2 /* pngwrite.c - general routines to write a PNG file
4 * Last changed in libpng 1.6.15 [November 20, 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
!= 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_ 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
) == 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)
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_WRITE_APNG_SUPPORTED
131 if ((info_ptr
->valid
& PNG_INFO_acTL
) != 0)
132 png_write_acTL(png_ptr
, info_ptr
->num_frames
, info_ptr
->num_plays
);
134 #ifdef PNG_GAMMA_SUPPORTED
135 # ifdef PNG_WRITE_gAMA_SUPPORTED
136 if ((info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) == 0 &&
137 (info_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_gAMA
) != 0 &&
138 (info_ptr
->valid
& PNG_INFO_gAMA
) != 0)
139 png_write_gAMA_fixed(png_ptr
, info_ptr
->colorspace
.gamma
);
143 #ifdef PNG_COLORSPACE_SUPPORTED
144 /* Write only one of sRGB or an ICC profile. If a profile was supplied
145 * and it matches one of the known sRGB ones issue a warning.
147 # ifdef PNG_WRITE_iCCP_SUPPORTED
148 if ((info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) == 0 &&
149 (info_ptr
->valid
& PNG_INFO_iCCP
) != 0)
151 # ifdef PNG_WRITE_sRGB_SUPPORTED
152 if ((info_ptr
->valid
& PNG_INFO_sRGB
) != 0)
153 png_app_warning(png_ptr
,
154 "profile matches sRGB but writing iCCP instead");
157 png_write_iCCP(png_ptr
, info_ptr
->iccp_name
,
158 info_ptr
->iccp_profile
);
160 # ifdef PNG_WRITE_sRGB_SUPPORTED
165 # ifdef PNG_WRITE_sRGB_SUPPORTED
166 if ((info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) == 0 &&
167 (info_ptr
->valid
& PNG_INFO_sRGB
) != 0)
168 png_write_sRGB(png_ptr
, info_ptr
->colorspace
.rendering_intent
);
169 # endif /* WRITE_sRGB */
170 #endif /* COLORSPACE */
172 #ifdef PNG_WRITE_sBIT_SUPPORTED
173 if ((info_ptr
->valid
& PNG_INFO_sBIT
) != 0)
174 png_write_sBIT(png_ptr
, &(info_ptr
->sig_bit
), info_ptr
->color_type
);
177 #ifdef PNG_COLORSPACE_SUPPORTED
178 # ifdef PNG_WRITE_cHRM_SUPPORTED
179 if ((info_ptr
->colorspace
.flags
& PNG_COLORSPACE_INVALID
) == 0 &&
180 (info_ptr
->colorspace
.flags
& PNG_COLORSPACE_FROM_cHRM
) != 0 &&
181 (info_ptr
->valid
& PNG_INFO_cHRM
) != 0)
182 png_write_cHRM_fixed(png_ptr
, &info_ptr
->colorspace
.end_points_xy
);
186 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
187 write_unknown_chunks(png_ptr
, info_ptr
, PNG_HAVE_IHDR
);
190 png_ptr
->mode
|= PNG_WROTE_INFO_BEFORE_PLTE
;
195 png_write_info(png_structrp png_ptr
, png_const_inforp info_ptr
)
197 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
201 png_debug(1, "in png_write_info");
203 if (png_ptr
== NULL
|| info_ptr
== NULL
)
206 png_write_info_before_PLTE(png_ptr
, info_ptr
);
208 if ((info_ptr
->valid
& PNG_INFO_PLTE
) != 0)
209 png_write_PLTE(png_ptr
, info_ptr
->palette
,
210 (png_uint_32
)info_ptr
->num_palette
);
212 else if ((info_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
) !=0)
213 png_error(png_ptr
, "Valid palette required for paletted images");
215 #ifdef PNG_WRITE_tRNS_SUPPORTED
216 if ((info_ptr
->valid
& PNG_INFO_tRNS
) !=0)
218 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
219 /* Invert the alpha channel (in tRNS) */
220 if ((png_ptr
->transformations
& PNG_INVERT_ALPHA
) != 0 &&
221 info_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
224 for (j
= 0; j
<(int)info_ptr
->num_trans
; j
++)
225 info_ptr
->trans_alpha
[j
] =
226 (png_byte
)(255 - info_ptr
->trans_alpha
[j
]);
229 png_write_tRNS(png_ptr
, info_ptr
->trans_alpha
, &(info_ptr
->trans_color
),
230 info_ptr
->num_trans
, info_ptr
->color_type
);
233 #ifdef PNG_WRITE_bKGD_SUPPORTED
234 if ((info_ptr
->valid
& PNG_INFO_bKGD
) != 0)
235 png_write_bKGD(png_ptr
, &(info_ptr
->background
), info_ptr
->color_type
);
238 #ifdef PNG_WRITE_hIST_SUPPORTED
239 if ((info_ptr
->valid
& PNG_INFO_hIST
) != 0)
240 png_write_hIST(png_ptr
, info_ptr
->hist
, info_ptr
->num_palette
);
243 #ifdef PNG_WRITE_oFFs_SUPPORTED
244 if ((info_ptr
->valid
& PNG_INFO_oFFs
) != 0)
245 png_write_oFFs(png_ptr
, info_ptr
->x_offset
, info_ptr
->y_offset
,
246 info_ptr
->offset_unit_type
);
249 #ifdef PNG_WRITE_pCAL_SUPPORTED
250 if ((info_ptr
->valid
& PNG_INFO_pCAL
) != 0)
251 png_write_pCAL(png_ptr
, info_ptr
->pcal_purpose
, info_ptr
->pcal_X0
,
252 info_ptr
->pcal_X1
, info_ptr
->pcal_type
, info_ptr
->pcal_nparams
,
253 info_ptr
->pcal_units
, info_ptr
->pcal_params
);
256 #ifdef PNG_WRITE_sCAL_SUPPORTED
257 if ((info_ptr
->valid
& PNG_INFO_sCAL
) != 0)
258 png_write_sCAL_s(png_ptr
, (int)info_ptr
->scal_unit
,
259 info_ptr
->scal_s_width
, info_ptr
->scal_s_height
);
262 #ifdef PNG_WRITE_pHYs_SUPPORTED
263 if ((info_ptr
->valid
& PNG_INFO_pHYs
) != 0)
264 png_write_pHYs(png_ptr
, info_ptr
->x_pixels_per_unit
,
265 info_ptr
->y_pixels_per_unit
, info_ptr
->phys_unit_type
);
268 #ifdef PNG_WRITE_tIME_SUPPORTED
269 if ((info_ptr
->valid
& PNG_INFO_tIME
) != 0)
271 png_write_tIME(png_ptr
, &(info_ptr
->mod_time
));
272 png_ptr
->mode
|= PNG_WROTE_tIME
;
276 #ifdef PNG_WRITE_sPLT_SUPPORTED
277 if ((info_ptr
->valid
& PNG_INFO_sPLT
) != 0)
278 for (i
= 0; i
< (int)info_ptr
->splt_palettes_num
; i
++)
279 png_write_sPLT(png_ptr
, info_ptr
->splt_palettes
+ i
);
282 #ifdef PNG_WRITE_TEXT_SUPPORTED
283 /* Check to see if we need to write text chunks */
284 for (i
= 0; i
< info_ptr
->num_text
; i
++)
286 png_debug2(2, "Writing header text chunk %d, type %d", i
,
287 info_ptr
->text
[i
].compression
);
288 /* An internationalized chunk? */
289 if (info_ptr
->text
[i
].compression
> 0)
291 #ifdef PNG_WRITE_iTXt_SUPPORTED
292 /* Write international chunk */
293 png_write_iTXt(png_ptr
,
294 info_ptr
->text
[i
].compression
,
295 info_ptr
->text
[i
].key
,
296 info_ptr
->text
[i
].lang
,
297 info_ptr
->text
[i
].lang_key
,
298 info_ptr
->text
[i
].text
);
299 /* Mark this chunk as written */
300 if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
301 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
303 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
305 png_warning(png_ptr
, "Unable to write international text");
309 /* If we want a compressed text chunk */
310 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_zTXt
)
312 #ifdef PNG_WRITE_zTXt_SUPPORTED
313 /* Write compressed chunk */
314 png_write_zTXt(png_ptr
, info_ptr
->text
[i
].key
,
315 info_ptr
->text
[i
].text
, info_ptr
->text
[i
].compression
);
316 /* Mark this chunk as written */
317 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
319 png_warning(png_ptr
, "Unable to write compressed text");
323 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
325 #ifdef PNG_WRITE_tEXt_SUPPORTED
326 /* Write uncompressed chunk */
327 png_write_tEXt(png_ptr
, info_ptr
->text
[i
].key
,
328 info_ptr
->text
[i
].text
,
330 /* Mark this chunk as written */
331 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
334 png_warning(png_ptr
, "Unable to write uncompressed text");
340 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
341 write_unknown_chunks(png_ptr
, info_ptr
, PNG_HAVE_PLTE
);
345 /* Writes the end of the PNG file. If you don't want to write comments or
346 * time information, you can pass NULL for info. If you already wrote these
347 * in png_write_info(), do not write them again here. If you have long
348 * comments, I suggest writing them here, and compressing them.
