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libpng/pngwrite.c
John Bowler 4792c8a751 compression code unification 
Unify the compression code so that inflate calls are localized to a common
routine.  Ground work for filter selection support.  Minor API changes to use
void* not byte* for data parameters.  Unification of some of the compression
code with the decompression code; IDAT_size replaces IDAT_read_size and
zbuffer_size, IDAT reading and writing is no longer controlled by the size of
the compression buffer.

Signed-off-by: John Bowler <jbowler@acm.org>
2015-11-30 13:39:49 -08:00

2077 lines
69 KiB
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/* pngwrite.c - general routines to write a PNG file
*
* Last changed in libpng 1.7.0 [(PENDING RELEASE)]
* Copyright (c) 1998-2015 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*/
#include "pngpriv.h"
#if defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
# include <errno.h>
#endif
#define PNG_SRC_FILE PNG_SRC_FILE_pngwrite
#ifdef PNG_WRITE_SUPPORTED
#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
/* Write out all the unknown chunks for the current given location */
static void
write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
unsigned int where)
{
if (info_ptr->unknown_chunks_num != 0)
{
png_const_unknown_chunkp up;
png_debug(5, "writing extra chunks");
for (up = info_ptr->unknown_chunks;
up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
++up)
if ((up->location & where) != 0)
{
/* If per-chunk unknown chunk handling is enabled use it, otherwise
* just write the chunks the application has set.
*/
#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
int keep = png_handle_as_unknown(png_ptr, up->name);
/* NOTE: this code is radically different from the read side in the
* matter of handling an ancillary unknown chunk. In the read side
* the default behavior is to discard it, in the code below the default
* behavior is to write it. Critical chunks are, however, only
* written if explicitly listed or if the default is set to write all
* unknown chunks.
*
* The default handling is also slightly weird - it is not possible to
* stop the writing of all unsafe-to-copy chunks!
*
* TODO: REVIEW: this would seem to be a bug.
*/
if (keep != PNG_HANDLE_CHUNK_NEVER &&
((up->name[3] & 0x20) /* safe-to-copy overrides everything */ ||
keep == PNG_HANDLE_CHUNK_ALWAYS ||
(keep == PNG_HANDLE_CHUNK_AS_DEFAULT &&
png_ptr->unknown_default == PNG_HANDLE_CHUNK_ALWAYS)))
#endif
{
/* TODO: review, what is wrong with a zero length unknown chunk? */
if (up->size == 0)
png_warning(png_ptr, "Writing zero-length unknown chunk");
png_write_chunk(png_ptr, up->name, up->data, up->size);
}
}
}
}
#endif /* WRITE_UNKNOWN_CHUNKS */
/* Writes all the PNG information. This is the suggested way to use the
* library. If you have a new chunk to add, make a function to write it,
* and put it in the correct location here. If you want the chunk written
* after the image data, put it in png_write_end(). I strongly encourage
* you to supply a PNG_INFO_ flag, and check info_ptr->valid before writing
* the chunk, as that will keep the code from breaking if you want to just
* write a plain PNG file. If you have long comments, I suggest writing
* them in png_write_end(), and compressing them.
*/
void PNGAPI
png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
{
png_debug(1, "in png_write_info_before_PLTE");
if (png_ptr == NULL || info_ptr == NULL)
return;
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
{
int color_type = PNG_COLOR_TYPE_FROM_FORMAT(info_ptr->format);
/* Write PNG signature; doesn't set PNG_HAVE_PNG_SIGNATURE if it has
* already been written (or rather, if at least 3 bytes have already been
* written; undocumented wackiness, it means the 'PNG' at the start can be
* replace by, e.g. "FOO" or "BAR" or "MNG").
*/
png_write_sig(png_ptr);
# ifdef PNG_MNG_FEATURES_SUPPORTED
if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 &&
png_ptr->mng_features_permitted != 0)
{
png_app_error(png_ptr,
"MNG features are not allowed in a PNG datastream");
/* Recovery: disable MNG features: */
png_ptr->mng_features_permitted = 0;
}
# endif /* MNG_FEATURES */
/* Write IHDR information. */
png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
info_ptr->bit_depth, color_type, info_ptr->compression_type,
info_ptr->filter_type, info_ptr->interlace_type);
# ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
/* This are used for checking later on: */
png_ptr->info_format = info_ptr->format;
# endif /* WRITE_TRANSFORMS */
/* This sets the flag that prevents re-entry to the 'before PLTE' case: */
affirm((png_ptr->mode & PNG_HAVE_IHDR) != 0);
/* The rest of these check to see if the valid field has the appropriate
* flag set, and if it does, writes the chunk.
*
* 1.6.0: COLORSPACE support controls the writing of these chunks too, and
* the chunks will be written if the WRITE routine is there and
* information is available in the COLORSPACE. (See
* png_colorspace_sync_info in png.c for where the valid flags get set.)
*
* Under certain circumstances the colorspace can be invalidated without
* syncing the info_struct 'valid' flags; this happens if libpng detects
* an error and calls png_error while the color space is being set, yet
* the application continues writing the PNG. So check the 'invalid'
* flag here too.
*/
# ifdef PNG_WRITE_gAMA_SUPPORTED /* enables GAMMA */
if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
(info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
(info_ptr->valid & PNG_INFO_gAMA) != 0)
{
/* This is the inverse of the test in png.c: */
affirm(info_ptr->colorspace.gamma >= 16 &&
info_ptr->colorspace.gamma <= 625000000);
png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
}
# endif /* WRITE_gAMA */
/* Write only one of sRGB or an ICC profile. If a profile was supplied
* and it matches one of the known sRGB ones issue a warning.
*/
# ifdef PNG_WRITE_iCCP_SUPPORTED /* enables COLORSPACE, GAMMA */
if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
(info_ptr->valid & PNG_INFO_iCCP) != 0)
{
# ifdef PNG_WRITE_sRGB_SUPPORTED
/* The app must have supplied an sRGB iCCP profile (and one that
* is recognized and therefore known to be correct) so we write
* that profile, even though it increases the size of the PNG
* significantly. A warning is reasonable:
*/
if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
png_app_warning(png_ptr,
"profile matches sRGB but writing iCCP instead");
# endif /* WRITE_sRGB */
png_write_iCCP(png_ptr, info_ptr->iccp_name,
info_ptr->iccp_profile);
}
# ifdef PNG_WRITE_sRGB_SUPPORTED
else /* iCCP not written */
# endif /* WRITE_sRGB */
# endif /* WRITE_iCCP */
# ifdef PNG_WRITE_sRGB_SUPPORTED /* enables COLORSPACE, GAMMA */
if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
(info_ptr->valid & PNG_INFO_sRGB) != 0)
png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
# endif /* WRITE_sRGB */
# ifdef PNG_WRITE_sBIT_SUPPORTED
if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
png_write_sBIT(png_ptr, &(info_ptr->sig_bit), color_type);
# endif /* WRITE_sBIT */
# ifdef PNG_WRITE_cHRM_SUPPORTED /* enables COLORSPACE */
if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
(info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
(info_ptr->valid & PNG_INFO_cHRM) != 0)
png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
# endif /* WRITE_cHRM */
# ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
/* The third arugment must encode only one bit, otherwise chunks will
* be written twice because the test in write_unknown_chunks is
* 'location & where'.
