// Copyright (C) 2008 Davis E. King (davis@dlib.net), Nils Labugt
// License: Boost Software License See LICENSE.txt for the full license.
#ifndef DLIB_PNG_LOADER_CPp_
#define DLIB_PNG_LOADER_CPp_
// only do anything with this file if DLIB_PNG_SUPPORT is defined
#ifdef DLIB_PNG_SUPPORT
#include "../array2d.h"
#include "../pixel.h"
#include "../dir_nav.h"
#include "png_loader.h"
#include <png.h>
namespace dlib
{
// ----------------------------------------------------------------------------------------
struct LibpngData
{
png_bytep* row_pointers_;
png_structp png_ptr_;
png_infop info_ptr_;
png_infop end_info_;
};
// ----------------------------------------------------------------------------------------
png_loader::
png_loader( const char* filename ) : height_( 0 ), width_( 0 )
{
read_image( filename );
}
// ----------------------------------------------------------------------------------------
png_loader::
png_loader( const std::string& filename ) : height_( 0 ), width_( 0 )
{
read_image( filename.c_str() );
}
// ----------------------------------------------------------------------------------------
png_loader::
png_loader( const dlib::file& f ) : height_( 0 ), width_( 0 )
{
read_image( f.full_name().c_str() );
}
// ----------------------------------------------------------------------------------------
const unsigned char* png_loader::get_row( unsigned i ) const
{
return ld_->row_pointers_[i];
}
// ----------------------------------------------------------------------------------------
png_loader::~png_loader()
{
if ( ld_ && ld_->row_pointers_ != NULL )
png_destroy_read_struct( &( ld_->png_ptr_ ), &( ld_->info_ptr_ ), &( ld_->end_info_ ) );
}
// ----------------------------------------------------------------------------------------
bool png_loader::is_gray() const
{
return ( color_type_ == PNG_COLOR_TYPE_GRAY );
}
// ----------------------------------------------------------------------------------------
bool png_loader::is_rgb() const
{
return ( color_type_ == PNG_COLOR_TYPE_RGB );
}
// ----------------------------------------------------------------------------------------
bool png_loader::is_rgba() const
{
return ( color_type_ == PNG_COLOR_TYPE_RGB_ALPHA );
}
// ----------------------------------------------------------------------------------------
void png_loader::read_image( const char* filename )
{
ld_.reset(new LibpngData);
if ( filename == NULL )
{
throw image_load_error("png_loader: invalid filename, it is NULL");
}
FILE *fp = fopen( filename, "rb" );
if ( !fp )
{
throw image_load_error(std::string("png_loader: unable to open file ") + filename);
}
png_byte sig[8];
if (fread( sig, 1, 8, fp ) != 8)
{
fclose( fp );
throw image_load_error(std::string("png_loader: error reading file ") + filename);
}
if ( png_sig_cmp( sig, 0, 8 ) != 0 )
{
fclose( fp );
throw image_load_error(std::string("png_loader: format error in file ") + filename);
}
ld_->png_ptr_ = png_create_read_struct( PNG_LIBPNG_VER_STRING, NULL, NULL, NULL );
if ( ld_->png_ptr_ == NULL )
{
fclose( fp );
throw image_load_error(std::string("png_loader: parse error in file ") + filename);
}
ld_->info_ptr_ = png_create_info_struct( ld_->png_ptr_ );
if ( ld_->info_ptr_ == NULL )
{
fclose( fp );
png_destroy_read_struct( &( ld_->png_ptr_ ), ( png_infopp )NULL, ( png_infopp )NULL );
throw image_load_error(std::string("png_loader: parse error in file ") + filename);
}
ld_->end_info_ = png_create_info_struct( ld_->png_ptr_ );
if ( ld_->end_info_ == NULL )
{
fclose( fp );
png_destroy_read_struct( &( ld_->png_ptr_ ), &( ld_->info_ptr_ ), ( png_infopp )NULL );
throw image_load_error(std::string("png_loader: parse error in file ") + filename);
}
png_init_io( ld_->png_ptr_, fp );
png_set_sig_bytes( ld_->png_ptr_, 8 );
// flags force one byte per channel output
png_read_png( ld_->png_ptr_, ld_->info_ptr_, PNG_TRANSFORM_STRIP_16 | PNG_TRANSFORM_PACKING, NULL );
height_ = png_get_image_height( ld_->png_ptr_, ld_->info_ptr_ );
width_ = png_get_image_width( ld_->png_ptr_, ld_->info_ptr_ );
bit_depth_ = png_get_bit_depth( ld_->png_ptr_, ld_->info_ptr_ );
color_type_ = png_get_color_type( ld_->png_ptr_, ld_-> info_ptr_ );
if (color_type_ != PNG_COLOR_TYPE_GRAY &&
color_type_ != PNG_COLOR_TYPE_RGB &&
color_type_ != PNG_COLOR_TYPE_RGB_ALPHA )
{
fclose( fp );
png_destroy_read_struct( &( ld_->png_ptr_ ), &( ld_->info_ptr_ ), &( ld_->end_info_ ) );
throw image_load_error(std::string("png_loader: unsupported color type in file ") + filename);
}
ld_->row_pointers_ = png_get_rows( ld_->png_ptr_, ld_->info_ptr_ );
// FIXME: the following call makes libpng crash. Why?
//png_read_end( ld_->png_ptr_, ld_->end_info_ );
fclose( fp );
if ( ld_->row_pointers_ == NULL )
{
throw image_load_error(std::string("png_loader: parse error in file ") + filename);
}
}
// ----------------------------------------------------------------------------------------
}
#endif // DLIB_PNG_SUPPORT
#endif // DLIB_PNG_LOADER_CPp_