writer.hpp
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/*
* 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
{
template< class ostream >
class writer
: public io_base
{
public:
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);
}
void write_info() const
{
if (setjmp(png_jmpbuf(m_png)))
{
throw error(m_error);
}
m_info.write();
}
void write_row(byte* bytes)
{
if (setjmp(png_jmpbuf(m_png)))
{
throw error(m_error);
}
png_write_row(m_png, bytes);
}
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
png::end_info::destroy
void destroy()
Definition end_info.hpp:53
png::end_info::write
void write() const
Definition end_info.hpp:64
png::error
Exception class to represent runtime errors related to png++ operation.
Definition error.hpp:59
png::info_base::get_png_info_ptr
png_info ** get_png_info_ptr()
Definition info_base.hpp:64
png::info_base::get_png_info
png_info * get_png_info() const
Definition info_base.hpp:59
png::info::write
void write() const
Definition info.hpp:116
png::io_base
Base class for PNG reader/writer classes.
Definition io_base.hpp:63
png::io_base::m_error
std::string m_error
Definition io_base.hpp:462
png::io_base::m_info
info m_info
Definition io_base.hpp:460
png::io_base::m_png
png_struct * m_png
Definition io_base.hpp:459
png::io_base::set_error
void set_error(char const *message)
Definition io_base.hpp:424
png::io_base::m_end_info
end_info m_end_info
Definition io_base.hpp:461
png::io_base::is_error
bool is_error() const
Definition io_base.hpp:442
png::io_base::io_base
io_base(png_struct *png)
Definition io_base.hpp:68
png::io_base::raise_error
void raise_error()
Definition io_base.hpp:447
png::io_base::reset_error
void reset_error()
Definition io_base.hpp:430
png::reader
The PNG reader class template. This is the low-level reading interface–use image class or consumer cl...
Definition reader.hpp:67
png::writer
PNG writer class template. This is the low-level writing interface–use image class or generator class...
Definition writer.hpp:68
png::writer::write_info
void write_info() const
Write info about PNG image.
Definition writer.hpp:104
png::writer::write_end_info
void write_end_info() const
Reads ending info about PNG image.
Definition writer.hpp:128
png::writer::writer
writer(ostream &stream)
Constructs a writer prepared to write PNG image into a stream.
Definition writer.hpp:74
png::writer::~writer
~writer()
Definition writer.hpp:83
png::writer::write_png
void write_png() const
Definition writer.hpp:89
png::writer::write_row
void write_row(byte *bytes)
Writes a row of image data at a time.
Definition writer.hpp:116
io_base.hpp
png
Definition color.hpp:37