*/
write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
# endif
}
else /* 1.7.0: flag multiple calls; previously ignored */
png_app_error(png_ptr,
"png_write_info_before_PLTE called more than once");
}
#ifdef PNG_WRITE_TEXT_SUPPORTED
static void
png_write_text(png_structrp png_ptr, png_const_inforp info_ptr)
/* Text chunk helper */
{
int i;
/* Check to see if we need to write text chunks */
for (i = 0; i < info_ptr->num_text; i++)
{
png_debug2(2, "Writing text chunk %d, type %d", i,
info_ptr->text[i].compression);
/* An internationalized chunk? */
if (info_ptr->text[i].compression > 0)
{
# ifdef PNG_WRITE_iTXt_SUPPORTED
/* Write international chunk */
png_write_iTXt(png_ptr, info_ptr->text[i].compression,
info_ptr->text[i].key, info_ptr->text[i].lang,
info_ptr->text[i].lang_key, info_ptr->text[i].text);
# else /* !WRITE_iTXT */
png_app_error(png_ptr, "Unable to write international text");
# endif /* !WRITE_iTXT */
/* Mark this chunk as written */
if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
else
info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
}
/* If we want a compressed text chunk */
else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
{
# ifdef PNG_WRITE_zTXt_SUPPORTED
/* Write compressed chunk */
png_write_zTXt(png_ptr, info_ptr->text[i].key,
info_ptr->text[i].text, info_ptr->text[i].compression);
# else /* !WRITE_zTXT */
png_app_error(png_ptr, "Unable to write compressed text");
# endif /* !WRITE_zTXT */
/* Mark this chunk as written */
info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
}
else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
{
# ifdef PNG_WRITE_tEXt_SUPPORTED
/* Write uncompressed chunk */
png_write_tEXt(png_ptr, info_ptr->text[i].key,
info_ptr->text[i].text, 0);
# else /* !WRITE_tEXt */
/* Can't get here TODO: why not? */
png_app_error(png_ptr, "Unable to write uncompressed text");
# endif /* !WRITE_tEXt */
/* Mark this chunk as written */
info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
}
}
}
#endif /* WRITE_TEXT */
void PNGAPI
png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
{
png_debug(1, "in png_write_info");
if (png_ptr == NULL || info_ptr == NULL)
return;
if ((png_ptr->mode & (PNG_HAVE_PLTE+PNG_HAVE_IDAT)) != 0)
{
png_app_error(png_ptr, "late call to png_write_info");
return;
}
/* The app may do this for us, and in 1.7.0 multiple calls are flagged as an
* application error, so this code must check:
*/
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
png_write_info_before_PLTE(png_ptr, info_ptr);
if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
png_write_PLTE(png_ptr, info_ptr->palette, info_ptr->num_palette);
/* Validate the consistency of the PNG being produced; a palette must have
* been written if a palette mapped PNG is to be valid:
*/
if ((png_ptr->mode & PNG_HAVE_PLTE) == 0 &&
png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
png_error(png_ptr, "Valid palette required for paletted images");
# ifdef PNG_WRITE_tRNS_SUPPORTED
if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
{
png_write_tRNS(png_ptr, info_ptr->trans_alpha,
&(info_ptr->trans_color), info_ptr->num_trans,
PNG_COLOR_TYPE_FROM_FORMAT(info_ptr->format));
}
# endif /* WRITE_tRNS */
# ifdef PNG_WRITE_bKGD_SUPPORTED
if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
png_write_bKGD(png_ptr, &(info_ptr->background),
PNG_COLOR_TYPE_FROM_FORMAT(info_ptr->format));
# endif /* WRITE_bKGD */
# ifdef PNG_WRITE_hIST_SUPPORTED
if ((info_ptr->valid & PNG_INFO_hIST) != 0)
png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
# endif /* WRITE_hIST */
# ifdef PNG_WRITE_oFFs_SUPPORTED
if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
info_ptr->offset_unit_type);
# endif /* WRITE_oFFs */
# ifdef PNG_WRITE_pCAL_SUPPORTED
if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
info_ptr->pcal_units, info_ptr->pcal_params);
# endif /* WRITE_pCAL */
# ifdef PNG_WRITE_sCAL_SUPPORTED
if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
png_write_sCAL_s(png_ptr, info_ptr->scal_unit, info_ptr->scal_s_width,
info_ptr->scal_s_height);
# endif /* WRITE_sCAL */
# ifdef PNG_WRITE_pHYs_SUPPORTED
if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
# endif /* WRITE_pHYs */
# ifdef PNG_WRITE_tIME_SUPPORTED
if ((info_ptr->valid & PNG_INFO_tIME) != 0)
png_write_tIME(png_ptr, &(info_ptr->mod_time));
# endif /* WRITE_tIME */
# ifdef PNG_WRITE_sPLT_SUPPORTED
if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
{
int i;
for (i = 0; i < info_ptr->splt_palettes_num; i++)
png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
}
# endif /* WRITE_sPLT */
# ifdef PNG_WRITE_TEXT_SUPPORTED
if (info_ptr->num_text > 0)
png_write_text(png_ptr, info_ptr);
# endif /* WRITE_TEXT */
# ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);
# endif /* WRITE_UNKNOWN_CHUNKS */
}
/* Writes the end of the PNG file. If you don't want to write comments or
* time information, you can pass NULL for info. If you already wrote these
* in png_write_info(), do not write them again here. If you have long
* comments, I suggest writing them here, and compressing them.
*/
void PNGAPI
png_write_end(png_structrp png_ptr, png_inforp info_ptr)
{
png_debug(1, "in png_write_end");
if (png_ptr == NULL)
return;
if ((png_ptr->mode &
(PNG_HAVE_IHDR+PNG_HAVE_IDAT+PNG_AFTER_IDAT+PNG_HAVE_IEND)) !=
(PNG_HAVE_IHDR+PNG_HAVE_IDAT+PNG_AFTER_IDAT))
{
/* Out of place png_write_end: */
if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
png_error(png_ptr, "Missing call to png_write_info");
else if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 && png_ptr->zowner == 0)
{
/* TODO: write unknown IDAT here, for the moment allow the app to write
* IDAT then call write_end:
*/
png_app_error(png_ptr, "No IDATs written into file");
png_ptr->mode |= PNG_HAVE_IDAT+PNG_AFTER_IDAT;
}
else if ((png_ptr->mode & PNG_AFTER_IDAT) == 0)
{
affirm(png_ptr->zowner == png_IDAT);
png_error(png_ptr, "incomplete PNG image"); /* unrecoverable */
}
else if ((png_ptr->mode & PNG_HAVE_IEND) != 0)
{
png_app_error(png_ptr, "multiple calls to png_write_end");
return;
}
else
impossible("not reached");
}
/* And double check that the image rows were all written; this is actually
* a harmless error on an interlaced image because the image rows with
* data were all passed in or the above check would not work.
*
* Don't do this if the IDAT came from unknowns (TBD) or the app, above.
*
* The check depends on the precise logic in png_write_row.
*/
else if (png_ptr->pass != 7U)
png_app_error(png_ptr, "png_write_row not called to last row");
else
debug(png_ptr->row_number == 0U);
/* See if user wants us to write information chunks */
if (info_ptr != NULL)
{
# ifdef PNG_WRITE_tIME_SUPPORTED
/* Check to see if user has supplied a time chunk */
if ((info_ptr->valid & PNG_INFO_tIME) != 0)
png_write_tIME(png_ptr, &(info_ptr->mod_time));
# endif
# ifdef PNG_WRITE_TEXT_SUPPORTED
if (info_ptr->num_text > 0)
png_write_text(png_ptr, info_ptr);
# endif /* WRITE_TEXT */
# ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);
# endif
}
/* Write end of PNG file */
png_write_IEND(png_ptr);
/* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
* and restored again in libpng-1.2.30, may cause some applications that
* do not set png_ptr->output_flush_fn to crash. If your application
* experiences a problem, please try building libpng with
* PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
* png-mng-implement at lists.sf.net .