351 png_write_end(png_structrp png_ptr
, png_inforp info_ptr
)
353 png_debug(1, "in png_write_end");
358 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) == 0)
359 png_error(png_ptr
, "No IDATs written into file");
361 #ifdef PNG_WRITE_APNG_SUPPORTED
362 if (png_ptr
->num_frames_written
!= png_ptr
->num_frames_to_write
)
363 png_error(png_ptr
, "Not enough frames written");
366 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
367 if (png_ptr
->num_palette_max
> png_ptr
->num_palette
)
368 png_benign_error(png_ptr
, "Wrote palette index exceeding num_palette");
371 /* See if user wants us to write information chunks */
372 if (info_ptr
!= NULL
)
374 #ifdef PNG_WRITE_TEXT_SUPPORTED
375 int i
; /* local index variable */
377 #ifdef PNG_WRITE_tIME_SUPPORTED
378 /* Check to see if user has supplied a time chunk */
379 if ((info_ptr
->valid
& PNG_INFO_tIME
) != 0 &&
380 (png_ptr
->mode
& PNG_WROTE_tIME
) == 0)
381 png_write_tIME(png_ptr
, &(info_ptr
->mod_time
));
384 #ifdef PNG_WRITE_TEXT_SUPPORTED
385 /* Loop through comment chunks */
386 for (i
= 0; i
< info_ptr
->num_text
; i
++)
388 png_debug2(2, "Writing trailer text chunk %d, type %d", i
,
389 info_ptr
->text
[i
].compression
);
390 /* An internationalized chunk? */
391 if (info_ptr
->text
[i
].compression
> 0)
393 #ifdef PNG_WRITE_iTXt_SUPPORTED
394 /* Write international chunk */
395 png_write_iTXt(png_ptr
,
396 info_ptr
->text
[i
].compression
,
397 info_ptr
->text
[i
].key
,
398 info_ptr
->text
[i
].lang
,
399 info_ptr
->text
[i
].lang_key
,
400 info_ptr
->text
[i
].text
);
401 /* Mark this chunk as written */
402 if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
403 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
405 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
407 png_warning(png_ptr
, "Unable to write international text");
411 else if (info_ptr
->text
[i
].compression
>= PNG_TEXT_COMPRESSION_zTXt
)
413 #ifdef PNG_WRITE_zTXt_SUPPORTED
414 /* Write compressed chunk */
415 png_write_zTXt(png_ptr
, info_ptr
->text
[i
].key
,
416 info_ptr
->text
[i
].text
, info_ptr
->text
[i
].compression
);
417 /* Mark this chunk as written */
418 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
420 png_warning(png_ptr
, "Unable to write compressed text");
424 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
426 #ifdef PNG_WRITE_tEXt_SUPPORTED
427 /* Write uncompressed chunk */
428 png_write_tEXt(png_ptr
, info_ptr
->text
[i
].key
,
429 info_ptr
->text
[i
].text
, 0);
430 /* Mark this chunk as written */
431 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
433 png_warning(png_ptr
, "Unable to write uncompressed text");
438 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
439 write_unknown_chunks(png_ptr
, info_ptr
, PNG_AFTER_IDAT
);
443 png_ptr
->mode
|= PNG_AFTER_IDAT
;
445 /* Write end of PNG file */
446 png_write_IEND(png_ptr
);
448 /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
449 * and restored again in libpng-1.2.30, may cause some applications that
450 * do not set png_ptr->output_flush_fn to crash. If your application
451 * experiences a problem, please try building libpng with
452 * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
453 * png-mng-implement at lists.sf.net .
455 #ifdef PNG_WRITE_FLUSH_SUPPORTED
456 # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
462 #ifdef PNG_CONVERT_tIME_SUPPORTED
464 png_convert_from_struct_tm(png_timep ptime
, PNG_CONST
struct tm
* ttime
)
466 png_debug(1, "in png_convert_from_struct_tm");
468 ptime
->year
= (png_uint_16
)(1900 + ttime
->tm_year
);
469 ptime
->month
= (png_byte
)(ttime
->tm_mon
+ 1);
470 ptime
->day
= (png_byte
)ttime
->tm_mday
;
471 ptime
->hour
= (png_byte
)ttime
->tm_hour
;
472 ptime
->minute
= (png_byte
)ttime
->tm_min
;
473 ptime
->second
= (png_byte
)ttime
->tm_sec
;
477 png_convert_from_time_t(png_timep ptime
, time_t ttime
)
481 png_debug(1, "in png_convert_from_time_t");
483 tbuf
= gmtime(&ttime
);
484 png_convert_from_struct_tm(ptime
, tbuf
);
488 /* Initialize png_ptr structure, and allocate any memory needed */
489 PNG_FUNCTION(png_structp
,PNGAPI
490 png_create_write_struct
,(png_const_charp user_png_ver
, png_voidp error_ptr
,
491 png_error_ptr error_fn
, png_error_ptr warn_fn
),PNG_ALLOCATED
)
493 #ifndef PNG_USER_MEM_SUPPORTED
494 png_structrp png_ptr
= png_create_png_struct(user_png_ver
, error_ptr
,
495 error_fn
, warn_fn
, NULL
, NULL
, NULL
);
497 return png_create_write_struct_2(user_png_ver
, error_ptr
, error_fn
,
498 warn_fn
, NULL
, NULL
, NULL
);
501 /* Alternate initialize png_ptr structure, and allocate any memory needed */
502 PNG_FUNCTION(png_structp
,PNGAPI
503 png_create_write_struct_2
,(png_const_charp user_png_ver
, png_voidp error_ptr
,
504 png_error_ptr error_fn
, png_error_ptr warn_fn
, png_voidp mem_ptr
,
505 png_malloc_ptr malloc_fn
, png_free_ptr free_fn
),PNG_ALLOCATED
)
507 png_structrp png_ptr
= png_create_png_struct(user_png_ver
, error_ptr
,
508 error_fn
, warn_fn
, mem_ptr
, malloc_fn
, free_fn
);
509 #endif /* USER_MEM */
512 /* Set the zlib control values to defaults; they can be overridden by the
513 * application after the struct has been created.
515 png_ptr
->zbuffer_size
= PNG_ZBUF_SIZE
;
517 /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
518 * pngwutil.c defaults it according to whether or not filters will be
519 * used, and ignores this setting.
521 png_ptr
->zlib_strategy
= PNG_Z_DEFAULT_STRATEGY
;
522 png_ptr
->zlib_level
= PNG_Z_DEFAULT_COMPRESSION
;
523 png_ptr
->zlib_mem_level
= 8;
524 png_ptr
->zlib_window_bits
= 15;
525 png_ptr
->zlib_method
= 8;
527 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
528 png_ptr
->zlib_text_strategy
= PNG_TEXT_Z_DEFAULT_STRATEGY
;
529 png_ptr
->zlib_text_level
= PNG_TEXT_Z_DEFAULT_COMPRESSION
;
530 png_ptr
->zlib_text_mem_level
= 8;
531 png_ptr
->zlib_text_window_bits
= 15;
532 png_ptr
->zlib_text_method
= 8;
533 #endif /* WRITE_COMPRESSED_TEXT */
535 /* This is a highly dubious configuration option; by default it is off,
536 * but it may be appropriate for private builds that are testing
537 * extensions not conformant to the current specification, or of
538 * applications that must not fail to write at all costs!
540 #ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
541 /* In stable builds only warn if an application error can be completely
544 png_ptr
->flags
|= PNG_FLAG_BENIGN_ERRORS_WARN
;
547 /* App warnings are warnings in release (or release candidate) builds but
548 * are errors during development.
550 #if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
551 png_ptr
->flags
|= PNG_FLAG_APP_WARNINGS_WARN
;
554 /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
555 * do it itself) avoiding setting the default function if it is not
558 png_set_write_fn(png_ptr
, NULL
, NULL
, NULL
);
565 /* Write a few rows of image data. If the image is interlaced,
566 * either you will have to write the 7 sub images, or, if you
567 * have called png_set_interlace_handling(), you will have to
568 * "write" the image seven times.
571 png_write_rows(png_structrp png_ptr
, png_bytepp row
,
572 png_uint_32 num_rows
)
574 png_uint_32 i
; /* row counter */
575 png_bytepp rp
; /* row pointer */
577 png_debug(1, "in png_write_rows");
582 /* Loop through the rows */
583 for (i
= 0, rp
= row
; i
< num_rows
; i
++, rp
++)
585 png_write_row(png_ptr
, *rp
);
589 /* Write the image. You only need to call this function once, even
590 * if you are writing an interlaced image.
