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/****************************************************************************\
Part of the XeTeX typesetting system
Copyright (c) 1994-2006 by SIL International
SIL Author(s): Jonathan Kew
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
\****************************************************************************/
/* this file is derived from the dvipdfmx project;
the original header follows... */
/* $Header: /home/cvsroot/dvipdfmx/src/pngimage.c,v 1.24 2004/09/11 14:50:29 hirata Exp $
This is dvipdfmx, an eXtended version of dvipdfm by Mark A. Wicks.
Copyright (C) 2002 by Jin-Hwan Cho and Shunsaku Hirata,
the dvipdfmx project team <dvipdfmx@project.ktug.or.kr>
Copyright (C) 1998, 1999 by Mark A. Wicks <mwicks@kettering.edu>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#if HAVE_CONFIG_H
#include <w2c/config.h>
#endif
/*
* PNG SUPPORT
*
* All bitdepth less than 16 is supported.
* Supported color types are: PALETTE, RGB, GRAY, RGB_ALPHA, GRAY_ALPHA.
* Supported ancillary chunks: tRNS, cHRM + gAMA, (sRGB), (iCCP)
*
* gAMA support is available only when cHRM exists. cHRM support is not
* tested well. CalRGB/CalGray colorspace is used for PNG images that
* have cHRM chunk (but not sRGB).
*
* LIMITATIONS
*
* Recent version of PDF (>= 1.5) support 16 bpc, but 16 bit bitdepth PNG
* images are automatically converted to 8 bit bitpedth image.
*
* TODO
*
* sBIT ? iTXT, tEXT and tIME as MetaData ?, pHYS (see below)
* 16 bpc support for PDF-1.5. JBIG compression for monochrome image.
* Predictor for deflate ?
*/
#define PNG_DEBUG_STR "PNG"
#define PNG_DEBUG 3
/*
* Write, MNG, Progressive not required.
*/
#define PNG_NO_WRITE_SUPPORTED
#define PNG_NO_MNG_FEATURES
#define PNG_NO_PROGRESSIVE_READ
#if 0
/* 16_TO_8 required. */
#define PNG_NO_READ_TRANSFORMS
#endif
#include <png.h>
#include "pngimage.h"
#define PDF_TRANS_TYPE_NONE 0
#define PDF_TRANS_TYPE_BINARY 1
#define PDF_TRANS_TYPE_ALPHA 2
int
check_for_png (FILE *png_file)
{
unsigned char sigbytes[4];
rewind (png_file);
if (fread (sigbytes, 1, sizeof(sigbytes), png_file) !=
sizeof(sigbytes) ||
(png_sig_cmp (sigbytes, 0, sizeof(sigbytes))))
return 0;
else
return 1;
}
int
png_scan_file (struct png_info *info, FILE *png_file)
{
png_bytep stream_data_ptr;
int trans_type;
/* Libpng stuff */
png_structp png_ptr;
png_infop png_info_ptr;
png_byte bpc, color_type;
png_uint_32 width, height, rowbytes;
rewind (png_file);
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (png_ptr == NULL ||
(png_info_ptr = png_create_info_struct (png_ptr)) == NULL) {
fprintf(stderr, "WARNING: %s: Creating Libpng read/info struct failed.", PNG_DEBUG_STR);
if (png_ptr)
png_destroy_read_struct(&png_ptr, NULL, NULL);
return -1;
}
/* Inititializing file IO. */
png_init_io (png_ptr, png_file);
/* Read PNG info-header and get some info. */
png_read_info(png_ptr, png_info_ptr);
color_type = png_get_color_type (png_ptr, png_info_ptr);
width = png_get_image_width (png_ptr, png_info_ptr);
height = png_get_image_height(png_ptr, png_info_ptr);
bpc = png_get_bit_depth (png_ptr, png_info_ptr);
info->xdpi = png_get_x_pixels_per_meter(png_ptr, png_info_ptr) * 0.0254;
info->ydpi = png_get_y_pixels_per_meter(png_ptr, png_info_ptr) * 0.0254;
if (info->xdpi == 0)
info->xdpi = 72;
if (info->ydpi == 0)
info->ydpi = 72;
/* Values listed below will not be modified in the remaining process. */
info->width = width;
info->height = height;
info->bits_per_component = bpc;
/* Cleanup */
if (png_info_ptr)
png_destroy_info_struct(png_ptr, &png_info_ptr);
if (png_ptr)
png_destroy_read_struct(&png_ptr, NULL, NULL);
return 0;
}
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