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//
// Copyright 2012 Christian Henning
//
// Distributed under 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_DETAIL_READER_BACKEND_HPP
#define BOOST_GIL_EXTENSION_IO_DETAIL_READER_BACKEND_HPP
#include <boost/gil/extension/io/png/tags.hpp>
#include <boost/gil/extension/io/png/detail/base.hpp>
#include <boost/gil/extension/io/png/detail/supported_types.hpp>
namespace boost { namespace gil {
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
#pragma warning(push)
#pragma warning(disable:4512) //assignment operator could not be generated
#pragma warning(disable:4611) //interaction between '_setjmp' and C++ object destruction is non-portable
#endif
///
/// PNG Backend
///
template<typename Device >
struct reader_backend< Device
, png_tag
>
: public detail::png_struct_info_wrapper
{
public:
using format_tag_t = png_tag;
using this_t = reader_backend<Device, png_tag>;
public:
reader_backend( const Device& io_dev
, const image_read_settings< png_tag >& settings
)
: _io_dev( io_dev )
, _settings( settings )
, _info()
, _scanline_length( 0 )
, _number_passes( 0 )
{
read_header();
if( _settings._dim.x == 0 )
{
_settings._dim.x = _info._width;
}
if( _settings._dim.y == 0 )
{
_settings._dim.y = _info._height;
}
}
void read_header()
{
using boost::gil::detail::PNG_BYTES_TO_CHECK;
// check the file's first few bytes
byte_t buf[PNG_BYTES_TO_CHECK];
io_error_if( _io_dev.read( buf
, PNG_BYTES_TO_CHECK
) != PNG_BYTES_TO_CHECK
, "png_check_validity: failed to read image"
);
io_error_if( png_sig_cmp( png_bytep(buf)
, png_size_t(0)
, PNG_BYTES_TO_CHECK
) != 0
, "png_check_validity: invalid png image"
);
// Create and initialize the png_struct with the desired error handler
// functions. If you want to use the default stderr and longjump method,
// you can supply NULL for the last three parameters. We also supply the
// the compiler header file version, so that we know if the application
// was compiled with a compatible version of the library. REQUIRED
get()->_struct = png_create_read_struct( PNG_LIBPNG_VER_STRING
, nullptr // user_error_ptr
, nullptr // user_error_fn
, nullptr // user_warning_fn
);
io_error_if( get()->_struct == nullptr
, "png_reader: fail to call png_create_write_struct()"
);
png_uint_32 user_chunk_data[4];
user_chunk_data[0] = 0;
user_chunk_data[1] = 0;
user_chunk_data[2] = 0;
user_chunk_data[3] = 0;
png_set_read_user_chunk_fn( get_struct()
, user_chunk_data
, this_t::read_user_chunk_callback
);
// Allocate/initialize the memory for image information. REQUIRED.
get()->_info = png_create_info_struct( get_struct() );
if( get_info() == nullptr )
{
png_destroy_read_struct( &get()->_struct
, nullptr
, nullptr
);
io_error( "png_reader: fail to call png_create_info_struct()" );
}
// Set error handling if you are using the setjmp/longjmp method (this is
// the normal method of doing things with libpng). REQUIRED unless you
// set up your own error handlers in the png_create_read_struct() earlier.
if( setjmp( png_jmpbuf( get_struct() )))
{
//free all of the memory associated with the png_ptr and info_ptr
png_destroy_read_struct( &get()->_struct
, &get()->_info
, nullptr
);
io_error( "png is invalid" );
}
png_set_read_fn( get_struct()
, static_cast< png_voidp >( &this->_io_dev )
, this_t::read_data
);
// Set up a callback function that will be
// called after each row has been read, which you can use to control
// a progress meter or the like.
png_set_read_status_fn( get_struct()
, this_t::read_row_callback
);
// Set up a callback which implements user defined transformation.
// @todo
png_set_read_user_transform_fn( get_struct()
, png_user_transform_ptr( nullptr )
);
png_set_keep_unknown_chunks( get_struct()
, PNG_HANDLE_CHUNK_ALWAYS
, nullptr
, 0
);
// Make sure we read the signature.
