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/* pngwrite.c - general routines to write a png file
libpng 1.0 beta 3 - version 0.89
For conditions of distribution and use, see copyright notice in png.h
Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
May 25, 1996
*/
/* get internal access to png.h */
#define PNG_INTERNAL
#include "png.h"
/* 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 encurage you to supply a PNG_INFO_ flag, and check
info->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
png_write_info(png_structp png_ptr, png_infop info)
{
png_write_sig(png_ptr); /* write PNG signature */
/* write IHDR information. */
png_write_IHDR(png_ptr, info->width, info->height, info->bit_depth,
info->color_type, info->compression_type, info->filter_type,
info->interlace_type);
/* the rest of these check to see if the valid field has the appropriate
flag set, and if it does, writes the chunk. */
#if defined(PNG_WRITE_gAMA_SUPPORTED)
if (info->valid & PNG_INFO_gAMA)
png_write_gAMA(png_ptr, info->gamma);
#endif
#if defined(PNG_WRITE_sBIT_SUPPORTED)
if (info->valid & PNG_INFO_sBIT)
png_write_sBIT(png_ptr, &(info->sig_bit), info->color_type);
#endif
#if defined(PNG_WRITE_cHRM_SUPPORTED)
if (info->valid & PNG_INFO_cHRM)
png_write_cHRM(png_ptr,
info->x_white, info->y_white,
info->x_red, info->y_red,
info->x_green, info->y_green,
info->x_blue, info->y_blue);
#endif
if (info->valid & PNG_INFO_PLTE)
png_write_PLTE(png_ptr, info->palette, info->num_palette);
else if (info->color_type == PNG_COLOR_TYPE_PALETTE)
png_error(png_ptr, "Valid palette required for paletted images\n");
#if defined(PNG_WRITE_tRNS_SUPPORTED)
if (info->valid & PNG_INFO_tRNS)
png_write_tRNS(png_ptr, info->trans, &(info->trans_values),
info->num_trans, info->color_type);
#endif
#if defined(PNG_WRITE_bKGD_SUPPORTED)
if (info->valid & PNG_INFO_bKGD)
png_write_bKGD(png_ptr, &(info->background), info->color_type);
#endif
#if defined(PNG_WRITE_hIST_SUPPORTED)
if (info->valid & PNG_INFO_hIST)
png_write_hIST(png_ptr, info->hist, info->num_palette);
#endif
#if defined(PNG_WRITE_pHYs_SUPPORTED)
if (info->valid & PNG_INFO_pHYs)
png_write_pHYs(png_ptr, info->x_pixels_per_unit,
info->y_pixels_per_unit, info->phys_unit_type);
#endif
#if defined(PNG_WRITE_oFFs_SUPPORTED)
if (info->valid & PNG_INFO_oFFs)
png_write_oFFs(png_ptr, info->x_offset, info->y_offset,
info->offset_unit_type);
#endif
#if defined(PNG_WRITE_tIME_SUPPORTED)
if (info->valid & PNG_INFO_tIME)
{
png_write_tIME(png_ptr, &(info->mod_time));
png_ptr->flags |= PNG_FLAG_WROTE_tIME;
}
#endif
#if defined(PNG_WRITE_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
/* Check to see if we need to write text chunks */
if (info->num_text)
{
int i; /* local counter */
/* loop through the text chunks */
for (i = 0; i < info->num_text; i++)
{
/* if chunk is compressed */
if (info->text[i].compression >= 0)
{
#if defined(PNG_WRITE_zTXt_SUPPORTED)
/* write compressed chunk */
png_write_zTXt(png_ptr, info->text[i].key,
info->text[i].text, info->text[i].text_length,
info->text[i].compression);
#else
png_warning(png_ptr, "Unable to write compressed text\n");
#endif
}
else
{
#if defined(PNG_WRITE_tEXt_SUPPORTED)
/* write uncompressed chunk */
png_write_tEXt(png_ptr, info->text[i].key,
info->text[i].text, info->text[i].text_length);
#else
png_warning(png_ptr, "Unable to write uncompressed text\n");
#endif
}
}
}
#endif
}
/* 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
png_write_end(png_structp png_ptr, png_infop info)
{
if (!(png_ptr->mode & PNG_HAVE_IDAT))
png_error(png_ptr, "No IDATs written into file");
/* see if user wants us to write information chunks */
if (info)
{
#if defined(PNG_WRITE_tIME_SUPPORTED)
/* check to see if user has supplied a time chunk */
if (info->valid & PNG_INFO_tIME &&
!(png_ptr->flags & PNG_FLAG_WROTE_tIME))
png_write_tIME(png_ptr, &(info->mod_time));
#endif
#if defined(PNG_WRITE_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
/* check to see if we need to write comment chunks */
if (info->num_text)
{
int i; /* local index variable */
