2 /* pngwrite.c - general routines to write a PNG file
4 * Last changed in libpng 1.6.9 [February 6, 2014]
5 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 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 #if defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
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
)
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
)
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 /* PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED */
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_ flag, and check info_ptr->valid before writing
79 * the chunk, as that will keep the code from breaking if you want to just
80 * write a plain PNG file. If you have long comments, I suggest writing
81 * 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
))
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
) && \
98 (png_ptr
->mng_features_permitted
))
100 png_warning(png_ptr
, "MNG features are not allowed in a PNG datastream");
101 png_ptr
->mng_features_permitted
= 0;
105 /* Write IHDR information. */
106 png_write_IHDR(png_ptr
, info_ptr
->width
, info_ptr
->height
,
107 info_ptr
->bit_depth
, info_ptr
->color_type
, info_ptr
->compression_type
,
108 info_ptr
->filter_type
,
109 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
110 info_ptr
->interlace_type
116 /* The rest of these check to see if the valid field has the appropriate
117 * flag set, and if it does, writes the chunk.
119 * 1.6.0: COLORSPACE support controls the writing of these chunks too, and
120 * the chunks will be written if the WRITE routine is there and information
121 * is available in the COLORSPACE. (See png_colorspace_sync_info in png.c
122 * for where the valid flags get set.)
124 * Under certain circumstances the colorspace can be invalidated without
125 * syncing the info_struct 'valid' flags; this happens if libpng detects and
126 * error and calls png_error while the color space is being set, yet the
127 * application continues writing the PNG. So check the 'invalid' flag here
130 #ifdef PNG_GAMMA_SUPPORTED
131 # ifdef PNG_WRITE_gAMA_SUPPORTED
132 if (!(info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) &&
133 (info_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_gAMA
) &&
134 (info_ptr
->valid
& PNG_INFO_gAMA
))
135 png_write_gAMA_fixed(png_ptr
, info_ptr
->colorspace
.gamma
);
139 #ifdef PNG_COLORSPACE_SUPPORTED
140 /* Write only one of sRGB or an ICC profile. If a profile was supplied
141 * and it matches one of the known sRGB ones issue a warning.
143 # ifdef PNG_WRITE_iCCP_SUPPORTED
144 if (!(info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) &&
145 (info_ptr
->valid
& PNG_INFO_iCCP
))
147 # ifdef PNG_WRITE_sRGB_SUPPORTED
148 if (info_ptr
->valid
& PNG_INFO_sRGB
)
149 png_app_warning(png_ptr
,
150 "profile matches sRGB but writing iCCP instead");
153 png_write_iCCP(png_ptr
, info_ptr
->iccp_name
,
154 info_ptr
->iccp_profile
);
156 # ifdef PNG_WRITE_sRGB_SUPPORTED
161 # ifdef PNG_WRITE_sRGB_SUPPORTED
162 if (!(info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) &&
163 (info_ptr
->valid
& PNG_INFO_sRGB
))
164 png_write_sRGB(png_ptr
, info_ptr
->colorspace
.rendering_intent
);
165 # endif /* WRITE_sRGB */
166 #endif /* COLORSPACE */
168 #ifdef PNG_WRITE_sBIT_SUPPORTED
169 if (info_ptr
->valid
& PNG_INFO_sBIT
)
170 png_write_sBIT(png_ptr
, &(info_ptr
->sig_bit
), info_ptr
->color_type
);
173 #ifdef PNG_COLORSPACE_SUPPORTED
174 # ifdef PNG_WRITE_cHRM_SUPPORTED
175 if (!(info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) &&
176 (info_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_cHRM
) &&
177 (info_ptr
->valid
& PNG_INFO_cHRM
))
178 png_write_cHRM_fixed(png_ptr
, &info_ptr
->colorspace
.end_points_xy
);
182 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
183 write_unknown_chunks(png_ptr
, info_ptr
, PNG_HAVE_IHDR
);
186 png_ptr
->mode
|= PNG_WROTE_INFO_BEFORE_PLTE
;
191 png_write_info(png_structrp png_ptr
, png_const_inforp info_ptr
)
193 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
197 png_debug(1, "in png_write_info");
199 if (png_ptr
== NULL
|| info_ptr
== NULL
)
202 png_write_info_before_PLTE(png_ptr
, info_ptr
);
204 if (info_ptr
->valid
& PNG_INFO_PLTE
)
205 png_write_PLTE(png_ptr
, info_ptr
->palette
,
206 (png_uint_32
)info_ptr
->num_palette
);
208 else if (info_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
209 png_error(png_ptr
, "Valid palette required for paletted images");
211 #ifdef PNG_WRITE_tRNS_SUPPORTED
212 if (info_ptr
->valid
& PNG_INFO_tRNS
)
214 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
215 /* Invert the alpha channel (in tRNS) */
216 if ((png_ptr
->transformations
& PNG_INVERT_ALPHA
) &&
217 info_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
220 for (j
= 0; j
<(int)info_ptr
->num_trans
; j
++)
221 info_ptr
->trans_alpha
[j
] =
222 (png_byte
)(255 - info_ptr
->trans_alpha
[j
]);
225 png_write_tRNS(png_ptr
, info_ptr
->trans_alpha
, &(info_ptr
->trans_color
),
226 info_ptr
->num_trans
, info_ptr
->color_type
);
229 #ifdef PNG_WRITE_bKGD_SUPPORTED
230 if (info_ptr
->valid
& PNG_INFO_bKGD
)
231 png_write_bKGD(png_ptr
, &(info_ptr
->background
), info_ptr
->color_type
);
234 #ifdef PNG_WRITE_hIST_SUPPORTED
235 if (info_ptr
->valid
& PNG_INFO_hIST
)
236 png_write_hIST(png_ptr
, info_ptr
->hist
, info_ptr
->num_palette
);
239 #ifdef PNG_WRITE_oFFs_SUPPORTED
240 if (info_ptr
->valid
& PNG_INFO_oFFs
)
241 png_write_oFFs(png_ptr
, info_ptr
->x_offset
, info_ptr
->y_offset
,
242 info_ptr
->offset_unit_type
);
245 #ifdef PNG_WRITE_pCAL_SUPPORTED
246 if (info_ptr
->valid
& PNG_INFO_pCAL
)
247 png_write_pCAL(png_ptr
, info_ptr
->pcal_purpose
, info_ptr
->pcal_X0
,
248 info_ptr
->pcal_X1
, info_ptr
->pcal_type
, info_ptr
->pcal_nparams
,
249 info_ptr
->pcal_units
, info_ptr
->pcal_params
);
252 #ifdef PNG_WRITE_sCAL_SUPPORTED
253 if (info_ptr
->valid
& PNG_INFO_sCAL
)
254 png_write_sCAL_s(png_ptr
, (int)info_ptr
->scal_unit
,
255 info_ptr
->scal_s_width
, info_ptr
->scal_s_height
);
258 #ifdef PNG_WRITE_pHYs_SUPPORTED
259 if (info_ptr
->valid
& PNG_INFO_pHYs
)
260 png_write_pHYs(png_ptr
, info_ptr
->x_pixels_per_unit
,
261 info_ptr
->y_pixels_per_unit
, info_ptr
->phys_unit_type
);
264 #ifdef PNG_WRITE_tIME_SUPPORTED
265 if (info_ptr
->valid
& PNG_INFO_tIME
)
267 png_write_tIME(png_ptr
, &(info_ptr
->mod_time
));
268 png_ptr
->mode
|= PNG_WROTE_tIME
;
272 #ifdef PNG_WRITE_sPLT_SUPPORTED
273 if (info_ptr
->valid
& PNG_INFO_sPLT
)
274 for (i
= 0; i
< (int)info_ptr
->splt_palettes_num
; i
++)
275 png_write_sPLT(png_ptr
, info_ptr
->splt_palettes
+ i
);
278 #ifdef PNG_WRITE_TEXT_SUPPORTED
279 /* Check to see if we need to write text chunks */
280 for (i
= 0; i
< info_ptr
->num_text
; i
++)
282 png_debug2(2, "Writing header text chunk %d, type %d", i
,
283 info_ptr
->text
[i
].compression
);
284 /* An internationalized chunk? */
285 if (info_ptr
->text
[i
].compression
> 0)
287 #ifdef PNG_WRITE_iTXt_SUPPORTED
288 /* Write international chunk */
289 png_write_iTXt(png_ptr
,
290 info_ptr
->text
[i
].compression
,
291 info_ptr
->text
[i
].key
,
292 info_ptr
->text
[i
].lang
,
293 info_ptr
->text
[i
].lang_key
,
294 info_ptr
->text
[i
].text
);
296 png_warning(png_ptr
, "Unable to write international text");
298 /* Mark this chunk as written */
299 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
302 /* If we want a compressed text chunk */
303 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_zTXt
)
305 #ifdef PNG_WRITE_zTXt_SUPPORTED
306 /* Write compressed chunk */
307 png_write_zTXt(png_ptr
, info_ptr
->text
[i
].key
,
308 info_ptr
->text
[i
].text
, 0,
309 info_ptr
->text
[i
].compression
);
311 png_warning(png_ptr
, "Unable to write compressed text");
313 /* Mark this chunk as written */
314 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
317 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
319 #ifdef PNG_WRITE_tEXt_SUPPORTED
320 /* Write uncompressed chunk */
321 png_write_tEXt(png_ptr
, info_ptr
->text
[i
].key
,
322 info_ptr
->text
[i
].text
,
324 /* Mark this chunk as written */
325 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
328 png_warning(png_ptr
, "Unable to write uncompressed text");
334 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
335 write_unknown_chunks(png_ptr
, info_ptr
, PNG_HAVE_PLTE
);
339 /* Writes the end of the PNG file. If you don't want to write comments or
340 * time information, you can pass NULL for info. If you already wrote these
341 * in png_write_info(), do not write them again here. If you have long
342 * comments, I suggest writing them here, and compressing them.
