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[devel] Trivial changes to commentary in pngwrite.c

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This commit is contained in:
Glenn Randers-Pehrson 2009-08-22 08:44:23 -05:00
parent ec323d3036
commit 3dfe93776f
1 changed files with 36 additions and 35 deletions
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71
pngwrite.c
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@ -1,7 +1,7 @@
/* pngwrite.c - general routines to write a PNG file /* pngwrite.c - general routines to write a PNG file
* *
* Last changed in libpng 1.4.0 [August 21, 2009] * Last changed in libpng 1.4.0 [August 22, 2009]
* Copyright (c) 1998-2009 Glenn Randers-Pehrson * Copyright (c) 1998-2009 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@ -11,7 +11,7 @@
* and license in png.h * and license in png.h
*/ */
/* get internal access to png.h */ /* Get internal access to png.h */
#include "png.h" #include "png.h"
#ifdef PNG_WRITE_SUPPORTED #ifdef PNG_WRITE_SUPPORTED
#include "pngpriv.h" #include "pngpriv.h"
@ -34,7 +34,8 @@ png_write_info_before_PLTE(png_structp png_ptr, png_infop info_ptr)
return; return;
if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE)) if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
{ {
png_write_sig(png_ptr); /* write PNG signature */ /* Write PNG signature */
png_write_sig(png_ptr);
#if defined(PNG_MNG_FEATURES_SUPPORTED) #if defined(PNG_MNG_FEATURES_SUPPORTED)
if ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)&&(png_ptr->mng_features_permitted)) if ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)&&(png_ptr->mng_features_permitted))
{ {
@ -42,7 +43,7 @@ png_write_info_before_PLTE(png_structp png_ptr, png_infop info_ptr)
png_ptr->mng_features_permitted=0; png_ptr->mng_features_permitted=0;
} }
#endif #endif
/* write IHDR information. */ /* Write IHDR information. */
png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height, png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type, info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
info_ptr->filter_type, info_ptr->filter_type,
@ -152,7 +153,7 @@ png_write_info(png_structp png_ptr, png_infop info_ptr)
if (info_ptr->valid & PNG_INFO_tRNS) if (info_ptr->valid & PNG_INFO_tRNS)
{ {
#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
/* invert the alpha channel (in tRNS) */ /* Invert the alpha channel (in tRNS) */
if ((png_ptr->transformations & PNG_INVERT_ALPHA) && if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{ {
@ -229,11 +230,11 @@ png_write_info(png_structp png_ptr, png_infop info_ptr)
{ {
png_debug2(2, "Writing header text chunk %d, type %d", i, png_debug2(2, "Writing header text chunk %d, type %d", i,
info_ptr->text[i].compression); info_ptr->text[i].compression);
/* an internationalized chunk? */ /* An internationalized chunk? */
if (info_ptr->text[i].compression > 0) if (info_ptr->text[i].compression > 0)
{ {
#if defined(PNG_WRITE_iTXt_SUPPORTED) #if defined(PNG_WRITE_iTXt_SUPPORTED)
/* write international chunk */ /* Write international chunk */
png_write_iTXt(png_ptr, png_write_iTXt(png_ptr,
info_ptr->text[i].compression, info_ptr->text[i].compression,
info_ptr->text[i].key, info_ptr->text[i].key,
@ -250,7 +251,7 @@ png_write_info(png_structp png_ptr, png_infop info_ptr)
else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt) else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
{ {
#if defined(PNG_WRITE_zTXt_SUPPORTED) #if defined(PNG_WRITE_zTXt_SUPPORTED)
/* write compressed chunk */ /* Write compressed chunk */
png_write_zTXt(png_ptr, info_ptr->text[i].key, png_write_zTXt(png_ptr, info_ptr->text[i].key,
