diff options
Diffstat (limited to 'lib/pngstream.hh')
| -rw-r--r-- | lib/pngstream.hh | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/lib/pngstream.hh b/lib/pngstream.hh new file mode 100644 index 0000000..77d4f54 --- /dev/null +++ b/lib/pngstream.hh @@ -0,0 +1,145 @@ +// 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) */ |