593 png_write_image(png_structrp png_ptr
, png_bytepp image
)
595 png_uint_32 i
; /* row index */
596 int pass
, num_pass
; /* pass variables */
597 png_bytepp rp
; /* points to current row */
602 png_debug(1, "in png_write_image");
604 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
605 /* Initialize interlace handling. If image is not interlaced,
606 * this will set pass to 1
608 num_pass
= png_set_interlace_handling(png_ptr
);
612 /* Loop through passes */
613 for (pass
= 0; pass
< num_pass
; pass
++)
615 /* Loop through image */
616 for (i
= 0, rp
= image
; i
< png_ptr
->height
; i
++, rp
++)
618 png_write_row(png_ptr
, *rp
);
623 #ifdef PNG_MNG_FEATURES_SUPPORTED
624 /* Performs intrapixel differencing */
626 png_do_write_intrapixel(png_row_infop row_info
, png_bytep row
)
628 png_debug(1, "in png_do_write_intrapixel");
630 if ((row_info
->color_type
& PNG_COLOR_MASK_COLOR
) != 0)
633 png_uint_32 row_width
= row_info
->width
;
634 if (row_info
->bit_depth
== 8)
639 if (row_info
->color_type
== PNG_COLOR_TYPE_RGB
)
642 else if (row_info
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
648 for (i
= 0, rp
= row
; i
< row_width
; i
++, rp
+= bytes_per_pixel
)
650 *(rp
) = (png_byte
)((*rp
- *(rp
+ 1)) & 0xff);
651 *(rp
+ 2) = (png_byte
)((*(rp
+ 2) - *(rp
+ 1)) & 0xff);
655 #ifdef PNG_WRITE_16BIT_SUPPORTED
656 else if (row_info
->bit_depth
== 16)
661 if (row_info
->color_type
== PNG_COLOR_TYPE_RGB
)
664 else if (row_info
->color_type
== PNG_COLOR_TYPE_RGB_ALPHA
)
670 for (i
= 0, rp
= row
; i
< row_width
; i
++, rp
+= bytes_per_pixel
)
672 png_uint_32 s0
= (*(rp
) << 8) | *(rp
+ 1);
673 png_uint_32 s1
= (*(rp
+ 2) << 8) | *(rp
+ 3);
674 png_uint_32 s2
= (*(rp
+ 4) << 8) | *(rp
+ 5);
675 png_uint_32 red
= (png_uint_32
)((s0
- s1
) & 0xffffL
);
676 png_uint_32 blue
= (png_uint_32
)((s2
- s1
) & 0xffffL
);
677 *(rp
) = (png_byte
)((red
>> 8) & 0xff);
678 *(rp
+ 1) = (png_byte
)(red
& 0xff);
679 *(rp
+ 4) = (png_byte
)((blue
>> 8) & 0xff);
680 *(rp
+ 5) = (png_byte
)(blue
& 0xff);
683 #endif /* WRITE_16BIT */
686 #endif /* MNG_FEATURES */
688 /* Called by user to write a row of image data */
690 png_write_row(png_structrp png_ptr
, png_const_bytep row
)
692 /* 1.5.6: moved from png_struct to be a local structure: */
693 png_row_info row_info
;
698 png_debug2(1, "in png_write_row (row %u, pass %d)",
699 png_ptr
->row_number
, png_ptr
->pass
);
701 /* Initialize transformations and other stuff if first time */
702 if (png_ptr
->row_number
== 0 && png_ptr
->pass
== 0)
704 /* Make sure we wrote the header info */
705 if ((png_ptr
->mode
& PNG_WROTE_INFO_BEFORE_PLTE
) == 0)
707 "png_write_info was never called before png_write_row");
709 /* Check for transforms that have been set but were defined out */
710 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
711 if ((png_ptr
->transformations
& PNG_INVERT_MONO
) != 0)
712 png_warning(png_ptr
, "PNG_WRITE_INVERT_SUPPORTED is not defined");
715 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
716 if ((png_ptr
->transformations
& PNG_FILLER
) != 0)
717 png_warning(png_ptr
, "PNG_WRITE_FILLER_SUPPORTED is not defined");
719 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
720 defined(PNG_READ_PACKSWAP_SUPPORTED)
721 if ((png_ptr
->transformations
& PNG_PACKSWAP
) != 0)
723 "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
726 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
727 if ((png_ptr
->transformations
& PNG_PACK
) != 0)
728 png_warning(png_ptr
, "PNG_WRITE_PACK_SUPPORTED is not defined");
731 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
732 if ((png_ptr
->transformations
& PNG_SHIFT
) != 0)
733 png_warning(png_ptr
, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
736 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
737 if ((png_ptr
->transformations
& PNG_BGR
) != 0)
738 png_warning(png_ptr
, "PNG_WRITE_BGR_SUPPORTED is not defined");
741 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
742 if ((png_ptr
->transformations
& PNG_SWAP_BYTES
) != 0)
743 png_warning(png_ptr
, "PNG_WRITE_SWAP_SUPPORTED is not defined");
746 png_write_start_row(png_ptr
);
749 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
750 /* If interlaced and not interested in row, return */
751 if (png_ptr
->interlaced
!= 0 &&
752 (png_ptr
->transformations
& PNG_INTERLACE
) != 0)
754 switch (png_ptr
->pass
)
757 if ((png_ptr
->row_number
& 0x07) != 0)
759 png_write_finish_row(png_ptr
);
765 if ((png_ptr
->row_number
& 0x07) != 0 || png_ptr
->width
< 5)
767 png_write_finish_row(png_ptr
);
773 if ((png_ptr
->row_number
& 0x07) != 4)
775 png_write_finish_row(png_ptr
);
781 if ((png_ptr
->row_number
& 0x03) != 0 || png_ptr
->width
< 3)
783 png_write_finish_row(png_ptr
);
789 if ((png_ptr
->row_number
& 0x03) != 2)
791 png_write_finish_row(png_ptr
);
797 if ((png_ptr
->row_number
& 0x01) != 0 || png_ptr
->width
< 2)
799 png_write_finish_row(png_ptr
);
805 if ((png_ptr
->row_number
& 0x01) == 0)
807 png_write_finish_row(png_ptr
);
812 default: /* error: ignore it */
818 /* Set up row info for transformations */
819 row_info
.color_type
= png_ptr
->color_type
;
820 row_info
.width
= png_ptr
->usr_width
;
821 row_info
.channels
= png_ptr
->usr_channels
;
822 row_info
.bit_depth
= png_ptr
->usr_bit_depth
;
823 row_info
.pixel_depth
= (png_byte
)(row_info
.bit_depth
* row_info
.channels
);
824 row_info
.rowbytes
= PNG_ROWBYTES(row_info
.pixel_depth
, row_info
.width
);
826 png_debug1(3, "row_info->color_type = %d", row_info
.color_type
);
827 png_debug1(3, "row_info->width = %u", row_info
.width
);
828 png_debug1(3, "row_info->channels = %d", row_info
.channels
);
829 png_debug1(3, "row_info->bit_depth = %d", row_info
.bit_depth
);
830 png_debug1(3, "row_info->pixel_depth = %d", row_info
.pixel_depth
);
831 png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info
.rowbytes
);
833 /* Copy user's row into buffer, leaving room for filter byte. */
834 memcpy(png_ptr
->row_buf
+ 1, row
, row_info
.rowbytes
);
836 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
837 /* Handle interlacing */
838 if (png_ptr
->interlaced
&& png_ptr
->pass
< 6 &&
839 (png_ptr
->transformations
& PNG_INTERLACE
) != 0)
841 png_do_write_interlace(&row_info
, png_ptr
->row_buf
+ 1, png_ptr
->pass
);
842 /* This should always get caught above, but still ... */
843 if (row_info
.width
== 0)
845 png_write_finish_row(png_ptr
);
851 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
852 /* Handle other transformations */
853 if (png_ptr
->transformations
!= 0)
854 png_do_write_transformations(png_ptr
, &row_info
);
857 /* At this point the row_info pixel depth must match the 'transformed' depth,
858 * which is also the output depth.
860 if (row_info
.pixel_depth
!= png_ptr
->pixel_depth
||
861 row_info
.pixel_depth
!= png_ptr
->transformed_pixel_depth
)
862 png_error(png_ptr
, "internal write transform logic error");
864 #ifdef PNG_MNG_FEATURES_SUPPORTED
865 /* Write filter_method 64 (intrapixel differencing) only if
866 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
867 * 2. Libpng did not write a PNG signature (this filter_method is only
868 * used in PNG datastreams that are embedded in MNG datastreams) and
869 * 3. The application called png_permit_mng_features with a mask that
870 * included PNG_FLAG_MNG_FILTER_64 and
871 * 4. The filter_method is 64 and
872 * 5. The color_type is RGB or RGBA
874 if ((png_ptr
->mng_features_permitted
& PNG_FLAG_MNG_FILTER_64
) != 0 &&
875 (png_ptr
->filter_type
== PNG_INTRAPIXEL_DIFFERENCING
))
877 /* Intrapixel differencing */
878 png_do_write_intrapixel(&row_info
, png_ptr
->row_buf
+ 1);
882 /* Added at libpng-1.5.10 */
883 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
884 /* Check for out-of-range palette index */
885 if (row_info
.color_type
== PNG_COLOR_TYPE_PALETTE
&&
886 png_ptr
->num_palette_max
>= 0)
887 png_do_check_palette_indexes(png_ptr
, &row_info
);
890 /* Find a filter if necessary, filter the row and write it out. */
891 png_write_find_filter(png_ptr
, &row_info
);
893 if (png_ptr
->write_row_fn
!= NULL
)
894 (*(png_ptr
->write_row_fn
))(png_ptr
, png_ptr
->row_number
, png_ptr
->pass
);
897 #ifdef PNG_WRITE_FLUSH_SUPPORTED
898 /* Set the automatic flush interval or 0 to turn flushing off */
900 png_set_flush(png_structrp png_ptr
, int nrows
)
902 png_debug(1, "in png_set_flush");
907 png_ptr
->flush_dist
= (nrows
< 0 ? 0 : nrows
);
910 /* Flush the current output buffers now */
912 png_write_flush(png_structrp png_ptr
)
914 png_debug(1, "in png_write_flush");
919 /* We have already written out all of the data */
920 if (png_ptr
->row_number
>= png_ptr
->num_rows
)
923 png_compress_IDAT(png_ptr
, NULL
, 0, Z_SYNC_FLUSH
);
924 png_ptr
->flush_rows
= 0;
927 #endif /* WRITE_FLUSH */
929 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
930 static void png_reset_filter_heuristics(png_structrp png_ptr
);/* forward decl */
933 /* Free any memory used in png_ptr struct without freeing the struct itself. */
935 png_write_destroy(png_structrp png_ptr
)
937 png_debug(1, "in png_write_destroy");
939 /* Free any memory zlib uses */
940 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_INITIALIZED
) != 0)
941 deflateEnd(&png_ptr
->zstream
);
943 /* Free our memory. png_free checks NULL for us. */
944 png_free_buffer_list(png_ptr
, &png_ptr
->zbuffer_list
);
945 png_free(png_ptr
, png_ptr
->row_buf
);
946 png_ptr
->row_buf
= NULL
;
947 #ifdef PNG_WRITE_FILTER_SUPPORTED
948 png_free(png_ptr
, png_ptr
->prev_row
);
949 png_free(png_ptr
, png_ptr
->sub_row
);
950 png_free(png_ptr
, png_ptr
->up_row
);
951 png_free(png_ptr
, png_ptr
->avg_row
);
952 png_free(png_ptr
, png_ptr
->paeth_row
);
953 png_ptr
->prev_row
= NULL
;
954 png_ptr
->sub_row
= NULL
;
955 png_ptr
->up_row
= NULL
;
956 png_ptr
->avg_row
= NULL
;
957 png_ptr
->paeth_row
= NULL
;
960 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
961 /* Use this to save a little code space, it doesn't free the filter_costs */
962 png_reset_filter_heuristics(png_ptr
);
963 png_free(png_ptr
, png_ptr
->filter_costs
);
964 png_free(png_ptr
, png_ptr
->inv_filter_costs
);
965 png_ptr
->filter_costs
= NULL
;
966 png_ptr
->inv_filter_costs
= NULL
;
969 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
970 png_free(png_ptr
, png_ptr
->chunk_list
);
971 png_ptr
->chunk_list
= NULL
;
974 /* The error handling and memory handling information is left intact at this
975 * point: the jmp_buf may still have to be freed. See png_destroy_png_struct
976 * for how this happens.
