2 /* pngwrite.c - general routines to write a PNG file
4 * Last changed in libpng 1.5.11 [June 14, 2012]
5 * Copyright (c) 1998-2012 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
16 #ifdef PNG_WRITE_SUPPORTED
18 /* Writes all the PNG information. This is the suggested way to use the
19 * library. If you have a new chunk to add, make a function to write it,
20 * and put it in the correct location here. If you want the chunk written
21 * after the image data, put it in png_write_end(). I strongly encourage
22 * you to supply a PNG_INFO_ flag, and check info_ptr->valid before writing
23 * the chunk, as that will keep the code from breaking if you want to just
24 * write a plain PNG file. If you have long comments, I suggest writing
25 * them in png_write_end(), and compressing them.
28 png_write_info_before_PLTE(png_structp png_ptr
, png_infop info_ptr
)
30 png_debug(1, "in png_write_info_before_PLTE");
32 if (png_ptr
== NULL
|| info_ptr
== NULL
)
35 if (!(png_ptr
->mode
& PNG_WROTE_INFO_BEFORE_PLTE
))
37 /* Write PNG signature */
38 png_write_sig(png_ptr
);
40 #ifdef PNG_MNG_FEATURES_SUPPORTED
41 if ((png_ptr
->mode
&PNG_HAVE_PNG_SIGNATURE
) && \
42 (png_ptr
->mng_features_permitted
))
44 png_warning(png_ptr
, "MNG features are not allowed in a PNG datastream");
45 png_ptr
->mng_features_permitted
= 0;
49 /* Write IHDR information. */
50 png_write_IHDR(png_ptr
, info_ptr
->width
, info_ptr
->height
,
51 info_ptr
->bit_depth
, info_ptr
->color_type
, info_ptr
->compression_type
,
52 info_ptr
->filter_type
,
53 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
54 info_ptr
->interlace_type
);
58 /* The rest of these check to see if the valid field has the appropriate
59 * flag set, and if it does, writes the chunk.
61 #ifdef PNG_WRITE_gAMA_SUPPORTED
62 if (info_ptr
->valid
& PNG_INFO_gAMA
)
63 png_write_gAMA_fixed(png_ptr
, info_ptr
->gamma
);
65 #ifdef PNG_WRITE_sRGB_SUPPORTED
66 if (info_ptr
->valid
& PNG_INFO_sRGB
)
67 png_write_sRGB(png_ptr
, (int)info_ptr
->srgb_intent
);
70 #ifdef PNG_WRITE_iCCP_SUPPORTED
71 if (info_ptr
->valid
& PNG_INFO_iCCP
)
72 png_write_iCCP(png_ptr
, info_ptr
->iccp_name
, PNG_COMPRESSION_TYPE_BASE
,
73 (png_charp
)info_ptr
->iccp_profile
, (int)info_ptr
->iccp_proflen
);
75 #ifdef PNG_WRITE_sBIT_SUPPORTED
76 if (info_ptr
->valid
& PNG_INFO_sBIT
)
77 png_write_sBIT(png_ptr
, &(info_ptr
->sig_bit
), info_ptr
->color_type
);
79 #ifdef PNG_WRITE_cHRM_SUPPORTED
80 if (info_ptr
->valid
& PNG_INFO_cHRM
)
81 png_write_cHRM_fixed(png_ptr
,
82 info_ptr
->x_white
, info_ptr
->y_white
,
83 info_ptr
->x_red
, info_ptr
->y_red
,
84 info_ptr
->x_green
, info_ptr
->y_green
,
85 info_ptr
->x_blue
, info_ptr
->y_blue
);
88 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
89 if (info_ptr
->unknown_chunks_num
)
91 png_unknown_chunk
*up
;
93 png_debug(5, "writing extra chunks");
95 for (up
= info_ptr
->unknown_chunks
;
96 up
< info_ptr
->unknown_chunks
+ info_ptr
->unknown_chunks_num
;
99 int keep
= png_handle_as_unknown(png_ptr
, up
->name
);
101 if (keep
!= PNG_HANDLE_CHUNK_NEVER
&&
103 !(up
->location
& PNG_HAVE_PLTE
) &&
104 !(up
->location
& PNG_HAVE_IDAT
) &&
105 !(up
->location
& PNG_AFTER_IDAT
) &&
106 ((up
->name
[3] & 0x20) || keep
== PNG_HANDLE_CHUNK_ALWAYS
||
107 (png_ptr
->flags
& PNG_FLAG_KEEP_UNSAFE_CHUNKS
)))
110 png_warning(png_ptr
, "Writing zero-length unknown chunk");
112 png_write_chunk(png_ptr
, up
->name
, up
->data
, up
->size
);
117 png_ptr
->mode
|= PNG_WROTE_INFO_BEFORE_PLTE
;
122 png_write_info(png_structp png_ptr
, png_infop info_ptr
)
124 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
128 png_debug(1, "in png_write_info");
130 if (png_ptr
== NULL
|| info_ptr
== NULL
)
133 png_write_info_before_PLTE(png_ptr
, info_ptr
);
135 if (info_ptr
->valid
& PNG_INFO_PLTE
)
136 png_write_PLTE(png_ptr
, info_ptr
->palette
,
137 (png_uint_32
)info_ptr
->num_palette
);
139 else if (info_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
140 png_error(png_ptr
, "Valid palette required for paletted images");
142 #ifdef PNG_WRITE_tRNS_SUPPORTED
143 if (info_ptr
->valid
& PNG_INFO_tRNS
)
145 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
146 /* Invert the alpha channel (in tRNS) */
147 if ((png_ptr
->transformations
& PNG_INVERT_ALPHA
) &&
148 info_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
)
151 for (j
= 0; j
<(int)info_ptr
->num_trans
; j
++)
152 info_ptr
->trans_alpha
[j
] =
153 (png_byte
)(255 - info_ptr
->trans_alpha
[j
]);
156 png_write_tRNS(png_ptr
, info_ptr
->trans_alpha
, &(info_ptr
->trans_color
),
157 info_ptr
->num_trans
, info_ptr
->color_type
);
160 #ifdef PNG_WRITE_bKGD_SUPPORTED
161 if (info_ptr
->valid
& PNG_INFO_bKGD
)
162 png_write_bKGD(png_ptr
, &(info_ptr
->background
), info_ptr
->color_type
);
165 #ifdef PNG_WRITE_hIST_SUPPORTED
166 if (info_ptr
->valid
& PNG_INFO_hIST
)
167 png_write_hIST(png_ptr
, info_ptr
->hist
, info_ptr
->num_palette
);
170 #ifdef PNG_WRITE_oFFs_SUPPORTED
171 if (info_ptr
->valid
& PNG_INFO_oFFs
)
172 png_write_oFFs(png_ptr
, info_ptr
->x_offset
, info_ptr
->y_offset
,
173 info_ptr
->offset_unit_type
);
176 #ifdef PNG_WRITE_pCAL_SUPPORTED
177 if (info_ptr
->valid
& PNG_INFO_pCAL
)
178 png_write_pCAL(png_ptr
, info_ptr
->pcal_purpose
, info_ptr
->pcal_X0
,
179 info_ptr
->pcal_X1
, info_ptr
->pcal_type
, info_ptr
->pcal_nparams
,
180 info_ptr
->pcal_units
, info_ptr
->pcal_params
);
183 #ifdef PNG_WRITE_sCAL_SUPPORTED
184 if (info_ptr
->valid
& PNG_INFO_sCAL
)
185 png_write_sCAL_s(png_ptr
, (int)info_ptr
->scal_unit
,
186 info_ptr
->scal_s_width
, info_ptr
->scal_s_height
);
189 #ifdef PNG_WRITE_pHYs_SUPPORTED
190 if (info_ptr
->valid
& PNG_INFO_pHYs
)
191 png_write_pHYs(png_ptr
, info_ptr
->x_pixels_per_unit
,
192 info_ptr
->y_pixels_per_unit
, info_ptr
->phys_unit_type
);
195 #ifdef PNG_WRITE_tIME_SUPPORTED
196 if (info_ptr
->valid
& PNG_INFO_tIME
)
198 png_write_tIME(png_ptr
, &(info_ptr
->mod_time
));
199 png_ptr
->mode
|= PNG_WROTE_tIME
;
203 #ifdef PNG_WRITE_sPLT_SUPPORTED
204 if (info_ptr
->valid
& PNG_INFO_sPLT
)
205 for (i
= 0; i
< (int)info_ptr
->splt_palettes_num
; i
++)
