793 lines
23 KiB
C
793 lines
23 KiB
C
|
|
#ifdef HAVE_CONFIG_H
|
|
#include "config.h"
|
|
#endif
|
|
|
|
#include <stdio.h>
|
|
#include <math.h>
|
|
#include <string.h>
|
|
#include <stdlib.h>
|
|
#include "gd.h"
|
|
|
|
/* JCE: Arrange HAVE_LIBPNG so that it can be set in gd.h */
|
|
#ifdef HAVE_LIBPNG
|
|
|
|
#include "gdhelpers.h"
|
|
#include "png.h" /* includes zlib.h and setjmp.h */
|
|
|
|
#define TRUE 1
|
|
#define FALSE 0
|
|
|
|
/*---------------------------------------------------------------------------
|
|
|
|
gd_png.c Copyright 1999 Greg Roelofs and Thomas Boutell
|
|
|
|
The routines in this file, gdImagePng*() and gdImageCreateFromPng*(),
|
|
are drop-in replacements for gdImageGif*() and gdImageCreateFromGif*(),
|
|
except that these functions are noisier in the case of errors (comment
|
|
out all fprintf() statements to disable that).
|
|
|
|
GD 2.0 supports RGBA truecolor and will read and write truecolor PNGs.
|
|
GD 2.0 supports 8 bits of color resolution per channel and
|
|
7 bits of alpha channel resolution. Images with more than 8 bits
|
|
per channel are reduced to 8 bits. Images with an alpha channel are
|
|
only able to resolve down to '1/128th opaque' instead of '1/256th',
|
|
and this conversion is also automatic. I very much doubt you can see it.
|
|
Both tRNS and true alpha are supported.
|
|
|
|
Gamma is ignored, and there is no support for text annotations.
|
|
|
|
Last updated: 9 February 2001
|
|
|
|
---------------------------------------------------------------------------*/
|
|
|
|
#ifndef PNG_SETJMP_NOT_SUPPORTED
|
|
typedef struct _jmpbuf_wrapper
|
|
{
|
|
jmp_buf jmpbuf;
|
|
}
|
|
jmpbuf_wrapper;
|
|
|
|
static jmpbuf_wrapper gdPngJmpbufStruct;
|
|
|
|
static void
|
|
gdPngErrorHandler (png_structp png_ptr, png_const_charp msg)
|
|
{
|
|
jmpbuf_wrapper *jmpbuf_ptr;
|
|
|
|
/* This function, aside from the extra step of retrieving the "error
|
|
* pointer" (below) and the fact that it exists within the application
|
|
* rather than within libpng, is essentially identical to libpng's
|
|
* default error handler. The second point is critical: since both
|
|
* setjmp() and longjmp() are called from the same code, they are
|
|
* guaranteed to have compatible notions of how big a jmp_buf is,
|
|
* regardless of whether _BSD_SOURCE or anything else has (or has not)
|
|
* been defined. */
|
|
|
|
fprintf (stderr, "gd-png: fatal libpng error: %s\n", msg);
|
|
fflush (stderr);
|
|
|
|
jmpbuf_ptr = png_get_error_ptr (png_ptr);
|
|
if (jmpbuf_ptr == NULL)
|
|
{ /* we are completely hosed now */
|
|
fprintf (stderr,
|
|
"gd-png: EXTREMELY fatal error: jmpbuf unrecoverable; terminating.\n");
|
|
fflush (stderr);
|
|
exit (99);
|
|
}
|
|
|
|
longjmp (jmpbuf_ptr->jmpbuf, 1);
|
|
}
|
|
#endif
|
|
|
|
static void
|
|
gdPngReadData (png_structp png_ptr, png_bytep data, png_size_t length)
|
|
{
|
|
gdGetBuf (data, length, (gdIOCtx *) png_get_io_ptr (png_ptr));
|
|
}
|
|
|
|
static void
|
|
gdPngWriteData (png_structp png_ptr, png_bytep data, png_size_t length)
|
|
{
|
|
gdPutBuf (data, length, (gdIOCtx *) png_get_io_ptr (png_ptr));
|
|
}
|
|
|
|
static void
|
|
gdPngFlushData (png_structp png_ptr)
|
|
{
|
|
}
|
|
|
|
gdImagePtr
|
|
gdImageCreateFromPng (FILE * inFile)
|
|
{
|
|
gdImagePtr im;
|
|
gdIOCtx *in = gdNewFileCtx (inFile);
|
|
im = gdImageCreateFromPngCtx (in);
|
|
in->gd_free (in);
|
|
return im;
|
|
}
|
|
|
|
|
|
/* This routine is based in part on the Chapter 13 demo code in "PNG: The
|
|
* Definitive Guide" (http://www.cdrom.com/pub/png/pngbook.html).