345 png_write_end(png_structrp png_ptr
, png_inforp info_ptr
)
347 png_debug(1, "in png_write_end");
352 if (!(png_ptr
->mode
& PNG_HAVE_IDAT
))
353 png_error(png_ptr
, "No IDATs written into file");
355 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
356 if (png_ptr
->num_palette_max
> png_ptr
->num_palette
)
357 png_benign_error(png_ptr
, "Wrote palette index exceeding num_palette");
360 /* See if user wants us to write information chunks */
361 if (info_ptr
!= NULL
)
363 #ifdef PNG_WRITE_TEXT_SUPPORTED
364 int i
; /* local index variable */
366 #ifdef PNG_WRITE_tIME_SUPPORTED
367 /* Check to see if user has supplied a time chunk */
368 if ((info_ptr
->valid
& PNG_INFO_tIME
) &&
369 !(png_ptr
->mode
& PNG_WROTE_tIME
))
370 png_write_tIME(png_ptr
, &(info_ptr
->mod_time
));
373 #ifdef PNG_WRITE_TEXT_SUPPORTED
374 /* Loop through comment chunks */
375 for (i
= 0; i
< info_ptr
->num_text
; i
++)
377 png_debug2(2, "Writing trailer text chunk %d, type %d", i
,
378 info_ptr
->text
[i
].compression
);
379 /* An internationalized chunk? */
380 if (info_ptr
->text
[i
].compression
> 0)
382 #ifdef PNG_WRITE_iTXt_SUPPORTED
383 /* Write international chunk */
384 png_write_iTXt(png_ptr
,
385 info_ptr
->text
[i
].compression
,
386 info_ptr
->text
[i
].key
,
387 info_ptr
->text
[i
].lang
,
388 info_ptr
->text
[i
].lang_key
,
389 info_ptr
->text
[i
].text
);
391 png_warning(png_ptr
, "Unable to write international text");
393 /* Mark this chunk as written */
394 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
397 else if (info_ptr
->text
[i
].compression
>= PNG_TEXT_COMPRESSION_zTXt
)
399 #ifdef PNG_WRITE_zTXt_SUPPORTED
400 /* Write compressed chunk */
401 png_write_zTXt(png_ptr
, info_ptr
->text
[i
].key
,
402 info_ptr
->text
[i
].text
, 0,
403 info_ptr
->text
[i
].compression
);
405 png_warning(png_ptr
, "Unable to write compressed text");
407 /* Mark this chunk as written */
408 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
411 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
413 #ifdef PNG_WRITE_tEXt_SUPPORTED
414 /* Write uncompressed chunk */
415 png_write_tEXt(png_ptr
, info_ptr
->text
[i
].key
,
416 info_ptr
->text
[i
].text
, 0);
418 png_warning(png_ptr
, "Unable to write uncompressed text");
421 /* Mark this chunk as written */
422 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
426 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
427 write_unknown_chunks(png_ptr
, info_ptr
, PNG_AFTER_IDAT
);
431 png_ptr
->mode
|= PNG_AFTER_IDAT
;
433 /* Write end of PNG file */
434 png_write_IEND(png_ptr
);
435 /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
436 * and restored again in libpng-1.2.30, may cause some applications that
437 * do not set png_ptr->output_flush_fn to crash. If your application
438 * experiences a problem, please try building libpng with
439 * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
440 * png-mng-implement at lists.sf.net .
442 #ifdef PNG_WRITE_FLUSH_SUPPORTED
443 # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
449 #ifdef PNG_CONVERT_tIME_SUPPORTED
451 png_convert_from_struct_tm(png_timep ptime
, PNG_CONST
struct tm
* ttime
)
453 png_debug(1, "in png_convert_from_struct_tm");
455 ptime
->year
= (png_uint_16
)(1900 + ttime
->tm_year
);
456 ptime
->month
= (png_byte
)(ttime
->tm_mon
+ 1);
457 ptime
->day
= (png_byte
)ttime
->tm_mday
;
458 ptime
->hour
= (png_byte
)ttime
->tm_hour
;
459 ptime
->minute
= (png_byte
)ttime
->tm_min
;
460 ptime
->second
= (png_byte
)ttime
->tm_sec
;
464 png_convert_from_time_t(png_timep ptime
, time_t ttime
)
468 png_debug(1, "in png_convert_from_time_t");
470 tbuf
= gmtime(&ttime
);
471 png_convert_from_struct_tm(ptime
, tbuf
);
475 /* Initialize png_ptr structure, and allocate any memory needed */
476 PNG_FUNCTION(png_structp
,PNGAPI
477 png_create_write_struct
,(png_const_charp user_png_ver
, png_voidp error_ptr
,
478 png_error_ptr error_fn
, png_error_ptr warn_fn
),PNG_ALLOCATED
)
480 #ifndef PNG_USER_MEM_SUPPORTED
481 png_structrp png_ptr
= png_create_png_struct(user_png_ver
, error_ptr
,
482 error_fn
, warn_fn
, NULL
, NULL
, NULL
);
484 return png_create_write_struct_2(user_png_ver
, error_ptr
, error_fn
,
485 warn_fn
, NULL
, NULL
, NULL
);
488 /* Alternate initialize png_ptr structure, and allocate any memory needed */
489 PNG_FUNCTION(png_structp
,PNGAPI
490 png_create_write_struct_2
,(png_const_charp user_png_ver
, png_voidp error_ptr
,
491 png_error_ptr error_fn
, png_error_ptr warn_fn
, png_voidp mem_ptr
,
492 png_malloc_ptr malloc_fn
, png_free_ptr free_fn
),PNG_ALLOCATED
)
494 png_structrp png_ptr
= png_create_png_struct(user_png_ver
, error_ptr
,
495 error_fn
, warn_fn
, mem_ptr
, malloc_fn
, free_fn
);
496 #endif /* PNG_USER_MEM_SUPPORTED */
499 /* Set the zlib control values to defaults; they can be overridden by the
500 * application after the struct has been created.
502 png_ptr
->zbuffer_size
= PNG_ZBUF_SIZE
;
504 /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
505 * pngwutil.c defaults it according to whether or not filters will be
506 * used, and ignores this setting.
508 png_ptr
->zlib_strategy
= PNG_Z_DEFAULT_STRATEGY
;
509 png_ptr
->zlib_level
= PNG_Z_DEFAULT_COMPRESSION
;
510 png_ptr
->zlib_mem_level
= 8;
511 png_ptr
->zlib_window_bits
= 15;
512 png_ptr
->zlib_method
= 8;
514 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
515 png_ptr
->zlib_text_strategy
= PNG_TEXT_Z_DEFAULT_STRATEGY
;
516 png_ptr
->zlib_text_level
= PNG_TEXT_Z_DEFAULT_COMPRESSION
;
517 png_ptr
->zlib_text_mem_level
= 8;
518 png_ptr
->zlib_text_window_bits
= 15;
519 png_ptr
->zlib_text_method
= 8;
520 #endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
522 /* This is a highly dubious configuration option; by default it is off,
523 * but it may be appropriate for private builds that are testing
524 * extensions not conformant to the current specification, or of
525 * applications that must not fail to write at all costs!
527 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
528 png_ptr
->flags
|= PNG_FLAG_BENIGN_ERRORS_WARN
;
529 /* In stable builds only warn if an application error can be completely
534 /* App warnings are warnings in release (or release candidate) builds but
535 * are errors during development.
537 #if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
538 png_ptr
->flags
|= PNG_FLAG_APP_WARNINGS_WARN
;
541 /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
542 * do it itself) avoiding setting the default function if it is not
545 png_set_write_fn(png_ptr
, NULL
, NULL
, NULL
);
552 /* Write a few rows of image data. If the image is interlaced,
553 * either you will have to write the 7 sub images, or, if you
554 * have called png_set_interlace_handling(), you will have to
555 * "write" the image seven times.
558 png_write_rows(png_structrp png_ptr
, png_bytepp row
,
559 png_uint_32 num_rows
)
561 png_uint_32 i
; /* row counter */
562 png_bytepp rp
; /* row pointer */
564 png_debug(1, "in png_write_rows");
569 /* Loop through the rows */
570 for (i
= 0, rp
= row
; i
< num_rows
; i
++, rp
++)
572 png_write_row(png_ptr
, *rp
);
576 /* Write the image. You only need to call this function once, even
577 * if you are writing an interlaced image.