206 png_write_sPLT(png_ptr
, info_ptr
->splt_palettes
+ i
);
209 #ifdef PNG_WRITE_TEXT_SUPPORTED
210 /* Check to see if we need to write text chunks */
211 for (i
= 0; i
< info_ptr
->num_text
; i
++)
213 png_debug2(2, "Writing header text chunk %d, type %d", i
,
214 info_ptr
->text
[i
].compression
);
215 /* An internationalized chunk? */
216 if (info_ptr
->text
[i
].compression
> 0)
218 #ifdef PNG_WRITE_iTXt_SUPPORTED
219 /* Write international chunk */
220 png_write_iTXt(png_ptr
,
221 info_ptr
->text
[i
].compression
,
222 info_ptr
->text
[i
].key
,
223 info_ptr
->text
[i
].lang
,
224 info_ptr
->text
[i
].lang_key
,
225 info_ptr
->text
[i
].text
);
227 png_warning(png_ptr
, "Unable to write international text");
229 /* Mark this chunk as written */
230 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
233 /* If we want a compressed text chunk */
234 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_zTXt
)
236 #ifdef PNG_WRITE_zTXt_SUPPORTED
237 /* Write compressed chunk */
238 png_write_zTXt(png_ptr
, info_ptr
->text
[i
].key
,
239 info_ptr
->text
[i
].text
, 0,
240 info_ptr
->text
[i
].compression
);
242 png_warning(png_ptr
, "Unable to write compressed text");
244 /* Mark this chunk as written */
245 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
248 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
250 #ifdef PNG_WRITE_tEXt_SUPPORTED
251 /* Write uncompressed chunk */
252 png_write_tEXt(png_ptr
, info_ptr
->text
[i
].key
,
253 info_ptr
->text
[i
].text
,
255 /* Mark this chunk as written */
256 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
259 png_warning(png_ptr
, "Unable to write uncompressed text");
265 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
266 if (info_ptr
->unknown_chunks_num
)
268 png_unknown_chunk
*up
;
270 png_debug(5, "writing extra chunks");
272 for (up
= info_ptr
->unknown_chunks
;
273 up
< info_ptr
->unknown_chunks
+ info_ptr
->unknown_chunks_num
;
276 int keep
= png_handle_as_unknown(png_ptr
, up
->name
);
277 if (keep
!= PNG_HANDLE_CHUNK_NEVER
&&
279 (up
->location
& PNG_HAVE_PLTE
) &&
280 !(up
->location
& PNG_HAVE_IDAT
) &&
281 !(up
->location
& PNG_AFTER_IDAT
) &&
282 ((up
->name
[3] & 0x20) || keep
== PNG_HANDLE_CHUNK_ALWAYS
||
283 (png_ptr
->flags
& PNG_FLAG_KEEP_UNSAFE_CHUNKS
)))
285 png_write_chunk(png_ptr
, up
->name
, up
->data
, up
->size
);
292 /* Writes the end of the PNG file. If you don't want to write comments or
293 * time information, you can pass NULL for info. If you already wrote these
294 * in png_write_info(), do not write them again here. If you have long
295 * comments, I suggest writing them here, and compressing them.
298 png_write_end(png_structp png_ptr
, png_infop info_ptr
)
300 png_debug(1, "in png_write_end");
305 if (!(png_ptr
->mode
& PNG_HAVE_IDAT
))
306 png_error(png_ptr
, "No IDATs written into file");
308 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
309 if (png_ptr
->num_palette_max
> png_ptr
->num_palette
)
310 png_benign_error(png_ptr
, "Wrote palette index exceeding num_palette");
313 /* See if user wants us to write information chunks */
314 if (info_ptr
!= NULL
)
316 #ifdef PNG_WRITE_TEXT_SUPPORTED
317 int i
; /* local index variable */
319 #ifdef PNG_WRITE_tIME_SUPPORTED
320 /* Check to see if user has supplied a time chunk */
321 if ((info_ptr
->valid
& PNG_INFO_tIME
) &&
322 !(png_ptr
->mode
& PNG_WROTE_tIME
))
323 png_write_tIME(png_ptr
, &(info_ptr
->mod_time
));
326 #ifdef PNG_WRITE_TEXT_SUPPORTED
327 /* Loop through comment chunks */
328 for (i
= 0; i
< info_ptr
->num_text
; i
++)
330 png_debug2(2, "Writing trailer text chunk %d, type %d", i
,
331 info_ptr
->text
[i
].compression
);
332 /* An internationalized chunk? */
333 if (info_ptr
->text
[i
].compression
> 0)
335 #ifdef PNG_WRITE_iTXt_SUPPORTED
336 /* Write international chunk */
337 png_write_iTXt(png_ptr
,
338 info_ptr
->text
[i
].compression
,
339 info_ptr
->text
[i
].key
,
340 info_ptr
->text
[i
].lang
,
341 info_ptr
->text
[i
].lang_key
,
342 info_ptr
->text
[i
].text
);
344 png_warning(png_ptr
, "Unable to write international text");
346 /* Mark this chunk as written */
347 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
350 else if (info_ptr
->text
[i
].compression
>= PNG_TEXT_COMPRESSION_zTXt
)
352 #ifdef PNG_WRITE_zTXt_SUPPORTED
353 /* Write compressed chunk */
354 png_write_zTXt(png_ptr
, info_ptr
->text
[i
].key
,
355 info_ptr
->text
[i
].text
, 0,
356 info_ptr
->text
[i
].compression
);
358 png_warning(png_ptr
, "Unable to write compressed text");
360 /* Mark this chunk as written */
361 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_zTXt_WR
;
364 else if (info_ptr
->text
[i
].compression
== PNG_TEXT_COMPRESSION_NONE
)
366 #ifdef PNG_WRITE_tEXt_SUPPORTED
367 /* Write uncompressed chunk */
368 png_write_tEXt(png_ptr
, info_ptr
->text
[i
].key
,
369 info_ptr
->text
[i
].text
, 0);
371 png_warning(png_ptr
, "Unable to write uncompressed text");
374 /* Mark this chunk as written */
375 info_ptr
->text
[i
].compression
= PNG_TEXT_COMPRESSION_NONE_WR
;
379 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
380 if (info_ptr
->unknown_chunks_num
)
382 png_unknown_chunk
*up
;
384 png_debug(5, "writing extra chunks");
386 for (up
= info_ptr
->unknown_chunks
;
387 up
< info_ptr
->unknown_chunks
+ info_ptr
->unknown_chunks_num
;
390 int keep
= png_handle_as_unknown(png_ptr
, up
->name
);
391 if (keep
!= PNG_HANDLE_CHUNK_NEVER
&&
393 (up
->location
& PNG_AFTER_IDAT
) &&
394 ((up
->name
[3] & 0x20) || keep
== PNG_HANDLE_CHUNK_ALWAYS
||
395 (png_ptr
->flags
& PNG_FLAG_KEEP_UNSAFE_CHUNKS
)))
397 png_write_chunk(png_ptr
, up
->name
, up
->data
, up
->size
);
404 png_ptr
->mode
|= PNG_AFTER_IDAT
;
406 /* Write end of PNG file */
407 png_write_IEND(png_ptr
);
408 /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
409 * and restored again in libpng-1.2.30, may cause some applications that
410 * do not set png_ptr->output_flush_fn to crash. If your application
411 * experiences a problem, please try building libpng with
412 * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
413 * png-mng-implement at lists.sf.net .