/* loop through comment chunks */
for (i = 0; i < info->num_text; i++)
{
#if defined(PNG_WRITE_zTXt_SUPPORTED)
/* check to see if comment is to be compressed */
if (info->text[i].compression >= 0)
{
/* write compressed chunk */
png_write_zTXt(png_ptr, info->text[i].key,
info->text[i].text, info->text[i].text_length,
info->text[i].compression);
}
#if defined(PNG_WRITE_tEXt_SUPPORTED)
else
#endif
#endif
#if defined(PNG_WRITE_tEXt_SUPPORTED)
{
/* write uncompressed chunk */
png_write_tEXt(png_ptr, info->text[i].key,
info->text[i].text, info->text[i].text_length);
}
#endif
}
}
#endif
}
png_ptr->mode |= PNG_AFTER_IDAT;
/* write end of png file */
png_write_IEND(png_ptr);
}
#if defined(PNG_WRITE_tIME_SUPPORTED)
void
png_convert_from_struct_tm(png_timep ptime, struct tm FAR * ttime)
{
ptime->year = (png_uint_16)(1900 + ttime->tm_year);
ptime->month = (png_byte)(ttime->tm_mon + 1);
ptime->day = (png_byte)ttime->tm_mday;
ptime->hour = (png_byte)ttime->tm_hour;
ptime->minute = (png_byte)ttime->tm_min;
ptime->second = (png_byte)ttime->tm_sec;
}
void
png_convert_from_time_t(png_timep ptime, time_t ttime)
{
struct tm *tbuf;
tbuf = gmtime(&ttime);
png_convert_from_struct_tm(ptime, tbuf);
}
#endif
/* initialize png structure, and allocate any memory needed */
png_structp
png_create_write_struct(png_const_charp user_png_ver, voidp error_ptr,
png_error_ptr warn_fn, png_error_ptr error_fn)
{
png_structp png_ptr;
if ((png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG)) == NULL)
{
return (png_structp)NULL;
}
if (setjmp(png_ptr->jmpbuf))
{
png_large_free(png_ptr, png_ptr->zbuf);
png_free(png_ptr, png_ptr->zstream);
png_destroy_struct(png_ptr);
return (png_structp)NULL;
}
png_set_error_fn(png_ptr, error_ptr, warn_fn, error_fn);
if (user_png_ver == NULL || strcmp(user_png_ver, png_libpng_ver))
{
if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0])
{
png_error(png_ptr, "Incompatible libpng versions");
}
else
{
png_warning(png_ptr, "Different libpng versions");
}
}
/* initialize zbuf - compression buffer */
png_ptr->zbuf_size = PNG_ZBUF_SIZE;
png_ptr->zbuf = png_large_malloc(png_ptr, png_ptr->zbuf_size);
png_set_write_fn(png_ptr, NULL, NULL, NULL);
png_ptr->do_free |= PNG_FREE_STRUCT;
return (png_ptr);
}
/* initialize png structure, and allocate any memory needed */
void
png_write_init(png_structp png_ptr)
{
jmp_buf tmp_jmp; /* to save current jump buffer */
/* save jump buffer and error functions */
png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));
/* reset all variables to 0 */
png_memset(png_ptr, 0, sizeof (png_struct));
/* restore jump buffer */
png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
/* initialize zbuf - compression buffer */
png_ptr->zbuf_size = PNG_ZBUF_SIZE;
png_ptr->zbuf = png_large_malloc(png_ptr, png_ptr->zbuf_size);
png_set_write_fn(png_ptr, NULL, NULL, NULL);
}
/* 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
png_write_rows(png_structp png_ptr, png_bytepp row,
png_uint_32 num_rows)
{
png_uint_32 i; /* row counter */
png_bytepp rp; /* row pointer */
/* loop through the rows */
for (i = 0, rp = row; i < num_rows; i++, rp++)
{
png_write_row(png_ptr, *rp);
}
}
/* write the image. You only need to call this function once, even
if you are writing an interlaced image. */
void
png_write_image(png_structp png_ptr, png_bytepp image)
{
png_uint_32 i; /* row index */
int pass, num_pass; /* pass variables */
png_bytepp rp; /* points to current row */
/* intialize interlace handling. If image is not interlaced,
this will set pass to 1 */
num_pass = png_set_interlace_handling(png_ptr);
/* loop through passes */
for (pass = 0; pass < num_pass; pass++)
{
/* loop through image */
for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
{
png_write_row(png_ptr, *rp);
}
}
}
/* called by user to write a row of image data */
void
png_write_row(png_structp png_ptr, png_bytep row)
{
/* initialize transformations and other stuff if first time */
if (png_ptr->row_number == 0 && png_ptr->pass == 0)
{
png_write_start_row(png_ptr);
}
#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
