer
!= NULL
)
2240 /* This is to give the caller an easier error detection in the NULL
2241 * case and guard against uninitialized variable problems:
2246 if (png_image_write_init(image
) != 0)
2248 png_image_write_control display
;
2251 memset(&display
, 0, (sizeof display
));
2252 display
.image
= image
;
2253 display
.buffer
= buffer
;
2254 display
.row_stride
= row_stride
;
2255 display
.colormap
= colormap
;
2256 display
.convert_to_8bit
= convert_to_8bit
;
2257 display
.memory
= png_voidcast(png_bytep
, memory
);
2258 display
.memory_bytes
= *memory_bytes
;
2259 display
.output_bytes
= 0;
2261 result
= png_safe_execute(image
, png_image_write_memory
, &display
);
2262 png_image_free(image
);
2264 /* write_memory returns true even if we ran out of buffer. */
2267 /* On out-of-buffer this function returns '0' but still updates
2270 if (memory
!= NULL
&& display
.output_bytes
> *memory_bytes
)
2273 *memory_bytes
= display
.output_bytes
;
2284 return png_image_error(image
,
2285 "png_image_write_to_memory: invalid argument");
2288 else if (image
!= NULL
)
2289 return png_image_error(image
,
2290 "png_image_write_to_memory: incorrect PNG_IMAGE_VERSION");
2296 #ifdef PNG_SIMPLIFIED_WRITE_STDIO_SUPPORTED
2298 png_image_write_to_stdio(png_imagep image
, FILE *file
, int convert_to_8bit
,
2299 const void *buffer
, png_int_32 row_stride
, const void *colormap
)
2301 /* Write the image to the given (FILE*). */
2302 if (image
!= NULL
&& image
->version
== PNG_IMAGE_VERSION
)
2304 if (file
!= NULL
&& buffer
!= NULL
)
2306 if (png_image_write_init(image
) != 0)
2308 png_image_write_control display
;
2311 /* This is slightly evil, but png_init_io doesn't do anything other
2312 * than this and we haven't changed the standard IO functions so
2313 * this saves a 'safe' function.
2315 image
->opaque
->png_ptr
->io_ptr
= file
;
2317 memset(&display
, 0, (sizeof display
));
2318 display
.image
= image
;
2319 display
.buffer
= buffer
;
2320 display
.row_stride
= row_stride
;
2321 display
.colormap
= colormap
;
2322 display
.convert_to_8bit
= convert_to_8bit
;
2324 result
= png_safe_execute(image
, png_image_write_main
, &display
);
2325 png_image_free(image
);
2334 return png_image_error(image
,
2335 "png_image_write_to_stdio: invalid argument");
2338 else if (image
!= NULL
)
2339 return png_image_error(image
,
2340 "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
2347 png_image_write_to_file(png_imagep image
, const char *file_name
,
2348 int convert_to_8bit
, const void *buffer
, png_int_32 row_stride
,
2349 const void *colormap
)
2351 /* Write the image to the named file. */
2352 if (image
!= NULL
&& image
->version
== PNG_IMAGE_VERSION
)
2354 if (file_name
!= NULL
&& buffer
!= NULL
)
2356 FILE *fp
= fopen(file_name
, "wb");
2360 if (png_image_write_to_stdio(image
, fp
, convert_to_8bit
, buffer
,
2361 row_stride
, colormap
) != 0)
2363 int error
; /* from fflush/fclose */
2365 /* Make sure the file is flushed correctly. */
2366 if (fflush(fp
) == 0 && ferror(fp
) == 0)
2368 if (fclose(fp
) == 0)
2371 error
= errno
; /* from fclose */
2376 error
= errno
; /* from fflush or ferror */
2380 (void)remove(file_name
);
2381 /* The image has already been cleaned up; this is just used to
2382 * set the error (because the original write succeeded).
2384 return png_image_error(image
, strerror(error
));
2389 /* Clean up: just the opened file. */
2391 (void)remove(file_name
);
2397 return png_image_error(image
, strerror(errno
));
2401 return png_image_error(image
,
2402 "png_image_write_to_file: invalid argument");
2405 else if (image
!= NULL
)
2406 return png_image_error(image
,
2407 "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
2412 #endif /* SIMPLIFIED_WRITE_STDIO */
2413 #endif /* SIMPLIFIED_WRITE */
2415 #ifdef PNG_WRITE_APNG_SUPPORTED
2417 png_write_frame_head(png_structp png_ptr
, png_infop info_ptr
,
2418 png_bytepp row_pointers
, png_uint_32 width
, png_uint_32 height
,
2419 png_uint_32 x_offset
, png_uint_32 y_offset
,
2420 png_uint_16 delay_num
, png_uint_16 delay_den
, png_byte dispose_op
,
2423 png_debug(1, "in png_write_frame_head");
2425 /* there is a chance this has been set after png_write_info was called,
2426 * so it would be set but not written. is there a way to be sure? */
2427 if ((info_ptr
->valid
& PNG_INFO_acTL
) == 0)
2428 png_error(png_ptr
, "png_write_frame_head(): acTL not set");
2430 png_write_reset(png_ptr
);
2432 png_write_reinit(png_ptr
, info_ptr
, width
, height
);
2434 if ((png_ptr
->apng_flags
& PNG_FIRST_FRAME_HIDDEN
) == 0 ||
2435 png_ptr
->num_frames_written
!= 0)
2436 png_write_fcTL(png_ptr
, width
, height
, x_offset
, y_offset
,
2437 delay_num
, delay_den
, dispose_op
, blend_op
);
2439 PNG_UNUSED(row_pointers
)
2443 png_write_frame_tail(png_structp png_ptr
, png_infop info_ptr
)
2445 png_debug(1, "in png_write_frame_tail");
2447 png_ptr
->num_frames_written
++;
2449 PNG_UNUSED(info_ptr
)
2451 #endif /* WRITE_APNG */