415 #ifdef PNG_WRITE_FLUSH_SUPPORTED
416 # ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
422 #ifdef PNG_CONVERT_tIME_SUPPORTED
423 /* "tm" structure is not supported on WindowsCE */
425 png_convert_from_struct_tm(png_timep ptime
, PNG_CONST
struct tm FAR
* ttime
)
427 png_debug(1, "in png_convert_from_struct_tm");
429 ptime
->year
= (png_uint_16
)(1900 + ttime
->tm_year
);
430 ptime
->month
= (png_byte
)(ttime
->tm_mon
+ 1);
431 ptime
->day
= (png_byte
)ttime
->tm_mday
;
432 ptime
->hour
= (png_byte
)ttime
->tm_hour
;
433 ptime
->minute
= (png_byte
)ttime
->tm_min
;
434 ptime
->second
= (png_byte
)ttime
->tm_sec
;
438 png_convert_from_time_t(png_timep ptime
, time_t ttime
)
442 png_debug(1, "in png_convert_from_time_t");
444 tbuf
= gmtime(&ttime
);
445 png_convert_from_struct_tm(ptime
, tbuf
);
449 /* Initialize png_ptr structure, and allocate any memory needed */
450 PNG_FUNCTION(png_structp
,PNGAPI
451 png_create_write_struct
,(png_const_charp user_png_ver
, png_voidp error_ptr
,
452 png_error_ptr error_fn
, png_error_ptr warn_fn
),PNG_ALLOCATED
)
454 #ifdef PNG_USER_MEM_SUPPORTED
455 return (png_create_write_struct_2(user_png_ver
, error_ptr
, error_fn
,
456 warn_fn
, NULL
, NULL
, NULL
));
459 /* Alternate initialize png_ptr structure, and allocate any memory needed */
460 static void png_reset_filter_heuristics(png_structp png_ptr
); /* forward decl */
462 PNG_FUNCTION(png_structp
,PNGAPI
463 png_create_write_struct_2
,(png_const_charp user_png_ver
, png_voidp error_ptr
,
464 png_error_ptr error_fn
, png_error_ptr warn_fn
, png_voidp mem_ptr
,
465 png_malloc_ptr malloc_fn
, png_free_ptr free_fn
),PNG_ALLOCATED
)
467 #endif /* PNG_USER_MEM_SUPPORTED */
468 volatile int png_cleanup_needed
= 0;
469 #ifdef PNG_SETJMP_SUPPORTED
473 #ifdef PNG_SETJMP_SUPPORTED
474 #ifdef USE_FAR_KEYWORD
479 png_debug(1, "in png_create_write_struct");
481 #ifdef PNG_USER_MEM_SUPPORTED
482 png_ptr
= (png_structp
)png_create_struct_2(PNG_STRUCT_PNG
,
483 (png_malloc_ptr
)malloc_fn
, (png_voidp
)mem_ptr
);
485 png_ptr
= (png_structp
)png_create_struct(PNG_STRUCT_PNG
);
486 #endif /* PNG_USER_MEM_SUPPORTED */
490 /* Added at libpng-1.2.6 */
491 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
492 png_ptr
->user_width_max
= PNG_USER_WIDTH_MAX
;
493 png_ptr
->user_height_max
= PNG_USER_HEIGHT_MAX
;
496 #ifdef PNG_SETJMP_SUPPORTED
497 /* Applications that neglect to set up their own setjmp() and then
498 * encounter a png_error() will longjmp here. Since the jmpbuf is
499 * then meaningless we abort instead of returning.
501 #ifdef USE_FAR_KEYWORD
502 if (setjmp(tmp_jmpbuf
))
504 if (setjmp(png_jmpbuf(png_ptr
))) /* sets longjmp to match setjmp */
506 #ifdef USE_FAR_KEYWORD
507 png_memcpy(png_jmpbuf(png_ptr
), tmp_jmpbuf
, png_sizeof(jmp_buf));
512 #ifdef PNG_USER_MEM_SUPPORTED
513 png_set_mem_fn(png_ptr
, mem_ptr
, malloc_fn
, free_fn
);
514 #endif /* PNG_USER_MEM_SUPPORTED */
515 png_set_error_fn(png_ptr
, error_ptr
, error_fn
, warn_fn
);
517 if (!png_user_version_check(png_ptr
, user_png_ver
))
518 png_cleanup_needed
= 1;
520 /* Initialize zbuf - compression buffer */
521 png_ptr
->zbuf_size
= PNG_ZBUF_SIZE
;
523 if (!png_cleanup_needed
)
525 png_ptr
->zbuf
= (png_bytep
)png_malloc_warn(png_ptr
,
527 if (png_ptr
->zbuf
== NULL
)
528 png_cleanup_needed
= 1;
531 if (png_cleanup_needed
)
533 /* Clean up PNG structure and deallocate any memory. */
534 png_free(png_ptr
, png_ptr
->zbuf
);
535 png_ptr
->zbuf
= NULL
;
536 #ifdef PNG_USER_MEM_SUPPORTED
537 png_destroy_struct_2((png_voidp
)png_ptr
,
538 (png_free_ptr
)free_fn
, (png_voidp
)mem_ptr
);
540 png_destroy_struct((png_voidp
)png_ptr
);
545 png_set_write_fn(png_ptr
, NULL
, NULL
, NULL
);
547 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
548 png_reset_filter_heuristics(png_ptr
);
555 /* Write a few rows of image data. If the image is interlaced,
556 * either you will have to write the 7 sub images, or, if you
557 * have called png_set_interlace_handling(), you will have to
558 * "write" the image seven times.
561 png_write_rows(png_structp png_ptr
, png_bytepp row
,
562 png_uint_32 num_rows
)
564 png_uint_32 i
; /* row counter */
565 png_bytepp rp
; /* row pointer */
567 png_debug(1, "in png_write_rows");
572 /* Loop through the rows */
573 for (i
= 0, rp
= row
; i
< num_rows
; i
++, rp
++)
575 png_write_row(png_ptr
, *rp
);
579 /* Write the image. You only need to call this function once, even
580 * if you are writing an interlaced image.