info_ptr->text[i].text, 0, info_ptr->text[i].text, 0,
info_ptr->text[i].compression); info_ptr->text[i].compression);
@ -263,7 +264,7 @@ png_write_info(png_structp png_ptr, png_infop info_ptr)
else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE) else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
{ {
#if defined(PNG_WRITE_tEXt_SUPPORTED) #if defined(PNG_WRITE_tEXt_SUPPORTED)
/* write uncompressed chunk */ /* Write uncompressed chunk */
png_write_tEXt(png_ptr, info_ptr->text[i].key, png_write_tEXt(png_ptr, info_ptr->text[i].key,
info_ptr->text[i].text, info_ptr->text[i].text,
0); 0);
@ -317,29 +318,29 @@ png_write_end(png_structp png_ptr, png_infop info_ptr)
if (!(png_ptr->mode & PNG_HAVE_IDAT)) if (!(png_ptr->mode & PNG_HAVE_IDAT))
png_error(png_ptr, "No IDATs written into file"); png_error(png_ptr, "No IDATs written into file");
/* see if user wants us to write information chunks */ /* See if user wants us to write information chunks */
if (info_ptr != NULL) if (info_ptr != NULL)
{ {
#if defined(PNG_WRITE_TEXT_SUPPORTED) #if defined(PNG_WRITE_TEXT_SUPPORTED)
int i; /* local index variable */ int i; /* local index variable */
#endif #endif
#if defined(PNG_WRITE_tIME_SUPPORTED) #if defined(PNG_WRITE_tIME_SUPPORTED)
/* check to see if user has supplied a time chunk */ /* Check to see if user has supplied a time chunk */
if ((info_ptr->valid & PNG_INFO_tIME) && if ((info_ptr->valid & PNG_INFO_tIME) &&
!(png_ptr->mode & PNG_WROTE_tIME)) !(png_ptr->mode & PNG_WROTE_tIME))
png_write_tIME(png_ptr, &(info_ptr->mod_time)); png_write_tIME(png_ptr, &(info_ptr->mod_time));
#endif #endif
#if defined(PNG_WRITE_TEXT_SUPPORTED) #if defined(PNG_WRITE_TEXT_SUPPORTED)
/* loop through comment chunks */ /* Loop through comment chunks */
for (i = 0; i < info_ptr->num_text; i++) for (i = 0; i < info_ptr->num_text; i++)
{ {
png_debug2(2, "Writing trailer text chunk %d, type %d", i, png_debug2(2, "Writing trailer text chunk %d, type %d", i,
info_ptr->text[i].compression); info_ptr->text[i].compression);
/* an internationalized chunk? */ /* An internationalized chunk? */
if (info_ptr->text[i].compression > 0) if (info_ptr->text[i].compression > 0)
{ {
#if defined(PNG_WRITE_iTXt_SUPPORTED) #if defined(PNG_WRITE_iTXt_SUPPORTED)
/* write international chunk */ /* Write international chunk */
png_write_iTXt(png_ptr, png_write_iTXt(png_ptr,
info_ptr->text[i].compression, info_ptr->text[i].compression,
info_ptr->text[i].key, info_ptr->text[i].key,
@ -355,7 +356,7 @@ png_write_end(png_structp png_ptr, png_infop info_ptr)
else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt) else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
{ {
#if defined(PNG_WRITE_zTXt_SUPPORTED) #if defined(PNG_WRITE_zTXt_SUPPORTED)
/* write compressed chunk */ /* Write compressed chunk */
png_write_zTXt(png_ptr, info_ptr->text[i].key, png_write_zTXt(png_ptr, info_ptr->text[i].key,
info_ptr->text[i].text, 0, info_ptr->text[i].text, 0,
info_ptr->text[i].compression); info_ptr->text[i].compression);
@ -368,7 +369,7 @@ png_write_end(png_structp png_ptr, png_infop info_ptr)
else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE) else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
{ {
#if defined(PNG_WRITE_tEXt_SUPPORTED) #if defined(PNG_WRITE_tEXt_SUPPORTED)
/* write uncompressed chunk */ /* Write uncompressed chunk */
png_write_tEXt(png_ptr, info_ptr->text[i].key, png_write_tEXt(png_ptr, info_ptr->text[i].key,
info_ptr->text[i].text, 0); info_ptr->text[i].text, 0);
#else #else
@ -406,7 +407,7 @@ png_write_end(png_structp png_ptr, png_infop info_ptr)
png_ptr->mode |= PNG_AFTER_IDAT; png_ptr->mode |= PNG_AFTER_IDAT;