// @todo make it an option
png_set_sig_bytes( get_struct()
, PNG_BYTES_TO_CHECK
);
// The call to png_read_info() gives us all of the information from the
// PNG file before the first IDAT (image data chunk). REQUIRED
png_read_info( get_struct()
, get_info()
);
///
/// Start reading the image information
///
// get PNG_IHDR chunk information from png_info structure
png_get_IHDR( get_struct()
, get_info()
, &this->_info._width
, &this->_info._height
, &this->_info._bit_depth
, &this->_info._color_type
, &this->_info._interlace_method
, &this->_info._compression_method
, &this->_info._filter_method
);
// get number of color channels in image
this->_info._num_channels = png_get_channels( get_struct()
, get_info()
);
#ifdef BOOST_GIL_IO_PNG_FLOATING_POINT_SUPPORTED
// Get CIE chromacities and referenced white point
if( this->_settings._read_cie_chromacities )
{
this->_info._valid_cie_colors = png_get_cHRM( get_struct()
, get_info()
, &this->_info._white_x, &this->_info._white_y
, &this->_info._red_x, &this->_info._red_y
, &this->_info._green_x, &this->_info._green_y
, &this->_info._blue_x, &this->_info._blue_y
);
}
// get the gamma value
if( this->_settings._read_file_gamma )
{
this->_info._valid_file_gamma = png_get_gAMA( get_struct()
, get_info()
, &this->_info._file_gamma
);
if( this->_info._valid_file_gamma == false )
{
this->_info._file_gamma = 1.0;
}
}
#else
// Get CIE chromacities and referenced white point
if( this->_settings._read_cie_chromacities )
{
this->_info._valid_cie_colors = png_get_cHRM_fixed( get_struct()
, get_info()
, &this->_info._white_x, &this->_info._white_y
, &this->_info._red_x, &this->_info._red_y
, &this->_info._green_x, &this->_info._green_y
, &this->_info._blue_x, &this->_info._blue_y
);
}
// get the gamma value
if( this->_settings._read_file_gamma )
{
this->_info._valid_file_gamma = png_get_gAMA_fixed( get_struct()
, get_info()
, &this->_info._file_gamma
);
if( this->_info._valid_file_gamma == false )
{
this->_info._file_gamma = 1;
}
}
#endif // BOOST_GIL_IO_PNG_FLOATING_POINT_SUPPORTED
// get the embedded ICC profile data
if( this->_settings._read_icc_profile )
{
#if PNG_LIBPNG_VER_MINOR >= 5
png_charp icc_name = png_charp( nullptr );
png_bytep profile = png_bytep( nullptr );
this->_info._valid_icc_profile = png_get_iCCP( get_struct()
, get_info()
, &icc_name
, &this->_info._iccp_compression_type
, &profile
, &this->_info._profile_length
);
#else
png_charp icc_name = png_charp( NULL );
png_charp profile = png_charp( NULL );
this->_info._valid_icc_profile = png_get_iCCP( get_struct()
, get_info()
, &icc_name
, &this->_info._iccp_compression_type
, &profile
, &this->_info._profile_length
);
#endif
if( icc_name )
{
this->_info._icc_name.append( icc_name
, std::strlen( icc_name )
);
}
if( this->_info._profile_length != 0 )
{
std:: copy_n (profile, this->_info._profile_length, std:: back_inserter (this->_info._profile));
}
}
// get the rendering intent
if( this->_settings._read_intent )
{
this->_info._valid_intent = png_get_sRGB( get_struct()
, get_info()
, &this->_info._intent
);
}
// get image palette information from png_info structure
if( this->_settings._read_palette )
{
png_colorp palette = png_colorp( nullptr );
this->_info._valid_palette = png_get_PLTE( get_struct()
, get_info()
, &palette
, &this->_info._num_palette
);
if( this->_info._num_palette > 0 )
{
this->_info._palette.resize( this->_info._num_palette );
std::copy( palette
, palette + this->_info._num_palette
, &this->_info._palette.front()
);
}
}
// get background color
if( this->_settings._read_background )
{
png_color_16p background = png_color_16p( nullptr );
this->_info._valid_background = png_get_bKGD( get_struct()
, get_info()
, &background
);
if( background )
{
this->_info._background = *background;
}
}
// get the histogram
if( this->_settings._read_histogram )
{
png_uint_16p histogram = png_uint_16p( nullptr );
this->_info._valid_histogram = png_get_hIST( get_struct()
, get_info()
, &histogram
);
if( histogram )
{
// the number of values is set by the number of colors inside
// the palette.