/* if interlaced and not interested in row, return */
if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
{
switch (png_ptr->pass)
{
case 0:
if (png_ptr->row_number & 7)
{
png_write_finish_row(png_ptr);
return;
}
break;
case 1:
if ((png_ptr->row_number & 7) || png_ptr->width < 5)
{
png_write_finish_row(png_ptr);
return;
}
break;
case 2:
if ((png_ptr->row_number & 7) != 4)
{
png_write_finish_row(png_ptr);
return;
}
break;
case 3:
if ((png_ptr->row_number & 3) || png_ptr->width < 3)
{
png_write_finish_row(png_ptr);
return;
}
break;
case 4:
if ((png_ptr->row_number & 3) != 2)
{
png_write_finish_row(png_ptr);
return;
}
break;
case 5:
if ((png_ptr->row_number & 1) || png_ptr->width < 2)
{
png_write_finish_row(png_ptr);
return;
}
break;
case 6:
if (!(png_ptr->row_number & 1))
{
png_write_finish_row(png_ptr);
return;
}
break;
}
}
#endif
/* set up row info for transformations */
png_ptr->row_info.color_type = png_ptr->color_type;
png_ptr->row_info.width = png_ptr->usr_width;
png_ptr->row_info.channels = png_ptr->usr_channels;
png_ptr->row_info.bit_depth = png_ptr->usr_bit_depth;
png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *
png_ptr->row_info.channels);
png_ptr->row_info.rowbytes = ((png_ptr->row_info.width *
(png_uint_32)png_ptr->row_info.pixel_depth + 7) >> 3);
/* copy users row into buffer, leaving room for filter byte */
png_memcpy(png_ptr->row_buf + 1, row, (png_size_t)png_ptr->row_info.rowbytes);
#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
/* handle interlacing */
if (png_ptr->interlaced && png_ptr->pass < 6 &&
(png_ptr->transformations & PNG_INTERLACE))
{
png_do_write_interlace(&(png_ptr->row_info),
png_ptr->row_buf + 1, png_ptr->pass);
/* this should always get caught above, but still ... */
if (!(png_ptr->row_info.width))
{
png_write_finish_row(png_ptr);
return;
}
}
#endif
/* handle other transformations */
if (png_ptr->transformations)
png_do_write_transformations(png_ptr);
/* find a filter if necessary, filter the row and write it out */
png_write_find_filter(png_ptr, &(png_ptr->row_info));
}
#if defined(PNG_WRITE_FLUSH_SUPPORTED)
/* Set the automatic flush interval or 0 to turn flushing off */
void
png_set_flush(png_structp png_ptr, int nrows)
{
png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);
}
/* flush the current output buffers now */
void
png_write_flush(png_structp png_ptr)
{
int wrote_IDAT;
/* We have already written out all of the data */
if (png_ptr->row_number >= png_ptr->num_rows)
return;
do
{
int ret;
/* compress the data */
ret = deflate(png_ptr->zstream, Z_SYNC_FLUSH);
wrote_IDAT = 0;
/* check for compression errors */
if (ret != Z_OK)
{
if (png_ptr->zstream->msg)
png_error(png_ptr, png_ptr->zstream->msg);
else
png_error(png_ptr, "zlib error");
}
if (!png_ptr->zstream->avail_out)
{
/* write the IDAT and reset the zlib output buffer */
png_write_IDAT(png_ptr, png_ptr->zbuf,
png_ptr->zbuf_size);
png_ptr->zstream->next_out = png_ptr->zbuf;
png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
wrote_IDAT = 1;
}
} while(wrote_IDAT == 1);
/* If there is any data left to be output, write it into a new IDAT */
if (png_ptr->zbuf_size != png_ptr->zstream->avail_out)
{
/* write the IDAT and reset the zlib output buffer */
png_write_IDAT(png_ptr, png_ptr->zbuf,
png_ptr->zbuf_size - png_ptr->zstream->avail_out);
png_ptr->zstream->next_out = png_ptr->zbuf;
png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
}
png_ptr->flush_rows = 0;
png_flush(png_ptr);
}
#endif /* PNG_WRITE_FLUSH_SUPPORTED */
/* free all memory used by the write */
void
png_destroy_write_struct(png_structpp png_ptr, png_infopp info_ptr)
{
if (info_ptr && *info_ptr)
{
png_destroy_struct((voidp)*info_ptr);
*info_ptr = (png_infop)NULL;
}
if (png_ptr && *png_ptr)
{
png_write_destroy(*png_ptr);
png_destroy_struct((voidp)*png_ptr);
*png_ptr = (png_structp)NULL;
}
}
/* free any memory used in png struct (old) */
void
png_write_destroy(png_structp png_ptr)
{
jmp_buf tmp_jmp; /* save jump buffer */
png_error_ptr error_fn;
png_error_ptr warning_fn;
png_voidp error_ptr;