/* write end of PNG file */ /* Write end of PNG file */
png_write_IEND(png_ptr); png_write_IEND(png_ptr);
/* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03, /* 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 * and restored again in libpng-1.2.30, may cause some applications that
@ -487,7 +488,7 @@ png_create_write_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
if (png_ptr == NULL) if (png_ptr == NULL)
return (NULL); return (NULL);
/* added at libpng-1.2.6 */ /* Added at libpng-1.2.6 */
#ifdef PNG_SET_USER_LIMITS_SUPPORTED #ifdef PNG_SET_USER_LIMITS_SUPPORTED
png_ptr->user_width_max=PNG_USER_WIDTH_MAX; png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
png_ptr->user_height_max=PNG_USER_HEIGHT_MAX; png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
@ -554,7 +555,7 @@ png_create_write_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
} }
} }
/* initialize zbuf - compression buffer */ /* Initialize zbuf - compression buffer */
png_ptr->zbuf_size = PNG_ZBUF_SIZE; png_ptr->zbuf_size = PNG_ZBUF_SIZE;
if (!png_cleanup_needed) if (!png_cleanup_needed)
{ {
@ -605,7 +606,7 @@ png_write_rows(png_structp png_ptr, png_bytepp row,
if (png_ptr == NULL) if (png_ptr == NULL)
return; return;
/* loop through the rows */ /* Loop through the rows */
for (i = 0, rp = row; i < num_rows; i++, rp++) for (i = 0, rp = row; i < num_rows; i++, rp++)
{ {
png_write_row(png_ptr, *rp); png_write_row(png_ptr, *rp);
@ -635,10 +636,10 @@ png_write_image(png_structp png_ptr, png_bytepp image)
#else #else
num_pass = 1; num_pass = 1;
#endif #endif
/* loop through passes */ /* Loop through passes */
for (pass = 0; pass < num_pass; pass++) for (pass = 0; pass < num_pass; pass++)
{ {
/* loop through image */ /* Loop through image */
for (i = 0, rp = image; i < png_ptr->height; i++, rp++) for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
{ {
png_write_row(png_ptr, *rp); png_write_row(png_ptr, *rp);
@ -646,7 +647,7 @@ png_write_image(png_structp png_ptr, png_bytepp image)
} }
} }
/* called by user to write a row of image data */ /* Called by user to write a row of image data */
void PNGAPI void PNGAPI
png_write_row(png_structp png_ptr, png_bytep row) png_write_row(png_structp png_ptr, png_bytep row)
{ {
@ -656,15 +657,15 @@ png_write_row(png_structp png_ptr, png_bytep row)
png_debug2(1, "in png_write_row (row %ld, pass %d)", png_debug2(1, "in png_write_row (row %ld, pass %d)",
png_ptr->row_number, png_ptr->pass); png_ptr->row_number, png_ptr->pass);
/* initialize transformations and other stuff if first time */ /* Initialize transformations and other stuff if first time */
if (png_ptr->row_number == 0 && png_ptr->pass == 0) if (png_ptr->row_number == 0 && png_ptr->pass == 0)
{ {
/* make sure we wrote the header info */ /* Make sure we wrote the header info */
if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE)) if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
png_error(png_ptr, png_error(png_ptr,
"png_write_info was never called before png_write_row"); "png_write_info was never called before png_write_row");
/* check for transforms that have been set but were defined out */ /* Check for transforms that have been set but were defined out */
#if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED) #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
if (png_ptr->transformations & PNG_INVERT_MONO) if (png_ptr->transformations & PNG_INVERT_MONO)
png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined"); png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
@ -698,7 +699,7 @@ png_write_row(png_structp png_ptr, png_bytep row)
} }
#if defined(PNG_WRITE_INTERLACING_SUPPORTED) #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