if( this->_settings._read_palette == false )
{
png_colorp palette = png_colorp( nullptr );
png_get_PLTE( get_struct()
, get_info()
, &palette
, &this->_info._num_palette
);
}
std::copy( histogram
, histogram + this->_info._num_palette
, &this->_info._histogram.front()
);
}
}
// get screen offsets for the given image
if( this->_settings._read_screen_offsets )
{
this->_info._valid_offset = png_get_oFFs( get_struct()
, get_info()
, &this->_info._offset_x
, &this->_info._offset_y
, &this->_info._off_unit_type
);
}
// get pixel calibration settings
if( this->_settings._read_pixel_calibration )
{
png_charp purpose = png_charp ( nullptr );
png_charp units = png_charp ( nullptr );
png_charpp params = png_charpp( nullptr );
this->_info._valid_pixel_calibration = png_get_pCAL( get_struct()
, get_info()
, &purpose
, &this->_info._X0
, &this->_info._X1
, &this->_info._cal_type
, &this->_info._num_params
, &units
, &params
);
if( purpose )
{
this->_info._purpose.append( purpose
, std::strlen( purpose )
);
}
if( units )
{
this->_info._units.append( units
, std::strlen( units )
);
}
if( this->_info._num_params > 0 )
{
this->_info._params.resize( this->_info._num_params );
for( png_CAL_nparam::type i = 0
; i < this->_info._num_params
; ++i
)
{
this->_info._params[i].append( params[i]
, std::strlen( params[i] )
);
}
}
}
// get the physical resolution
if( this->_settings._read_physical_resolution )
{
this->_info._valid_resolution = png_get_pHYs( get_struct()
, get_info()
, &this->_info._res_x
, &this->_info._res_y
, &this->_info._phy_unit_type
);
}
// get the image resolution in pixels per meter.
if( this->_settings._read_pixels_per_meter )
{
this->_info._pixels_per_meter = png_get_pixels_per_meter( get_struct()
, get_info()
);
}
// get number of significant bits for each color channel
if( this->_settings._read_number_of_significant_bits )
{
png_color_8p sig_bits = png_color_8p( nullptr );
this->_info._valid_significant_bits = png_get_sBIT( get_struct()
, get_info()
, &sig_bits
);
// @todo Is there one or more colors?