583 png_write_image(png_structp png_ptr
, png_bytepp image
)
585 png_uint_32 i
; /* row index */
586 int pass
, num_pass
; /* pass variables */
587 png_bytepp rp
; /* points to current row */
592 png_debug(1, "in png_write_image");
594 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
595 /* Initialize interlace handling. If image is not interlaced,
596 * this will set pass to 1
598 num_pass
= png_set_interlace_handling(png_ptr
);
602 /* Loop through passes */
603 for (pass
= 0; pass
< num_pass
; pass
++)
605 /* Loop through image */
606 for (i
= 0, rp
= image
; i
< png_ptr
->height
; i
++, rp
++)
608 png_write_row(png_ptr
, *rp
);
613 /* Called by user to write a row of image data */
615 png_write_row(png_structp png_ptr
, png_const_bytep row
)
617 /* 1.5.6: moved from png_struct to be a local structure: */
618 png_row_info row_info
;
623 png_debug2(1, "in png_write_row (row %u, pass %d)",
624 png_ptr
->row_number
, png_ptr
->pass
);
626 /* Initialize transformations and other stuff if first time */
627 if (png_ptr
->row_number
== 0 && png_ptr
->pass
== 0)
629 /* Make sure we wrote the header info */
630 if (!(png_ptr
->mode
& PNG_WROTE_INFO_BEFORE_PLTE
))
632 "png_write_info was never called before png_write_row");
634 /* Check for transforms that have been set but were defined out */
635 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
636 if (png_ptr
->transformations
& PNG_INVERT_MONO
)
637 png_warning(png_ptr
, "PNG_WRITE_INVERT_SUPPORTED is not defined");
640 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
641 if (png_ptr
->transformations
& PNG_FILLER
)
642 png_warning(png_ptr
, "PNG_WRITE_FILLER_SUPPORTED is not defined");
644 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
645 defined(PNG_READ_PACKSWAP_SUPPORTED)
646 if (png_ptr
->transformations
& PNG_PACKSWAP
)
648 "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
651 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
652 if (png_ptr
->transformations
& PNG_PACK
)
653 png_warning(png_ptr
, "PNG_WRITE_PACK_SUPPORTED is not defined");
656 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
657 if (png_ptr
->transformations
& PNG_SHIFT
)
658 png_warning(png_ptr
, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
661 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
662 if (png_ptr
->transformations
& PNG_BGR
)
663 png_warning(png_ptr
, "PNG_WRITE_BGR_SUPPORTED is not defined");
666 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
667 if (png_ptr
->transformations
& PNG_SWAP_BYTES
)
668 png_warning(png_ptr
, "PNG_WRITE_SWAP_SUPPORTED is not defined");
671 png_write_start_row(png_ptr
);
674 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
675 /* If interlaced and not interested in row, return */
676 if (png_ptr
->interlaced
&& (png_ptr
->transformations
& PNG_INTERLACE
))
678 switch (png_ptr
->pass
)
681 if (png_ptr
->row_number
& 0x07)
683 png_write_finish_row(png_ptr
);
689 if ((png_ptr
->row_number
& 0x07) || png_ptr
->width
< 5)
691 png_write_finish_row(png_ptr
);
697 if ((png_ptr
->row_number
& 0x07) != 4)
699 png_write_finish_row(png_ptr
);
705 if ((png_ptr
->row_number
& 0x03) || png_ptr
->width
< 3)
707 png_write_finish_row(png_ptr
);
713 if ((png_ptr
->row_number
& 0x03) != 2)
715 png_write_finish_row(png_ptr
);
721 if ((png_ptr
->row_number
& 0x01) || png_ptr
->width
< 2)
723 png_write_finish_row(png_ptr
);
729 if (!(png_ptr
->row_number
& 0x01))
731 png_write_finish_row(png_ptr
);
736 default: /* error: ignore it */
742 /* Set up row info for transformations */
743 row_info
.color_type
= png_ptr
->color_type
;
744 row_info
.width
= png_ptr
->usr_width
;
745 row_info
.channels
= png_ptr
->usr_channels
;
746 row_info
.bit_depth
= png_ptr
->usr_bit_depth
;
747 row_info
.pixel_depth
= (png_byte
)(row_info
.bit_depth
* row_info
.channels
);
748 row_info
.rowbytes
= PNG_ROWBYTES(row_info
.pixel_depth
, row_info
.width
);
750 png_debug1(3, "row_info->color_type = %d", row_info
.color_type
);
751 png_debug1(3, "row_info->width = %u", row_info
.width
);
752 png_debug1(3, "row_info->channels = %d", row_info
.channels
);
753 png_debug1(3, "row_info->bit_depth = %d", row_info
.bit_depth
);
754 png_debug1(3, "row_info->pixel_depth = %d", row_info
.pixel_depth
);
755 png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info
.rowbytes
);
757 /* Copy user's row into buffer, leaving room for filter byte. */
758 png_memcpy(png_ptr
->row_buf
+ 1, row
, row_info
.rowbytes
);
760 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
761 /* Handle interlacing */
762 if (png_ptr
->interlaced
&& png_ptr
->pass
< 6 &&
763 (png_ptr
->transformations
& PNG_INTERLACE
))
765 png_do_write_interlace(&row_info
, png_ptr
->row_buf
+ 1, png_ptr
->pass
);
766 /* This should always get caught above, but still ... */
767 if (!(row_info
.width
))
769 png_write_finish_row(png_ptr
);
775 #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
776 /* Handle other transformations */
777 if (png_ptr
->transformations
)
778 png_do_write_transformations(png_ptr
, &row_info
);
781 /* At this point the row_info pixel depth must match the 'transformed' depth,
782 * which is also the output depth.