*/
# ifdef PNG_WRITE_FLUSH_SUPPORTED
# ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
png_flush(png_ptr);
# endif
# endif
}
#ifdef PNG_CONVERT_tIME_SUPPORTED
void PNGAPI
png_convert_from_struct_tm(png_timep ptime, PNG_CONST struct tm * ttime)
{
png_debug(1, "in png_convert_from_struct_tm");
ptime->year = png_check_u16(0/*TODO: fixme*/, 1900 + ttime->tm_year);
ptime->month = png_check_byte(0/*TODO: fixme*/, ttime->tm_mon + 1);
ptime->day = png_check_byte(0/*TODO: fixme*/, ttime->tm_mday);
ptime->hour = png_check_byte(0/*TODO: fixme*/, ttime->tm_hour);
ptime->minute = png_check_byte(0/*TODO: fixme*/, ttime->tm_min);
ptime->second = png_check_byte(0/*TODO: fixme*/, ttime->tm_sec);
}
void PNGAPI
png_convert_from_time_t(png_timep ptime, time_t ttime)
{
struct tm *tbuf;
png_debug(1, "in png_convert_from_time_t");
tbuf = gmtime(&ttime);
png_convert_from_struct_tm(ptime, tbuf);
}
#endif
/* Initialize png_ptr structure, and allocate any memory needed */
PNG_FUNCTION(png_structp,PNGAPI
png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
{
#ifndef PNG_USER_MEM_SUPPORTED
png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
error_fn, warn_fn, NULL, NULL, NULL);
#else
return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
warn_fn, NULL, NULL, NULL);
}
/* Alternate initialize png_ptr structure, and allocate any memory needed */
PNG_FUNCTION(png_structp,PNGAPI
png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
{
png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
#endif /* USER_MEM */
if (png_ptr != NULL)
{
/* Set the zlib control values to defaults; they can be overridden by the
* application after the struct has been created.
*/
png_ptr->IDAT_size = PNG_ZBUF_SIZE;
/* The 'zlib_strategy' setting is irrelevant because png_default_claim in
* pngwutil.c defaults it according to whether or not filters will be
* used, and ignores this setting.
*/
png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
png_ptr->zlib_mem_level = 8;
png_ptr->zlib_window_bits = 15;
png_ptr->zlib_method = 8;
#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
png_ptr->zlib_text_mem_level = 8;
png_ptr->zlib_text_window_bits = 15;
png_ptr->zlib_text_method = 8;
#endif /* WRITE_COMPRESSED_TEXT */
/* This is a highly dubious configuration option; by default it is off,
* but it may be appropriate for private builds that are testing
* extensions not conformant to the current specification, or of
* applications that must not fail to write at all costs!
*/
#ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
/* In stable builds only warn if an application error can be completely
* handled.
*/
png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
#endif
/* App warnings are warnings in release (or release candidate) builds but
* are errors during development.
*/
#if PNG_RELEASE_BUILD
png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
#endif
}
return png_ptr;
}
/* Write a few rows of image data. If the image is interlaced,
* either you will have to write the 7 sub images, or, if you
* have called png_set_interlace_handling(), you will have to
* "write" the image seven times.
*/
void PNGAPI
png_write_rows(png_structrp png_ptr, png_bytepp row,
png_uint_32 num_rows)
{
png_debug(1, "in png_write_rows");
if (png_ptr == NULL || row == NULL)
return;
/* Loop through the rows */
while (num_rows-- > 0)
png_write_row(png_ptr, *row++);
}
/* Write the image. You only need to call this function once, even
* if you are writing an interlaced image.
*/
void PNGAPI
png_write_image(png_structrp png_ptr, png_bytepp image)
{
int num_pass; /* pass variables */
if (png_ptr == NULL || image == NULL)
return;
png_debug(1, "in png_write_image");
#ifdef PNG_WRITE_INTERLACING_SUPPORTED
/* Initialize interlace handling. If image is not interlaced,
* this will set pass to 1
*/
num_pass = png_set_interlace_handling(png_ptr);
#else
num_pass = 1;
if (png_ptr->interlaced)
{
png_app_error(png_ptr, "no interlace support");
return;
}
#endif
/* Loop through passes */
while (num_pass-- > 0)
{
png_bytepp rp = image; /* points to current row */
png_uint_32 num_rows = png_ptr->height;
/* Loop through image */
while (num_rows-- > 0)
png_write_row(png_ptr, *rp++);
}
}
#if defined(PNG_WRITE_INTERLACING_SUPPORTED) ||\
defined(PNG_WRITE_TRANSFORMS_SUPPORTED)
static void
write_row_buffered(png_structrp png_ptr, png_const_bytep row,
int first_row_in_pass, int last_pass_row, int end_of_image,
void (*copy_fn)(png_const_structrp png_ptr, png_bytep row_buffer,
png_const_bytep row, png_uint_32 x, unsigned int count, unsigned int p),
unsigned int copy_parameter)
{
unsigned int max_pixels = png_max_pixel_block(png_ptr);
const unsigned int pass = png_ptr->pass;
const png_uint_32 width = png_ptr->interlaced == PNG_INTERLACE_NONE ?
png_ptr->width : PNG_PASS_COLS(png_ptr->width, pass);
png_uint_32 x;
unsigned int filters;
png_byte prev_pixels[4*2*2]; /* 2 pixels up to 4 2-byte channels each */
memset(prev_pixels, 0U, sizeof prev_pixels);
for (x = 0U, filters = 0U; x < width; x += max_pixels)
{
int finish = 0;
union
{
PNG_ROW_BUFFER_ALIGN_TYPE force_buffer_alignment;
png_byte buffer[PNG_ROW_BUFFER_SIZE];
} pixel_buffer;
if (max_pixels > width - x)
max_pixels = (unsigned int)/*SAFE*/(width - x);
if (end_of_image && x + max_pixels >= width)
finish = 1;
/* Copy a block of input pixels into the buffer, effecting the interlace
* on the way if required. The argument is the number of pixels in the
* buffer, not the number handled from the input which will be larger in
* the interlaced case.
*/
copy_fn(png_ptr, pixel_buffer.buffer, row, x, max_pixels, copy_parameter);
/* Now pixel_buffer[0..max_pixels-1] contains max_pixels pixels which may
* need to be transformed (the interlace has already been handled).
*/
# ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
if (png_ptr->transform_list != NULL)
{
png_transform_control tc;
/* The initial values are the memory format, this was worked out in
* png_init_row_info below.