|
|
*/
|
|
gdImagePtr
|
|
gdImageCreateFromPngCtx (gdIOCtx * infile)
|
|
{
|
|
png_byte sig[8];
|
|
png_structp png_ptr;
|
|
png_infop info_ptr;
|
|
png_uint_32 width, height, rowbytes;
|
|
int bit_depth, color_type, interlace_type;
|
|
int num_palette, num_trans;
|
|
png_colorp palette;
|
|
png_color_16p trans_gray_rgb;
|
|
png_color_16p trans_color_rgb;
|
|
png_bytep trans;
|
|
png_bytep image_data = NULL;
|
|
png_bytepp row_pointers = NULL;
|
|
gdImagePtr im = NULL;
|
|
int i, j, *open = NULL;
|
|
volatile int transparent = -1;
|
|
volatile int palette_allocated = FALSE;
|
|
|
|
/* Make sure the signature can't match by dumb luck -- TBB */
|
|
/* GRR: isn't sizeof(infile) equal to the size of the pointer? */
|
|
memset (infile, 0, sizeof (infile));
|
|
|
|
/* first do a quick check that the file really is a PNG image; could
|
|
* have used slightly more general png_sig_cmp() function instead */
|
|
gdGetBuf (sig, 8, infile);
|
|
if (!png_check_sig (sig, 8))
|
|
return NULL; /* bad signature */
|
|
|
|
#ifndef PNG_SETJMP_NOT_SUPPORTED
|
|
png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING, &gdPngJmpbufStruct,
|
|
gdPngErrorHandler, NULL);
|
|
#else
|
|
png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
|
|
#endif
|
|
if (png_ptr == NULL)
|
|
{
|
|
fprintf (stderr, "gd-png error: cannot allocate libpng main struct\n");
|
|
return NULL;
|
|
}
|
|
|
|
info_ptr = png_create_info_struct (png_ptr);
|
|
if (info_ptr == NULL)
|
|
{
|
|
fprintf (stderr, "gd-png error: cannot allocate libpng info struct\n");
|
|
png_destroy_read_struct (&png_ptr, NULL, NULL);
|
|
return NULL;
|
|
}
|
|
|
|
/* we could create a second info struct here (end_info), but it's only
|
|
* useful if we want to keep pre- and post-IDAT chunk info separated
|
|
* (mainly for PNG-aware image editors and converters) */
|
|
|
|
/* setjmp() must be called in every non-callback function that calls a
|
|
* PNG-reading libpng function */
|
|
#ifndef PNG_SETJMP_NOT_SUPPORTED
|
|
if (setjmp (gdPngJmpbufStruct.jmpbuf))
|
|
{
|
|
fprintf (stderr, "gd-png error: setjmp returns error condition\n");
|
|
png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
|
|
return NULL;
|
|
}
|
|
#endif
|
|
|
|
png_set_sig_bytes (png_ptr, 8); /* we already read the 8 signature bytes */
|
|
|
|
png_set_read_fn (png_ptr, (void *) infile, gdPngReadData);
|
|
png_read_info (png_ptr, info_ptr); /* read all PNG info up to image data */
|
|
|
|
png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
|
|
&interlace_type, NULL, NULL);
|
|
if ((color_type == PNG_COLOR_TYPE_RGB) ||
|
|
(color_type == PNG_COLOR_TYPE_RGB_ALPHA))
|
|
{
|
|
im = gdImageCreateTrueColor ((int) width, (int) height);
|
|
}
|
|
else
|
|
{
|
|