784 if (row_info
.pixel_depth
!= png_ptr
->pixel_depth
||
785 row_info
.pixel_depth
!= png_ptr
->transformed_pixel_depth
)
786 png_error(png_ptr
, "internal write transform logic error");
788 #ifdef PNG_MNG_FEATURES_SUPPORTED
789 /* Write filter_method 64 (intrapixel differencing) only if
790 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
791 * 2. Libpng did not write a PNG signature (this filter_method is only
792 * used in PNG datastreams that are embedded in MNG datastreams) and
793 * 3. The application called png_permit_mng_features with a mask that
794 * included PNG_FLAG_MNG_FILTER_64 and
795 * 4. The filter_method is 64 and
796 * 5. The color_type is RGB or RGBA
798 if ((png_ptr
->mng_features_permitted
& PNG_FLAG_MNG_FILTER_64
) &&
799 (png_ptr
->filter_type
== PNG_INTRAPIXEL_DIFFERENCING
))
801 /* Intrapixel differencing */
802 png_do_write_intrapixel(&row_info
, png_ptr
->row_buf
+ 1);
806 /* Added at libpng-1.5.10 */
807 #ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
808 /* Check for out-of-range palette index */
809 if (row_info
.color_type
== PNG_COLOR_TYPE_PALETTE
&&
810 png_ptr
->num_palette_max
>= 0)
811 png_do_check_palette_indexes(png_ptr
, &row_info
);
814 /* Find a filter if necessary, filter the row and write it out. */
815 png_write_find_filter(png_ptr
, &row_info
);
817 if (png_ptr
->write_row_fn
!= NULL
)
818 (*(png_ptr
->write_row_fn
))(png_ptr
, png_ptr
->row_number
, png_ptr
->pass
);
821 #ifdef PNG_WRITE_FLUSH_SUPPORTED
822 /* Set the automatic flush interval or 0 to turn flushing off */
824 png_set_flush(png_structp png_ptr
, int nrows
)
826 png_debug(1, "in png_set_flush");
831 png_ptr
->flush_dist
= (nrows
< 0 ? 0 : nrows
);
834 /* Flush the current output buffers now */
836 png_write_flush(png_structp png_ptr
)
840 png_debug(1, "in png_write_flush");
845 /* We have already written out all of the data */
846 if (png_ptr
->row_number
>= png_ptr
->num_rows
)
853 /* Compress the data */
854 ret
= deflate(&png_ptr
->zstream
, Z_SYNC_FLUSH
);
857 /* Check for compression errors */
860 if (png_ptr
->zstream
.msg
!= NULL
)
861 png_error(png_ptr
, png_ptr
->zstream
.msg
);
864 png_error(png_ptr
, "zlib error");
867 if (!(png_ptr
->zstream
.avail_out
))
869 /* Write the IDAT and reset the zlib output buffer */
870 png_write_IDAT(png_ptr
, png_ptr
->zbuf
, png_ptr
->zbuf_size
);
873 } while (wrote_IDAT
== 1);
875 /* If there is any data left to be output, write it into a new IDAT */
876 if (png_ptr
->zbuf_size
!= png_ptr
->zstream
.avail_out
)
878 /* Write the IDAT and reset the zlib output buffer */
879 png_write_IDAT(png_ptr
, png_ptr
->zbuf
,
880 png_ptr
->zbuf_size
- png_ptr
->zstream
.avail_out
);
882 png_ptr
->flush_rows
= 0;
885 #endif /* PNG_WRITE_FLUSH_SUPPORTED */
887 /* Free all memory used by the write */
889 png_destroy_write_struct(png_structpp png_ptr_ptr
, png_infopp info_ptr_ptr
)
891 png_structp png_ptr
= NULL
;
892 png_infop info_ptr
= NULL
;
893 #ifdef PNG_USER_MEM_SUPPORTED
894 png_free_ptr free_fn
= NULL
;
895 png_voidp mem_ptr
= NULL
;
898 png_debug(1, "in png_destroy_write_struct");
900 if (png_ptr_ptr
!= NULL
)
901 png_ptr
= *png_ptr_ptr
;
903 #ifdef PNG_USER_MEM_SUPPORTED
906 free_fn
= png_ptr
->free_fn
;
907 mem_ptr
= png_ptr
->mem_ptr
;
911 if (info_ptr_ptr
!= NULL
)
912 info_ptr
= *info_ptr_ptr
;
914 if (info_ptr
!= NULL
)
918 png_free_data(png_ptr
, info_ptr
, PNG_FREE_ALL
, -1);
920 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
921 if (png_ptr
->num_chunk_list
)
923 png_free(png_ptr
, png_ptr
->chunk_list
);
924 png_ptr
->num_chunk_list
= 0;
929 #ifdef PNG_USER_MEM_SUPPORTED
930 png_destroy_struct_2((png_voidp
)info_ptr
, (png_free_ptr
)free_fn
,
933 png_destroy_struct((png_voidp
)info_ptr
);
935 *info_ptr_ptr
= NULL
;
940 png_write_destroy(png_ptr
);
941 #ifdef PNG_USER_MEM_SUPPORTED
942 png_destroy_struct_2((png_voidp
)png_ptr
, (png_free_ptr
)free_fn
,
945 png_destroy_struct((png_voidp
)png_ptr
);
952 /* Free any memory used in png_ptr struct (old method) */
954 png_write_destroy(png_structp png_ptr
)
956 #ifdef PNG_SETJMP_SUPPORTED
957 jmp_buf tmp_jmp
; /* Save jump buffer */
959 png_error_ptr error_fn
;
960 #ifdef PNG_WARNINGS_SUPPORTED
961 png_error_ptr warning_fn
;
964 #ifdef PNG_USER_MEM_SUPPORTED
965 png_free_ptr free_fn
;
968 png_debug(1, "in png_write_destroy");
970 /* Free any memory zlib uses */
971 if (png_ptr
->zlib_state
!= PNG_ZLIB_UNINITIALIZED
)
972 deflateEnd(&png_ptr
->zstream
);
974 /* Free our memory. png_free checks NULL for us. */
975 png_free(png_ptr
, png_ptr
->zbuf
);
976 png_free(png_ptr
, png_ptr
->row_buf
);
977 #ifdef PNG_WRITE_FILTER_SUPPORTED
978 png_free(png_ptr
, png_ptr
->prev_row
);
979 png_free(png_ptr
, png_ptr
->sub_row
);
980 png_free(png_ptr
, png_ptr
->up_row
);
981 png_free(png_ptr
, png_ptr
->avg_row
);
982 png_free(png_ptr
, png_ptr
->paeth_row
);
985 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
986 /* Use this to save a little code space, it doesn't free the filter_costs */
987 png_reset_filter_heuristics(png_ptr
);
988 png_free(png_ptr
, png_ptr
->filter_costs
);
989 png_free(png_ptr
, png_ptr
->inv_filter_costs
);
992 #ifdef PNG_SETJMP_SUPPORTED
993 /* Reset structure */
994 png_memcpy(tmp_jmp
, png_ptr
->longjmp_buffer
, png_sizeof(jmp_buf));
997 error_fn
= png_ptr
->error_fn
;
998 #ifdef PNG_WARNINGS_SUPPORTED
999 warning_fn
= png_ptr
->warning_fn
;
1001 error_ptr
= png_ptr
->error_ptr
;
1002 #ifdef PNG_USER_MEM_SUPPORTED
1003 free_fn
= png_ptr
->free_fn
;
1006 png_memset(png_ptr
, 0, png_sizeof(png_struct
));
1008 png_ptr
->error_fn
= error_fn
;
1009 #ifdef PNG_WARNINGS_SUPPORTED
1010 png_ptr
->warning_fn
= warning_fn
;
1012 png_ptr
->error_ptr
= error_ptr
;
1013 #ifdef PNG_USER_MEM_SUPPORTED
1014 png_ptr
->free_fn
= free_fn
;
1017 #ifdef PNG_SETJMP_SUPPORTED
1018 png_memcpy(png_ptr
->longjmp_buffer
, tmp_jmp
, png_sizeof(jmp_buf));
1022 /* Allow the application to select one or more row filters to use. */
1024 png_set_filter(png_structp png_ptr
, int method
, int filters
)
1026 png_debug(1, "in png_set_filter");
1028 if (png_ptr
== NULL
)
1031 #ifdef PNG_MNG_FEATURES_SUPPORTED
1032 if ((png_ptr
->mng_features_permitted
& PNG_FLAG_MNG_FILTER_64
) &&
1033 (method
== PNG_INTRAPIXEL_DIFFERENCING
))
1034 method
= PNG_FILTER_TYPE_BASE
;
1037 if (method
== PNG_FILTER_TYPE_BASE
)
1039 switch (filters
& (PNG_ALL_FILTERS
| 0x07))
1041 #ifdef PNG_WRITE_FILTER_SUPPORTED
1044 case 7: png_warning(png_ptr
, "Unknown row filter for method 0");
1045 #endif /* PNG_WRITE_FILTER_SUPPORTED */
1046 case PNG_FILTER_VALUE_NONE
:
1047 png_ptr
->do_filter
= PNG_FILTER_NONE
; break;
1049 #ifdef PNG_WRITE_FILTER_SUPPORTED
1050 case PNG_FILTER_VALUE_SUB
:
1051 png_ptr
->do_filter
= PNG_FILTER_SUB
; break;
1053 case PNG_FILTER_VALUE_UP
:
1054 png_ptr
->do_filter
= PNG_FILTER_UP
; break;
1056 case PNG_FILTER_VALUE_AVG
:
1057 png_ptr
->do_filter
= PNG_FILTER_AVG
; break;
1059 case PNG_FILTER_VALUE_PAETH
:
1060 png_ptr
->do_filter
= PNG_FILTER_PAETH
; break;
1063 png_ptr
->do_filter
= (png_byte
)filters
; break;
1066 png_warning(png_ptr
, "Unknown row filter for method 0");
1067 #endif /* PNG_WRITE_FILTER_SUPPORTED */
1070 /* If we have allocated the row_buf, this means we have already started
1071 * with the image and we should have allocated all of the filter buffers
1072 * that have been selected. If prev_row isn't already allocated, then
1073 * it is too late to start using the filters that need it, since we
1074 * will be missing the data in the previous row. If an application
1075 * wants to start and stop using particular filters during compression,
1076 * it should start out with all of the filters, and then add and
1077 * remove them after the start of compression.