980 /* Free all memory used by the write.
981 * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
982 * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
983 * the passed in info_structs but it would quietly fail to free any of the data
984 * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
988 png_destroy_write_struct(png_structpp png_ptr_ptr
, png_infopp info_ptr_ptr
)
990 png_debug(1, "in png_destroy_write_struct");
992 if (png_ptr_ptr
!= NULL
)
994 png_structrp png_ptr
= *png_ptr_ptr
;
996 if (png_ptr
!= NULL
) /* added in libpng 1.6.0 */
998 png_destroy_info_struct(png_ptr
, info_ptr_ptr
);
1000 *png_ptr_ptr
= NULL
;
1001 png_write_destroy(png_ptr
);
1002 png_destroy_png_struct(png_ptr
);
1007 /* Allow the application to select one or more row filters to use. */
1009 png_set_filter(png_structrp png_ptr
, int method
, int filters
)
1011 png_debug(1, "in png_set_filter");
1013 if (png_ptr
== NULL
)
1016 #ifdef PNG_MNG_FEATURES_SUPPORTED
1017 if ((png_ptr
->mng_features_permitted
& PNG_FLAG_MNG_FILTER_64
) != 0 &&
1018 (method
== PNG_INTRAPIXEL_DIFFERENCING
))
1019 method
= PNG_FILTER_TYPE_BASE
;
1022 if (method
== PNG_FILTER_TYPE_BASE
)
1024 switch (filters
& (PNG_ALL_FILTERS
| 0x07))
1026 #ifdef PNG_WRITE_FILTER_SUPPORTED
1029 case 7: png_app_error(png_ptr
, "Unknown row filter for method 0");
1031 #endif /* WRITE_FILTER */
1032 case PNG_FILTER_VALUE_NONE
:
1033 png_ptr
->do_filter
= PNG_FILTER_NONE
; break;
1035 #ifdef PNG_WRITE_FILTER_SUPPORTED
1036 case PNG_FILTER_VALUE_SUB
:
1037 png_ptr
->do_filter
= PNG_FILTER_SUB
; break;
1039 case PNG_FILTER_VALUE_UP
:
1040 png_ptr
->do_filter
= PNG_FILTER_UP
; break;
1042 case PNG_FILTER_VALUE_AVG
:
1043 png_ptr
->do_filter
= PNG_FILTER_AVG
; break;
1045 case PNG_FILTER_VALUE_PAETH
:
1046 png_ptr
->do_filter
= PNG_FILTER_PAETH
; break;
1049 png_ptr
->do_filter
= (png_byte
)filters
; break;
1052 png_app_error(png_ptr
, "Unknown row filter for method 0");
1053 #endif /* WRITE_FILTER */
1056 /* If we have allocated the row_buf, this means we have already started
1057 * with the image and we should have allocated all of the filter buffers
1058 * that have been selected. If prev_row isn't already allocated, then
1059 * it is too late to start using the filters that need it, since we
1060 * will be missing the data in the previous row. If an application
1061 * wants to start and stop using particular filters during compression,
1062 * it should start out with all of the filters, and then add and
1063 * remove them after the start of compression.
1065 if (png_ptr
->row_buf
!= NULL
)
1067 #ifdef PNG_WRITE_FILTER_SUPPORTED
1068 if ((png_ptr
->do_filter
& PNG_FILTER_SUB
) != 0 &&
1069 png_ptr
->sub_row
== NULL
)
1071 png_ptr
->sub_row
= (png_bytep
)png_malloc(png_ptr
,
1072 (png_ptr
->rowbytes
+ 1));
1073 png_ptr
->sub_row
[0] = PNG_FILTER_VALUE_SUB
;
1076 if ((png_ptr
->do_filter
& PNG_FILTER_UP
) != 0 &&
1077 png_ptr
->up_row
== NULL
)
1079 if (png_ptr
->prev_row
== NULL
)
1081 png_warning(png_ptr
, "Can't add Up filter after starting");
1082 png_ptr
->do_filter
= (png_byte
)(png_ptr
->do_filter
&
1088 png_ptr
->up_row
= (png_bytep
)png_malloc(png_ptr
,
1089 (png_ptr
->rowbytes
+ 1));
1090 png_ptr
->up_row
[0] = PNG_FILTER_VALUE_UP
;
1094 if ((png_ptr
->do_filter
& PNG_FILTER_AVG
) != 0 &&
1095 png_ptr
->avg_row
== NULL
)
1097 if (png_ptr
->prev_row
== NULL
)
1099 png_warning(png_ptr
, "Can't add Average filter after starting");
1100 png_ptr
->do_filter
= (png_byte
)(png_ptr
->do_filter
&
1106 png_ptr
->avg_row
= (png_bytep
)png_malloc(png_ptr
,
1107 (png_ptr
->rowbytes
+ 1));
1108 png_ptr
->avg_row
[0] = PNG_FILTER_VALUE_AVG
;
1112 if ((png_ptr
->do_filter
& PNG_FILTER_PAETH
) != 0 &&
1113 png_ptr
->paeth_row
== NULL
)
1115 if (png_ptr
->prev_row
== NULL
)
1117 png_warning(png_ptr
, "Can't add Paeth filter after starting");
1118 png_ptr
->do_filter
&= (png_byte
)(~PNG_FILTER_PAETH
);
1123 png_ptr
->paeth_row
= (png_bytep
)png_malloc(png_ptr
,
1124 (png_ptr
->rowbytes
+ 1));
1125 png_ptr
->paeth_row
[0] = PNG_FILTER_VALUE_PAETH
;
1129 if (png_ptr
->do_filter
== PNG_NO_FILTERS
)
1130 #endif /* WRITE_FILTER */
1131 png_ptr
->do_filter
= PNG_FILTER_NONE
;
1135 png_error(png_ptr
, "Unknown custom filter method");
1138 /* This allows us to influence the way in which libpng chooses the "best"
1139 * filter for the current scanline. While the "minimum-sum-of-absolute-
1140 * differences metric is relatively fast and effective, there is some
1141 * question as to whether it can be improved upon by trying to keep the
1142 * filtered data going to zlib more consistent, hopefully resulting in
1143 * better compression.
1145 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* GRR 970116 */
1146 /* Convenience reset API. */
1148 png_reset_filter_heuristics(png_structrp png_ptr
)
1150 /* Clear out any old values in the 'weights' - this must be done because if
1151 * the app calls set_filter_heuristics multiple times with different
1152 * 'num_weights' values we would otherwise potentially have wrong sized
1155 png_ptr
->num_prev_filters
= 0;
1156 png_ptr
->heuristic_method
= PNG_FILTER_HEURISTIC_UNWEIGHTED
;
1157 if (png_ptr
->prev_filters
!= NULL
)
1159 png_bytep old
= png_ptr
->prev_filters
;
1160 png_ptr
->prev_filters
= NULL
;
1161 png_free(png_ptr
, old
);
1163 if (png_ptr
->filter_weights
!= NULL
)
1165 png_uint_16p old
= png_ptr
->filter_weights
;
1166 png_ptr
->filter_weights
= NULL
;
1167 png_free(png_ptr
, old
);
1170 if (png_ptr
->inv_filter_weights
!= NULL
)
1172 png_uint_16p old
= png_ptr
->inv_filter_weights
;
1173 png_ptr
->inv_filter_weights
= NULL
;
1174 png_free(png_ptr
, old
);
1177 /* Leave the filter_costs - this array is fixed size. */
1181 png_init_filter_heuristics(png_structrp png_ptr
, int heuristic_method
,
1184 if (png_ptr
== NULL
)
1187 /* Clear out the arrays */
1188 png_reset_filter_heuristics(png_ptr
);
1190 /* Check arguments; the 'reset' function makes the correct settings for the
1191 * unweighted case, but we must handle the weight case by initializing the
1192 * arrays for the caller.
1194 if (heuristic_method
== PNG_FILTER_HEURISTIC_WEIGHTED
)
1198 if (num_weights
> 0)
1200 png_ptr
->prev_filters
= (png_bytep
)png_malloc(png_ptr
,
1201 (png_uint_32
)((sizeof (png_byte
)) * num_weights
));
1203 /* To make sure that the weighting starts out fairly */
1204 for (i
= 0; i
< num_weights
; i
++)
1206 png_ptr
->prev_filters
[i
] = 255;
1209 png_ptr
->filter_weights
= (png_uint_16p
)png_malloc(png_ptr
,
1210 (png_uint_32
)((sizeof (png_uint_16
)) * num_weights
));
1212 png_ptr
->inv_filter_weights
= (png_uint_16p
)png_malloc(png_ptr
,
1213 (png_uint_32
)((sizeof (png_uint_16
)) * num_weights
));
1215 for (i
= 0; i
< num_weights
; i
++)
1217 png_ptr
->inv_filter_weights
[i
] =
1218 png_ptr
->filter_weights
[i
] = PNG_WEIGHT_FACTOR
;
1221 /* Safe to set this now */
1222 png_ptr
->num_prev_filters
= (png_byte
)num_weights
;
1225 /* If, in the future, there are other filter methods, this would
1226 * need to be based on png_ptr->filter.