im = gdImageCreate ((int) width, (int) height);
|
|
}
|
|
if (im == NULL)
|
|
{
|
|
fprintf (stderr, "gd-png error: cannot allocate gdImage struct\n");
|
|
png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
|
|
gdFree (image_data);
|
|
gdFree (row_pointers);
|
|
return NULL;
|
|
}
|
|
|
|
if (bit_depth == 16)
|
|
png_set_strip_16 (png_ptr);
|
|
else if (bit_depth < 8)
|
|
png_set_packing (png_ptr); /* expand to 1 byte per pixel */
|
|
switch (color_type)
|
|
{
|
|
case PNG_COLOR_TYPE_PALETTE:
|
|
png_get_PLTE (png_ptr, info_ptr, &palette, &num_palette);
|
|
#ifdef DEBUG
|
|
fprintf (stderr, "gd-png color_type is palette, colors: %d\n",
|
|
num_palette);
|
|
#endif /* DEBUG */
|
|
if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS))
|
|
{
|
|
/* gd 2.0: we support this rather thoroughly now. Grab the
|
|
first fully transparent entry, if any, as the value of
|
|
the simple-transparency index, mostly for backwards
|
|
binary compatibility. The alpha channel is where it's
|
|
really at these days. */
|
|
int firstZero = 1;
|
|
png_get_tRNS (png_ptr, info_ptr, &trans, &num_trans, NULL);
|
|
for (i = 0; i < num_trans; ++i)
|
|
{
|
|
im->alpha[i] = gdAlphaMax - (trans[i] >> 1);
|
|
if ((trans[i] == 0) && (firstZero))
|
|
{
|
|
/* 2.0.5: long-forgotten patch from Wez Furlong */
|
|
transparent = i;
|
|
firstZero = 0;
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
|
|
case PNG_COLOR_TYPE_GRAY:
|
|
case PNG_COLOR_TYPE_GRAY_ALPHA:
|
|
/* create a fake palette and check for single-shade transparency */
|
|
if ((palette =
|
|
(png_colorp) gdMalloc (256 * sizeof (png_color))) == NULL)
|
|
{
|
|
fprintf (stderr, "gd-png error: cannot allocate gray palette\n");
|
|
png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
|
|
return NULL;
|
|
}
|
|
palette_allocated = TRUE;
|
|
if (bit_depth < 8)
|
|
{
|
|
num_palette = 1 << bit_depth;
|
|
for (i = 0; i < 256; ++i)
|
|
{
|
|
j = (255 * i) / (num_palette - 1);
|
|
palette[i].red = palette[i].green = palette[i].blue = j;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
num_palette = 256;
|
|
for (i = 0; i < 256; ++i)
|
|
{
|
|
palette[i].red = palette[i].green = palette[i].blue = i;
|
|
}
|
|
}
|
|
if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS))
|
|
{
|
|
png_get_tRNS (png_ptr, info_ptr, NULL, NULL, &trans_gray_rgb);
|
|
if (bit_depth == 16) /* png_set_strip_16() not yet in effect */
|
|
transparent = trans_gray_rgb->gray >> 8;
|
|
else
|
|
transparent = trans_gray_rgb->gray;
|
|
/* Note slight error in 16-bit case: up to 256 16-bit shades
|
|
* may get mapped to a single 8-bit shade, and only one of them
|
|
* is supposed to be transparent. IOW, both opaque pixels and
|
|
* transparent pixels will be mapped into the transparent entry.