1079 if (png_ptr
->row_buf
!= NULL
)
1081 #ifdef PNG_WRITE_FILTER_SUPPORTED
1082 if ((png_ptr
->do_filter
& PNG_FILTER_SUB
) && png_ptr
->sub_row
== NULL
)
1084 png_ptr
->sub_row
= (png_bytep
)png_malloc(png_ptr
,
1085 (png_ptr
->rowbytes
+ 1));
1086 png_ptr
->sub_row
[0] = PNG_FILTER_VALUE_SUB
;
1089 if ((png_ptr
->do_filter
& PNG_FILTER_UP
) && png_ptr
->up_row
== NULL
)
1091 if (png_ptr
->prev_row
== NULL
)
1093 png_warning(png_ptr
, "Can't add Up filter after starting");
1094 png_ptr
->do_filter
= (png_byte
)(png_ptr
->do_filter
&
1100 png_ptr
->up_row
= (png_bytep
)png_malloc(png_ptr
,
1101 (png_ptr
->rowbytes
+ 1));
1102 png_ptr
->up_row
[0] = PNG_FILTER_VALUE_UP
;
1106 if ((png_ptr
->do_filter
& PNG_FILTER_AVG
) && png_ptr
->avg_row
== NULL
)
1108 if (png_ptr
->prev_row
== NULL
)
1110 png_warning(png_ptr
, "Can't add Average filter after starting");
1111 png_ptr
->do_filter
= (png_byte
)(png_ptr
->do_filter
&
1117 png_ptr
->avg_row
= (png_bytep
)png_malloc(png_ptr
,
1118 (png_ptr
->rowbytes
+ 1));
1119 png_ptr
->avg_row
[0] = PNG_FILTER_VALUE_AVG
;
1123 if ((png_ptr
->do_filter
& PNG_FILTER_PAETH
) &&
1124 png_ptr
->paeth_row
== NULL
)
1126 if (png_ptr
->prev_row
== NULL
)
1128 png_warning(png_ptr
, "Can't add Paeth filter after starting");
1129 png_ptr
->do_filter
&= (png_byte
)(~PNG_FILTER_PAETH
);
1134 png_ptr
->paeth_row
= (png_bytep
)png_malloc(png_ptr
,
1135 (png_ptr
->rowbytes
+ 1));
1136 png_ptr
->paeth_row
[0] = PNG_FILTER_VALUE_PAETH
;
1140 if (png_ptr
->do_filter
== PNG_NO_FILTERS
)
1141 #endif /* PNG_WRITE_FILTER_SUPPORTED */
1142 png_ptr
->do_filter
= PNG_FILTER_NONE
;
1146 png_error(png_ptr
, "Unknown custom filter method");
1149 /* This allows us to influence the way in which libpng chooses the "best"
1150 * filter for the current scanline. While the "minimum-sum-of-absolute-
1151 * differences metric is relatively fast and effective, there is some
1152 * question as to whether it can be improved upon by trying to keep the
1153 * filtered data going to zlib more consistent, hopefully resulting in
1154 * better compression.
1156 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* GRR 970116 */
1157 /* Convenience reset API. */
1159 png_reset_filter_heuristics(png_structp png_ptr
)
1161 /* Clear out any old values in the 'weights' - this must be done because if
1162 * the app calls set_filter_heuristics multiple times with different
1163 * 'num_weights' values we would otherwise potentially have wrong sized
1166 png_ptr
->num_prev_filters
= 0;
1167 png_ptr
->heuristic_method
= PNG_FILTER_HEURISTIC_UNWEIGHTED
;
1168 if (png_ptr
->prev_filters
!= NULL
)
1170 png_bytep old
= png_ptr
->prev_filters
;
1171 png_ptr
->prev_filters
= NULL
;
1172 png_free(png_ptr
, old
);
1174 if (png_ptr
->filter_weights
!= NULL
)
1176 png_uint_16p old
= png_ptr
->filter_weights
;
1177 png_ptr
->filter_weights
= NULL
;
1178 png_free(png_ptr
, old
);
1181 if (png_ptr
->inv_filter_weights
!= NULL
)
1183 png_uint_16p old
= png_ptr
->inv_filter_weights
;
1184 png_ptr
->inv_filter_weights
= NULL
;
1185 png_free(png_ptr
, old
);
1188 /* Leave the filter_costs - this array is fixed size. */
1192 png_init_filter_heuristics(png_structp png_ptr
, int heuristic_method
,
1195 if (png_ptr
== NULL
)
1198 /* Clear out the arrays */
1199 png_reset_filter_heuristics(png_ptr
);
1201 /* Check arguments; the 'reset' function makes the correct settings for the
1202 * unweighted case, but we must handle the weight case by initializing the
1203 * arrays for the caller.
1205 if (heuristic_method
== PNG_FILTER_HEURISTIC_WEIGHTED
)
1209 if (num_weights
> 0)
1211 png_ptr
->prev_filters
= (png_bytep
)png_malloc(png_ptr
,
1212 (png_uint_32
)(png_sizeof(png_byte
) * num_weights
));
1214 /* To make sure that the weighting starts out fairly */
1215 for (i
= 0; i
< num_weights
; i
++)
1217 png_ptr
->prev_filters
[i
] = 255;
1220 png_ptr
->filter_weights
= (png_uint_16p
)png_malloc(png_ptr
,
1221 (png_uint_32
)(png_sizeof(png_uint_16
) * num_weights
));
1223 png_ptr
->inv_filter_weights
= (png_uint_16p
)png_malloc(png_ptr
,
1224 (png_uint_32
)(png_sizeof(png_uint_16
) * num_weights
));
1226 for (i
= 0; i
< num_weights
; i
++)
1228 png_ptr
->inv_filter_weights
[i
] =
1229 png_ptr
->filter_weights
[i
] = PNG_WEIGHT_FACTOR
;
1232 /* Safe to set this now */
1233 png_ptr
->num_prev_filters
= (png_byte
)num_weights
;
1236 /* If, in the future, there are other filter methods, this would
1237 * need to be based on png_ptr->filter.