580 png_write_image(png_structrp png_ptr
, png_bytepp image
)
582 png_uint_32 i
; /* row index */
583 int pass
, num_pass
; /* pass variables */
584 png_bytepp rp
; /* points to current row */
589 png_debug(1, "in png_write_image");
591 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
592 /* Initialize interlace handling. If image is not interlaced,
593 * this will set pass to 1
595 num_pass
= png_set_interlace_handling(png_ptr
);
599 /* Loop through passes */
600 for (pass
= 0; pass
< num_pass
; pass
++)
602 /* Loop through image */
603 for (i
= 0, rp
= image
; i
< png_ptr
->height
; i
++, rp
++)
605 png_write_row(png_ptr
, *rp
);
610 #ifdef PNG_MNG_FEATURES_SUPPORTED
611 /* Performs intrapixel differencing */
613 png_do_write_intrapixel(png_row_infop row_info
, png_bytep row
)
615 png_debug(1, "in png_do_write_intrapixel");
617 if ((row_info
->color_type
& PNG_COLOR_MASK_COLOR
))
620 png_uint_32 row_width
= row_info
->width
;
621 if (row_info
->bit_depth
== 8)
626 if (row_info
->color_type
== PNG_COLOR_TYPE_RGB
)
629 else if (row_info
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
635 for (i
= 0, rp
= row
; i
< row_width
; i
++, rp
+= bytes_per_pixel
)
637 *(rp
) = (png_byte
)((*rp
- *(rp
+ 1)) & 0xff);
638 *(rp
+ 2) = (png_byte
)((*(rp
+ 2) - *(rp
+ 1)) & 0xff);
642 #ifdef PNG_WRITE_16BIT_SUPPORTED
643 else if (row_info
->bit_depth
== 16)
648 if (row_info
->color_type
== PNG_COLOR_TYPE_RGB
)
651 else if (row_info
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
657 for (i
= 0, rp
= row
; i
< row_width
; i
++, rp
+= bytes_per_pixel
)
659 png_uint_32 s0
= (*(rp
) << 8) | *(rp
+ 1);
660 png_uint_32 s1
= (*(rp
+ 2) << 8) | *(rp
+ 3);
661 png_uint_32 s2
= (*(rp
+ 4) << 8) | *(rp
+ 5);
662 png_uint_32 red
= (png_uint_32
)((s0
- s1
) & 0xffffL
);
663 png_uint_32 blue
= (png_uint_32
)((s2
- s1
) & 0xffffL
);
664 *(rp
) = (png_byte
)((red
>> 8) & 0xff);
665 *(rp
+ 1) = (png_byte
)(red
& 0xff);
666 *(rp
+ 4) = (png_byte
)((blue
>> 8) & 0xff);
667 *(rp
+ 5) = (png_byte
)(blue
& 0xff);
670 #endif /* PNG_WRITE_16BIT_SUPPORTED */
673 #endif /* PNG_MNG_FEATURES_SUPPORTED */
675 /* Called by user to write a row of image data */
677 png_write_row(png_structrp png_ptr
, png_const_bytep row
)
679 /* 1.5.6: moved from png_struct to be a local structure: */
680 png_row_info row_info
;
685 png_debug2(1, "in png_write_row (row %u, pass %d)",
686 png_ptr
->row_number
, png_ptr
->pass
);
688 /* Initialize transformations and other stuff if first time */
689 if (png_ptr
->row_number
== 0 && png_ptr
->pass
== 0)
691 /* Make sure we wrote the header info */
692 if (!(png_ptr
->mode
& PNG_WROTE_INFO_BEFORE_PLTE
))
694 "png_write_info was never called before png_write_row");
696 /* Check for transforms that have been set but were defined out */
697 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
698 if (png_ptr
->transformations
& PNG_INVERT_MONO
)
699 png_warning(png_ptr
, "PNG_WRITE_INVERT_SUPPORTED is not defined");
702 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
703 if (png_ptr
->transformations
& PNG_FILLER
)
704 png_warning(png_ptr
, "PNG_WRITE_FILLER_SUPPORTED is not defined");
706 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
707 defined(PNG_READ_PACKSWAP_SUPPORTED)
708 if (png_ptr
->transformations
& PNG_PACKSWAP
)
710 "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
713 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
714 if (png_ptr
->transformations
& PNG_PACK
)
715 png_warning(png_ptr
, "PNG_WRITE_PACK_SUPPORTED is not defined");
718 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
719 if (png_ptr
->transformations
& PNG_SHIFT
)
720 png_warning(png_ptr
, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
723 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
724 if (png_ptr
->transformations
& PNG_BGR
)
725 png_warning(png_ptr
, "PNG_WRITE_BGR_SUPPORTED is not defined");
728 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
729 if (png_ptr
->transformations
& PNG_SWAP_BYTES
)
730 png_warning(png_ptr
, "PNG_WRITE_SWAP_SUPPORTED is not defined");
733 png_write_start_row(png_ptr
);
736 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
737 /* If interlaced and not interested in row, return */
738 if (png_ptr
->interlaced
&& (png_ptr
->transformations
& PNG_INTERLACE
))
740 switch (png_ptr
->pass
)
743 if (png_ptr
->row_number
& 0x07)
745 png_write_finish_row(png_ptr
);
751 if ((png_ptr
->row_number
& 0x07) || png_ptr
->width
< 5)
753 png_write_finish_row(png_ptr
);
759 if ((png_ptr
->row_number
& 0x07) != 4)
761 png_write_finish_row(png_ptr
);
767 if ((png_ptr
->row_number
& 0x03) || png_ptr
->width
< 3)
769 png_write_finish_row(png_ptr
);
775 if ((png_ptr
->row_number
& 0x03) != 2)
777 png_write_finish_row(png_ptr
);
783 if ((png_ptr
->row_number
& 0x01) || png_ptr
->width
< 2)
785 png_write_finish_row(png_ptr
);
791 if (!(png_ptr
->row_number
& 0x01))
793 png_write_finish_row(png_ptr
);
798 default: /* error: ignore it */
804 /* Set up row info for transformations */
805 row_info
.color_type
= png_ptr
->color_type
;
806 row_info
.width
= png_ptr
->usr_width
;
807 row_info
.channels
= png_ptr
->usr_channels
;
808 row_info
.bit_depth
= png_ptr
->usr_bit_depth
;
809 row_info
.pixel_depth
= (png_byte
)(row_info
.bit_depth
* row_info
.channels
);
810 row_info
.rowbytes
= PNG_ROWBYTES(row_info
.pixel_depth
, row_info
.width
);
812 png_debug1(3, "row_info->color_type = %d", row_info
.color_type
);
813 png_debug1(3, "row_info->width = %u", row_info
.width
);
814 png_debug1(3, "row_info->channels = %d", row_info
.channels
);
815 png_debug1(3, "row_info->bit_depth = %d", row_info
.bit_depth
);
816 png_debug1(3, "row_info->pixel_depth = %d", row_info
.pixel_depth
);
817 png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info
.rowbytes
);
819 /* Copy user's row into buffer, leaving room for filter byte. */
820 memcpy(png_ptr
->row_buf
+ 1, row
, row_info
.rowbytes
);
822 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
823 /* Handle interlacing */
824 if (png_ptr
->interlaced
&& png_ptr
->pass
< 6 &&
825 (png_ptr
->transformations
& PNG_INTERLACE
))
827 png_do_write_interlace(&row_info
, png_ptr
->row_buf
+ 1, png_ptr
->pass
);
828 /* This should always get caught above, but still ... */
829 if (!(row_info
.width
))
831 png_write_finish_row(png_ptr
);
837 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
838 /* Handle other transformations */
839 if (png_ptr
->transformations
)
840 png_do_write_transformations(png_ptr
, &row_info
);
843 /* At this point the row_info pixel depth must match the 'transformed' depth,
844 * which is also the output depth.
846 if (row_info
.pixel_depth
!= png_ptr
->pixel_depth
||
847 row_info
.pixel_depth
!= png_ptr
->transformed_pixel_depth
)
848 png_error(png_ptr
, "internal write transform logic error");
850 #ifdef PNG_MNG_FEATURES_SUPPORTED
851 /* Write filter_method 64 (intrapixel differencing) only if
852 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
853 * 2. Libpng did not write a PNG signature (this filter_method is only
854 * used in PNG datastreams that are embedded in MNG datastreams) and
855 * 3. The application called png_permit_mng_features with a mask that
856 * included PNG_FLAG_MNG_FILTER_64 and
857 * 4. The filter_method is 64 and
858 * 5. The color_type is RGB or RGBA
860 if ((png_ptr
->mng_features_permitted
& PNG_FLAG_MNG_FILTER_64
) &&
861 (png_ptr
->filter_type
== PNG_INTRAPIXEL_DIFFERENCING
))
863 /* Intrapixel differencing */
864 png_do_write_intrapixel(&row_info
, png_ptr
->row_buf
+ 1);
868 /* Added at libpng-1.5.10 */
869 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
870 /* Check for out-of-range palette index */
871 if (row_info
.color_type
== PNG_COLOR_TYPE_PALETTE
&&
872 png_ptr
->num_palette_max
>= 0)
873 png_do_check_palette_indexes(png_ptr
, &row_info
);
876 /* Find a filter if necessary, filter the row and write it out. */
877 png_write_find_filter(png_ptr
, &row_info
);
879 if (png_ptr
->write_row_fn
!= NULL
)
880 (*(png_ptr
->write_row_fn
))(png_ptr
, png_ptr
->row_number
, png_ptr
->pass
);
883 #ifdef PNG_WRITE_FLUSH_SUPPORTED
884 /* Set the automatic flush interval or 0 to turn flushing off */
886 png_set_flush(png_structrp png_ptr
, int nrows
)
888 png_debug(1, "in png_set_flush");
893 png_ptr
->flush_dist
= (nrows
< 0 ?