|
|
* There is no particularly good way around this in the case
|
|
* that all 256 8-bit shades are used, but one could write some
|
|
* custom 16-bit code to handle the case where there are gdFree
|
|
* palette entries. This error will be extremely rare in
|
|
* general, though. (Quite possibly there is only one such
|
|
* image in existence.) */
|
|
}
|
|
break;
|
|
|
|
case PNG_COLOR_TYPE_RGB:
|
|
case PNG_COLOR_TYPE_RGB_ALPHA:
|
|
/* gd 2.0: we now support truecolor. See the comment above
|
|
for a rare situation in which the transparent pixel may not
|
|
work properly with 16-bit channels. */
|
|
if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS))
|
|
{
|
|
png_get_tRNS (png_ptr, info_ptr, NULL, NULL, &trans_color_rgb);
|
|
if (bit_depth == 16) /* png_set_strip_16() not yet in effect */
|
|
transparent = gdTrueColor (trans_color_rgb->red >> 8,
|
|
trans_color_rgb->green >> 8,
|
|
trans_color_rgb->blue >> 8);
|
|
else
|
|
transparent = gdTrueColor (trans_color_rgb->red,
|
|
trans_color_rgb->green,
|
|
trans_color_rgb->blue);
|
|
}
|
|
break;
|
|
}
|
|
|
|
png_read_update_info (png_ptr, info_ptr);
|
|
|
|
/* allocate space for the PNG image data */
|
|
rowbytes = png_get_rowbytes (png_ptr, info_ptr);
|
|
if ((image_data = (png_bytep) gdMalloc (rowbytes * height)) == NULL)
|
|
{
|
|
fprintf (stderr, "gd-png error: cannot allocate image data\n");
|
|
png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
|
|
return NULL;
|
|
}
|
|
if ((row_pointers =
|
|
(png_bytepp) gdMalloc (height * sizeof (png_bytep))) == NULL)
|
|
{
|
|
fprintf (stderr, "gd-png error: cannot allocate row pointers\n");
|
|
png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
|
|
gdFree (image_data);
|
|
return NULL;
|
|
}
|
|
|
|
/* set the individual row_pointers to point at the correct offsets */
|
|
for (j = 0; j < height; ++j)
|
|
{
|
|
row_pointers[j] = image_data + j * rowbytes;
|
|
}
|
|
|
|
png_read_image (png_ptr, row_pointers); /* read whole image... */
|
|
png_read_end (png_ptr, NULL); /* ...done! */
|
|
|
|
if (!im->trueColor)
|
|
{
|
|
im->colorsTotal = num_palette;
|
|
/* load the palette and mark all entries "open" (unused) for now */
|
|
open = im->open;
|
|
for (i = 0; i < num_palette; ++i)
|
|
{
|
|
im->red[i] = palette[i].red;
|
|
im->green[i] = palette[i].green;
|
|
im->blue[i] = palette[i].blue;
|
|
open[i] = 1;
|
|
}
|
|
for (i = num_palette; i < gdMaxColors; ++i)
|
|
{
|
|
open[i] = 1;
|
|
}
|
|
}
|
|
/* 2.0.12: Slaven Rezic: palette images are not the only images
|
|
with a simple transparent color setting */
|
|
im->transparent = transparent;
|
|
im->interlace = (interlace_type == PNG_INTERLACE_ADAM7);
|
|
|
|
/* can't nuke structs until done with palette */
|
|
png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
|
|
switch (color_type)
|
|
{
|
|
case PNG_COLOR_TYPE_RGB:
|
|
for (j = 0; j < height; j++)