1239 if (png_ptr
->filter_costs
== NULL
)
1241 png_ptr
->filter_costs
= (png_uint_16p
)png_malloc(png_ptr
,
1242 (png_uint_32
)(png_sizeof(png_uint_16
) * PNG_FILTER_VALUE_LAST
));
1244 png_ptr
->inv_filter_costs
= (png_uint_16p
)png_malloc(png_ptr
,
1245 (png_uint_32
)(png_sizeof(png_uint_16
) * PNG_FILTER_VALUE_LAST
));
1248 for (i
= 0; i
< PNG_FILTER_VALUE_LAST
; i
++)
1250 png_ptr
->inv_filter_costs
[i
] =
1251 png_ptr
->filter_costs
[i
] = PNG_COST_FACTOR
;
1254 /* All the arrays are inited, safe to set this: */
1255 png_ptr
->heuristic_method
= PNG_FILTER_HEURISTIC_WEIGHTED
;
1257 /* Return the 'ok' code. */
1260 else if (heuristic_method
== PNG_FILTER_HEURISTIC_DEFAULT
||
1261 heuristic_method
== PNG_FILTER_HEURISTIC_UNWEIGHTED
)
1267 png_warning(png_ptr
, "Unknown filter heuristic method");
1272 /* Provide floating and fixed point APIs */
1273 #ifdef PNG_FLOATING_POINT_SUPPORTED
1275 png_set_filter_heuristics(png_structp png_ptr
, int heuristic_method
,
1276 int num_weights
, png_const_doublep filter_weights
,
1277 png_const_doublep filter_costs
)
1279 png_debug(1, "in png_set_filter_heuristics");
1281 /* The internal API allocates all the arrays and ensures that the elements of
1282 * those arrays are set to the default value.
1284 if (!png_init_filter_heuristics(png_ptr
, heuristic_method
, num_weights
))
1287 /* If using the weighted method copy in the weights. */
1288 if (heuristic_method
== PNG_FILTER_HEURISTIC_WEIGHTED
)
1291 for (i
= 0; i
< num_weights
; i
++)
1293 if (filter_weights
[i
] <= 0.0)
1295 png_ptr
->inv_filter_weights
[i
] =
1296 png_ptr
->filter_weights
[i
] = PNG_WEIGHT_FACTOR
;
1301 png_ptr
->inv_filter_weights
[i
] =
1302 (png_uint_16
)(PNG_WEIGHT_FACTOR
*filter_weights
[i
]+.5);
1304 png_ptr
->filter_weights
[i
] =
1305 (png_uint_16
)(PNG_WEIGHT_FACTOR
/filter_weights
[i
]+.5);
1309 /* Here is where we set the relative costs of the different filters. We
1310 * should take the desired compression level into account when setting
1311 * the costs, so that Paeth, for instance, has a high relative cost at low
1312 * compression levels, while it has a lower relative cost at higher
1313 * compression settings. The filter types are in order of increasing
1314 * relative cost, so it would be possible to do this with an algorithm.
1316 for (i
= 0; i
< PNG_FILTER_VALUE_LAST
; i
++) if (filter_costs
[i
] >= 1.0)
1318 png_ptr
->inv_filter_costs
[i
] =
1319 (png_uint_16
)(PNG_COST_FACTOR
/ filter_costs
[i
] + .5);
1321 png_ptr
->filter_costs
[i
] =
1322 (png_uint_16
)(PNG_COST_FACTOR
* filter_costs
[i
] + .5);
1326 #endif /* FLOATING_POINT */
1328 #ifdef PNG_FIXED_POINT_SUPPORTED
1330 png_set_filter_heuristics_fixed(png_structp png_ptr
, int heuristic_method
,
1331 int num_weights
, png_const_fixed_point_p filter_weights
,
1332 png_const_fixed_point_p filter_costs
)
1334 png_debug(1, "in png_set_filter_heuristics_fixed");
1336 /* The internal API allocates all the arrays and ensures that the elements of
1337 * those arrays are set to the default value.
1339 if (!png_init_filter_heuristics(png_ptr
, heuristic_method
, num_weights
))
1342 /* If using the weighted method copy in the weights. */
1343 if (heuristic_method
== PNG_FILTER_HEURISTIC_WEIGHTED
)
1346 for (i
= 0; i
< num_weights
; i
++)
1348 if (filter_weights
[i
] <= 0)
1350 png_ptr
->inv_filter_weights
[i
] =
1351 png_ptr
->filter_weights
[i
] = PNG_WEIGHT_FACTOR
;
1356 png_ptr
->inv_filter_weights
[i
] = (png_uint_16
)
1357 ((PNG_WEIGHT_FACTOR
*filter_weights
[i
]+PNG_FP_HALF
)/PNG_FP_1
);
1359 png_ptr
->filter_weights
[i
] = (png_uint_16
)((PNG_WEIGHT_FACTOR
*
1360 PNG_FP_1
+(filter_weights
[i
]/2))/filter_weights
[i
]);
1364 /* Here is where we set the relative costs of the different filters. We
1365 * should take the desired compression level into account when setting
1366 * the costs, so that Paeth, for instance, has a high relative cost at low
1367 * compression levels, while it has a lower relative cost at higher
1368 * compression settings. The filter types are in order of increasing
1369 * relative cost, so it would be possible to do this with an algorithm.
1371 for (i
= 0; i
< PNG_FILTER_VALUE_LAST
; i
++)
1372 if (filter_costs
[i
] >= PNG_FP_1
)
1376 /* Use a 32 bit unsigned temporary here because otherwise the
1377 * intermediate value will be a 32 bit *signed* integer (ANSI rules)
1378 * and this will get the wrong answer on division.
1380 tmp
= PNG_COST_FACTOR
*PNG_FP_1
+ (filter_costs
[i
]/2);
1381 tmp
/= filter_costs
[i
];
1383 png_ptr
->inv_filter_costs
[i
] = (png_uint_16
)tmp
;
1385 tmp
= PNG_COST_FACTOR
* filter_costs
[i
] + PNG_FP_HALF
;
1388 png_ptr
->filter_costs
[i
] = (png_uint_16
)tmp
;
1392 #endif /* FIXED_POINT */
1393 #endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
1396 png_set_compression_level(png_structp png_ptr
, int level
)
1398 png_debug(1, "in png_set_compression_level");
1400 if (png_ptr
== NULL
)
1403 png_ptr
->flags
|= PNG_FLAG_ZLIB_CUSTOM_LEVEL
;
1404 png_ptr
->zlib_level
= level
;
1408 png_set_compression_mem_level(png_structp png_ptr
, int mem_level
)
1410 png_debug(1, "in png_set_compression_mem_level");
1412 if (png_ptr
== NULL
)
1415 png_ptr
->flags
|= PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL
;
1416 png_ptr
->zlib_mem_level
= mem_level
;
1420 png_set_compression_strategy(png_structp png_ptr
, int strategy
)
1422 png_debug(1, "in png_set_compression_strategy");
1424 if (png_ptr
== NULL
)
1427 png_ptr
->flags
|= PNG_FLAG_ZLIB_CUSTOM_STRATEGY
;
1428 png_ptr
->zlib_strategy
= strategy
;
1431 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1432 * smaller value of window_bits if it can do so safely.