1228 if (png_ptr
->filter_costs
== NULL
)
1230 png_ptr
->filter_costs
= (png_uint_16p
)png_malloc(png_ptr
,
1231 (png_uint_32
)((sizeof (png_uint_16
)) * PNG_FILTER_VALUE_LAST
));
1233 png_ptr
->inv_filter_costs
= (png_uint_16p
)png_malloc(png_ptr
,
1234 (png_uint_32
)((sizeof (png_uint_16
)) * PNG_FILTER_VALUE_LAST
));
1237 for (i
= 0; i
< PNG_FILTER_VALUE_LAST
; i
++)
1239 png_ptr
->inv_filter_costs
[i
] =
1240 png_ptr
->filter_costs
[i
] = PNG_COST_FACTOR
;
1243 /* All the arrays are inited, safe to set this: */
1244 png_ptr
->heuristic_method
= PNG_FILTER_HEURISTIC_WEIGHTED
;
1246 /* Return the 'ok' code. */
1249 else if (heuristic_method
== PNG_FILTER_HEURISTIC_DEFAULT
||
1250 heuristic_method
== PNG_FILTER_HEURISTIC_UNWEIGHTED
)
1256 png_warning(png_ptr
, "Unknown filter heuristic method");
1261 /* Provide floating and fixed point APIs */
1262 #ifdef PNG_FLOATING_POINT_SUPPORTED
1264 png_set_filter_heuristics(png_structrp png_ptr
, int heuristic_method
,
1265 int num_weights
, png_const_doublep filter_weights
,
1266 png_const_doublep filter_costs
)
1268 png_debug(1, "in png_set_filter_heuristics");
1270 /* The internal API allocates all the arrays and ensures that the elements of
1271 * those arrays are set to the default value.
1273 if (png_init_filter_heuristics(png_ptr
, heuristic_method
, num_weights
) == 0)
1276 /* If using the weighted method copy in the weights. */
1277 if (heuristic_method
== PNG_FILTER_HEURISTIC_WEIGHTED
)
1280 for (i
= 0; i
< num_weights
; i
++)
1282 if (filter_weights
[i
] <= 0.0)
1284 png_ptr
->inv_filter_weights
[i
] =
1285 png_ptr
->filter_weights
[i
] = PNG_WEIGHT_FACTOR
;
1290 png_ptr
->inv_filter_weights
[i
] =
1291 (png_uint_16
)(PNG_WEIGHT_FACTOR
*filter_weights
[i
]+.5);
1293 png_ptr
->filter_weights
[i
] =
1294 (png_uint_16
)(PNG_WEIGHT_FACTOR
/filter_weights
[i
]+.5);
1298 /* Here is where we set the relative costs of the different filters. We
1299 * should take the desired compression level into account when setting
1300 * the costs, so that Paeth, for instance, has a high relative cost at low
1301 * compression levels, while it has a lower relative cost at higher
1302 * compression settings. The filter types are in order of increasing
1303 * relative cost, so it would be possible to do this with an algorithm.
1305 for (i
= 0; i
< PNG_FILTER_VALUE_LAST
; i
++) if (filter_costs
[i
] >= 1.0)
1307 png_ptr
->inv_filter_costs
[i
] =
1308 (png_uint_16
)(PNG_COST_FACTOR
/ filter_costs
[i
] + .5);
1310 png_ptr
->filter_costs
[i
] =
1311 (png_uint_16
)(PNG_COST_FACTOR
* filter_costs
[i
] + .5);
1315 #endif /* FLOATING_POINT */
1317 #ifdef PNG_FIXED_POINT_SUPPORTED
1319 png_set_filter_heuristics_fixed(png_structrp png_ptr
, int heuristic_method
,
1320 int num_weights
, png_const_fixed_point_p filter_weights
,
1321 png_const_fixed_point_p filter_costs
)
1323 png_debug(1, "in png_set_filter_heuristics_fixed");
1325 /* The internal API allocates all the arrays and ensures that the elements of
1326 * those arrays are set to the default value.
1328 if (png_init_filter_heuristics(png_ptr
, heuristic_method
, num_weights
) == 0)
1331 /* If using the weighted method copy in the weights. */
1332 if (heuristic_method
== PNG_FILTER_HEURISTIC_WEIGHTED
)
1335 for (i
= 0; i
< num_weights
; i
++)
1337 if (filter_weights
[i
] <= 0)
1339 png_ptr
->inv_filter_weights
[i
] =
1340 png_ptr
->filter_weights
[i
] = PNG_WEIGHT_FACTOR
;
1345 png_ptr
->inv_filter_weights
[i
] = (png_uint_16
)
1346 ((PNG_WEIGHT_FACTOR
*filter_weights
[i
]+PNG_FP_HALF
)/PNG_FP_1
);
1348 png_ptr
->filter_weights
[i
] = (png_uint_16
)((PNG_WEIGHT_FACTOR
*
1349 PNG_FP_1
+(filter_weights
[i
]/2))/filter_weights
[i
]);
1353 /* Here is where we set the relative costs of the different filters. We
1354 * should take the desired compression level into account when setting
1355 * the costs, so that Paeth, for instance, has a high relative cost at low
1356 * compression levels, while it has a lower relative cost at higher
1357 * compression settings. The filter types are in order of increasing
1358 * relative cost, so it would be possible to do this with an algorithm.
1360 for (i
= 0; i
< PNG_FILTER_VALUE_LAST
; i
++)
1361 if (filter_costs
[i
] >= PNG_FP_1
)
1365 /* Use a 32 bit unsigned temporary here because otherwise the
1366 * intermediate value will be a 32 bit *signed* integer (ANSI rules)
1367 * and this will get the wrong answer on division.
1369 tmp
= PNG_COST_FACTOR
*PNG_FP_1
+ (filter_costs
[i
]/2);
1370 tmp
/= filter_costs
[i
];
1372 png_ptr
->inv_filter_costs
[i
] = (png_uint_16
)tmp
;
1374 tmp
= PNG_COST_FACTOR
* filter_costs
[i
] + PNG_FP_HALF
;
1377 png_ptr
->filter_costs
[i
] = (png_uint_16
)tmp
;
1381 #endif /* FIXED_POINT */
1382 #endif /* WRITE_WEIGHTED_FILTER */
1385 png_set_compression_level(png_structrp png_ptr
, int level
)
1387 png_debug(1, "in png_set_compression_level");
1389 if (png_ptr
== NULL
)
1392 png_ptr
->zlib_level
= level
;
1396 png_set_compression_mem_level(png_structrp png_ptr
, int mem_level
)
1398 png_debug(1, "in png_set_compression_mem_level");
1400 if (png_ptr
== NULL
)
1403 png_ptr
->zlib_mem_level
= mem_level
;
1407 png_set_compression_strategy(png_structrp png_ptr
, int strategy
)
1409 png_debug(1, "in png_set_compression_strategy");
1411 if (png_ptr
== NULL
)
1414 /* The flag setting here prevents the libpng dynamic selection of strategy.
1416 png_ptr
->flags
|= PNG_FLAG_ZLIB_CUSTOM_STRATEGY
;
1417 png_ptr
->zlib_strategy
= strategy
;
1420 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1421 * smaller value of window_bits if it can do so safely.
1424 png_set_compression_window_bits(png_structrp png_ptr
, int window_bits
)
1426 if (png_ptr
== NULL
)
1429 /* Prior to 1.6.0 this would warn but then set the window_bits value, this
1430 * meant that negative window bits values could be selected which would cause
1431 * libpng to write a non-standard PNG file with raw deflate or gzip
1432 * compressed IDAT or ancillary chunks. Such files can be read and there is
1433 * no warning on read, so this seems like a very bad idea.
1435 if (window_bits
> 15)
1437 png_warning(png_ptr
, "Only compression windows <= 32k supported by PNG");
1441 else if (window_bits
< 8)
1443 png_warning(png_ptr
, "Only compression windows >= 256 supported by PNG");
1447 png_ptr
->zlib_window_bits
= window_bits
;
1451 png_set_compression_method(png_structrp png_ptr
, int method
)
1453 png_debug(1, "in png_set_compression_method");
1455 if (png_ptr
== NULL
)
1458 /* This would produce an invalid PNG file if it worked, but it doesn't and
1459 * deflate will fault it, so it is harmless to just warn here.
1462 png_warning(png_ptr
, "Only compression method 8 is supported by PNG");
1464 png_ptr
->zlib_method
= method
;
1467 /* The following were added to libpng-1.5.4 */
1468 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1470 png_set_text_compression_level(png_structrp png_ptr
, int level
)
1472 png_debug(1, "in png_set_text_compression_level");
1474 if (png_ptr
== NULL
)
1477 png_ptr
->zlib_text_level
= level
;
1481 png_set_text_compression_mem_level(png_structrp png_ptr
, int mem_level
)
1483 png_debug(1, "in png_set_text_compression_mem_level");
1485 if (png_ptr
== NULL
)
1488 png_ptr
->zlib_text_mem_level
= mem_level
;
1492 png_set_text_compression_strategy(png_structrp png_ptr
, int strategy
)
1494 png_debug(1, "in png_set_text_compression_strategy");
1496 if (png_ptr
== NULL
)
1499 png_ptr
->zlib_text_strategy
= strategy
;
1502 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1503 * smaller value of window_bits if it can do so safely.
1506 png_set_text_compression_window_bits(png_structrp png_ptr
, int window_bits
)
1508 if (png_ptr
== NULL
)
1511 if (window_bits
> 15)
1513 png_warning(png_ptr
, "Only compression windows <= 32k supported by PNG");
1517 else if (window_bits
< 8)
1519 png_warning(png_ptr
, "Only compression windows >= 256 supported by PNG");
1523 png_ptr
->zlib_text_window_bits
= window_bits
;
1527 png_set_text_compression_method(png_structrp png_ptr
, int method
)
1529 png_debug(1, "in png_set_text_compression_method");
1531 if (png_ptr
== NULL
)
1535 png_warning(png_ptr
, "Only compression method 8 is supported by PNG");
1537 png_ptr
->zlib_text_method
= method
;
1539 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
1540 /* end of API added to libpng-1.5.4 */
1543 png_set_write_status_fn(png_structrp png_ptr
, png_write_status_ptr write_row_fn
)
1545 if (png_ptr
== NULL
)
1548 png_ptr
->write_row_fn
= write_row_fn
;
1551 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1553 png_set_write_user_transform_fn(png_structrp png_ptr
, png_user_transform_ptr
1554 write_user_transform_fn
)
1556 png_debug(1, "in png_set_write_user_transform_fn");
1558 if (png_ptr
== NULL
)
1561 png_ptr
->transformations
|= PNG_USER_TRANSFORM
;
1562 png_ptr
->write_user_transform_fn
= write_user_transform_fn
;
1567 #ifdef PNG_INFO_IMAGE_SUPPORTED
1569 png_write_png(png_structrp png_ptr
, png_inforp info_ptr
,
1570 int transforms
, voidp params
)
1572 if (png_ptr
== NULL
|| info_ptr
== NULL
)
1575 if ((info_ptr
->valid
& PNG_INFO_IDAT
) == 0)
1577 png_app_error(png_ptr
, "no rows for png_write_image to write");
1581 /* Write the file header information. */
1582 png_write_info(png_ptr
, info_ptr
);
1584 /* ------ these transformations don't touch the info structure ------- */
1586 /* Invert monochrome pixels */
1587 if ((transforms
& PNG_TRANSFORM_INVERT_MONO
) != 0)
1588 #ifdef PNG_WRITE_INVERT_SUPPORTED
1589 png_set_invert_mono(png_ptr
);
1591 png_app_error(png_ptr
, "PNG_TRANSFORM_INVERT_MONO not supported");
1594 /* Shift the pixels up to a legal bit depth and fill in
1595 * as appropriate to correctly scale the image.