|
|
{
|
|
int boffset = 0;
|
|
for (i = 0; i < width; i++)
|
|
{
|
|
register png_byte r = row_pointers[j][boffset++];
|
|
register png_byte g = row_pointers[j][boffset++];
|
|
register png_byte b = row_pointers[j][boffset++];
|
|
im->tpixels[j][i] = gdTrueColor (r, g, b);
|
|
}
|
|
}
|
|
break;
|
|
case PNG_COLOR_TYPE_RGB_ALPHA:
|
|
for (j = 0; j < height; j++)
|
|
{
|
|
int boffset = 0;
|
|
for (i = 0; i < width; i++)
|
|
{
|
|
register png_byte r = row_pointers[j][boffset++];
|
|
register png_byte g = row_pointers[j][boffset++];
|
|
register png_byte b = row_pointers[j][boffset++];
|
|
/* gd has only 7 bits of alpha channel resolution, and
|
|
127 is transparent, 0 opaque. A moment of convenience,
|
|
a lifetime of compatibility. */
|
|
register png_byte a = gdAlphaMax -
|
|
(row_pointers[j][boffset++] >> 1);
|
|
im->tpixels[j][i] = gdTrueColorAlpha (r, g, b, a);
|
|
}
|
|
}
|
|
break;
|
|
default:
|
|
/* Palette image, or something coerced to be one */
|
|
for (j = 0; j < height; ++j)
|
|
{
|
|
for (i = 0; i < width; ++i)
|
|
{
|
|
register png_byte idx = row_pointers[j][i];
|
|
im->pixels[j][i] = idx;
|
|
open[idx] = 0;
|
|
}
|
|
}
|
|
}
|
|
#ifdef DEBUG
|
|
if (!im->trueColor)
|
|
{
|
|
for (i = num_palette; i < gdMaxColors; ++i)
|
|
{
|
|
if (!open[i])
|
|
{
|
|
fprintf (stderr,
|
|
"gd-png warning: image data references out-of-range"
|
|
" color index (%d)\n", i);
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
if (palette_allocated)
|
|
gdFree (palette);
|
|
gdFree (image_data);
|
|
gdFree (row_pointers);
|
|
|
|
return im;
|
|
}
|
|
|
|
|
|
void
|
|
gdImagePngEx (gdImagePtr im, FILE * outFile, int level)
|
|
{
|
|
gdIOCtx *out = gdNewFileCtx (outFile);
|
|
gdImagePngCtxEx (im, out, level);
|
|
out->gd_free (out);
|
|
}
|
|
|
|
void
|
|
gdImagePng (gdImagePtr im, FILE * outFile)
|
|
{
|
|
gdIOCtx *out = gdNewFileCtx (outFile);
|
|
gdImagePngCtxEx (im, out, -1);
|
|
out->gd_free (out);
|
|
}
|
|
|
|
void *
|
|
gdImagePngPtr (gdImagePtr im, int *size)
|
|
{
|
|
void *rv;
|
|
gdIOCtx *out = gdNewDynamicCtx (2048, NULL);
|
|
gdImagePngCtxEx (im, out, -1);
|
|
rv = gdDPExtractData (out, size);
|
|
out->gd_free (out);
|
|
return rv;
|
|
}
|
|
|
|
void *
|
|
gdImagePngPtrEx (gdImagePtr im, int *size, int level)
|
|
{
|
|
void *rv;
|
|
gdIOCtx *out = gdNewDynamicCtx (2048, NULL);
|
|
gdImagePngCtxEx (im, out, level);
|
|
rv = gdDPExtractData (out, size);
|
|
out->gd_free (out);
|
|
return rv;
|
|
}
|
|
|
|
void
|
|
gdImagePngCtx (gdImagePtr im, gdIOCtx * outfile)
|
|
{
|
|
/* 2.0.13: 'return' here was an error, thanks to Kevin Smith */
|
|
gdImagePngCtxEx (im, outfile, -1);
|
|
}
|
|
|
|
/* This routine is based in part on code from Dale Lutz (Safe Software Inc.)
|
|
* and in part on demo code from Chapter 15 of "PNG: The Definitive Guide"
|
|
* (http://www.cdrom.com/pub/png/pngbook.html).
