diff options
Diffstat (limited to 'lib/pngstream.cc')
| -rw-r--r-- | lib/pngstream.cc | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/lib/pngstream.cc b/lib/pngstream.cc new file mode 100644 index 0000000..d9344b4 --- /dev/null +++ b/lib/pngstream.cc @@ -0,0 +1,257 @@ +// pngstream.cc -- image streams producing PNG files +// Copyright (C) 2008, 2009, 2016 SEIKO EPSON CORPORATION +// +// This file is part of the '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. + + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include "pngstream.hh" + +#include <iostream> + +namespace iscan +{ + pngstream::pngstream (FILE *fp, const string& name) + : _stream (fp), _header (false), _footer (false) + { + if (!_stream) throw std::invalid_argument ("invalid file handle"); +#if HAVE_PNG_H + init (); +#endif + } + + pngstream::~pngstream (void) + { + try + { + flush (); + } + catch (const std::exception& oops) + { + std::cerr << oops.what (); + } + +#if HAVE_PNG_H + lib->destroy_write_struct (&_png, &_info); +#endif + } + + basic_imgstream& + pngstream::write (const byte_type *line, size_type n) + { + if (!line || 0 == n) return *this; +#if HAVE_PNG_H + if (!_header) + { + write_header (); + } + set_error_handler (_png, _info); + lib->write_row (_png, (png_byte *) line); +#endif + return *this; + } + + basic_imgstream& + pngstream::flush (void) + { +#if HAVE_PNG_H + set_error_handler (_png, _info); + + if (_header && !_footer && _png->num_rows == _png->flush_rows) + { + lib->write_end (_png, _info); + _footer = true; + } +#endif + fflush (_stream); + + return *this; + } + + bool + pngstream::is_usable (void) + { + if (lib) + { + return lib->is_usable; + } + + lib = new (std::nothrow) png_lib_handle (); + if (!lib) + { + return false; + } + + lib->is_usable = false; + lib->message = string (); + lib->lib = NULL; +#if HAVE_PNG_H + try + { + // Some PNG libraries are *not* linked with libz which leads + // to a "file not found" error when calling dlopen. We just + // dlopen the libz library explicitly to work around this. + basic_imgstream::dlopen ("libz"); + basic_imgstream::dlopen ("libpng12", validate); + } + catch (std::runtime_error& e) + { + lib->message = e.what (); + return lib->is_usable; + } +#endif /* HAVE_PNG_H */ + + return lib->is_usable; + } + +#if HAVE_PNG_H +#define funcsym(name) \ + lib->name \ + = ((pngstream::png_lib_handle::name##_f) \ + basic_imgstream::dlsym (lib->lib, "png_"#name)); +#endif + + bool + pngstream::validate (lt_dlhandle h) + { + if (!h) return false; + +#if HAVE_PNG_H + lib->lib = h; + + funcsym (access_version_number); + funcsym (create_write_struct); + funcsym (create_info_struct); + funcsym (destroy_write_struct); + funcsym (init_io); + funcsym (set_IHDR); + funcsym (set_pHYs); + funcsym (set_invert_mono); + funcsym (write_info); + funcsym (write_row); + funcsym (write_flush); + funcsym (write_end); + + if (lib->access_version_number + && lib->create_write_struct + && lib->create_info_struct + && lib->destroy_write_struct + && lib->init_io + && lib->set_IHDR + && lib->set_pHYs + && lib->set_invert_mono + && lib->write_info + && lib->write_row + && lib->write_flush + && lib->write_end) + { + lib->is_usable = (PNG_LIBPNG_VER <= lib->access_version_number ()); + } +#endif /* HAVE_PNG_H */ + + return lib->is_usable; + } + +#if HAVE_PNG_H +#undef funcsym +#endif + + basic_imgstream& + pngstream::write_header (void) + { + check_consistency (); + +#if HAVE_PNG_H + set_error_handler (_png, _info); + + if (mono == _cspc) + { + _bits = 1; + lib->set_invert_mono (_png); + } + + lib->init_io (_png, _stream); + + lib->set_IHDR (_png, _info, _h_sz, _v_sz, _bits, + (RGB == _cspc + ? PNG_COLOR_TYPE_RGB : PNG_COLOR_TYPE_GRAY), + PNG_INTERLACE_NONE, + PNG_COMPRESSION_TYPE_DEFAULT, + PNG_FILTER_TYPE_DEFAULT); + + size_type hres = size_type (100 / 2.54 * _hres + 0.5); + size_type vres = size_type (100 / 2.54 * _vres + 0.5); + lib->set_pHYs (_png, _info, hres, vres, PNG_RESOLUTION_METER); + + lib->write_info (_png, _info); +#endif /* HAVE_PNG_H */ + + _header = true; + return *this; + } + + void + pngstream::check_consistency (void) const + { + if (!(mono == _cspc || grey == _cspc || RGB == _cspc)) + { + throw std::logic_error ("unsupported colour space"); + } + } + + void + pngstream::init (void) + { + if (!is_usable ()) + { + throw std::runtime_error (lib->message); + } + +#if HAVE_PNG_H + _png = lib->create_write_struct (version_string, + NULL, NULL, NULL); + _info = NULL; + if (!_png) throw std::bad_alloc (); + + _info = lib->create_info_struct (_png); + if (!_info) + { + lib->destroy_write_struct (&_png, NULL); + throw std::bad_alloc (); + } +#endif /* HAVE_PNG_H */ + } + + pngstream::png_lib_handle *pngstream::lib = NULL; + +#if HAVE_PNG_H + png_const_charp pngstream::version_string = PNG_LIBPNG_VER_STRING; +#endif + +} // namespace iscan |