1597 if ((transforms
& PNG_TRANSFORM_SHIFT
) != 0)
1598 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1599 if ((info_ptr
->valid
& PNG_INFO_sBIT
) != 0)
1600 png_set_shift(png_ptr
, &info_ptr
->sig_bit
);
1602 png_app_error(png_ptr
, "PNG_TRANSFORM_SHIFT not supported");
1605 /* Pack pixels into bytes */
1606 if ((transforms
& PNG_TRANSFORM_PACKING
) != 0)
1607 #ifdef PNG_WRITE_PACK_SUPPORTED
1608 png_set_packing(png_ptr
);
1610 png_app_error(png_ptr
, "PNG_TRANSFORM_PACKING not supported");
1613 /* Swap location of alpha bytes from ARGB to RGBA */
1614 if ((transforms
& PNG_TRANSFORM_SWAP_ALPHA
) != 0)
1615 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1616 png_set_swap_alpha(png_ptr
);
1618 png_app_error(png_ptr
, "PNG_TRANSFORM_SWAP_ALPHA not supported");
1621 /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
1622 * RGB, note that the code expects the input color type to be G or RGB; no
1625 if ((transforms
& (PNG_TRANSFORM_STRIP_FILLER_AFTER
|
1626 PNG_TRANSFORM_STRIP_FILLER_BEFORE
)) != 0)
1628 #ifdef PNG_WRITE_FILLER_SUPPORTED
1629 if ((transforms
& PNG_TRANSFORM_STRIP_FILLER_AFTER
) != 0)
1631 if ((transforms
& PNG_TRANSFORM_STRIP_FILLER_BEFORE
) != 0)
1632 png_app_error(png_ptr
,
1633 "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
1635 /* Continue if ignored - this is the pre-1.6.10 behavior */
1636 png_set_filler(png_ptr
, 0, PNG_FILLER_AFTER
);
1639 else if ((transforms
& PNG_TRANSFORM_STRIP_FILLER_BEFORE
) != 0)
1640 png_set_filler(png_ptr
, 0, PNG_FILLER_BEFORE
);
1642 png_app_error(png_ptr
, "PNG_TRANSFORM_STRIP_FILLER not supported");
1646 /* Flip BGR pixels to RGB */
1647 if ((transforms
& PNG_TRANSFORM_BGR
) != 0)
1648 #ifdef PNG_WRITE_BGR_SUPPORTED
1649 png_set_bgr(png_ptr
);
1651 png_app_error(png_ptr
, "PNG_TRANSFORM_BGR not supported");
1654 /* Swap bytes of 16-bit files to most significant byte first */
1655 if ((transforms
& PNG_TRANSFORM_SWAP_ENDIAN
) != 0)
1656 #ifdef PNG_WRITE_SWAP_SUPPORTED
1657 png_set_swap(png_ptr
);
1659 png_app_error(png_ptr
, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
1662 /* Swap bits of 1, 2, 4 bit packed pixel formats */
1663 if ((transforms
& PNG_TRANSFORM_PACKSWAP
) != 0)
1664 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1665 png_set_packswap(png_ptr
);
1667 png_app_error(png_ptr
, "PNG_TRANSFORM_PACKSWAP not supported");
1670 /* Invert the alpha channel from opacity to transparency */
1671 if ((transforms
& PNG_TRANSFORM_INVERT_ALPHA
) != 0)
1672 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1673 png_set_invert_alpha(png_ptr
);
1675 png_app_error(png_ptr
, "PNG_TRANSFORM_INVERT_ALPHA not supported");
1678 /* ----------------------- end of transformations ------------------- */
1680 /* Write the bits */
1681 png_write_image(png_ptr
, info_ptr
->row_pointers
);
1683 /* It is REQUIRED to call this to finish writing the rest of the file */
1684 png_write_end(png_ptr
, info_ptr
);
1691 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
1692 #ifdef PNG_STDIO_SUPPORTED /* currently required for png_image_write_* */
1693 /* Initialize the write structure - general purpose utility. */
1695 png_image_write_init(png_imagep image
)
1697 png_structp png_ptr
= png_create_write_struct(PNG_LIBPNG_VER_STRING
, image
,
1698 png_safe_error
, png_safe_warning
);
1700 if (png_ptr
!= NULL
)
1702 png_infop info_ptr
= png_create_info_struct(png_ptr
);
1704 if (info_ptr
!= NULL
)
1706 png_controlp control
= png_voidcast(png_controlp
,
1707 png_malloc_warn(png_ptr
, (sizeof *control
)));
1709 if (control
!= NULL
)
1711 memset(control
, 0, (sizeof *control
));
1713 control
->png_ptr
= png_ptr
;
1714 control
->info_ptr
= info_ptr
;
1715 control
->for_write
= 1;
1717 image
->opaque
= control
;
1721 /* Error clean up */
1722 png_destroy_info_struct(png_ptr
, &info_ptr
);
1725 png_destroy_write_struct(&png_ptr
, NULL
);
1728 return png_image_error(image
, "png_image_write_: out of memory");
1731 /* Arguments to png_image_write_main: */
1736 png_const_voidp buffer
;
1737 png_int_32 row_stride
;
1738 png_const_voidp colormap
;
1739 int convert_to_8bit
;
1740 /* Local variables: */
1741 png_const_voidp first_row
;
1742 ptrdiff_t row_bytes
;
1743 png_voidp local_row
;
1744 } png_image_write_control
;
1746 /* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
1747 * do any necessary byte swapping. The component order is defined by the
1748 * png_image format value.
1751 png_write_image_16bit(png_voidp argument
)
1753 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
1755 png_imagep image
= display
->image
;
1756 png_structrp png_ptr
= image
->opaque
->png_ptr
;
1758 png_const_uint_16p input_row
= png_voidcast(png_const_uint_16p
,
1759 display
->first_row
);
1760 png_uint_16p output_row
= png_voidcast(png_uint_16p
, display
->local_row
);
1761 png_uint_16p row_end
;
1762 const int channels
= (image
->format
& PNG_FORMAT_FLAG_COLOR
) != 0 ? 3 : 1;
1764 png_uint_32 y
= image
->height
;
1766 if ((image
->format
& PNG_FORMAT_FLAG_ALPHA
) != 0)
1768 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1769 if ((image
->format
& PNG_FORMAT_FLAG_AFIRST
) != 0)
1772 ++input_row
; /* To point to the first component */
1782 png_error(png_ptr
, "png_write_image: internal call error");
1784 /* Work out the output row end and count over this, note that the increment
1785 * above to 'row' means that row_end can actually be beyond the end of the
1786 * row; this is correct.
1788 row_end
= output_row
+ image
->width
* (channels
+1);
1792 png_const_uint_16p in_ptr
= input_row
;
1793 png_uint_16p out_ptr
= output_row
;
1795 while (out_ptr
< row_end
)
1797 const png_uint_16 alpha
= in_ptr
[aindex
];
1798 png_uint_32 reciprocal
= 0;
1801 out_ptr
[aindex
] = alpha
;
1803 /* Calculate a reciprocal. The correct calculation is simply
1804 * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
1805 * allows correct rounding by adding .5 before the shift. 'reciprocal'
1806 * is only initialized when required.
1808 if (alpha
> 0 && alpha
< 65535)
1809 reciprocal
= ((0xffff<<15)+(alpha
>>1))/alpha
;
1812 do /* always at least one channel */
1814 png_uint_16 component
= *in_ptr
++;
1816 /* The following gives 65535 for an alpha of 0, which is fine,
1817 * otherwise if 0/0 is represented as some other value there is more
1818 * likely to be a discontinuity which will probably damage
1819 * compression when moving from a fully transparent area to a
1820 * nearly transparent one. (The assumption here is that opaque
1821 * areas tend not to be 0 intensity.)
1823 if (component
>= alpha
)
1826 /* component<alpha, so component/alpha is less than one and
1827 * component*reciprocal is less than 2^31.
1829 else if (component
> 0 && alpha
< 65535)
1831 png_uint_32 calc
= component
* reciprocal
;
1832 calc
+= 16384; /* round to nearest */
1833 component
= (png_uint_16
)(calc
>> 15);
1836 *out_ptr
++ = component
;
1840 /* Skip to next component (skip the intervening alpha channel) */
1845 png_write_row(png_ptr
, png_voidcast(png_const_bytep
, display
->local_row
));
1846 input_row
+= display
->row_bytes
/(sizeof (png_uint_16
));
1852 /* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
1853 * is present it must be removed from the components, the components are then
1854 * written in sRGB encoding. No components are added or removed.
1856 * Calculate an alpha reciprocal to reverse pre-multiplication. As above the
1857 * calculation can be done to 15 bits of accuracy; however, the output needs to
1858 * be scaled in the range 0..255*65535, so include that scaling here.