|
|
*/
|
|
void
|
|
gdImagePngCtxEx (gdImagePtr im, gdIOCtx * outfile, int level)
|
|
{
|
|
int i, j, bit_depth = 0, interlace_type;
|
|
int width = im->sx;
|
|
int height = im->sy;
|
|
int colors = im->colorsTotal;
|
|
int *open = im->open;
|
|
int mapping[gdMaxColors]; /* mapping[gd_index] == png_index */
|
|
png_byte trans_values[256];
|
|
png_color_16 trans_rgb_value;
|
|
png_color palette[gdMaxColors];
|
|
png_structp png_ptr;
|
|
png_infop info_ptr;
|
|
volatile int transparent = im->transparent;
|
|
volatile int remap = FALSE;
|
|
|
|
|
|
#ifndef PNG_SETJMP_NOT_SUPPORTED
|
|
png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING,
|
|
&gdPngJmpbufStruct, gdPngErrorHandler,
|
|
NULL);
|
|
#else
|
|
png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
|
|
#endif
|
|
if (png_ptr == NULL)
|
|
{
|
|
fprintf (stderr, "gd-png error: cannot allocate libpng main struct\n");
|
|
return;
|
|
}
|
|
|
|
info_ptr = png_create_info_struct (png_ptr);
|
|
if (info_ptr == NULL)
|
|
{
|
|
fprintf (stderr, "gd-png error: cannot allocate libpng info struct\n");
|
|
png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
|
|
return;
|
|
}
|
|
|
|
#ifndef PNG_SETJMP_NOT_SUPPORTED
|
|
if (setjmp (gdPngJmpbufStruct.jmpbuf))
|
|
{
|
|
fprintf (stderr, "gd-png error: setjmp returns error condition\n");
|
|
png_destroy_write_struct (&png_ptr, &info_ptr);
|
|
return;
|
|
}
|
|
#endif
|
|
|
|
png_set_write_fn (png_ptr, (void *) outfile, gdPngWriteData,
|
|
gdPngFlushData);
|
|
|
|
/* This is best for palette images, and libpng defaults to it for
|
|
palette images anyway, so we don't need to do it explicitly.
|
|
What to ideally do for truecolor images depends, alas, on the image.
|
|
gd is intentionally imperfect and doesn't spend a lot of time
|
|
fussing with such things. */
|
|
/* png_set_filter(png_ptr, 0, PNG_FILTER_NONE); */
|
|
|
|
/* 2.0.12: this is finally a parameter */
|
|
png_set_compression_level (png_ptr, level);
|
|
|
|
/* can set this to a smaller value without compromising compression if all
|
|
* image data is 16K or less; will save some decoder memory [min == 8] */
|
|
/* png_set_compression_window_bits(png_ptr, 15); */
|
|
|
|
if (!im->trueColor)
|
|
{
|
|
if (transparent >= im->colorsTotal ||
|
|
(transparent >= 0 && open[transparent]))
|
|
transparent = -1;
|
|
}
|
|
if (!im->trueColor)
|
|
{
|
|
for (i = 0; i < gdMaxColors; ++i)
|
|
mapping[i] = -1;
|
|
}
|
|
if (!im->trueColor)
|
|
{
|
|
/* count actual number of colors used (colorsTotal == high-water mark) */
|
|
colors = 0;
|
|
for (i = 0; i < im->colorsTotal; ++i)
|
|
{
|
|
if (!open[i])
|
|
{
|
|
mapping[i] = colors;
|
|
++colors;
|
|
}
|
|
}
|
|
if (colors < im->colorsTotal)
|
|
{
|
|
remap = TRUE;
|
|
}
|
|
if (colors <= 2)
|
|
bit_depth = 1;
|
|
else if (colors <= 4)
|
|
bit_depth = 2;
|
|
else if (colors <= 16)
|
|
bit_depth = 4;
|
|
else
|
|
bit_depth = 8;
|
|
}
|
|
interlace_type = im->interlace ? PNG_INTERLACE_ADAM7 : PNG_INTERLACE_NONE;
|
|
|
|
if (im->trueColor)
|
|
{
|
|
if (im->saveAlphaFlag)
|
|
{
|
|
png_set_IHDR (png_ptr, info_ptr, width, height, 8,
|
|
PNG_COLOR_TYPE_RGB_ALPHA, interlace_type,
|
|
PNG_COMPRESSION_TYPE_DEFAULT,