/* if interlaced and not interested in row, return */ /* If interlaced and not interested in row, return */
if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE)) if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
{ {
switch (png_ptr->pass) switch (png_ptr->pass)
@ -756,7 +757,7 @@ png_write_row(png_structp png_ptr, png_bytep row)
} }
#endif #endif
/* set up row info for transformations */ /* Set up row info for transformations */
png_ptr->row_info.color_type = png_ptr->color_type; png_ptr->row_info.color_type = png_ptr->color_type;
png_ptr->row_info.width = png_ptr->usr_width; png_ptr->row_info.width = png_ptr->usr_width;
png_ptr->row_info.channels = png_ptr->usr_channels; png_ptr->row_info.channels = png_ptr->usr_channels;
@ -834,7 +835,7 @@ png_set_flush(png_structp png_ptr, int nrows)
png_ptr->flush_dist = (nrows < 0 ? 0 : nrows); png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);
} }
/* flush the current output buffers now */ /* Flush the current output buffers now */
void PNGAPI void PNGAPI
png_write_flush(png_structp png_ptr) png_write_flush(png_structp png_ptr)
{ {
@ -852,11 +853,11 @@ png_write_flush(png_structp png_ptr)
{ {
int ret; int ret;
/* compress the data */ /* Compress the data */
ret = deflate(&png_ptr->zstream, Z_SYNC_FLUSH); ret = deflate(&png_ptr->zstream, Z_SYNC_FLUSH);
wrote_IDAT = 0; wrote_IDAT = 0;
/* check for compression errors */ /* Check for compression errors */
if (ret != Z_OK) if (ret != Z_OK)
{ {
if (png_ptr->zstream.msg != NULL) if (png_ptr->zstream.msg != NULL)
@ -867,7 +868,7 @@ png_write_flush(png_structp png_ptr)
if (!(png_ptr->zstream.avail_out)) if (!(png_ptr->zstream.avail_out))
{ {
/* write the IDAT and reset the zlib output buffer */ /* Write the IDAT and reset the zlib output buffer */
png_write_IDAT(png_ptr, png_ptr->zbuf, png_write_IDAT(png_ptr, png_ptr->zbuf,
png_ptr->zbuf_size); png_ptr->zbuf_size);
png_ptr->zstream.next_out = png_ptr->zbuf; png_ptr->zstream.next_out = png_ptr->zbuf;
@ -879,7 +880,7 @@ png_write_flush(png_structp png_ptr)
/* If there is any data left to be output, write it into a new IDAT */ /* 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) if (png_ptr->zbuf_size != png_ptr->zstream.avail_out)
{ {
/* write the IDAT and reset the zlib output buffer */ /* Write the IDAT and reset the zlib output buffer */
png_write_IDAT(png_ptr, png_ptr->zbuf, png_write_IDAT(png_ptr, png_ptr->zbuf,
png_ptr->zbuf_size - png_ptr->zstream.avail_out); png_ptr->zbuf_size - png_ptr->zstream.avail_out);
png_ptr->zstream.next_out = png_ptr->zbuf; png_ptr->zstream.next_out = png_ptr->zbuf;
@ -1312,7 +1313,7 @@ png_set_compression_window_bits(png_structp png_ptr, int window_bits)
else if (window_bits < 8) else if (window_bits < 8)
png_warning(png_ptr, "Only compression windows >= 256 supported by PNG"); png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
#ifndef WBITS_8_OK #ifndef WBITS_8_OK
/* avoid libpng bug with 256-byte windows */ /* Avoid libpng bug with 256-byte windows */
if (window_bits == 8) if (window_bits == 8)
{ {
png_warning(png_ptr, "Compression window is being reset to 512"); png_warning(png_ptr, "Compression window is being reset to 512");
@ -1446,7 +1447,7 @@ png_write_png(png_structp png_ptr, png_infop info_ptr,
/* It is REQUIRED to call this to finish writing the rest of the file */ /* It is REQUIRED to call this to finish writing the rest of the file */
png_write_end(png_ptr, info_ptr); png_write_end(png_ptr, info_ptr);
transforms = transforms; /* quiet compiler warnings */ transforms = transforms; /* Quiet compiler warnings */
params = params; params = params;
} }
#endif #endif