*/
memset(&tc, 0, sizeof tc);
tc.png_ptr = png_ptr;
tc.sp = tc.dp = pixel_buffer.buffer;
tc.width = max_pixels; /* width of block that we have */
tc.format = png_ptr->row_format;
tc.range = png_ptr->row_range;
tc.bit_depth = png_ptr->row_bit_depth;
/* tc.init == 0 */
/* tc.caching: not used */
/* tc.palette: not used */
debug(PNG_TC_PIXEL_DEPTH(tc) == png_ptr->row_input_pixel_depth);
/* Run the list. */
png_run_transform_list_backwards(png_ptr, &tc);
/* Make sure the format that resulted is compatible with PNG: */
affirm((tc.format & PNG_BIC_MASK(PNG_FORMAT_FLAG_ALPHA +
PNG_FORMAT_FLAG_COLOR + PNG_FORMAT_FLAG_LINEAR +
PNG_FORMAT_FLAG_COLORMAP)) == 0);
/* Now we must have the PNG format from the IHDR: */
affirm(png_ptr->bit_depth == tc.bit_depth &&
png_ptr->color_type == PNG_COLOR_TYPE_FROM_FORMAT(tc.format));
}
# endif /* WRITE_TRANSFORMS */
/* Call png_write_filter_row to write this block of data, the test on
* maxpixels says if this is the final block in the row, 'filters' is
* initialized when 0 is 0 then preserved here for later blocks:
*/
filters = png_write_filter_row(png_ptr, prev_pixels, pixel_buffer.buffer,
x, max_pixels, first_row_in_pass, last_pass_row, filters, finish);
}
}
#endif /* WRITE { INTERLACING || TRANSFORMS } */
#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
static void
copy_row(png_const_structrp png_ptr, png_bytep row_buffer,
png_const_bytep row, png_uint_32 x, unsigned int count,
unsigned int pixel_depth)
{
/* Copy row[x..x+count] pixels to row_buffer. */
png_copy_row(png_ptr, row_buffer, row, x, count, pixel_depth, 1/*clear*/);
}
#endif /* WRITE_TRANSFORMS */
#ifdef PNG_WRITE_INTERLACING_SUPPORTED
static void
interlace_row_lbd(png_const_structrp png_ptr, png_bytep dp, png_const_bytep sp,
png_uint_32 x, unsigned int count, const unsigned int B)
{
/* Pick out the correct pixels for the interlace pass. The basic idea here
* is to go through the row with a source pointer and a destination pointer
* (sp and dp), and copy the correct pixels for the pass. As the row gets
* compacted, sp will always be >= dp, so we should never overwrite anything.
* See the default: case for the easiest code to understand.
*/
const unsigned int pass = png_ptr->pass;
png_uint_32 i = PNG_COL_FROM_PASS_COL(x, pass);
const unsigned int inc = PNG_PASS_COL_OFFSET(pass);
/* For pixels less than one byte wide the correct pixels have to be
* extracted from the input bytes. Because we are reading data in
* the application memory format we cannot rely on the PNG big
* endian order. Notice that this was apparently broken before
* 1.7.0.
*
* In libpng 1.7.0 libpng uses a classic bit-pump to optimize the
* extraction. In all passes before the last (6/7) no two pixels
* are adjacent in the input, so we are always extracting 1 bit.
* At present the code uses an 8-bit buffer to avoid coding for
* different byte sexes, but this could easily be changed.
*
* 'i' is the bit-index of bit in the input (sp[]), so,
* considering the 1-bit per pixel case, sp[i>>3] is the byte
* and the bit is bit (i&7) (0 lowest) on swapped (little endian)
* data or 7-(i&7) on PNG default (big-endian) data.
*
* Define these macros, where:
*
* B: the log2 bit depth (0, 1, 2 for 1bpp, 2bpp or 4bpp) of
* the data; this should be a constant.
* sp: the source pointer (sp) (a png_const_bytep)
* i: the pixel index in the input (png_uint_32)
* j: the bit index in the output (unsigned int)
*
* Unlike 'i', 'j' is interpreted directly; for LSB bytes it counts
* up, for MSB it counts down.
*
* NOTE: this could all be expanded to eliminate the code below by
* the time honoured copy'n'paste into three separate functions. This
* might be worth doing in the future.
*/
# define PIXEL_MASK ((1U << (1<<B))-1U)
# define BIT_MASK ((1U << (3-(B)))-1U) /* within a byte */
# define SP_BYTE (sp[i>>(3-(B))]) /* byte to use */
# define SP_OFFSET_LSB ((BIT_MASK & i) << (B))
# define SP_OFFSET_MSB ((BIT_MASK & ~i) << (B))
# define SP_PIXEL(sex) ((SP_BYTE >> SP_OFFSET_ ## sex) & PIXEL_MASK)
{
unsigned int j;
unsigned int d;
/* The data is always in the PNG, big-endian, format: */
for (j = 8U, d = 0U; count > 0U; --count, i += inc)
{ /* big-endian */
j -= 1U<<B;
d |= SP_PIXEL(MSB) << j;
if (j == 0U) *dp++ = png_check_byte(png_ptr, d), j = 8U, d = 0U;
}
/* The end condition: if j is not 0 the last byte was not
* written:
*/
if (j != 0U) *dp = png_check_byte(png_ptr, d);
}
# undef PIXEL_MASK
# undef BIT_MASK
# undef SP_BYTE
# undef SP_OFFSET_MSB
# undef SP_OFFSET_LSB
# undef SP_PIXEL
}
static void
interlace_row_byte(png_const_structrp png_ptr, png_bytep dp, png_const_bytep sp,
png_uint_32 x, unsigned int count, unsigned int cbytes)
{
const unsigned int pass = png_ptr->pass;
const unsigned int inc = PNG_PASS_COL_OFFSET(pass);
/* Loop through the input copying each pixel to the correct place
* in the output. Note that the loop may be executed 0 times if
* this is called on a narrow image that does not contain this
* pass.
*/
for (sp += PNG_COL_FROM_PASS_COL(x, pass) * cbytes; count > 0;
--count, sp += inc * cbytes, dp += cbytes)
memcpy(dp, sp, cbytes);
}
#endif /* WRITE_INTERLACING */
static void
write_row_unbuffered(png_structrp png_ptr, png_const_bytep row,
int first_row_in_pass, int last_pass_row, int end_of_image)
{
/* Split the row into blocks of the appropriate size: */
const unsigned int input_depth = png_ptr->row_input_pixel_depth;
unsigned int max_pixels = png_max_pixel_block(png_ptr);
png_uint_32 max_bytes = max_pixels;
const unsigned int pass = png_ptr->pass;
const png_uint_32 width = png_ptr->interlaced == PNG_INTERLACE_NONE ?
png_ptr->width : PNG_PASS_COLS(png_ptr->width, pass);
png_uint_32 x;
unsigned int filters;
png_byte prev_pixels[4*2*2]; /* 2 pixels up to 4 2-byte channels each */
/* max_pixels is at most 16 bits, input_depth is at most 64, so the product
* always fits in 32 bits:
*/
max_bytes *= input_depth; /* bits */
debug(input_depth <= 64 && (max_bytes & 7U) == 0U);
max_bytes >>= 3;
memset(prev_pixels, 0U, sizeof prev_pixels);
for (x = 0U, filters = 0U; x < width; x += max_pixels, row += max_bytes)
{
int finish = 0;
if (max_pixels > width - x)
{
max_bytes = width - x;
max_pixels = (unsigned int)/*SAFE*/max_bytes;
max_bytes = (max_bytes * input_depth + 7U) >> 3;
}
if (end_of_image && x + max_pixels >= width)
finish = 1;
filters = png_write_filter_row(png_ptr, prev_pixels, row, x, max_pixels,
first_row_in_pass, last_pass_row, filters, finish);
}
}
static void
write_row_core(png_structrp png_ptr, png_const_bytep row,
int first_row_in_pass, int last_pass_row, int end_of_image)
{
# ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
if (png_ptr->transform_list != NULL)
write_row_buffered(png_ptr, row, first_row_in_pass, last_pass_row,
end_of_image, copy_row, png_ptr->row_input_pixel_depth);
else
# endif /* WRITE_TRANSFORMS */
/* If control reaches this point the intermediate buffer is not required and
* the input data can be used unmodified.