|
|
PNG_FILTER_TYPE_DEFAULT);
|
|
}
|
|
else
|
|
{
|
|
png_set_IHDR (png_ptr, info_ptr, width, height, 8,
|
|
PNG_COLOR_TYPE_RGB, interlace_type,
|
|
PNG_COMPRESSION_TYPE_DEFAULT,
|
|
PNG_FILTER_TYPE_DEFAULT);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
png_set_IHDR (png_ptr, info_ptr, width, height, bit_depth,
|
|
PNG_COLOR_TYPE_PALETTE, interlace_type,
|
|
PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
|
|
}
|
|
if (im->trueColor && (!im->saveAlphaFlag) && (transparent >= 0))
|
|
{
|
|
/* 2.0.9: fixed by Thomas Winzig */
|
|
trans_rgb_value.red = gdTrueColorGetRed (im->transparent);
|
|
trans_rgb_value.green = gdTrueColorGetGreen (im->transparent);
|
|
trans_rgb_value.blue = gdTrueColorGetBlue (im->transparent);
|
|
png_set_tRNS (png_ptr, info_ptr, 0, 0, &trans_rgb_value);
|
|
}
|
|
if (!im->trueColor)
|
|
{
|
|
/* Oy veh. Remap the PNG palette to put the
|
|
entries with interesting alpha channel
|
|
values first. This minimizes the size
|
|
of the tRNS chunk and thus the size
|
|
of the PNG file as a whole. */
|
|
int tc = 0;
|
|
int i;
|
|
int j;
|
|
int k;
|
|
for (i = 0; (i < im->colorsTotal); i++)
|
|
{
|
|
if ((!im->open[i]) && (im->alpha[i] != gdAlphaOpaque))
|
|
{
|
|
tc++;
|
|
}
|
|
}
|
|
if (tc)
|
|
{
|
|
#if 0
|
|
for (i = 0; (i < im->colorsTotal); i++)
|
|
{
|
|
trans_values[i] = 255 -
|
|
((im->alpha[i] << 1) + (im->alpha[i] >> 6));
|
|
}
|
|
png_set_tRNS (png_ptr, info_ptr, trans_values, 256, NULL);
|
|
#endif
|
|
if (!remap)
|
|
{
|
|
remap = TRUE;
|
|
}
|
|
/* (Semi-)transparent indexes come up from the bottom
|
|
of the list of real colors; opaque
|
|
indexes come down from the top */
|
|
j = 0;
|
|
k = colors - 1;
|
|
for (i = 0; (i < im->colorsTotal); i++)
|
|
{
|
|
if (!im->open[i])
|
|
{
|
|
if (im->alpha[i] != gdAlphaOpaque)
|
|
{
|
|
/* Andrew Hull: >> 6, not >> 7! (gd 2.0.5) */
|
|
trans_values[j] = 255 -
|
|
((im->alpha[i] << 1) + (im->alpha[i] >> 6));
|
|
mapping[i] = j++;
|
|
}
|
|
else
|
|
{
|
|
mapping[i] = k--;
|
|
}
|
|
}
|
|
}
|
|
png_set_tRNS (png_ptr, info_ptr, trans_values, tc, NULL);
|
|
}
|
|
}
|
|
|
|
/* convert palette to libpng layout */
|
|
if (!im->trueColor)
|
|
{
|
|
if (remap)
|
|
for (i = 0; i < im->colorsTotal; ++i)
|
|
{
|
|
if (mapping[i] < 0)
|
|
continue;
|
|
palette[mapping[i]].red = im->red[i];
|
|
palette[mapping[i]].green = im->green[i];
|
|
palette[mapping[i]].blue = im->blue[i];
|
|
}
|
|
else
|
|
for (i = 0; i < colors; ++i)
|
|
{
|
|
palette[i].red = im->red[i];
|
|
palette[i].green = im->green[i];
|
|
palette[i].blue = im->blue[i];
|
|
}
|
|
png_set_PLTE (png_ptr, info_ptr, palette, colors);
|
|
}
|
|
|
|
/* write out the PNG header info (everything up to first IDAT) */
|
|
png_write_info (png_ptr, info_ptr);
|
|
|
|
/* make sure < 8-bit images are packed into pixels as tightly as possible */
|
|
png_set_packing (png_ptr);
|
|
|
|
/* This code allocates a set of row buffers and copies the gd image data
|
|
* into them only in the case that remapping is necessary; in gd 1.3 and
|
|
* later, the im->pixels array is laid out identically to libpng's row
|
|
* pointers and can be passed to png_write_image() function directly.