1860 #define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+(alpha>>1))/alpha)
1863 png_unpremultiply(png_uint_32 component
, png_uint_32 alpha
,
1864 png_uint_32 reciprocal
/*from the above macro*/)
1866 /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
1867 * is represented as some other value there is more likely to be a
1868 * discontinuity which will probably damage compression when moving from a
1869 * fully transparent area to a nearly transparent one. (The assumption here
1870 * is that opaque areas tend not to be 0 intensity.)
1872 * There is a rounding problem here; if alpha is less than 128 it will end up
1873 * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
1874 * output change for this too.
1876 if (component
>= alpha
|| alpha
< 128)
1879 /* component<alpha, so component/alpha is less than one and
1880 * component*reciprocal is less than 2^31.
1882 else if (component
> 0)
1884 /* The test is that alpha/257 (rounded) is less than 255, the first value
1885 * that becomes 255 is 65407.
1886 * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
1887 * be exact!) [Could also test reciprocal != 0]
1891 component
*= reciprocal
;
1892 component
+= 64; /* round to nearest */
1899 /* Convert the component to sRGB. */
1900 return (png_byte
)PNG_sRGB_FROM_LINEAR(component
);
1908 png_write_image_8bit(png_voidp argument
)
1910 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
1912 png_imagep image
= display
->image
;
1913 png_structrp png_ptr
= image
->opaque
->png_ptr
;
1915 png_const_uint_16p input_row
= png_voidcast(png_const_uint_16p
,
1916 display
->first_row
);
1917 png_bytep output_row
= png_voidcast(png_bytep
, display
->local_row
);
1918 png_uint_32 y
= image
->height
;
1919 const int channels
= (image
->format
& PNG_FORMAT_FLAG_COLOR
) != 0 ? 3 : 1;
1921 if ((image
->format
& PNG_FORMAT_FLAG_ALPHA
) != 0)
1926 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
1927 if ((image
->format
& PNG_FORMAT_FLAG_AFIRST
) != 0)
1930 ++input_row
; /* To point to the first component */
1938 /* Use row_end in place of a loop counter: */
1939 row_end
= output_row
+ image
->width
* (channels
+1);
1943 png_const_uint_16p in_ptr
= input_row
;
1944 png_bytep out_ptr
= output_row
;
1946 while (out_ptr
< row_end
)
1948 png_uint_16 alpha
= in_ptr
[aindex
];
1949 png_byte alphabyte
= (png_byte
)PNG_DIV257(alpha
);
1950 png_uint_32 reciprocal
= 0;
1953 /* Scale and write the alpha channel. */
1954 out_ptr
[aindex
] = alphabyte
;
1956 if (alphabyte
> 0 && alphabyte
< 255)
1957 reciprocal
= UNP_RECIPROCAL(alpha
);
1960 do /* always at least one channel */
1961 *out_ptr
++ = png_unpremultiply(*in_ptr
++, alpha
, reciprocal
);
1964 /* Skip to next component (skip the intervening alpha channel) */
1967 } /* while out_ptr < row_end */
1969 png_write_row(png_ptr
, png_voidcast(png_const_bytep
,
1970 display
->local_row
));
1971 input_row
+= display
->row_bytes
/(sizeof (png_uint_16
));
1977 /* No alpha channel, so the row_end really is the end of the row and it
1978 * is sufficient to loop over the components one by one.
1980 png_bytep row_end
= output_row
+ image
->width
* channels
;
1984 png_const_uint_16p in_ptr
= input_row
;
1985 png_bytep out_ptr
= output_row
;
1987 while (out_ptr
< row_end
)
1989 png_uint_32 component
= *in_ptr
++;
1992 *out_ptr
++ = (png_byte
)PNG_sRGB_FROM_LINEAR(component
);
1995 png_write_row(png_ptr
, output_row
);
1996 input_row
+= display
->row_bytes
/(sizeof (png_uint_16
));
2004 png_image_set_PLTE(png_image_write_control
*display
)
2006 const png_imagep image
= display
->image
;
2007 const void *cmap
= display
->colormap
;
2008 const int entries
= image
->colormap_entries
> 256 ? 256 :
2009 (int)image
->colormap_entries
;
2011 /* NOTE: the caller must check for cmap != NULL and entries != 0 */
2012 const png_uint_32 format
= image
->format
;
2013 const int channels
= PNG_IMAGE_SAMPLE_CHANNELS(format
);
2015 # if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
2016 defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
2017 const int afirst
= (format
& PNG_FORMAT_FLAG_AFIRST
) != 0 &&
2018 (format
& PNG_FORMAT_FLAG_ALPHA
) != 0;
2023 # ifdef PNG_FORMAT_BGR_SUPPORTED
2024 const int bgr
= (format
& PNG_FORMAT_FLAG_BGR
) != 0 ? 2 : 0;
2030 png_color palette
[256];
2033 memset(tRNS
, 255, (sizeof tRNS
));
2034 memset(palette
, 0, (sizeof palette
));
2036 for (i
=num_trans
=0; i
<entries
; ++i
)
2038 /* This gets automatically converted to sRGB with reversal of the
2039 * pre-multiplication if the color-map has an alpha channel.
2041 if ((format
& PNG_FORMAT_FLAG_LINEAR
) != 0)
2043 png_const_uint_16p entry
= png_voidcast(png_const_uint_16p
, cmap
);
2045 entry
+= i
* channels
;
2047 if ((channels
& 1) != 0) /* no alpha */
2049 if (channels
>= 3) /* RGB */
2051 palette
[i
].blue
= (png_byte
)PNG_sRGB_FROM_LINEAR(255 *
2053 palette
[i
].green
= (png_byte
)PNG_sRGB_FROM_LINEAR(255 *
2055 palette
[i
].red
= (png_byte
)PNG_sRGB_FROM_LINEAR(255 *
2060 palette
[i
].blue
= palette
[i
].red
= palette
[i
].green
=
2061 (png_byte
)PNG_sRGB_FROM_LINEAR(255 * *entry
);
2066 png_uint_16 alpha
= entry
[afirst
? 0 : channels
-1];
2067 png_byte alphabyte
= (png_byte
)PNG_DIV257(alpha
);
2068 png_uint_32 reciprocal
= 0;
2070 /* Calculate a reciprocal, as in the png_write_image_8bit code above
2071 * this is designed to produce a value scaled to 255*65535 when
2072 * divided by 128 (i.e. asr 7).
2074 if (alphabyte
> 0 && alphabyte
< 255)
2075 reciprocal
= (((0xffff*0xff)<<7)+(alpha
>>1))/alpha
;
2077 tRNS
[i
] = alphabyte
;
2078 if (alphabyte
< 255)
2081 if (channels
>= 3) /* RGB */
2083 palette
[i
].blue
= png_unpremultiply(entry
[afirst
+ (2 ^ bgr
)],
2085 palette
[i
].green
= png_unpremultiply(entry
[afirst
+ 1], alpha
,
2087 palette
[i
].red
= png_unpremultiply(entry
[afirst
+ bgr
], alpha
,
2092 palette
[i
].blue
= palette
[i
].red
= palette
[i
].green
=
2093 png_unpremultiply(entry
[afirst
], alpha
, reciprocal
);
2097 else /* Color-map has sRGB values */
2099 png_const_bytep entry
= png_voidcast(png_const_bytep
, cmap
);
2101 entry
+= i
* channels
;
2106 tRNS
[i
] = entry
[afirst
? 0 : 3];
2111 palette
[i
].blue
= entry
[afirst
+ (2 ^ bgr
)];
2112 palette
[i
].green
= entry
[afirst
+ 1];
2113 palette
[i
].red
= entry
[afirst
+ bgr
];
2117 tRNS
[i
] = entry
[1 ^ afirst
];
2122 palette
[i
].blue
= palette
[i
].red
= palette
[i
].green
=
2139 png_set_PLTE(image
->opaque
->png_ptr
, image
->opaque
->info_ptr
, palette
,
2143 png_set_tRNS(image
->opaque
->png_ptr
, image
->opaque
->info_ptr
, tRNS
,
2146 image
->colormap_entries
= entries
;
2150 png_image_write_main(png_voidp argument
)
2152 png_image_write_control
*display
= png_voidcast(png_image_write_control
*,
2154 png_imagep image
= display
->image
;
2155 png_structrp png_ptr
= image
->opaque
->png_ptr
;
2156 png_inforp info_ptr
= image
->opaque
->info_ptr
;
2157 png_uint_32 format
= image
->format
;
2159 /* The following four ints are actually booleans */
2160 int colormap
= (format
& PNG_FORMAT_FLAG_COLORMAP
);
2161 int linear
= !colormap
&& (format
& PNG_FORMAT_FLAG_LINEAR
); /* input */
2162 int alpha
= !colormap
&& (format
& PNG_FORMAT_FLAG_ALPHA
);
2163 int write_16bit
= linear
&& !colormap
&& (display
->convert_to_8bit
== 0);
2165 # ifdef PNG_BENIGN_ERRORS_SUPPORTED
2166 /* Make sure we error out on any bad situation */
2167 png_set_benign_errors(png_ptr
, 0/*error*/);
2170 /* Default the 'row_stride' parameter if required. */
2171 if (display
->row_stride
== 0)
2172 display
->row_stride
= PNG_IMAGE_ROW_STRIDE(*image
);
2174 /* Set the required transforms then write the rows in the correct order. */
2175 if ((format
& PNG_FORMAT_FLAG_COLORMAP
) != 0)
2177 if (display
->colormap
!= NULL
&& image
->colormap_entries
> 0)
2179 png_uint_32 entries
= image
->colormap_entries
;
2181 png_set_IHDR(png_ptr
, info_ptr
, image
->width
, image
->height
,
2182 entries
> 16 ? 8 : (entries
> 4 ? 4 : (entries
> 2 ? 2 : 1)),
2183 PNG_COLOR_TYPE_PALETTE
, PNG_INTERLACE_NONE
,
2184 PNG_COMPRESSION_TYPE_BASE
, PNG_FILTER_TYPE_BASE
);
2186 png_image_set_PLTE(display
);
2190 png_error(image
->opaque
->png_ptr
,
2191 "no color-map for color-mapped image");
2195 png_set_IHDR(png_ptr
, info_ptr
, image
->width
, image
->height
,
2196 write_16bit
? 16 : 8,
2197 ((format
& PNG_FORMAT_FLAG_COLOR
) ? PNG_COLOR_MASK_COLOR
: 0) +
2198 ((format
& PNG_FORMAT_FLAG_ALPHA
) ? PNG_COLOR_MASK_ALPHA
: 0),
2199 PNG_INTERLACE_NONE
, PNG_COMPRESSION_TYPE_BASE
, PNG_FILTER_TYPE_BASE
);
2201 /* Counter-intuitively the data transformations must be called *after*
2202 * png_write_info, not before as in the read code, but the 'set' functions
2203 * must still be called before. Just set the color space information, never
2204 * write an interlaced image.
