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Diffstat (limited to 'src/png/writer.hpp')
| -rw-r--r-- | src/png/writer.hpp | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/src/png/writer.hpp b/src/png/writer.hpp new file mode 100644 index 000000000..448dfd50b --- /dev/null +++ b/src/png/writer.hpp @@ -0,0 +1,199 @@ +/* + * Copyright (C) 2007,2008 Alex Shulgin + * + * This file is part of png++ the C++ wrapper for libpng. PNG++ is free + * software; the exact copying conditions are as follows: + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN + * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED + * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ +#ifndef PNGPP_WRITER_HPP_INCLUDED +#define PNGPP_WRITER_HPP_INCLUDED + +#include <cassert> +#include "io_base.hpp" + +namespace png +{ + + /** + * \brief PNG writer class template. This is the low-level + * writing interface--use image class or generator class to + * actually write images. + * + * The \c ostream template parameter specifies the type of output + * stream to work with. The \c ostream class should implement the + * minimum of the following interface: + * + * \code + * class my_ostream + * { + * public: + * void write(char const*, size_t); + * void flush(); + * bool good(); + * }; + * \endcode + * + * With the semantics similar to the \c std::ostream. Naturally, + * \c std::ostream fits this requirement and can be used with the + * writer class as is. + * + * \see image, reader, generator, io_base + */ + template< class ostream > + class writer + : public io_base + { + public: + /** + * \brief Constructs a writer prepared to write PNG image into + * a \a stream. + */ + explicit writer(ostream& stream) + : io_base(png_create_write_struct(PNG_LIBPNG_VER_STRING, + static_cast< io_base* >(this), + raise_error, + 0)) + { + png_set_write_fn(m_png, & stream, write_data, flush_data); + } + + ~writer() + { + m_end_info.destroy(); + png_destroy_write_struct(& m_png, m_info.get_png_info_ptr()); + } + + void write_png() const + { + if (setjmp(png_jmpbuf(m_png))) + { + throw error(m_error); + } + png_write_png(m_png, + m_info.get_png_info(), + /* transforms = */ 0, + /* params = */ 0); + } + + /** + * \brief Write info about PNG image. + */ + void write_info() const + { + if (setjmp(png_jmpbuf(m_png))) + { + throw error(m_error); + } + m_info.write(); + } + + /** + * \brief Writes a row of image data at a time. + */ + void write_row(byte* bytes) + { + if (setjmp(png_jmpbuf(m_png))) + { + throw error(m_error); + } + png_write_row(m_png, bytes); + } + + /** + * \brief Reads ending info about PNG image. + */ + void write_end_info() const + { + if (setjmp(png_jmpbuf(m_png))) + { + throw error(m_error); + } + m_end_info.write(); + } + + private: + static void write_data(png_struct* png, byte* data, png_size_t length) + { + io_base* io = static_cast< io_base* >(png_get_error_ptr(png)); + writer* wr = static_cast< writer* >(io); + wr->reset_error(); + ostream* stream = reinterpret_cast< ostream* >(png_get_io_ptr(png)); + try + { + stream->write(reinterpret_cast< char* >(data), length); + if (!stream->good()) + { + wr->set_error("ostream::write() failed"); + } + } + catch (std::exception const& error) + { + wr->set_error(error.what()); + } + catch (...) + { + assert(!"caught something wrong"); + wr->set_error("write_data: caught something wrong"); + } + if (wr->is_error()) + { + wr->raise_error(); + } + } + + static void flush_data(png_struct* png) + { + io_base* io = static_cast< io_base* >(png_get_error_ptr(png)); + writer* wr = static_cast< writer* >(io); + wr->reset_error(); + ostream* stream = reinterpret_cast< ostream* >(png_get_io_ptr(png)); + try + { + stream->flush(); + if (!stream->good()) + { + wr->set_error("ostream::flush() failed"); + } + } + catch (std::exception const& error) + { + wr->set_error(error.what()); + } + catch (...) + { + assert(!"caught something wrong"); + wr->set_error("flush_data: caught something wrong"); + } + if (wr->is_error()) + { + wr->raise_error(); + } + } + }; + +} // namespace png + +#endif // PNGPP_WRITER_HPP_INCLUDED |