*/
write_row_unbuffered(png_ptr, row, first_row_in_pass, last_pass_row,
end_of_image);
}
/* Write a single non-interlaced row. */
static void
write_row_non_interlaced(png_structrp png_ptr, png_const_bytep row)
{
const png_uint_32 row_number = png_ptr->row_number+1U;
const int last_pass_row = row_number == png_ptr->height;
write_row_core(png_ptr, row, row_number == 1U, last_pass_row,
last_pass_row);
if (!last_pass_row)
png_ptr->row_number = row_number;
else
{
png_ptr->row_number = 0U;
png_ptr->pass = 7U;
}
}
/* Write a single interlaced row. */
static void
write_row_interlaced(png_structrp png_ptr, png_const_bytep row)
{
/* row_number is the row in the pass. The app must only call png_write_row
* the correct number of times. 'pass' is set to 7U at the end.
*/
const png_uint_32 row_number = png_ptr->row_number+1U;
unsigned int pass = png_ptr->pass;
const int last_pass_row = row_number == PNG_PASS_ROWS(png_ptr->height, pass);
write_row_core(png_ptr, row, row_number == 1U, last_pass_row,
last_pass_row && pass == PNG_LAST_PASS(png_ptr->width, png_ptr->height));
if (!last_pass_row)
png_ptr->row_number = row_number;
else
{
png_ptr->row_number = 0U;
do
++pass;
while (pass < 7U &&
!PNG_PASS_IN_IMAGE(png_ptr->width, png_ptr->height, pass));
png_ptr->pass = 0x7U & pass;
}
}
#ifdef PNG_WRITE_INTERLACING_SUPPORTED
/* Interlace a row then write it out. */
static int
interlace_row(png_structrp png_ptr, png_const_bytep row)
{
/* row_number is in the image, it may not be in the pass and, likewise, the
* pass may not exist.
*/
const png_uint_32 row_number = png_ptr->row_number; /* in image */
const unsigned int pass = png_ptr->pass;
const int write_row = png_ptr->width > PNG_PASS_START_COL(pass) &&
PNG_ROW_IN_INTERLACE_PASS(row_number, pass);
if (write_row)
{
const int last_pass_row =
PNG_LAST_PASS_ROW(row_number, pass, png_ptr->height);
if (pass < 6)
{
/* Libpng is doing the interlacing and pixels need to be selected
* from the input row for this pass.
*/
/* row interlacing uses either the log bit depth for low bit
* depth input or the byte count for 8bpp or bigger pixels.
*/
const unsigned int input_depth = png_ptr->row_input_pixel_depth;
unsigned int B = 0; /* log2(input_depth) */
const int end_of_image = last_pass_row &&
pass == PNG_LAST_PASS(png_ptr->width, png_ptr->height);
switch (input_depth)
{
case 4U: /* B will be 2 */
++B;
/*FALL THROUGH*/
case 2U: /* B will be 1 */
++B;
/*FALL THROUGH*/
case 1U: /* B will be 0 */
write_row_buffered(png_ptr, row,
row_number == PNG_PASS_START_ROW(pass), last_pass_row,
end_of_image, interlace_row_lbd, B);
break;
default: /* Parameter is the pixel size in bytes */
write_row_buffered(png_ptr, row,
row_number == PNG_PASS_START_ROW(pass), last_pass_row,
end_of_image, interlace_row_byte, input_depth >> 3);
break;
}
}
else /* pass 6; no interlacing required */
write_row_core(png_ptr, row, row_number == 1U, last_pass_row,
last_pass_row);
}
if (row_number+1U < png_ptr->height)
png_ptr->row_number = row_number+1U;
else
{
png_ptr->row_number = 0U;
png_ptr->pass = 0x7U & (pass+1U);
}
return write_row;
}
#endif /* WRITE_INTERLACING */
/* Called by user to write a row of image data */
void PNGAPI
png_write_row(png_structrp png_ptr, png_const_bytep row)
{
if (png_ptr != NULL)
{
const unsigned int pass = png_ptr->pass;
const png_uint_32 row_number = png_ptr->row_number;
/* Unlike the read code initialization happens automatically: */
if (row_number == 0 && pass == 0)
{
png_init_row_info(png_ptr); /* doesn't change row/pass/width */
# ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
/* If the app takes a png_info from a read operation and if the app
* has performed transforms on the data the png_info can contain
* IHDR information that cannot be represented in PNG. The code
* that writes the IHDR takes the color type from the
* png_info::format. The app adds transforms, before or after
* writing the IHDR, then the IHDR color_type stored in
* png_struct::color_type is used in png_init_row_info above to work
* out the actual row format.
*
* Prior to 1.7.0 this was not verified (there was no easy way to do
* so). Now we can check it here, however this is an:
*
* API CHANGE: in 1.7.0 an error may be flagged against bogus
* info_struct formats even though the app had removed them itself.
* It's just a warning at present.
*
* The test is that either the row_format produced by the write
* transforms exactly matches that in the original
* info_struct::format or that the info_struct::format was a simple
* mapping of the color_type that ended up in the IHDR:
*/
if (png_ptr->row_format != png_ptr->info_format &&
PNG_FORMAT_FROM_COLOR_TYPE(png_ptr->color_type) !=
png_ptr->info_format)
png_app_warning(png_ptr,
"info_struct format does not match IHDR");
# endif /* WRITE_TRANSFORMS */
}
else if (pass == 7U) /* too many calls; write already ended */
{
debug(png_ptr->row_number == 0U);
png_app_error(png_ptr, "Too many calls to png_write_row");
return;
}
/* Make sure there is a row to write: */
if (row == NULL)
{
png_app_error(png_ptr, "NULL row pointer to png_write_row");
return;
}
if (png_ptr->interlaced == PNG_INTERLACE_NONE)
write_row_non_interlaced(png_ptr, row);
# ifdef PNG_WRITE_INTERLACING_SUPPORTED
/* Optional: libpng does the interlacing, app passes every row of the
* image the required number of times.
*/
else if (png_ptr->do_interlace != 0U)
{
if (!interlace_row(png_ptr, row))
return; /* row skipped; skip the write callback */
}
# endif
else /* app does the interlacing */
write_row_interlaced(png_ptr, row);
/* API CHANGE: 1.7.0: this is now called after png_struct::row_number and
* png_struct::pass have been updated and, at the end of the image, after
* the deflate stream has been closed. The order of the call with respect
* to the flush operation has also changed. The callback can't discover
* any of this unless it relies on the write callbacks to find the row
* data, and that was never predictable.
*/
if (png_ptr->write_row_fn != NULL)
(*(png_ptr->write_row_fn))(png_ptr, row_number, pass);
} /* png_ptr != NULL */
}
/* Free any memory used in png_ptr struct without freeing the struct itself. */
static void
png_write_destroy(png_structrp png_ptr)
{
png_debug(1, "in png_write_destroy");
/* Free any memory zlib uses */
if (png_ptr->zstream.state != NULL)
{
int ret = deflateEnd(&png_ptr->zstream);
if (ret != Z_OK)
{
png_zstream_error(&png_ptr->zstream, ret);
png_warning(png_ptr, png_ptr->zstream.msg);
}
}
/* Free our memory. png_free checks NULL for us. */
png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
#ifdef PNG_WRITE_FILTER_SUPPORTED
png_free(png_ptr, png_ptr->row_buffer);
png_ptr->row_buffer = NULL;
#endif /* WRITE_FILTER */
#ifdef PNG_TRANSFORM_MECH_SUPPORTED
png_transform_free(png_ptr, &png_ptr->transform_list);
#endif
#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
png_free(png_ptr, png_ptr->chunk_list);
png_ptr->chunk_list = NULL;
#endif
/* The error handling and memory handling information is left intact at this
* point: the jmp_buf may still have to be freed. See png_destroy_png_struct
* for how this happens.
