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// pngstream.hh -- image streams producing PNG files
// Copyright (C) 2008, 2009 SEIKO EPSON CORPORATION
//
// This file is part of 'iscan' program.
//
// The 'iscan' program is free-ish 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 FITNESS
// FOR A PARTICULAR PURPOSE or MERCHANTABILITY.
// See the GNU General Public License for more details.
//
// You should have received a verbatim copy of the GNU General Public
// License along with this program; if not, write to:
//
// Free Software Foundation, Inc.
// 59 Temple Place, Suite 330
// Boston, MA 02111-1307 USA
//
// As a special exception, the copyright holders give permission
// to link the code of this program with the esmod library and
// distribute linked combinations including the two. You must obey
// the GNU General Public License in all respects for all of the
// code used other then esmod.
#ifndef iscan_pngstream_hh_included
#define iscan_pngstream_hh_included
#ifndef __cplusplus
#error "This is a C++ header file; use a C++ compiler to compile it."
#endif
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "basic-imgstream.hh"
#include <cstdio>
#include <string>
#include <ios>
#if HAVE_PNG_H
#include <png.h>
#endif
namespace iscan
{
using std::string;
class pngstream : public basic_imgstream
{
public:
typedef basic_imgstream::byte_type byte_type;
typedef basic_imgstream::size_type size_type;
explicit pngstream (FILE *fp, const string& name = string ());
virtual ~pngstream (void);
virtual basic_imgstream& write (const byte_type *line, size_type n);
virtual basic_imgstream& flush (void);
static bool is_usable (void);
private:
basic_imgstream& write_header (void);
void check_consistency (void) const;
void init (void);
FILE *_stream;
bool _header;
bool _footer;
static bool validate (lt_dlhandle h);
struct png_lib_handle
{
bool is_usable;
string message;
lt_dlhandle lib;
#if HAVE_PNG_H
fundecl (png_uint_32, access_version_number,
void);
fundecl (png_structp, create_write_struct,
png_const_charp, png_voidp, png_error_ptr, png_error_ptr);
fundecl (png_infop , create_info_struct ,
png_structp);
fundecl (void, destroy_write_struct,
png_structpp, png_infopp);
fundecl (void, init_io,
png_structp, FILE *);
fundecl (void, set_IHDR,
png_structp, png_infop, png_uint_32, png_uint_32, int,
int, int, int, int);
fundecl (void, set_pHYs,
png_structp, png_infop, png_uint_32, png_uint_32, int);
fundecl (void, set_invert_mono, png_structp);
fundecl (void, write_info,
png_structp, png_infop);
fundecl (void, write_row,
png_structp, png_bytep);
fundecl (void, write_flush,
png_structp);
fundecl (void, write_end,
png_structp, png_infop);
#endif /* HAVE_PNG_H */
};
static png_lib_handle *lib;
#if HAVE_PNG_H
friend void set_error_handler (png_structp, png_infop);
png_structp _png;
png_infop _info;
static png_const_charp version_string;
#endif
};
// implementation
// This function needs to be expanded verbatim at the location it's
// invoked for the setjmp call to work as intended.
#if HAVE_PNG_H
#define set_error_handler(png, info) \
{ \
if (!png || !info || setjmp (png_jmpbuf (png))) \
{ \
pngstream::lib->destroy_write_struct (&png, &info); \
png = NULL; \
info = NULL; \
throw std::ios_base::failure ("write error"); \
} \
}
#endif
} // namespace iscan
#endif /* !defined (iscan_pngstream_hh_included) */
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