2207 if (write_16bit
!= 0)
2209 /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
2210 png_set_gAMA_fixed(png_ptr
, info_ptr
, PNG_GAMMA_LINEAR
);
2212 if ((image
->flags
& PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB
) == 0)
2213 png_set_cHRM_fixed(png_ptr
, info_ptr
,
2215 /* white */ 31270, 32900,
2216 /* red */ 64000, 33000,
2217 /* green */ 30000, 60000,
2218 /* blue */ 15000, 6000
2222 else if ((image
->flags
& PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB
) == 0)
2223 png_set_sRGB(png_ptr
, info_ptr
, PNG_sRGB_INTENT_PERCEPTUAL
);
2225 /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
2226 * space must still be gamma encoded.
2229 png_set_gAMA_fixed(png_ptr
, info_ptr
, PNG_GAMMA_sRGB_INVERSE
);
2231 /* Write the file header. */
2232 png_write_info(png_ptr
, info_ptr
);
2234 /* Now set up the data transformations (*after* the header is written),
2235 * remove the handled transformations from the 'format' flags for checking.
2237 * First check for a little endian system if writing 16 bit files.
2239 if (write_16bit
!= 0)
2241 PNG_CONST png_uint_16 le
= 0x0001;
2243 if ((*(png_const_bytep
) & le
) != 0)
2244 png_set_swap(png_ptr
);
2247 # ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
2248 if ((format
& PNG_FORMAT_FLAG_BGR
) != 0)
2250 if (colormap
== 0 && (format
& PNG_FORMAT_FLAG_COLOR
) != 0)
2251 png_set_bgr(png_ptr
);
2252 format
&= ~PNG_FORMAT_FLAG_BGR
;
2256 # ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
2257 if ((format
& PNG_FORMAT_FLAG_AFIRST
) != 0)
2259 if (colormap
== 0 && (format
& PNG_FORMAT_FLAG_ALPHA
) != 0)
2260 png_set_swap_alpha(png_ptr
);
2261 format
&= ~PNG_FORMAT_FLAG_AFIRST
;
2265 /* If there are 16 or fewer color-map entries we wrote a lower bit depth
2266 * above, but the application data is still byte packed.
2268 if (colormap
!= 0 && image
->colormap_entries
<= 16)
2269 png_set_packing(png_ptr
);
2271 /* That should have handled all (both) the transforms. */
2272 if ((format
& ~(png_uint_32
)(PNG_FORMAT_FLAG_COLOR
| PNG_FORMAT_FLAG_LINEAR
|
2273 PNG_FORMAT_FLAG_ALPHA
| PNG_FORMAT_FLAG_COLORMAP
)) != 0)
2274 png_error(png_ptr
, "png_write_image: unsupported transformation");
2277 png_const_bytep row
= png_voidcast(png_const_bytep
, display
->buffer
);
2278 ptrdiff_t row_bytes
= display
->row_stride
;
2281 row_bytes
*= (sizeof (png_uint_16
));
2284 row
+= (image
->height
-1) * (-row_bytes
);
2286 display
->first_row
= row
;
2287 display
->row_bytes
= row_bytes
;
2290 /* Apply 'fast' options if the flag is set. */
2291 if ((image
->flags
& PNG_IMAGE_FLAG_FAST
) != 0)
2293 png_set_filter(png_ptr
, PNG_FILTER_TYPE_BASE
, PNG_NO_FILTERS
);
2294 /* NOTE: determined by experiment using pngstest, this reflects some
2295 * balance between the time to write the image once and the time to read
2296 * it about 50 times. The speed-up in pngstest was about 10-20% of the
2297 * total (user) time on a heavily loaded system.
2299 png_set_compression_level(png_ptr
, 3);
2302 /* Check for the cases that currently require a pre-transform on the row
2303 * before it is written. This only applies when the input is 16-bit and
2304 * either there is an alpha channel or it is converted to 8-bit.
2306 if ((linear
!= 0 && alpha
!= 0 ) ||
2307 (colormap
== 0 && display
->convert_to_8bit
!= 0))
2309 png_bytep row
= png_voidcast(png_bytep
, png_malloc(png_ptr
,
2310 png_get_rowbytes(png_ptr
, info_ptr
)));
2313 display
->local_row
= row
;
2314 if (write_16bit
!= 0)
2315 result
= png_safe_execute(image
, png_write_image_16bit
, display
);
2317 result
= png_safe_execute(image
, png_write_image_8bit
, display
);
2318 display
->local_row
= NULL
;
2320 png_free(png_ptr
, row
);
2322 /* Skip the 'write_end' on error: */
2327 /* Otherwise this is the case where the input is in a format currently
2328 * supported by the rest of the libpng write code; call it directly.
2332 png_const_bytep row
= png_voidcast(png_const_bytep
, display
->first_row
);
2333 ptrdiff_t row_bytes
= display
->row_bytes
;
2334 png_uint_32 y
= image
->height
;
2338 png_write_row(png_ptr
, row
);
2343 png_write_end(png_ptr
, info_ptr
);
2348 png_image_write_to_stdio(png_imagep image
, FILE *file
, int convert_to_8bit
,
2349 const void *buffer
, png_int_32 row_stride
, const void *colormap
)
2351 /* Write the image to the given (FILE*). */
2352 if (image
!= NULL
&& image
->version
== PNG_IMAGE_VERSION
)
2356 if (png_image_write_init(image
) != 0)
2358 png_image_write_control display
;
2361 /* This is slightly evil, but png_init_io doesn't do anything other
2362 * than this and we haven't changed the standard IO functions so
2363 * this saves a 'safe' function.
2365 image
->opaque
->png_ptr
->io_ptr
= file
;
2367 memset(&display
, 0, (sizeof display
));
2368 display
.image
= image
;
2369 display
.buffer
= buffer
;
2370 display
.row_stride
= row_stride
;
2371 display
.colormap
= colormap
;
2372 display
.convert_to_8bit
= convert_to_8bit
;
2374 result
= png_safe_execute(image
, png_image_write_main
, &display
);
2375 png_image_free(image
);
2384 return png_image_error(image
,
2385 "png_image_write_to_stdio: invalid argument");
2388 else if (image
!= NULL
)
2389 return png_image_error(image
,
2390 "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
2397 png_image_write_to_file(png_imagep image
, const char *file_name
,
2398 int convert_to_8bit
, const void *buffer
, png_int_32 row_stride
,
2399 const void *colormap
)
2401 /* Write the image to the named file. */
2402 if (image
!= NULL
&& image
->version
== PNG_IMAGE_VERSION
)
2404 if (file_name
!= NULL
)
2406 FILE *fp
= fopen(file_name
, "wb");
2410 if (png_image_write_to_stdio(image
, fp
, convert_to_8bit
, buffer
,
2411 row_stride
, colormap
) != 0)
2413 int error
; /* from fflush/fclose */
2415 /* Make sure the file is flushed correctly. */
2416 if (fflush(fp
) == 0 && ferror(fp
) == 0)
2418 if (fclose(fp
) == 0)
2421 error
= errno
; /* from fclose */
2426 error
= errno
; /* from fflush or ferror */
2430 (void)remove(file_name
);
2431 /* The image has already been cleaned up; this is just used to
2432 * set the error (because the original write succeeded).
2434 return png_image_error(image
, strerror(error
));
2439 /* Clean up: just the opened file. */
2441 (void)remove(file_name
);
2447 return png_image_error(image
, strerror(errno
));
2451 return png_image_error(image
,
2452 "png_image_write_to_file: invalid argument");
2455 else if (image
!= NULL
)
2456 return png_image_error(image
,
2457 "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
2463 #endif /* SIMPLIFIED_WRITE */
2465 #ifdef PNG_WRITE_APNG_SUPPORTED
2467 png_write_frame_head(png_structp png_ptr
, png_infop info_ptr
,
2468 png_bytepp row_pointers
, png_uint_32 width
, png_uint_32 height
,
2469 png_uint_32 x_offset
, png_uint_32 y_offset
,
2470 png_uint_16 delay_num
, png_uint_16 delay_den
, png_byte dispose_op
,
2473 png_debug(1, "in png_write_frame_head");
2475 /* there is a chance this has been set after png_write_info was called,
2476 * so it would be set but not written. is there a way to be sure? */
2477 if ((info_ptr
->valid
& PNG_INFO_acTL
) == 0)
2478 png_error(png_ptr
, "png_write_frame_head(): acTL not set");
2480 png_write_reset(png_ptr
);
2482 png_write_reinit(png_ptr
, info_ptr
, width
, height
);
2484 if ((png_ptr
->apng_flags
& PNG_FIRST_FRAME_HIDDEN
) == 0 ||
2485 png_ptr
->num_frames_written
!= 0)
2486 png_write_fcTL(png_ptr
, width
, height
, x_offset
, y_offset
,
2487 delay_num
, delay_den
, dispose_op
, blend_op
);
2489 PNG_UNUSED(row_pointers
)
2493 png_write_frame_tail(png_structp png_ptr
, png_infop info_ptr
)
2495 png_debug(1, "in png_write_frame_tail");
2497 png_ptr
->num_frames_written
++;
2499 PNG_UNUSED(info_ptr
)
2501 #endif /* WRITE_APNG */