1435 png_set_compression_window_bits(png_structp png_ptr
, int window_bits
)
1437 if (png_ptr
== NULL
)
1440 if (window_bits
> 15)
1441 png_warning(png_ptr
, "Only compression windows <= 32k supported by PNG");
1443 else if (window_bits
< 8)
1444 png_warning(png_ptr
, "Only compression windows >= 256 supported by PNG");
1447 /* Avoid libpng bug with 256-byte windows */
1448 if (window_bits
== 8)
1450 png_warning(png_ptr
, "Compression window is being reset to 512");
1455 png_ptr
->flags
|= PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS
;
1456 png_ptr
->zlib_window_bits
= window_bits
;
1460 png_set_compression_method(png_structp png_ptr
, int method
)
1462 png_debug(1, "in png_set_compression_method");
1464 if (png_ptr
== NULL
)
1468 png_warning(png_ptr
, "Only compression method 8 is supported by PNG");
1470 png_ptr
->flags
|= PNG_FLAG_ZLIB_CUSTOM_METHOD
;
1471 png_ptr
->zlib_method
= method
;
1474 /* The following were added to libpng-1.5.4 */
1475 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
1477 png_set_text_compression_level(png_structp png_ptr
, int level
)
1479 png_debug(1, "in png_set_text_compression_level");
1481 if (png_ptr
== NULL
)
1484 png_ptr
->flags
|= PNG_FLAG_ZTXT_CUSTOM_LEVEL
;
1485 png_ptr
->zlib_text_level
= level
;
1489 png_set_text_compression_mem_level(png_structp png_ptr
, int mem_level
)
1491 png_debug(1, "in png_set_text_compression_mem_level");
1493 if (png_ptr
== NULL
)
1496 png_ptr
->flags
|= PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL
;
1497 png_ptr
->zlib_text_mem_level
= mem_level
;
1501 png_set_text_compression_strategy(png_structp png_ptr
, int strategy
)
1503 png_debug(1, "in png_set_text_compression_strategy");
1505 if (png_ptr
== NULL
)
1508 png_ptr
->flags
|= PNG_FLAG_ZTXT_CUSTOM_STRATEGY
;
1509 png_ptr
->zlib_text_strategy
= strategy
;
1512 /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
1513 * smaller value of window_bits if it can do so safely.
1516 png_set_text_compression_window_bits(png_structp png_ptr
, int window_bits
)
1518 if (png_ptr
== NULL
)
1521 if (window_bits
> 15)
1522 png_warning(png_ptr
, "Only compression windows <= 32k supported by PNG");
1524 else if (window_bits
< 8)
1525 png_warning(png_ptr
, "Only compression windows >= 256 supported by PNG");
1528 /* Avoid libpng bug with 256-byte windows */
1529 if (window_bits
== 8)
1531 png_warning(png_ptr
, "Text compression window is being reset to 512");
1536 png_ptr
->flags
|= PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS
;
1537 png_ptr
->zlib_text_window_bits
= window_bits
;
1541 png_set_text_compression_method(png_structp png_ptr
, int method
)
1543 png_debug(1, "in png_set_text_compression_method");
1545 if (png_ptr
== NULL
)
1549 png_warning(png_ptr
, "Only compression method 8 is supported by PNG");
1551 png_ptr
->flags
|= PNG_FLAG_ZTXT_CUSTOM_METHOD
;
1552 png_ptr
->zlib_text_method
= method
;
1554 #endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
1555 /* end of API added to libpng-1.5.4 */
1558 png_set_write_status_fn(png_structp png_ptr
, png_write_status_ptr write_row_fn
)
1560 if (png_ptr
== NULL
)
1563 png_ptr
->write_row_fn
= write_row_fn
;
1566 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
1568 png_set_write_user_transform_fn(png_structp png_ptr
, png_user_transform_ptr
1569 write_user_transform_fn
)
1571 png_debug(1, "in png_set_write_user_transform_fn");
1573 if (png_ptr
== NULL
)
1576 png_ptr
->transformations
|= PNG_USER_TRANSFORM
;
1577 png_ptr
->write_user_transform_fn
= write_user_transform_fn
;
1582 #ifdef PNG_INFO_IMAGE_SUPPORTED
1584 png_write_png(png_structp png_ptr
, png_infop info_ptr
,
1585 int transforms
, voidp params
)
1587 if (png_ptr
== NULL
|| info_ptr
== NULL
)
1590 /* Write the file header information. */
1591 png_write_info(png_ptr
, info_ptr
);
1593 /* ------ these transformations don't touch the info structure ------- */
1595 #ifdef PNG_WRITE_INVERT_SUPPORTED
1596 /* Invert monochrome pixels */
1597 if (transforms
& PNG_TRANSFORM_INVERT_MONO
)
1598 png_set_invert_mono(png_ptr
);
1601 #ifdef PNG_WRITE_SHIFT_SUPPORTED
1602 /* Shift the pixels up to a legal bit depth and fill in
1603 * as appropriate to correctly scale the image.
1605 if ((transforms
& PNG_TRANSFORM_SHIFT
)
1606 && (info_ptr
->valid
& PNG_INFO_sBIT
))
1607 png_set_shift(png_ptr
, &info_ptr
->sig_bit
);
1610 #ifdef PNG_WRITE_PACK_SUPPORTED
1611 /* Pack pixels into bytes */
1612 if (transforms
& PNG_TRANSFORM_PACKING
)
1613 png_set_packing(png_ptr
);
1616 #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
1617 /* Swap location of alpha bytes from ARGB to RGBA */
1618 if (transforms
& PNG_TRANSFORM_SWAP_ALPHA
)
1619 png_set_swap_alpha(png_ptr
);
1622 #ifdef PNG_WRITE_FILLER_SUPPORTED
1623 /* Pack XRGB/RGBX/ARGB/RGBA into RGB (4 channels -> 3 channels) */
1624 if (transforms
& PNG_TRANSFORM_STRIP_FILLER_AFTER
)
1625 png_set_filler(png_ptr
, 0, PNG_FILLER_AFTER
);
1627 else if (transforms
& PNG_TRANSFORM_STRIP_FILLER_BEFORE
)
1628 png_set_filler(png_ptr
, 0, PNG_FILLER_BEFORE
);
1631 #ifdef PNG_WRITE_BGR_SUPPORTED
1632 /* Flip BGR pixels to RGB */
1633 if (transforms
& PNG_TRANSFORM_BGR
)
1634 png_set_bgr(png_ptr
);
1637 #ifdef PNG_WRITE_SWAP_SUPPORTED
1638 /* Swap bytes of 16-bit files to most significant byte first */
1639 if (transforms
& PNG_TRANSFORM_SWAP_ENDIAN
)
1640 png_set_swap(png_ptr
);
1643 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
1644 /* Swap bits of 1, 2, 4 bit packed pixel formats */
1645 if (transforms
& PNG_TRANSFORM_PACKSWAP
)
1646 png_set_packswap(png_ptr
);
1649 #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
1650 /* Invert the alpha channel from opacity to transparency */
1651 if (transforms
& PNG_TRANSFORM_INVERT_ALPHA
)
1652 png_set_invert_alpha(png_ptr
);
1655 /* ----------------------- end of transformations ------------------- */
1657 /* Write the bits */
1658 if (info_ptr
->valid
& PNG_INFO_IDAT
)
1659 png_write_image(png_ptr
, info_ptr
->row_pointers
);
1661 /* It is REQUIRED to call this to finish writing the rest of the file */
1662 png_write_end(png_ptr
, info_ptr
);
1664 PNG_UNUSED(transforms
) /* Quiet compiler warnings */
1668 #endif /* PNG_WRITE_SUPPORTED */