*/
}
/* Free all memory used by the write.
* In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
* *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
* the passed in info_structs but it would quietly fail to free any of the data
* inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
* has no png_ptr.)
*/
void PNGAPI
png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
{
png_debug(1, "in png_destroy_write_struct");
if (png_ptr_ptr != NULL)
{
png_structrp png_ptr = *png_ptr_ptr;
if (png_ptr != NULL) /* added in libpng 1.6.0 */
{
png_destroy_info_struct(png_ptr, info_ptr_ptr);
*png_ptr_ptr = NULL;
png_write_destroy(png_ptr);
png_destroy_png_struct(png_ptr);
}
}
}
void PNGAPI
png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn)
{
if (png_ptr == NULL)
return;
png_ptr->write_row_fn = write_row_fn;
}
#ifdef PNG_WRITE_PNG_SUPPORTED
void PNGAPI
png_write_png(png_structrp png_ptr, png_inforp info_ptr,
int transforms, voidp params)
{
if (png_ptr == NULL || info_ptr == NULL)
return;
if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
{
png_app_error(png_ptr, "no rows for png_write_image to write");
return;
}
/* Write the file header information. */
png_write_info(png_ptr, info_ptr);
/* ------ these transformations don't touch the info structure ------- */
/* Invert monochrome pixels */
if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
#ifdef PNG_WRITE_INVERT_SUPPORTED
png_set_invert_mono(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
#endif
/* Shift the pixels up to a legal bit depth and fill in
* as appropriate to correctly scale the image.
*/
if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
#ifdef PNG_WRITE_SHIFT_SUPPORTED
if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
png_set_shift(png_ptr, &info_ptr->sig_bit);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
#endif
/* Pack pixels into bytes */
if ((transforms & PNG_TRANSFORM_PACKING) != 0)
#ifdef PNG_WRITE_PACK_SUPPORTED
png_set_packing(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
#endif
/* Swap location of alpha bytes from ARGB to RGBA */
if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
png_set_swap_alpha(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
#endif
/* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
* RGB, note that the code expects the input color type to be G or RGB; no
* alpha channel.
*/
if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
{
#ifdef PNG_WRITE_FILLER_SUPPORTED
if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
{
if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
png_app_error(png_ptr,
"PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
/* Continue if ignored - this is the pre-1.6.10 behavior */
png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
}
else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
#endif
}
/* Flip BGR pixels to RGB */
if ((transforms & PNG_TRANSFORM_BGR) != 0)
#ifdef PNG_WRITE_BGR_SUPPORTED
png_set_bgr(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
#endif
/* Swap bytes of 16-bit files to most significant byte first */
if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
#ifdef PNG_WRITE_SWAP_SUPPORTED
png_set_swap(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
#endif
/* Swap bits of 1, 2, 4 bit packed pixel formats */
if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
png_set_packswap(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
#endif
/* Invert the alpha channel from opacity to transparency */
if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
png_set_invert_alpha(png_ptr);
#else
png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
#endif
/* ----------------------- end of transformations ------------------- */
/* Write the bits */
png_write_image(png_ptr, info_ptr->row_pointers);
/* It is REQUIRED to call this to finish writing the rest of the file */
png_write_end(png_ptr, info_ptr);
PNG_UNUSED(params)
}
#endif /* WRITE_PNG */
#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
#ifdef PNG_STDIO_SUPPORTED /* currently required for png_image_write_* */
/* Initialize the write structure - general purpose utility. */
static int
png_image_write_init(png_imagep image)
{
png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
png_safe_error, png_safe_warning);
if (png_ptr != NULL)
{
png_infop info_ptr = png_create_info_struct(png_ptr);
if (info_ptr != NULL)
{
png_controlp control = png_voidcast(png_controlp,
png_malloc_warn(png_ptr, (sizeof *control)));
if (control != NULL)
{
memset(control, 0, (sizeof *control));
control->png_ptr = png_ptr;
control->info_ptr = info_ptr;
control->for_write = 1;
image->opaque = control;
return 1;
}
/* Error clean up */
png_destroy_info_struct(png_ptr, &info_ptr);
}
png_destroy_write_struct(&png_ptr, NULL);
}
return png_image_error(image, "png_image_write_: out of memory");
}
/* Arguments to png_image_write_main: */
typedef struct
{
/* Arguments: */
png_imagep image;
png_const_voidp buffer;
png_int_32 row_stride;
png_const_voidp colormap;
int convert_to_8bit;
/* Local variables: */
png_const_voidp first_row;
ptrdiff_t row_bytes;
png_voidp local_row;
} png_image_write_control;
/* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
* do any necessary byte swapping. The component order is defined by the
* png_image format value.
*/
static int
png_write_image_16bit(png_voidp argument)
{
png_image_write_control *display = png_voidcast(png_image_write_control*,
argument);
png_imagep image = display->image;
png_structrp png_ptr = image->opaque->png_ptr;
png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
display->first_row);
png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
png_uint_16p row_end;
const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
int aindex = 0;
png_uint_32 y = image->height;
if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
{
# ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
{
aindex = -1;
++input_row; /* To point to the first component */
++output_row;
}
else
# endif
aindex = channels;
}
else
png_error(png_ptr, "png_write_image: internal call error");
/* Work out the output row end and count over this, note that the increment
* above to 'row' means that row_end can actually be beyond the end of the
* row; this is correct.
*/
row_end = output_row + image->width * (channels+1);
while (y-- > 0)
{
png_const_uint_16p in_ptr = input_row;
png_uint_16p out_ptr = output_row;
while (out_ptr < row_end)
{
const png_uint_16 alpha = in_ptr[aindex];
png_uint_32 reciprocal = 0;
int c;
out_ptr[aindex] = alpha;
/* Calculate a reciprocal. The correct calculation is simply
* component/alpha*65535 << 15. (I.e. 15 bits of precision); this
* allows correct rounding by adding .5 before the shift. 'reciprocal'
* is only initialized when required.
*/
if (alpha > 0 && alpha < 65535)
reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;
c = channels;
do /* always at least one channel */
{
png_uint_16 component = *in_ptr++;
/* The following gives 65535 for an alpha of 0, which is fine,
* otherwise if 0/0 is represented as some other value there is more
* likely to be a discontinuity which will probably damage
* compression when moving from a fully transparent area to a
* nearly transparent one. (The assumption here is that opaque
* areas tend not to be 0 intensity.)
*/
if (component >= alpha)
component = 65535;
/* component<alpha, so component/alpha is less than one and
* component*reciprocal is less than 2^31.
*/
else if (component > 0 && alpha < 65535)
{
png_uint_32 calc = component * reciprocal;
calc += 16384; /* round to nearest */
component = png_check_u16(png_ptr, calc >> 15);
}
*out_ptr++ = component;
}
while (--c > 0);
/* Skip to next component (skip the intervening alpha channel) */
++in_ptr;
++out_ptr;
}
png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
input_row += display->row_bytes/(sizeof (png_uint_16));
}
return 1;
}
/* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
* is present it must be removed from the components, the components are then
* written in sRGB encoding. No components are added or removed.