0 : nrows
);
896 /* Flush the current output buffers now */
898 png_write_flush(png_structrp png_ptr
)
900 png_debug(1, "in png_write_flush");
905 /* We have already written out all of the data */
906 if (png_ptr
->row_number
>= png_ptr
->num_rows
)
909 png_compress_IDAT(png_ptr
, NULL
, 0, Z_SYNC_FLUSH
);
910 png_ptr
->flush_rows
= 0;
913 #endif /* PNG_WRITE_FLUSH_SUPPORTED */
915 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
916 static void png_reset_filter_heuristics(png_structrp png_ptr
);/* forward decl */
919 /* Free any memory used in png_ptr struct without freeing the struct itself. */
921 png_write_destroy(png_structrp png_ptr
)
923 png_debug(1, "in png_write_destroy");
925 /* Free any memory zlib uses */
926 if (png_ptr
->flags
& PNG_FLAG_ZSTREAM_INITIALIZED
)
927 deflateEnd(&png_ptr
->zstream
);
929 /* Free our memory. png_free checks NULL for us. */
930 png_free_buffer_list(png_ptr
, &png_ptr
->zbuffer_list
);
931 png_free(png_ptr
, png_ptr
->row_buf
);
932 #ifdef PNG_WRITE_FILTER_SUPPORTED
933 png_free(png_ptr
, png_ptr
->prev_row
);
934 png_free(png_ptr
, png_ptr
->sub_row
);
935 png_free(png_ptr
, png_ptr
->up_row
);
936 png_free(png_ptr
, png_ptr
->avg_row
);
937 png_free(png_ptr
, png_ptr
->paeth_row
);
940 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
941 /* Use this to save a little code space, it doesn't free the filter_costs */
942 png_reset_filter_heuristics(png_ptr
);
943 png_free(png_ptr
, png_ptr
->filter_costs
);
944 png_free(png_ptr
, png_ptr
->inv_filter_costs
);
947 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
948 png_free(png_ptr
, png_ptr
->chunk_list
);
951 /* The error handling and memory handling information is left intact at this
952 * point: the jmp_buf may still have to be freed. See png_destroy_png_struct
953 * for how this happens.
957 /* Free all memory used by the write.
958 * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
959 * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
960 * the passed in info_structs but it would quietly fail to free any of the data
961 * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
965 png_destroy_write_struct(png_structpp png_ptr_ptr
, png_infopp info_ptr_ptr
)
967 png_debug(1, "in png_destroy_write_struct");
969 if (png_ptr_ptr
!= NULL
)
971 png_structrp png_ptr
= *png_ptr_ptr
;
973 if (png_ptr
!= NULL
) /* added in libpng 1.6.0 */
975 png_destroy_info_struct(png_ptr
, info_ptr_ptr
);
978 png_write_destroy(png_ptr
);
979 png_destroy_png_struct(png_ptr
);
984 /* Allow the application to select one or more row filters to use. */
986 png_set_filter(png_structrp png_ptr
, int method
, int filters
)
988 png_debug(1, "in png_set_filter");
993 #ifdef PNG_MNG_FEATURES_SUPPORTED
994 if ((png_ptr
->mng_features_permitted
& PNG_FLAG_MNG_FILTER_64
) &&
995 (method
== PNG_INTRAPIXEL_DIFFERENCING
))
996 method
= PNG_FILTER_TYPE_BASE
;
999 if (method
== PNG_FILTER_TYPE_BASE
)
1001 switch (filters
& (PNG_ALL_FILTERS
| 0x07))
1003 #ifdef PNG_WRITE_FILTER_SUPPORTED
1006 case 7: png_app_error(png_ptr
, "Unknown row filter for method 0");
1008 #endif /* PNG_WRITE_FILTER_SUPPORTED */
1009 case PNG_FILTER_VALUE_NONE
:
1010 png_ptr
->do_filter
= PNG_FILTER_NONE
; break;
1012 #ifdef PNG_WRITE_FILTER_SUPPORTED
1013 case PNG_FILTER_VALUE_SUB
:
1014 png_ptr
->do_filter
= PNG_FILTER_SUB
; break;
1016 case PNG_FILTER_VALUE_UP
:
1017 png_ptr
->do_filter
= PNG_FILTER_UP
; break;
1019 case PNG_FILTER_VALUE_AVG
:
1020 png_ptr
->do_filter
= PNG_FILTER_AVG
; break;
1022 case PNG_FILTER_VALUE_PAETH
:
1023 png_ptr
->do_filter
= PNG_FILTER_PAETH
; break;
1026 png_ptr
->do_filter
= (png_byte
)filters
; break;
1029 png_app_error(png_ptr
, "Unknown row filter for method 0");
1030 #endif /* PNG_WRITE_FILTER_SUPPORTED */
1033 /* If we have allocated the row_buf, this means we have already started
1034 * with the image and we should have allocated all of the filter buffers
1035 * that have been selected. If prev_row isn't already allocated, then
1036 * it is too late to start using the filters that need it, since we
1037 * will be missing the data in the previous row. If an application
1038 * wants to start and stop using particular filters during compression,
1039 * it should start out with all of the filters, and then add and
1040 * remove them after the start of compression.
1042 if (png_ptr
->row_buf
!= NULL
)
1044 #ifdef PNG_WRITE_FILTER_SUPPORTED
1045 if ((png_ptr
->do_filter
& PNG_FILTER_SUB
) && png_ptr
->sub_row
== NULL
)
1047 png_ptr
->sub_row
= (png_bytep
)png_malloc(png_ptr
,
1048 (png_ptr
->rowbytes
+ 1));
1049 png_ptr
->sub_row
[0] = PNG_FILTER_VALUE_SUB
;
1052 if ((png_ptr
->do_filter
& PNG_FILTER_UP
) && png_ptr
->up_row
== NULL
)
1054 if (png_ptr
->prev_row
== NULL
)
1056 png_warning(png_ptr
, "Can't add Up filter after starting");
1057 png_ptr
->do_filter
= (png_byte
)(png_ptr
->do_filter
&
1063 png_ptr
->up_row
= (png_bytep
)png_malloc(png_ptr
,
1064 (png_ptr
->rowbytes
+ 1));
1065 png_ptr
->up_row
[0] = PNG_FILTER_VALUE_UP
;
1069 if ((png_ptr
->do_filter
& PNG_FILTER_AVG
) && png_ptr
->avg_row
== NULL
)
1071 if (png_ptr
->prev_row
== NULL
)
1073 png_warning(png_ptr
, "Can't add Average filter after starting");
1074 png_ptr
->do_filter
= (png_byte
)(png_ptr
->do_filter
&
1080 png_ptr
->avg_row
= (png_bytep
)png_malloc(png_ptr
,
1081 (png_ptr
->rowbytes
+ 1));
1082 png_ptr
->avg_row
[0] = PNG_FILTER_VALUE_AVG
;
1086 if ((png_ptr
->do_filter
& PNG_FILTER_PAETH
) &&
1087 png_ptr
->paeth_row
== NULL
)
1089 if (png_ptr
->prev_row
== NULL
)
1091 png_warning(png_ptr
, "Can't add Paeth filter after starting");
1092 png_ptr
->do_filter
&= (png_byte
)(~PNG_FILTER_PAETH
);
1097 png_ptr
->paeth_row
= (png_bytep
)png_malloc(png_ptr
,
1098 (png_ptr
->rowbytes
+ 1));
1099 png_ptr
->paeth_row
[0] = PNG_FILTER_VALUE_PAETH
;
1103 if (png_ptr
->do_filter
== PNG_NO_FILTERS
)
1104 #endif /* PNG_WRITE_FILTER_SUPPORTED */
1105 png_ptr
->do_filter
= PNG_FILTER_NONE
;
1109 png_error(png_ptr
, "Unknown custom filter method");
1112 /* This allows us to influence the way in which libpng chooses the "best"
1113 * filter for the current scanline. While the "minimum-sum-of-absolute-
1114 * differences metric is relatively fast and effective, there is some
1115 * question as to whether it can be improved upon by trying to keep the
1116 * filtered data going to zlib more consistent, hopefully resulting in
1117 * better compression.
1119 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* GRR 970116 */
1120 /* Convenience reset API. */
1122 png_reset_filter_heuristics(png_structrp png_ptr
)
1124 /* Clear out any old values in the 'weights' - this must be done because if
1125 * the app calls set_filter_heuristics multiple times with different
1126 * 'num_weights' values we would otherwise potentially have wrong sized
1129 png_ptr
->num_prev_filters
= 0;
1130 png_ptr
->heuristic_method
= PNG_FILTER_HEURISTIC_UNWEIGHTED
;
1131 if (png_ptr
->prev_filters
!= NULL
)
1133 png_bytep old
= png_ptr
->prev_filters
;
1134 png_ptr
->prev_filters
= NULL
;
1135 png_free(png_ptr
, old
);
1137 if (png_ptr
->filter_weights
!= NULL
)
1139 png_uint_16p old
= png_ptr
->filter_weights
;
1140 png_ptr
->filter_weights
= NULL
;
1141 png_free(png_ptr
, old
);
1144 if (png_ptr
->inv_filter_weights
!= NULL
)
1146 png_uint_16p old
= png_ptr
->inv_filter_weights
;
1147 png_ptr
->inv_filter_weights
= NULL
;
1148 png_free(png_ptr
, old
);
1151 /* Leave the filter_costs - this array is fixed size. */
1155 png_init_filter_heuristics(png_structrp png_ptr
, int heuristic_method
,
1158 if (png_ptr
== NULL
)
1161 /* Clear out the arrays */
1162 png_reset_filter_heuristics(png_ptr
);
1164 /* Check arguments; the 'reset' function makes the correct settings for the
1165 * unweighted case, but we must handle the weight case by initializing the
1166 * arrays for the caller.