/* free any memory zlib uses */
deflateEnd(png_ptr->zstream);
png_free(png_ptr, png_ptr->zstream);
/* free our memory. png_free checks NULL for us. */
png_large_free(png_ptr, png_ptr->zbuf);
png_large_free(png_ptr, png_ptr->row_buf);
png_large_free(png_ptr, png_ptr->prev_row);
png_large_free(png_ptr, png_ptr->sub_row);
png_large_free(png_ptr, png_ptr->up_row);
png_large_free(png_ptr, png_ptr->avg_row);
png_large_free(png_ptr, png_ptr->paeth_row);
/* reset structure */
png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));
error_fn = png_ptr->error_fn;
warning_fn = png_ptr->warning_fn;
error_ptr = png_ptr->error_ptr;
png_memset(png_ptr, 0, sizeof (png_struct));
png_ptr->error_fn = error_fn;
png_ptr->warning_fn = warning_fn;
png_ptr->error_ptr = error_ptr;
png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
}
/* Allow the application to select one or more filters to use */
void
png_set_filter(png_structp png_ptr, int method, int filters)
{
/* We allow 'method' only for future expansion of the base filter method */
if (method == 0)
{
switch (filters & (PNG_ALL_FILTERS | 0x07))
{
case 5:
case 6:
case 7: png_warning(png_ptr, "Unknown custom row filter for method 0");
case 0: png_ptr->do_filter = PNG_FILTER_NONE; break;
case 1: png_ptr->do_filter = PNG_FILTER_SUB; break;
case 2: png_ptr->do_filter = PNG_FILTER_UP; break;
case 3: png_ptr->do_filter = PNG_FILTER_AVG; break;
case 4: png_ptr->do_filter = PNG_FILTER_PAETH; break;
default: png_ptr->do_filter = (png_byte)filters; break;
}
/* If we have allocated the row_buf, then we should have also allocated
* all of the filter buffers that have been selected.
*/
if (png_ptr->row_buf)
{
if (png_ptr->do_filter & PNG_FILTER_SUB && !(png_ptr->sub_row))
{
png_ptr->sub_row = (png_bytep )png_large_malloc(png_ptr,
png_ptr->rowbytes + 1);
png_ptr->sub_row[0] = 1; /* Set the row filter type */
}
if (png_ptr->do_filter & PNG_FILTER_UP && !(png_ptr->up_row))
{
if (!(png_ptr->prev_row))
{
png_warning(png_ptr, "Can't to add up filter after starting");
png_ptr->do_filter &= ~PNG_FILTER_UP;
}
else
{
png_ptr->up_row = (png_bytep )png_large_malloc(png_ptr,
png_ptr->rowbytes + 1);
png_ptr->up_row[0] = 2; /* Set the row filter type */
}
}
if (png_ptr->do_filter & PNG_FILTER_AVG && !(png_ptr->avg_row))
{
if (!(png_ptr->prev_row))
{
png_warning(png_ptr, "Can't add average filter after starting");
png_ptr->do_filter &= ~PNG_FILTER_AVG;
}
else
{
png_ptr->up_row = (png_bytep )png_large_malloc(png_ptr,
png_ptr->rowbytes + 1);
png_ptr->up_row[0] = 3; /* Set the row filter type */
}
}
if (png_ptr->do_filter & PNG_FILTER_PAETH && !(png_ptr->paeth_row))
{
if (!(png_ptr->prev_row))
{
png_warning(png_ptr, "Can't add Paeth filter after starting");
png_ptr->do_filter &= ~PNG_FILTER_PAETH;
}
else
{
png_ptr->paeth_row = (png_bytep )png_large_malloc(png_ptr,
png_ptr->rowbytes + 1);
png_ptr->paeth_row[0] = 4; /* Set the row filter type */
}
}
if (png_ptr->do_filter == PNG_NO_FILTERS)
png_ptr->do_filter = PNG_FILTER_NONE;
}
}
else
png_error(png_ptr, "Unknown custom filter method");
}
void
png_set_compression_level(png_structp png_ptr, int level)
{
png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_LEVEL;
png_ptr->zlib_level = level;
}
void
png_set_compression_mem_level(png_structp png_ptr, int mem_level)
{
png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL;
png_ptr->zlib_mem_level = mem_level;
}
void
png_set_compression_strategy(png_structp png_ptr, int strategy)
{
png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
png_ptr->zlib_strategy = strategy;
}
void
png_set_compression_window_bits(png_structp png_ptr, int window_bits)
{
if (window_bits > 15)
png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS;
png_ptr->zlib_window_bits = window_bits;
}
void
png_set_compression_method(png_structp png_ptr, int method)
{
if (method != 8)
png_warning(png_ptr, "Only compression method 8 is supported by PNG");
png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_METHOD;
png_ptr->zlib_method = method;
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.