*
* Calculate an alpha reciprocal to reverse pre-multiplication. As above the
* calculation can be done to 15 bits of accuracy; however, the output needs to
* be scaled in the range 0..255*65535, so include that scaling here.
*/
#define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+(alpha>>1))/alpha)
static png_byte
png_unpremultiply(png_const_structrp png_ptr, png_uint_32 component,
png_uint_32 alpha, png_uint_32 reciprocal/*from the above macro*/)
{
/* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
* is represented as some other value there is more likely to be a
* discontinuity which will probably damage compression when moving from a
* fully transparent area to a nearly transparent one. (The assumption here
* is that opaque areas tend not to be 0 intensity.)
*
* There is a rounding problem here; if alpha is less than 128 it will end up
* as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
* output change for this too.
*/
if (component >= alpha || alpha < 128)
return 255;
/* component<alpha, so component/alpha is less than one and
* component*reciprocal is less than 2^31.
*/
else if (component > 0)
{
/* The test is that alpha/257 (rounded) is less than 255, the first value
* that becomes 255 is 65407.
* NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
* be exact!) [Could also test reciprocal != 0]
*/
if (alpha < 65407)
{
component *= reciprocal;
component += 64; /* round to nearest */
component >>= 7;
}
else
component *= 255;
/* Convert the component to sRGB. */
return PNG_sRGB_FROM_LINEAR(png_ptr, component);
}
else
return 0;
PNG_UNUSEDRC(png_ptr)
}
static int
png_write_image_8bit(png_voidp argument)
{
png_image_write_control *display = png_voidcast(png_image_write_control*,
argument);
png_imagep image = display->image;
png_structrp png_ptr = image->opaque->png_ptr;
png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
display->first_row);
png_bytep output_row = png_voidcast(png_bytep, display->local_row);
png_uint_32 y = image->height;
const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
{
png_bytep row_end;
int aindex;
# ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
{
aindex = -1;
++input_row; /* To point to the first component */
++output_row;
}
else
# endif
aindex = channels;
/* Use row_end in place of a loop counter: */
row_end = output_row + image->width * (channels+1);
while (y-- > 0)
{
png_const_uint_16p in_ptr = input_row;
png_bytep out_ptr = output_row;
while (out_ptr < row_end)
{
png_uint_16 alpha = in_ptr[aindex];
png_byte alphabyte = png_check_byte(png_ptr, PNG_DIV257(alpha));
png_uint_32 reciprocal = 0;
int c;
/* Scale and write the alpha channel. */
out_ptr[aindex] = alphabyte;
if (alphabyte > 0 && alphabyte < 255)
reciprocal = UNP_RECIPROCAL(alpha);
c = channels;
do /* always at least one channel */
*out_ptr++ = png_unpremultiply(png_ptr, *in_ptr++, alpha,
reciprocal);
while (--c > 0);
/* Skip to next component (skip the intervening alpha channel) */
++in_ptr;
++out_ptr;
} /* while out_ptr < row_end */
png_write_row(png_ptr, png_voidcast(png_const_bytep,
display->local_row));
input_row += display->row_bytes/(sizeof (png_uint_16));
} /* while y */
}
else
{
/* No alpha channel, so the row_end really is the end of the row and it
* is sufficient to loop over the components one by one.
*/
png_bytep row_end = output_row + image->width * channels;
while (y-- > 0)
{
png_const_uint_16p in_ptr = input_row;
png_bytep out_ptr = output_row;
while (out_ptr < row_end)
{
png_uint_32 component = *in_ptr++;
component *= 255;
*out_ptr++ = PNG_sRGB_FROM_LINEAR(png_ptr, component);
}
png_write_row(png_ptr, output_row);
input_row += display->row_bytes/(sizeof (png_uint_16));
}
}
return 1;
}
static void
png_image_set_PLTE(png_image_write_control *display)
{
const png_imagep image = display->image;
const void *cmap = display->colormap;
const int entries = image->colormap_entries > 256 ? 256 :
(int)image->colormap_entries;
/* NOTE: the caller must check for cmap != NULL and entries != 0 */
const png_uint_32 format = image->format;
const int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
# if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
const int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
(format & PNG_FORMAT_FLAG_ALPHA) != 0;
# else
# define afirst 0
# endif
# ifdef PNG_FORMAT_BGR_SUPPORTED
const int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
# else
# define bgr 0
# endif
int i, num_trans;
png_color palette[256];
png_byte tRNS[256];
memset(tRNS, 255, (sizeof tRNS));
memset(palette, 0, (sizeof palette));
for (i=num_trans=0; i<entries; ++i)
{
/* This gets automatically converted to sRGB with reversal of the
* pre-multiplication if the color-map has an alpha channel.
*/
if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
{
png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);
entry += i * channels;
if ((channels & 1) != 0) /* no alpha */
{
if (channels >= 3) /* RGB */
{
palette[i].blue = PNG_sRGB_FROM_LINEAR(
display->image->opaque->png_ptr, 255 * entry[(2 ^ bgr)]);
palette[i].green = PNG_sRGB_FROM_LINEAR(
display->image->opaque->png_ptr, 255 * entry[1]);
palette[i].red = PNG_sRGB_FROM_LINEAR(
display->image->opaque->png_ptr, 255 * entry[bgr]);
}
else /* Gray */
palette[i].blue = palette[i].red = palette[i].green =
PNG_sRGB_FROM_LINEAR(display->image->opaque->png_ptr,
255 * *entry);
}
else /* alpha */
{
png_uint_16 alpha = entry[afirst ? 0 : channels-1];
png_byte alphabyte = png_check_byte(
display->image->opaque->png_ptr, PNG_DIV257(alpha));
png_uint_32 reciprocal = 0;
/* Calculate a reciprocal, as in the png_write_image_8bit code above
* this is designed to produce a value scaled to 255*65535 when
* divided by 128 (i.e. asr 7).