1168 if (heuristic_method
== PNG_FILTER_HEURISTIC_WEIGHTED
)
1172 if (num_weights
> 0)
1174 png_ptr
->prev_filters
= (png_bytep
)png_malloc(png_ptr
,
1175 (png_uint_32
)((sizeof (png_byte
)) * num_weights
));
1177 /* To make sure that the weighting starts out fairly */
1178 for (i
= 0; i
< num_weights
; i
++)
1180 png_ptr
->prev_filters
[i
] = 255;
1183 png_ptr
->filter_weights
= (png_uint_16p
)png_malloc(png_ptr
,
1184 (png_uint_32
)((sizeof (png_uint_16
)) * num_weights
));
1186 png_ptr
->inv_filter_weights
= (png_uint_16p
)png_malloc(png_ptr
,
1187 (png_uint_32
)((sizeof (png_uint_16
)) * num_weights
));
1189 for (i
= 0; i
< num_weights
; i
++)
1191 png_ptr
->inv_filter_weights
[i
] =
1192 png_ptr
->filter_weights
[i
] = PNG_WEIGHT_FACTOR
;
1195 /* Safe to set this now */
1196 png_ptr
->num_prev_filters
= (png_byte
)num_weights
;
1199 /* If, in the future, there are other filter methods, this would
1200 * need to be based on png_ptr->filter.
1202 if (png_ptr
->filter_costs
== NULL
)
1204 png_ptr
->filter_costs
= (png_uint_16p
)png_malloc(png_ptr
,
1205 (png_uint_32
)((sizeof (png_uint_16
)) * PNG_FILTER_VALUE_LAST
));
1207 png_ptr
->inv_filter_costs
= (png_uint_16p
)png_malloc(png_ptr
,
1208 (png_uint_32
)((sizeof (png_uint_16
)) * PNG_FILTER_VALUE_LAST
));
1211 for (i
= 0; i
< PNG_FILTER_VALUE_LAST
; i
++)
1213 png_ptr
->inv_filter_costs
[i
] =
1214 png_ptr
->filter_costs
[i
] = PNG_COST_FACTOR
;
1217 /* All the arrays are inited, safe to set this: */
1218 png_ptr
->heuristic_method
= PNG_FILTER_HEURISTIC_WEIGHTED
;
1220 /* Return the 'ok' code. */
1223 else if (heuristic_method
== PNG_FILTER_HEURISTIC_DEFAULT
||
1224 heuristic_method
== PNG_FILTER_HEURISTIC_UNWEIGHTED
)
1230 png_warning(png_ptr
, "Unknown filter heuristic method");
1235 /* Provide floating and fixed point APIs */
1236 #ifdef PNG_FLOATING_POINT_SUPPORTED
1238 png_set_filter_heuristics(png_structrp png_ptr
, int heuristic_method
,
1239 int num_weights
, png_const_doublep filter_weights
,
1240 png_const_doublep filter_costs
)
1242 png_debug(1, "in png_set_filter_heuristics");
1244 /* The internal API allocates all the arrays and ensures that the elements of
1245 * those arrays are set to the default value.
1247 if (!png_init_filter_heuristics(png_ptr
, heuristic_method
, num_weights
))
1250 /* If using the weighted method copy in the weights. */
1251 if (heuristic_method
== PNG_FILTER_HEURISTIC_WEIGHTED
)
1254 for (i
= 0; i
< num_weights
; i
++)
1256 if (filter_weights
[i
] <= 0.0)
1258 png_ptr
->inv_filter_weights
[i
] =
1259 png_ptr
->filter_weights
[i
] = PNG_WEIGHT_FACTOR
;
1264 png_ptr
->inv_filter_weights
[i
] =
1265 (png_uint_16
)(PNG_WEIGHT_FACTOR
*filter_weights
[i
]+.5);
1267 png_ptr
->filter_weights
[i
] =
1268 (png_uint_16
)(PNG_WEIGHT_FACTOR
/filter_weights
[i
]+.5);
1272 /* Here is where we set the relative costs of the different filters. We
1273 * should take the desired compression level into account when setting
1274 * the costs, so that Paeth, for instance, has a high relative cost at low
1275 * compression levels, while it has a lower relative cost at higher
1276 * compression settings. The filter types are in order of increasing
1277 * relative cost, so it would be possible to do this with an algorithm.
1279 for (i
= 0; i
< PNG_FILTER_VALUE_LAST
; i
++) if (filter_costs
[i
] >= 1.0)
1281 png_ptr
->inv_filter_costs
[i
] =
1282 (png_uint_16
)(PNG_COST_FACTOR
/ filter_costs
[i
] + .5);
1284 png_ptr
->filter_costs
[i
] =
1285 (png_uint_16
)(PNG_COST_FACTOR
* filter_costs
[i
] + .5);
1289 #endif /* FLOATING_POINT */
1291 #ifdef PNG_FIXED_POINT_SUPPORTED
1293 png_set_filter_heuristics_fixed(png_structrp png_ptr
, int heuristic_method
,
1294 int num_weights
, png_const_fixed_point_p filter_weights
,
1295 png_const_fixed_point_p filter_costs
)
1297 png_debug(1, "in png_set_filter_heuristics_fixed");
1299 /* The internal API allocates all the arrays and ensures that the elements of
1300 * those arrays are set to the default value.
1302 if (!png_init_filter_heuristics(png_ptr
, heuristic_method
, num_weights
))
1305 /* If using the weighted method copy in the weights. */
1306 if (heuristic_method
== PNG_FILTER_HEURISTIC_WEIGHTED
)
1309 for (i
= 0; i
< num_weights
; i
++)
1311 if (filter_weights
[i
] <= 0)
1313 png_ptr
->inv_filter_weights
[i
] =
1314 png_ptr
->filter_weights
[i
] = PNG_WEIGHT_FACTOR
;
1319 png_ptr
->inv_filter_weights
[i
] = (png_uint_16
)
1320 ((PNG_WEIGHT_FACTOR
*filter_weights
[i
]+PNG_FP_HALF
)/PNG_FP_1
);
1322 png_ptr
->filter_weights
[i
] = (png_uint_16
)((PNG_WEIGHT_FACTOR
*
1323 PNG_FP_1
+(filter_weights
[i
]/2))/filter_weights
[i
]);
1327 /* Here is where we set the relative costs of the different filters. We
1328 * should take the desired compression level into account when setting
1329 * the costs, so that Paeth, for instance, has a high relative cost at low
1330 * compression levels, while it has a lower relative cost at higher
1331 * compression settings. The filter types are in order of increasing
1332 * relative cost, so it would be possible to do this with an algorithm.
1334 for (i
= 0; i
< PNG_FILTER_VALUE_LAST
; i
++)
1335 if (filter_costs
[i
] >= PNG_FP_1
)
1339 /* Use a 32 bit unsigned temporary here because otherwise the
1340 * intermediate value will be a 32 bit *signed* integer (ANSI rules)
1341 * and this will get the wrong answer on division.
1343 tmp
= PNG_COST_FACTOR
*PNG_FP_1
+ (filter_costs
[i
]/2);
1344 tmp
/= filter_costs
[i
];
1346 png_ptr
->inv_filter_costs
[i
] = (png_uint_16
)tmp
;
1348 tmp
= PNG_COST_FACTOR
* filter_costs
[i
] + PNG_FP_HALF
;
1351 png_ptr
->filter_costs
[i
] = (png_uint_16
)tmp
;
1355 #endif /* FIXED_POINT */
1356 #endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
1359 png_set_compression_level(png_structrp png_ptr
, int level
)
1361 png_debug(1, "in png_set_compression_level");
1363 if (png_ptr
== NULL
)
1366 png_ptr
->zlib_level
= level
;
1370 png_set_compression_mem_level(png_structrp png_ptr
, int mem_level
)
1372 png_debug(1, "in png_set_compression_mem_level");
1374 if (png_ptr
== NULL
)
1377 png_ptr
->zlib_mem_level
= mem_level
;
1381 png_set_compression_strategy(png_structrp png_ptr
, int strategy
)
1383 png_debug(1, "in png_set_compression_strategy");
1385 if (png_ptr
== NULL
)
1388 /* The flag setting here prevents the libpng dynamic selection of strategy.
1390 png_ptr
->flags
|= PNG_FLAG_ZLIB_CUSTOM_STRATEGY
;
1391 png_ptr
->zlib_strategy
= strategy
;
1394 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1395 * smaller value of window_bits if it can do so safely.
1398 png_set_compression_window_bits(png_structrp png_ptr
, int window_bits
)
1400 if (png_ptr
== NULL
)
1403 /* Prior to 1.6.0 this would warn but then set the window_bits value, this
1404 * meant that negative window bits values could be selected which would cause
1405 * libpng to write a non-standard PNG file with raw deflate or gzip
1406 * compressed IDAT or ancillary chunks. Such files can be read and there is
1407 * no warning on read, so this seems like a very bad idea.
1409 if (window_bits
> 15)
1411 png_warning(png_ptr
, "Only compression windows <= 32k supported by PNG");
1415 else if (window_bits
< 8)
1417 png_warning(png_ptr
, "Only compression windows >= 256 supported by PNG");
1421 png_ptr
->zlib_window_bits
= window_bits
;
1425 png_set_compression_method(png_structrp png_ptr
, int method
)
1427 png_debug(1, "in png_set_compression_method");
1429 if (png_ptr
== NULL
)
1432 /* This would produce an invalid PNG file if it worked, but it doesn't and
1433 * deflate will fault it, so it is harmless to just warn here.
