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/*
Copyright 2012 Kenneth Riddile and Christian Henning
Use, modification and distribution are subject to the Boost Software License,
Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
http://www.boost.org/LICENSE_1_0.txt).
*/
/*************************************************************************************************/
#ifndef BOOST_GIL_EXTENSION_IO_TARGA_DETAIL_SCANLINE_READ_HPP
#define BOOST_GIL_EXTENSION_IO_TARGA_DETAIL_SCANLINE_READ_HPP
////////////////////////////////////////////////////////////////////////////////////////
/// \file
/// \brief
/// \author Kenneth Riddile and Christian Henning \n
///
/// \date 2012 \n
///
////////////////////////////////////////////////////////////////////////////////////////
#include <vector>
#include <boost/gil/io/base.hpp>
#include <boost/gil/io/bit_operations.hpp>
#include <boost/gil/io/conversion_policies.hpp>
#include <boost/gil/io/row_buffer_helper.hpp>
#include <boost/gil/io/reader_base.hpp>
#include <boost/gil/io/device.hpp>
#include <boost/gil/io/scanline_read_iterator.hpp>
#include <boost/gil/io/typedefs.hpp>
#include <boost/gil/extension/io/targa/detail/reader_backend.hpp>
#include <boost/gil/extension/io/targa/detail/is_allowed.hpp>
namespace boost { namespace gil {
///
/// Targa Scanline Reader
///
template< typename Device >
class scanline_reader< Device
, targa_tag
>
: public reader_backend< Device
, targa_tag
>
{
public:
typedef targa_tag tag_t;
typedef reader_backend < Device, tag_t > backend_t;
typedef scanline_reader< Device, tag_t > this_t;
typedef scanline_read_iterator< this_t > iterator_t;
public:
//
// Constructor
//
scanline_reader( Device& device
, const image_read_settings< targa_tag >& settings
)
: backend_t( device
, settings
)
{
initialize();
}
/// Read part of image defined by View and return the data.
void read( byte_t* dst, int pos )
{
// jump to scanline
long offset = this->_info._offset
+ ( this->_info._height - 1 - pos ) * static_cast< long >( this->_scanline_length );
this->_io_dev.seek( offset );
read_row( dst );
}
/// Skip over a scanline.
void skip( byte_t*, int )
{
this->_io_dev.seek( static_cast<long>( this->_scanline_length )
, SEEK_CUR
);
}
iterator_t begin() { return iterator_t( *this ); }
iterator_t end() { return iterator_t( *this, this->_info._height ); }
private:
void initialize()
{
if( this->_info._color_map_type != targa_color_map_type::_rgb )
{
io_error( "scanline reader cannot read indexed targa files." );
}
if( this->_info._image_type != targa_image_type::_rgb )
{
io_error( "scanline reader cannot read this targa image type." );
}
switch( this->_info._image_type )
{
case targa_image_type::_rgb:
{
if( this->_info._color_map_type != targa_color_map_type::_rgb )
{
io_error( "Inconsistent color map type and image type in targa file." );
}
if( this->_info._color_map_length != 0 )
{
io_error( "Non-indexed targa files containing a palette are not supported." );
}
if( this->_info._screen_origin_bit )
{
io_error( "scanline reader cannot read targa files which have screen origin bit set." );
}
switch( this->_info._bits_per_pixel )
{
case 24:
case 32:
{
this->_scanline_length = this->_info._width * ( this->_info._bits_per_pixel / 8 );
// jump to first scanline
this->_io_dev.seek( static_cast< long >( this->_info._offset ));
break;
}
default:
{
io_error( "Unsupported bit depth in targa file." );
break;
}
}
break;
}
default:
{
io_error( "Unsupported image type in targa file." );
break;
}
}
}
void read_row( byte_t* dst )
{
this->_io_dev.read( dst, this->_scanline_length );
}
};
} // namespace gil
} // namespace boost
#endif
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