*/
if (alphabyte > 0 && alphabyte < 255)
reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha;
tRNS[i] = alphabyte;
if (alphabyte < 255)
num_trans = i+1;
if (channels >= 3) /* RGB */
{
palette[i].blue = png_unpremultiply(
display->image->opaque->png_ptr, entry[afirst + (2 ^ bgr)],
alpha, reciprocal);
palette[i].green = png_unpremultiply(
display->image->opaque->png_ptr, entry[afirst + 1], alpha,
reciprocal);
palette[i].red = png_unpremultiply(
display->image->opaque->png_ptr, entry[afirst + bgr], alpha,
reciprocal);
}
else /* gray */
palette[i].blue = palette[i].red = palette[i].green =
png_unpremultiply(display->image->opaque->png_ptr,
entry[afirst], alpha, reciprocal);
}
}
else /* Color-map has sRGB values */
{
png_const_bytep entry = png_voidcast(png_const_bytep, cmap);
entry += i * channels;
switch (channels)
{
case 4:
tRNS[i] = entry[afirst ? 0 : 3];
if (tRNS[i] < 255)
num_trans = i+1;
/* FALL THROUGH */
case 3:
palette[i].blue = entry[afirst + (2 ^ bgr)];
palette[i].green = entry[afirst + 1];
palette[i].red = entry[afirst + bgr];
break;
case 2:
tRNS[i] = entry[1 ^ afirst];
if (tRNS[i] < 255)
num_trans = i+1;
/* FALL THROUGH */
case 1:
palette[i].blue = palette[i].red = palette[i].green =
entry[afirst];
break;
default:
break;
}
}
}
# ifdef afirst
# undef afirst
# endif
# ifdef bgr
# undef bgr
# endif
png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
entries);
if (num_trans > 0)
png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
num_trans, NULL);
image->colormap_entries = entries;
}
static int
png_image_write_main(png_voidp argument)
{
png_image_write_control *display = png_voidcast(png_image_write_control*,
argument);
png_imagep image = display->image;
png_structrp png_ptr = image->opaque->png_ptr;
png_inforp info_ptr = image->opaque->info_ptr;
png_uint_32 format = image->format;
/* The following four ints are actually booleans */
int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
int write_16bit = linear && !colormap && (display->convert_to_8bit == 0);
# ifdef PNG_BENIGN_ERRORS_SUPPORTED
/* Make sure we error out on any bad situation */
png_set_benign_errors(png_ptr, 0/*error*/);
# endif
/* Default the 'row_stride' parameter if required. */
if (display->row_stride == 0)
display->row_stride = PNG_IMAGE_ROW_STRIDE(*image);
/* Set the required transforms then write the rows in the correct order. */
if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
{
if (display->colormap != NULL && image->colormap_entries > 0)
{
png_uint_32 entries = image->colormap_entries;
png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)),
PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
png_image_set_PLTE(display);
}
else
png_error(image->opaque->png_ptr,
"no color-map for color-mapped image");
}
else
png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
write_16bit ? 16 : 8,
((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) +
((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0),
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
/* Counter-intuitively the data transformations must be called *after*
* png_write_info, not before as in the read code, but the 'set' functions
* must still be called before. Just set the color space information, never
* write an interlaced image.
*/
if (write_16bit != 0)
{
/* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);
if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
png_set_cHRM_fixed(png_ptr, info_ptr,
/* color x y */
/* white */ 31270, 32900,
/* red */ 64000, 33000,
/* green */ 30000, 60000,
/* blue */ 15000, 6000
);
}
else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
/* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
* space must still be gamma encoded.
*/
else
png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
/* Write the file header. */
png_write_info(png_ptr, info_ptr);
/* Now set up the data transformations (*after* the header is written),
* remove the handled transformations from the 'format' flags for checking.
*
* First check for a little endian system if writing 16 bit files.
*/
if (write_16bit != 0)
{
PNG_CONST png_uint_16 le = 0x0001;
if ((*(png_const_bytep) & le) != 0)
png_set_swap(png_ptr);
}
# ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
if ((format & PNG_FORMAT_FLAG_BGR) != 0)
{
if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
png_set_bgr(png_ptr);
format &= PNG_BIC_MASK(PNG_FORMAT_FLAG_BGR);
}
# endif
# ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
{
if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
png_set_swap_alpha(png_ptr);
format &= PNG_BIC_MASK(PNG_FORMAT_FLAG_AFIRST);
}
# endif
/* If there are 16 or fewer color-map entries we wrote a lower bit depth
* above, but the application data is still byte packed.
*/
if (colormap != 0 && image->colormap_entries <= 16)
png_set_packing(png_ptr);
/* That should have handled all (both) the transforms. */
if ((format & PNG_BIC_MASK(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR |
PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0)
png_error(png_ptr, "png_write_image: unsupported transformation");
{
png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
ptrdiff_t row_bytes = display->row_stride;
if (linear != 0)
row_bytes *= (sizeof (png_uint_16));
if (row_bytes < 0)
row += (image->height-1) * (-row_bytes);
display->first_row = row;
display->row_bytes = row_bytes;
}
/* Apply 'fast' options if the flag is set. */
if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0)
{
# ifdef PNG_WRITE_FILTER_SUPPORTED
png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
# endif /* WRITE_FILTER */
/* NOTE: determined by experiment using pngstest, this reflects some
* balance between the time to write the image once and the time to read
* it about 50 times. The speed-up in pngstest was about 10-20% of the
* total (user) time on a heavily loaded system.
*/
# ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
png_set_compression_level(png_ptr, 3);
# endif /* WRITE_CUSTOMIZE_COMPRESSION */
}
/* Check for the cases that currently require a pre-transform on the row
* before it is written. This only applies when the input is 16-bit and
* either there is an alpha channel or it is converted to 8-bit.
*/
if ((linear != 0 && alpha != 0 ) ||
(colormap == 0 && display->convert_to_8bit != 0))
{
png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
png_get_rowbytes(png_ptr, info_ptr)));
int result;
display->local_row = row;
if (write_16bit != 0)
result = png_safe_execute(image, png_write_image_16bit, display);
else
result = png_safe_execute(image, png_write_image_8bit, display);
display->local_row = NULL;
png_free(png_ptr, row);
/* Skip the 'write_end' on error: */
if (result == 0)
return 0;
}
/* Otherwise this is the case where the input is in a format currently
* supported by the rest of the libpng write code; call it directly.
*/
else
{
png_const_bytep row = png_voidcast(png_const_bytep, display->first_row);
ptrdiff_t row_bytes = display->row_bytes;
png_uint_32 y = image->height;
while (y-- > 0)
{
png_write_row(png_ptr, row);
row += row_bytes;
}
}
png_write_end(png_ptr, info_ptr);
return 1;
}
int PNGAPI
png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
const void *buffer, png_int_32 row_stride, const void *colormap)
{
/* Write the image to the given (FILE*). */
if (image != NULL && image->version == PNG_IMAGE_VERSION)
{
if (file != NULL)
{
if (png_image_write_init(image) != 0 &&
png_image_init_io(image, file) != 0)
{
png_image_write_control display;
int result;
memset(&display, 0, (sizeof display));
display.image = image;
display.buffer = buffer;
display.row_stride = row_stride;
display.colormap = colormap;
display.convert_to_8bit = convert_to_8bit;
result = png_safe_execute(image, png_image_write_main, &display);
png_image_free(image);
return result;
}
else
return 0;
}
else
return png_image_error(image,
"png_image_write_to_stdio: invalid argument");
}
else if (image != NULL)
return png_image_error(image,
"png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
else
return 0;
}
int PNGAPI
png_image_write_to_file(png_imagep image, const char *file_name,
int convert_to_8bit, const void *buffer, png_int_32 row_stride,
const void *colormap)
{
/* Write the image to the named file. */
if (image != NULL && image->version == PNG_IMAGE_VERSION)
{
if (file_name != NULL)
{
FILE *fp = fopen(file_name, "wb");
if (fp != NULL)
{
if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
row_stride, colormap) != 0)
{
int error; /* from fflush/fclose */
/* Make sure the file is flushed correctly. */
if (fflush(fp) == 0 && ferror(fp) == 0)
{
if (fclose(fp) == 0)
return 1;
error = errno; /* from fclose */
}
else
{
error = errno; /* from fflush or ferror */
(void)fclose(fp);
}
(void)remove(file_name);
/* The image has already been cleaned up; this is just used to
* set the error (because the original write succeeded).
*/
return png_image_error(image, strerror(error));
}
else
{
/* Clean up: just the opened file. */
(void)fclose(fp);
(void)remove(file_name);
return 0;
}
}
else
return png_image_error(image, strerror(errno));
}
else
return png_image_error(image,
"png_image_write_to_file: invalid argument");
}
else if (image != NULL)
return png_image_error(image,
"png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
else
return 0;
}
#endif /* STDIO */
#endif /* SIMPLIFIED_WRITE */
#endif /* WRITE */
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