1436 png_warning(png_ptr
, "Only compression method 8 is supported by PNG");
1438 png_ptr
->zlib_method
= method
;
1441 /* The following were added to libpng-1.5.4 */
1442 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1444 png_set_text_compression_level(png_structrp png_ptr
, int level
)
1446 png_debug(1, "in png_set_text_compression_level");
1448 if (png_ptr
== NULL
)
1451 png_ptr
->zlib_text_level
= level
;
1455 png_set_text_compression_mem_level(png_structrp png_ptr
, int mem_level
)
1457 png_debug(1, "in png_set_text_compression_mem_level");
1459 if (png_ptr
== NULL
)
1462 png_ptr
->zlib_text_mem_level
= mem_level
;
1466 png_set_text_compression_strategy(png_structrp png_ptr
, int strategy
)
1468 png_debug(1, "in png_set_text_compression_strategy");
1470 if (png_ptr
== NULL
)
1473 png_ptr
->zlib_text_strategy
= strategy
;
1476 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1477 * smaller value of window_bits if it can do so safely.
1480 png_set_text_compression_window_bits(png_structrp png_ptr
, int window_bits
)
1482 if (png_ptr
== NULL
)
1485 if (window_bits
> 15)
1487 png_warning(png_ptr
, "Only compression windows <= 32k supported by PNG");
1491 else if (window_bits
< 8)
1493 png_warning(png_ptr
, "Only compression windows >= 256 supported by PNG");
1497 png_ptr
->zlib_text_window_bits
= window_bits
;
1501 png_set_text_compression_method(png_structrp png_ptr
, int method
)
1503 png_debug(1, "in png_set_text_compression_method");
1505 if (png_ptr
== NULL
)
1509 png_warning(png_ptr
, "Only compression method 8 is supported by PNG");
1511 png_ptr
->zlib_text_method
= method
;
1513 #endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
1514 /* end of API added to libpng-1.5.4 */
1517 png_set_write_status_fn(png_structrp png_ptr
, png_write_status_ptr write_row_fn
)
1519 if (png_ptr
== NULL
)
1522 png_ptr
->write_row_fn
= write_row_fn
;
1525 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1527 png_set_write_user_transform_fn(png_structrp png_ptr
, png_user_transform_ptr
1528 write_user_transform_fn
)
1530 png_debug(1, "in png_set_write_user_transform_fn");
1532 if (png_ptr
== NULL
)
1535 png_ptr
->transformations
|= PNG_USER_TRANSFORM
;
1536 png_ptr
->write_user_transform_fn
= write_user_transform_fn
;
1541 #ifdef PNG_INFO_IMAGE_SUPPORTED
1543 png_write_png(png_structrp png_ptr
, png_inforp info_ptr
,
1544 int transforms
, voidp params
)
1546 if (png_ptr
== NULL
|| info_ptr
== NULL
)
1549 /* Write the file header information. */
1550 png_write_info(png_ptr
, info_ptr
);
1552 /* ------ these transformations don't touch the info structure ------- */
1554 #ifdef PNG_WRITE_INVERT_SUPPORTED
1555 /* Invert monochrome pixels */
1556 if (transforms
& PNG_TRANSFORM_INVERT_MONO
)
1557 png_set_invert_mono(png_ptr
);
1560 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1561 /* Shift the pixels up to a legal bit depth and fill in
1562 * as appropriate to correctly scale the image.
1564 if ((transforms
& PNG_TRANSFORM_SHIFT
)
1565 && (info_ptr
->valid
& PNG_INFO_sBIT
))
1566 png_set_shift(png_ptr
, &info_ptr
->sig_bit
);
1569 #ifdef PNG_WRITE_PACK_SUPPORTED
1570 /* Pack pixels into bytes */
1571 if (transforms
& PNG_TRANSFORM_PACKING
)
1572 png_set_packing(png_ptr
);
1575 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1576 /* Swap location of alpha bytes from ARGB to RGBA */
1577 if (transforms
& PNG_TRANSFORM_SWAP_ALPHA
)
1578 png_set_swap_alpha(png_ptr
);
1581 #ifdef PNG_WRITE_FILLER_SUPPORTED
1582 /* Pack XRGB/RGBX/ARGB/RGBA into RGB (4 channels -> 3 channels) */
1583 if (transforms
& PNG_TRANSFORM_STRIP_FILLER_AFTER
)
1584 png_set_filler(png_ptr
, 0, PNG_FILLER_AFTER
);
1586 else if (transforms
& PNG_TRANSFORM_STRIP_FILLER_BEFORE
)
1587 png_set_filler(png_ptr
, 0, PNG_FILLER_BEFORE
);
1590 #ifdef PNG_WRITE_BGR_SUPPORTED
1591 /* Flip BGR pixels to RGB */
1592 if (transforms
& PNG_TRANSFORM_BGR
)
1593 png_set_bgr(png_ptr
);
1596 #ifdef PNG_WRITE_SWAP_SUPPORTED
1597 /* Swap bytes of 16-bit files to most significant byte first */
1598 if (transforms
& PNG_TRANSFORM_SWAP_ENDIAN
)
1599 png_set_swap(png_ptr
);
1602 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1603 /* Swap bits of 1, 2, 4 bit packed pixel formats */
1604 if (transforms
& PNG_TRANSFORM_PACKSWAP
)
1605 png_set_packswap(png_ptr
);
1608 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1609 /* Invert the alpha channel from opacity to transparency */
1610 if (transforms
& PNG_TRANSFORM_INVERT_ALPHA
)
1611 png_set_invert_alpha(png_ptr
);
1614 /* ----------------------- end of transformations ------------------- */
1616 /* Write the bits */
1617 if (info_ptr
->valid
& PNG_INFO_IDAT
)
1618 png_write_image(png_ptr
, info_ptr
->row_pointers
);
1620 /* It is REQUIRED to call this to finish writing the rest of the file */
1621 png_write_end(png_ptr
, info_ptr
);
1623 PNG_UNUSED(transforms
) /* Quiet compiler warnings */
1629 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
1630 #ifdef PNG_STDIO_SUPPORTED /* currently required for png_image_write_* */
1631 /* Initialize the write structure - general purpose utility. */
1633 png_image_write_init(png_imagep image
)
1635 png_structp png_ptr
= png_create_write_struct(PNG_LIBPNG_VER_STRING
, image
,
1636 png_safe_error
, png_safe_warning
);
1638 if (png_ptr
!= NULL
)
1640 png_infop info_ptr
= png_create_info_struct(png_ptr
);
1642 if (info_ptr
!= NULL
)
1644 png_controlp control
= png_voidcast(png_controlp
,
1645 png_malloc_warn(png_ptr
, (sizeof *control
)));
1647 if (control
!= NULL
)
1649 memset(control
, 0, (sizeof *control
));
1651 control
->png_ptr
= png_ptr
;
1652 control
->info_ptr
= info_ptr
;
1653 control
->for_write
= 1;
1655 image
->opaque
= control
;
1659 /* Error clean up */
1660 png_destroy_info_struct(png_ptr
, &info_ptr
);
1663 png_destroy_write_struct(&png_ptr
, NULL
);
1666 return png_image_error(image
, "png_image_write_: out of memory");
1669 /* Arguments to png_image_write_main: */
1674 png_const_voidp buffer
;
1675 png_int_32 row_stride
;
1676 png_const_voidp colormap
;
1677 int convert_to_8bit
;
1678 /* Local variables: */
1679 png_const_voidp first_row
;
1680 ptrdiff_t row_bytes
;
1681 png_voidp local_row
;
1682 } png_image_write_control
;
1684 /* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
1685 * do any necessary byte swapping. The component order is defined by the
1686 * png_image format value.
1689 png_write_image_16bit(png_voidp argument
)
1691 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
1693 png_imagep image
= display
->image
;
1694 png_structrp png_ptr
= image
->opaque
->png_ptr
;
1696 png_const_uint_16p input_row
= png_voidcast(png_const_uint_16p
,
1697 display
->first_row
);
1698 png_uint_16p output_row
= png_voidcast(png_uint_16p
, display
->local_row
);
1699 png_uint_16p row_end
;
1700 const int channels
= (image
->format
& PNG_FORMAT_FLAG_COLOR
) ?
3 : 1;
1702 png_uint_32 y
= image
->height
;
1704 if (image
->format
& PNG_FORMAT_FLAG_ALPHA
)
1706 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1707 if (image
->format
& PNG_FORMAT_FLAG_AFIRST
)
1710 ++input_row
; /* To point to the first component */
1720 png_error(png_ptr
, "png_write_image: internal call error");
1722 /* Work out the output row end and count over this, note that the increment
1723 * above to 'row' means that row_end can actually be beyond the end of the
1724 * row; this is correct.
1726 row_end
= output_row
+ image
->width
* (channels
+1);
1730 png_const_uint_16p in_ptr
= input_row
;
1731 png_uint_16p out_ptr
= output_row
;
1733 while (out_ptr
< row_end
)
1735 const png_uint_16 alpha
= in_ptr
[aindex
];
1736 png_uint_32 reciprocal
= 0;
1739 out_ptr
[aindex
] = alpha
;
1741 /* Calculate a reciprocal. The correct calculation is simply
1742 * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
1743 * allows correct rounding by adding .5 before the shift. 'reciprocal'
1744 * is only initialized when required.
1746 if (alpha
> 0 && alpha
< 65535)
1747 reciprocal
= ((0xffff<<15)+(alpha
>>1))/alpha
;
1750 do /* always at least one channel */
1752 png_uint_16 component
= *in_ptr
++;
1754 /* The following gives 65535 for an alpha of 0, which is fine,
1755 * otherwise if 0/0 is represented as some other value there is more
1756 * likely to be a discontinuity which will probably damage
1757 * compression when moving from a fully transparent area to a
1758 * nearly transparent one. (The assumption here is that opaque
1759 * areas tend not to be 0 intensity.)
1761 if (component
>= alpha
)
1764 /* component<alpha, so component/alpha is less than one and
1765 * component*reciprocal is less than 2^31.