if( sig_bits )
{
this->_info._sig_bits = *sig_bits;
}
}
#ifndef BOOST_GIL_IO_PNG_1_4_OR_LOWER
#ifdef BOOST_GIL_IO_PNG_FLOATING_POINT_SUPPORTED
// get physical scale settings
if( this->_settings._read_scale_factors )
{
this->_info._valid_scale_factors = png_get_sCAL( get_struct()
, get_info()
, &this->_info._scale_unit
, &this->_info._scale_width
, &this->_info._scale_height
);
}
#else
#ifdef BOOST_GIL_IO_PNG_FIXED_POINT_SUPPORTED
if( this->_settings._read_scale_factors )
{
this->_info._valid_scale_factors = png_get_sCAL_fixed( get_struct()
, get_info()
, &this->_info._scale_unit
, &this->_info._scale_width
, &this->_info._scale_height
);
}
#else
if( this->_settings._read_scale_factors )
{
png_charp scale_width = nullptr;
png_charp scale_height = nullptr;
this->_info._valid_scale_factors = png_get_sCAL_s(
get_struct(), get_info(), &this->_info._scale_unit, &scale_width, &scale_height);
if (this->_info._valid_scale_factors)
{
if( scale_width )
{
this->_info._scale_width.append( scale_width
, std::strlen( scale_width )
);
}
if( scale_height )
{
this->_info._scale_height.append( scale_height
, std::strlen( scale_height )
);
}
}
}
#endif // BOOST_GIL_IO_PNG_FIXED_POINT_SUPPORTED
#endif // BOOST_GIL_IO_PNG_FLOATING_POINT_SUPPORTED
#endif // BOOST_GIL_IO_PNG_1_4_OR_LOWER
// get comments information from png_info structure
if( this->_settings._read_comments )
{
png_textp text = png_textp( nullptr );
this->_info._valid_text = png_get_text( get_struct()
, get_info()
, &text
, &this->_info._num_text
);
if( this->_info._num_text > 0 )
{
this->_info._text.resize( this->_info._num_text );
for( png_num_text::type i = 0
; i < this->_info._num_text
; ++i
)
{
this->_info._text[i]._compression = text[i].compression;
this->_info._text[i]._key.append( text[i].key
, std::strlen( text[i].key )
);
this->_info._text[i]._text.append( text[i].text
, std::strlen( text[i].text )
);
}
}
}
// get last modification time
if( this->_settings._read_last_modification_time )
{
png_timep mod_time = png_timep( nullptr );
this->_info._valid_modification_time = png_get_tIME( get_struct()
, get_info()
, &mod_time
);
if( mod_time )
{
this->_info._mod_time = *mod_time;
}
}
// get transparency data
if( this->_settings._read_transparency_data )
{
png_bytep trans = png_bytep ( nullptr );
png_color_16p trans_values = png_color_16p( nullptr );
this->_info._valid_transparency_factors = png_get_tRNS( get_struct()
, get_info()
, &trans
, &this->_info._num_trans
, &trans_values
);
if( trans )
{
//@todo What to do, here? How do I know the length of the "trans" array?
}
if( this->_info._num_trans )
{
this->_info._trans_values.resize( this->_info._num_trans );
std::copy( trans_values
, trans_values + this->_info._num_trans
, &this->_info._trans_values.front()
);
}
}
// @todo One day!
/*
if( false )
{
png_unknown_chunkp unknowns = png_unknown_chunkp( NULL );
int num_unknowns = static_cast< int >( png_get_unknown_chunks( get_struct()
, get_info()
, &unknowns
)
);
}
*/
}
/// Check if image is large enough.
void check_image_size( const point_t& img_dim )
{
if( _settings._dim.x > 0 )
{
if( img_dim.x < _settings._dim.x ) { io_error( "Supplied image is too small" ); }
}
else
{
if( img_dim.x < _info._width ) { io_error( "Supplied image is too small" ); }
}
if( _settings._dim.y > 0 )
{
if( img_dim.y < _settings._dim.y ) { io_error( "Supplied image is too small" ); }
}
else
{
if( img_dim.y < _info._height ) { io_error( "Supplied image is too small" ); }
}
}
protected:
static void read_data( png_structp png_ptr
, png_bytep data
, png_size_t length
)
{
static_cast<Device*>(png_get_io_ptr(png_ptr) )->read( data
, length );
}
static void flush( png_structp png_ptr )
{
static_cast<Device*>(png_get_io_ptr(png_ptr) )->flush();
}
static int read_user_chunk_callback( png_struct* /* png_ptr */
, png_unknown_chunkp /* chunk */
)
{
// @todo
return 0;
}
static void read_row_callback( png_structp /* png_ptr */
, png_uint_32 /* row_number */
, int /* pass */
)
{
// @todo
}
public:
Device _io_dev;
image_read_settings< png_tag > _settings;
image_read_info < png_tag > _info;
std::size_t _scanline_length;
std::size_t _number_passes;
};
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
#pragma warning(pop)
#endif
} // namespace gil
} // namespace boost
#endif