|
|
* The remapping case could be accomplished with less memory for non-
|
|
* interlaced images, but interlacing causes some serious complications. */
|
|
if (im->trueColor)
|
|
{
|
|
int channels = im->saveAlphaFlag ? 4 : 3;
|
|
/* Our little 7-bit alpha channel trick costs us a bit here. */
|
|
png_bytep *row_pointers;
|
|
row_pointers = gdMalloc (sizeof (png_bytep) * height);
|
|
if (row_pointers == NULL)
|
|
{
|
|
fprintf (stderr, "gd-png error: unable to allocate row_pointers\n");
|
|
}
|
|
for (j = 0; j < height; ++j)
|
|
{
|
|
int bo = 0;
|
|
if ((row_pointers[j] =
|
|
(png_bytep) gdMalloc (width * channels)) == NULL)
|
|
{
|
|
fprintf (stderr, "gd-png error: unable to allocate rows\n");
|
|
for (i = 0; i < j; ++i)
|
|
gdFree (row_pointers[i]);
|
|
return;
|
|
}
|
|
for (i = 0; i < width; ++i)
|
|
{
|
|
unsigned char a;
|
|
row_pointers[j][bo++] = gdTrueColorGetRed (im->tpixels[j][i]);
|
|
row_pointers[j][bo++] = gdTrueColorGetGreen (im->tpixels[j][i]);
|
|
row_pointers[j][bo++] = gdTrueColorGetBlue (im->tpixels[j][i]);
|
|
if (im->saveAlphaFlag)
|
|
{
|
|
/* convert the 7-bit alpha channel to an 8-bit alpha channel.
|
|
We do a little bit-flipping magic, repeating the MSB
|
|
as the LSB, to ensure that 0 maps to 0 and
|
|
127 maps to 255. We also have to invert to match
|
|
PNG's convention in which 255 is opaque. */
|
|
a = gdTrueColorGetAlpha (im->tpixels[j][i]);
|
|
/* Andrew Hull: >> 6, not >> 7! (gd 2.0.5) */
|
|
row_pointers[j][bo++] = 255 - ((a << 1) + (a >> 6));
|
|
}
|
|
}
|
|
}
|
|
|
|
png_write_image (png_ptr, row_pointers);
|
|
png_write_end (png_ptr, info_ptr);
|
|
|
|
for (j = 0; j < height; ++j)
|
|
gdFree (row_pointers[j]);
|
|
gdFree (row_pointers);
|
|
}
|
|
else
|
|
{
|
|
if (remap)
|
|
{
|
|
png_bytep *row_pointers;
|
|
row_pointers = gdMalloc (sizeof (png_bytep) * height);
|
|
if (row_pointers == NULL)
|
|
{
|
|
fprintf (stderr,
|
|
"gd-png error: unable to allocate row_pointers\n");
|
|
}
|
|
for (j = 0; j < height; ++j)
|
|
{
|
|
if ((row_pointers[j] = (png_bytep) gdMalloc (width)) == NULL)
|
|
{
|
|
fprintf (stderr, "gd-png error: unable to allocate rows\n");
|
|
for (i = 0; i < j; ++i)
|
|
gdFree (row_pointers[i]);
|
|
return;
|
|
}
|
|
for (i = 0; i < width; ++i)
|
|
row_pointers[j][i] = mapping[im->pixels[j][i]];
|
|
}
|
|
|
|
png_write_image (png_ptr, row_pointers);
|
|
png_write_end (png_ptr, info_ptr);
|
|
|
|
for (j = 0; j < height; ++j)
|
|
gdFree (row_pointers[j]);
|
|
gdFree (row_pointers);
|
|
}
|
|
else
|
|
{
|
|
png_write_image (png_ptr, im->pixels);
|
|
png_write_end (png_ptr, info_ptr);
|
|
}
|
|
}
|
|
/* 1.6.3: maybe we should give that memory BACK! TBB */
|
|
png_destroy_write_struct (&png_ptr, &info_ptr);
|
|
}
|
|
|
|
|
|
#endif /* HAVE_LIBPNG */
|