1767 else if (component
> 0 && alpha
< 65535)
1769 png_uint_32 calc
= component
* reciprocal
;
1770 calc
+= 16384; /* round to nearest */
1771 component
= (png_uint_16
)(calc
>> 15);
1774 *out_ptr
++ = component
;
1778 /* Skip to next component (skip the intervening alpha channel) */
1783 png_write_row(png_ptr
, png_voidcast(png_const_bytep
, display
->local_row
));
1784 input_row
+= display
->row_bytes
/(sizeof (png_uint_16
));
1790 /* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
1791 * is present it must be removed from the components, the components are then
1792 * written in sRGB encoding. No components are added or removed.
1794 * Calculate an alpha reciprocal to reverse pre-multiplication. As above the
1795 * calculation can be done to 15 bits of accuracy; however, the output needs to
1796 * be scaled in the range 0..255*65535, so include that scaling here.
1798 #define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+(alpha>>1))/alpha)
1801 png_unpremultiply(png_uint_32 component
, png_uint_32 alpha
,
1802 png_uint_32 reciprocal
/*from the above macro*/)
1804 /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
1805 * is represented as some other value there is more likely to be a
1806 * discontinuity which will probably damage compression when moving from a
1807 * fully transparent area to a nearly transparent one. (The assumption here
1808 * is that opaque areas tend not to be 0 intensity.)
1810 * There is a rounding problem here; if alpha is less than 128 it will end up
1811 * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
1812 * output change for this too.
1814 if (component
>= alpha
|| alpha
< 128)
1817 /* component<alpha, so component/alpha is less than one and
1818 * component*reciprocal is less than 2^31.
1820 else if (component
> 0)
1822 /* The test is that alpha/257 (rounded) is less than 255, the first value
1823 * that becomes 255 is 65407.
1824 * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
1825 * be exact!) [Could also test reciprocal != 0]
1829 component
*= reciprocal
;
1830 component
+= 64; /* round to nearest */
1837 /* Convert the component to sRGB. */
1838 return (png_byte
)PNG_sRGB_FROM_LINEAR(component
);
1846 png_write_image_8bit(png_voidp argument
)
1848 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
1850 png_imagep image
= display
->image
;
1851 png_structrp png_ptr
= image
->opaque
->png_ptr
;
1853 png_const_uint_16p input_row
= png_voidcast(png_const_uint_16p
,
1854 display
->first_row
);
1855 png_bytep output_row
= png_voidcast(png_bytep
, display
->local_row
);
1856 png_uint_32 y
= image
->height
;
1857 const int channels
= (image
->format
& PNG_FORMAT_FLAG_COLOR
) ?
3 : 1;
1859 if (image
->format
& PNG_FORMAT_FLAG_ALPHA
)
1864 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1865 if (image
->format
& PNG_FORMAT_FLAG_AFIRST
)
1868 ++input_row
; /* To point to the first component */
1876 /* Use row_end in place of a loop counter: */
1877 row_end
= output_row
+ image
->width
* (channels
+1);
1881 png_const_uint_16p in_ptr
= input_row
;
1882 png_bytep out_ptr
= output_row
;
1884 while (out_ptr
< row_end
)
1886 png_uint_16 alpha
= in_ptr
[aindex
];
1887 png_byte alphabyte
= (png_byte
)PNG_DIV257(alpha
);
1888 png_uint_32 reciprocal
= 0;
1891 /* Scale and write the alpha channel. */
1892 out_ptr
[aindex
] = alphabyte
;
1894 if (alphabyte
> 0 && alphabyte
< 255)
1895 reciprocal
= UNP_RECIPROCAL(alpha
);
1898 do /* always at least one channel */
1899 *out_ptr
++ = png_unpremultiply(*in_ptr
++, alpha
, reciprocal
);
1902 /* Skip to next component (skip the intervening alpha channel) */
1905 } /* while out_ptr < row_end */
1907 png_write_row(png_ptr
, png_voidcast(png_const_bytep
,
1908 display
->local_row
));
1909 input_row
+= display
->row_bytes
/(sizeof (png_uint_16
));
1915 /* No alpha channel, so the row_end really is the end of the row and it
1916 * is sufficient to loop over the components one by one.
1918 png_bytep row_end
= output_row
+ image
->width
* channels
;
1922 png_const_uint_16p in_ptr
= input_row
;
1923 png_bytep out_ptr
= output_row
;
1925 while (out_ptr
< row_end
)
1927 png_uint_32 component
= *in_ptr
++;
1930 *out_ptr
++ = (png_byte
)PNG_sRGB_FROM_LINEAR(component
);
1933 png_write_row(png_ptr
, output_row
);
1934 input_row
+= display
->row_bytes
/(sizeof (png_uint_16
));
1942 png_image_set_PLTE(png_image_write_control
*display
)
1944 const png_imagep image
= display
->image
;
1945 const void *cmap
= display
->colormap
;
1946 const int entries
= image
->colormap_entries
> 256 ?
256 :
1947 (int)image
->colormap_entries
;
1949 /* NOTE: the caller must check for cmap != NULL and entries != 0 */
1950 const png_uint_32 format
= image
->format
;
1951 const int channels
= PNG_IMAGE_SAMPLE_CHANNELS(format
);
1953 # if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
1954 defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
1955 const int afirst
= (format
& PNG_FORMAT_FLAG_AFIRST
) != 0 &&
1956 (format
& PNG_FORMAT_FLAG_ALPHA
) != 0;
1961 # ifdef PNG_FORMAT_BGR_SUPPORTED
1962 const int bgr
= (format
& PNG_FORMAT_FLAG_BGR
) ?
2 : 0;
1968 png_color palette
[256];
1971 memset(tRNS
, 255, (sizeof tRNS
));
1972 memset(palette
, 0, (sizeof palette
));
1974 for (i
=num_trans
=0; i
<entries
; ++i
)
1976 /* This gets automatically converted to sRGB with reversal of the
1977 * pre-multiplication if the color-map has an alpha channel.
1979 if (format
& PNG_FORMAT_FLAG_LINEAR
)
1981 png_const_uint_16p entry
= png_voidcast(png_const_uint_16p
, cmap
);
1983 entry
+= i
* channels
;
1985 if (channels
& 1) /* no alpha */
1987 if (channels
>= 3) /* RGB */
1989 palette
[i
].blue
= (png_byte
)PNG_sRGB_FROM_LINEAR(255 *
1991 palette
[i
].green
= (png_byte
)PNG_sRGB_FROM_LINEAR(255 *
1993 palette
[i
].red
= (png_byte
)PNG_sRGB_FROM_LINEAR(255 *
1998 palette
[i
].blue
= palette
[i
].red
= palette
[i
].green
=
1999 (png_byte
)PNG_sRGB_FROM_LINEAR(255 * *entry
);
2004 png_uint_16 alpha
= entry
[afirst ?
0 : channels
-1];
2005 png_byte alphabyte
= (png_byte
)PNG_DIV257(alpha
);
2006 png_uint_32 reciprocal
= 0;
2008 /* Calculate a reciprocal, as in the png_write_image_8bit code above
2009 * this is designed to produce a value scaled to 255*65535 when
2010 * divided by 128 (i.e. asr 7).
2012 if (alphabyte
> 0 && alphabyte
< 255)
2013 reciprocal
= (((0xffff*0xff)<<7)+(alpha
>>1))/alpha
;
2015 tRNS
[i
] = alphabyte
;
2016 if (alphabyte
< 255)
2019 if (channels
>= 3) /* RGB */
2021 palette
[i
].blue
= png_unpremultiply(entry
[afirst
+ (2 ^ bgr
)],
2023 palette
[i
].green
= png_unpremultiply(entry
[afirst
+ 1], alpha
,
2025 palette
[i
].red
= png_unpremultiply(entry
[afirst
+ bgr
], alpha
,
2030 palette
[i
].blue
= palette
[i
].red
= palette
[i
].green
=
2031 png_unpremultiply(entry
[afirst
], alpha
, reciprocal
);
2035 else /* Color-map has sRGB values */
2037 png_const_bytep entry
= png_voidcast(png_const_bytep
, cmap
);
2039 entry
+= i
* channels
;
2044 tRNS
[i
] = entry
[afirst ?
0 : 3];
2049 palette
[i
].blue
= entry
[afirst
+ (2 ^ bgr
)];
2050 palette
[i
].green
= entry
[afirst
+ 1];
2051 palette
[i
].red
= entry
[afirst
+ bgr
];
2055 tRNS
[i
] = entry
[1 ^ afirst
];
2060 palette
[i
].blue
= palette
[i
].red
= palette
[i
].green
=
2077 png_set_PLTE(image
->opaque
->png_ptr
, image
->opaque
->info_ptr
, palette
,
2081 png_set_tRNS(image
->opaque
->png_ptr
, image
->opaque
->info_ptr
, tRNS
,
2084 image
->colormap_entries
= entries
;
2088 png_image_write_main(png_voidp argument
)
2090 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
2092 png_imagep image
= display
->image
;
2093 png_structrp png_ptr
= image
->opaque
->png_ptr
;
2094 png_inforp info_ptr
= image
->opaque
->info_ptr
;
2095 png_uint_32 format
= image
->format
;
2097 int colormap
= (format
& PNG_FORMAT_FLAG_COLORMAP
) != 0;
2098 int linear
= !colormap
&& (format
& PNG_FORMAT_FLAG_LINEAR
) != 0; /* input */
2099 int alpha
= !colormap
&& (format
& PNG_FORMAT_FLAG_ALPHA
) != 0;
2100 int write_16bit
= linear
&& !colormap
&& !display
->convert_to_8bit
;
2102 # ifdef PNG_BENIGN_ERRORS_SUPPORTED
2103 /* Make sure we error out on any bad situation */
2104 png_set_benign_errors(png_ptr
, 0/*error*/);
2107 /* Default the 'row_stride' parameter if required. */
2108 if (display
->row_stride
== 0)
2109 display
->row_stride
= PNG_IMAGE_ROW_STRIDE(*image
);
2111 /* Set the required transforms then write the rows in the correct order. */
2112 if (format
& PNG_FORMAT_FLAG_COLORMAP
)
2114 if (display
->colormap
!= NULL
&& image
->colormap_entries
> 0)
2116 png_uint_32 entries
= image
->colormap_entries
;
2118 png_set_IHDR(png_ptr
, info_ptr
, image
->width
, image
->height
,
2119 entries
> 16 ?
8 : (entries
> 4 ?
4 : (entries
> 2 ?
2 : 1)),
2120 PNG_COLOR_TYPE_PALETTE
, PNG_INTERLACE_NONE
,
2121 PNG_COMPRESSION_TYPE_BASE
, PNG_FILTER_TYPE_BASE
);
2123 png_image_set_PLTE(display
);
2127 png_error(image
->opaque
->png_ptr
,
2128 "no color-map for color-mapped image");
2132 png_set_IHDR(png_ptr
, info_ptr
, image
->width
, image
->height
,
2133 write_16bit ?
16 : 8,
2134 ((format
& PNG_FORMAT_FLAG_COLOR
) ? PNG_COLOR_MASK_COLOR
: 0) +
2135 ((format
& PNG_FORMAT_FLAG_ALPHA
) ? PNG_COLOR_MASK_ALPHA
: 0),
2136 PNG_INTERLACE_NONE
, PNG_COMPRESSION_TYPE_BASE
, PNG_FILTER_TYPE_BASE
);
2138 /* Counter-intuitively the data transformations must be called *after*
2139 * png_write_info, not before as in the read code, but the 'set' functions
2140 * must still be called before. Just set the color space information, never
2141 * write an interlaced image.
2146 /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
2147 png_set_gAMA_fixed(png_ptr
, info_ptr
, PNG_GAMMA_LINEAR
);
2149 if (!(image
->flags
& PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB
))
2150 png_set_cHRM_fixed(png_ptr
, info_ptr
,
2152 /* white */ 31270, 32900,
2153 /* red */ 64000, 33000,
2154 /* green */ 30000, 60000,
2155 /* blue */ 15000, 6000
2159 else if (!(image
->flags
& PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB
))
2160 png_set_sRGB(png_ptr
, info_ptr
, PNG_sRGB_INTENT_PERCEPTUAL
);
2162 /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
2163 * space must still be gamma encoded.
2166 png_set_gAMA_fixed(png_ptr
, info_ptr
, PNG_GAMMA_sRGB_INVERSE
);
2168 /* Write the file header. */
2169 png_write_info(png_ptr
, info_ptr
);
2171 /* Now set up the data transformations (*after* the header is written),
2172 * remove the handled transformations from the 'format' flags for checking.
2174 * First check for a little endian system if writing 16 bit files.
2178 PNG_CONST png_uint_16 le
= 0x0001;
2180 if (*(png_const_bytep
)&le
)
2181 png_set_swap(png_ptr
);
2184 # ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
2185 if (format
& PNG_FORMAT_FLAG_BGR
)
2187 if (!colormap
&& (format
& PNG_FORMAT_FLAG_COLOR
) != 0)
2188 png_set_bgr(png_ptr
);
2189 format
&= ~PNG_FORMAT_FLAG_BGR
;
2193 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
2194 if (format
& PNG_FORMAT_FLAG_AFIRST
)
2196 if (!colormap
&& (format
& PNG_FORMAT_FLAG_ALPHA
) != 0)
2197 png_set_swap_alpha(png_ptr
);
2198 format
&= ~PNG_FORMAT_FLAG_AFIRST
;
2202 /* If there are 16 or fewer color-map entries we wrote a lower bit depth
2203 * above, but the application data is still byte packed.
2205 if (colormap
&& image
->colormap_entries
<= 16)
2206 png_set_packing(png_ptr
);
2208 /* That should have handled all (both) the transforms. */
2209 if ((format
& ~(png_uint_32
)(PNG_FORMAT_FLAG_COLOR
| PNG_FORMAT_FLAG_LINEAR
|
2210 PNG_FORMAT_FLAG_ALPHA
| PNG_FORMAT_FLAG_COLORMAP
)) != 0)
2211 png_error(png_ptr
, "png_write_image: unsupported transformation");
2214 png_const_bytep row
= png_voidcast(png_const_bytep
, display
->buffer
);
2215 ptrdiff_t row_bytes
= display
->row_stride
;
2218 row_bytes
*= (sizeof (png_uint_16
));
2221 row
+= (image
->height
-1) * (-row_bytes
);
2223 display
->first_row
= row
;
2224 display
->row_bytes
= row_bytes
;
2227 /* Apply 'fast' options if the flag is set. */
2228 if ((image
->flags
& PNG_IMAGE_FLAG_FAST
) != 0)
2230 png_set_filter(png_ptr
, PNG_FILTER_TYPE_BASE
, PNG_NO_FILTERS
);
2231 /* NOTE: determined by experiment using pngstest, this reflects some
2232 * balance between the time to write the image once and the time to read
2233 * it about 50 times. The speed-up in pngstest was about 10-20% of the
2234 * total (user) time on a heavily loaded system.
2236 png_set_compression_level(png_ptr
, 3);
2239 /* Check for the cases that currently require a pre-transform on the row
2240 * before it is written. This only applies when the input is 16-bit and
2241 * either there is an alpha channel or it is converted to 8-bit.
2243 if ((linear
&& alpha
) || (!colormap
&& display
->convert_to_8bit
))
2245 png_bytep row
= png_voidcast(png_bytep
, png_malloc(png_ptr
,
2246 png_get_rowbytes(png_ptr
, info_ptr
)));
2249 display
->local_row
= row
;
2251 result
= png_safe_execute(image
, png_write_image_16bit
, display
);
2253 result
= png_safe_execute(image
, png_write_image_8bit
, display
);
2254 display
->local_row
= NULL
;
2256 png_free(png_ptr
, row
);
2258 /* Skip the 'write_end' on error: */
2263 /* Otherwise this is the case where the input is in a format currently
2264 * supported by the rest of the libpng write code; call it directly.
2268 png_const_bytep row
= png_voidcast(png_const_bytep
, display
->first_row
);
2269 ptrdiff_t row_bytes
= display
->row_bytes
;
2270 png_uint_32 y
= image
->height
;
2274 png_write_row(png_ptr
, row
);
2279 png_write_end(png_ptr
, info_ptr
);
2284 png_image_write_to_stdio(png_imagep image
, FILE *file
, int convert_to_8bit
,
2285 const void *buffer
, png_int_32 row_stride
, const void *colormap
)
2287 /* Write the image to the given (FILE*). */
2288 if (image
!= NULL
&& image
->version
== PNG_IMAGE_VERSION
)
2292 if (png_image_write_init(image
))
2294 png_image_write_control display
;
2297 /* This is slightly evil, but png_init_io doesn't do anything other
2298 * than this and we haven't changed the standard IO functions so
2299 * this saves a 'safe' function.
2301 image
->opaque
->png_ptr
->io_ptr
= file
;
2303 memset(&display
, 0, (sizeof display
));
2304 display
.image
= image
;
2305 display
.buffer
= buffer
;
2306 display
.row_stride
= row_stride
;
2307 display
.colormap
= colormap
;
2308 display
.convert_to_8bit
= convert_to_8bit
;
2310 result
= png_safe_execute(image
, png_image_write_main
, &display
);
2311 png_image_free(image
);
2320 return png_image_error(image
,
2321 "png_image_write_to_stdio: invalid argument");
2324 else if (image
!= NULL
)
2325 return png_image_error(image
,
2326 "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
2333 png_image_write_to_file(png_imagep image
, const char *file_name
,
2334 int convert_to_8bit
, const void *buffer
, png_int_32 row_stride
,
2335 const void *colormap
)
2337 /* Write the image to the named file. */
2338 if (image
!= NULL
&& image
->version
== PNG_IMAGE_VERSION
)
2340 if (file_name
!= NULL
)
2342 FILE *fp
= fopen(file_name
, "wb");
2346 if (png_image_write_to_stdio(image
, fp
, convert_to_8bit
, buffer
,
2347 row_stride
, colormap
))
2349 int error
; /* from fflush/fclose */
2351 /* Make sure the file is flushed correctly. */
2352 if (fflush(fp
) == 0 && ferror(fp
) == 0)
2354 if (fclose(fp
) == 0)
2357 error
= errno
; /* from fclose */
2362 error
= errno
; /* from fflush or ferror */
2366 (void)remove(file_name
);
2367 /* The image has already been cleaned up; this is just used to
2368 * set the error (because the original write succeeded).
2370 return png_image_error(image
, strerror(error
));
2375 /* Clean up: just the opened file. */
2377 (void)remove(file_name
);
2383 return png_image_error(image
, strerror(errno
));
2387 return png_image_error(image
,
2388 "png_image_write_to_file: invalid argument");
2391 else if (image
!= NULL
)
2392 return png_image_error(image
,
2393 "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
2398 #endif /* PNG_STDIO_SUPPORTED */
2399 #endif /* SIMPLIFIED_WRITE */
2400 #endif /* PNG_WRITE_SUPPORTED */