coco
223 lines
7.9 KiB
C++
223 lines
7.9 KiB
C++
// 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>
|
|
#include "../string.h"
|
|
#include "../byte_orderer.h"
|
|
#include <sstream>
|
|
#include <cstring>
|
|
|
|
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_graya() const
|
|
{
|
|
return ( color_type_ == PNG_COLOR_TYPE_GRAY_ALPHA );
|
|
}
|
|
|
|
// ----------------------------------------------------------------------------------------
|
|
|
|
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 );
|
|
}
|
|
|
|
// ----------------------------------------------------------------------------------------
|
|
|
|
// Don't do anything when libpng calls us to tell us about an error. Just return to
|
|
// our own code and throw an exception (at the long jump target).
|
|
void png_loader_user_error_fn_silent(png_structp png_struct, png_const_charp )
|
|
{
|
|
longjmp(png_jmpbuf(png_struct),1);
|
|
}
|
|
void png_loader_user_warning_fn_silent(png_structp , png_const_charp )
|
|
{
|
|
}
|
|
|
|
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, &png_loader_user_error_fn_silent, &png_loader_user_warning_fn_silent );
|
|
if ( ld_->png_ptr_ == NULL )
|
|
{
|
|
fclose( fp );
|
|
std::ostringstream sout;
|
|
sout << "Error, unable to allocate png structure while opening file " << filename << std::endl;
|
|
const char* runtime_version = png_get_header_ver(NULL);
|
|
if (runtime_version && std::strcmp(PNG_LIBPNG_VER_STRING, runtime_version) != 0)
|
|
{
|
|
sout << "This is happening because you compiled against one version of libpng, but then linked to another." << std::endl;
|
|
sout << "Compiled against libpng version: " << PNG_LIBPNG_VER_STRING << std::endl;
|
|
sout << "Linking to this version of libpng: " << runtime_version << std::endl;
|
|
}
|
|
throw image_load_error(sout.str());
|
|
}
|
|
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);
|
|
}
|
|
|
|
if (setjmp(png_jmpbuf(ld_->png_ptr_)))
|
|
{
|
|
// If we get here, we had a problem writing the file
|
|
fclose(fp);
|
|
png_destroy_read_struct( &( ld_->png_ptr_ ), &( ld_->info_ptr_ ), &( ld_->end_info_ ) );
|
|
throw image_load_error(std::string("png_loader: parse error in file ") + filename);
|
|
}
|
|
|
|
png_set_palette_to_rgb(ld_->png_ptr_);
|
|
|
|
png_init_io( ld_->png_ptr_, fp );
|
|
png_set_sig_bytes( ld_->png_ptr_, 8 );
|
|
// flags force one byte per channel output
|
|
byte_orderer bo;
|
|
int png_transforms = PNG_TRANSFORM_PACKING;
|
|
if (bo.host_is_little_endian())
|
|
png_transforms |= PNG_TRANSFORM_SWAP_ENDIAN;
|
|
png_read_png( ld_->png_ptr_, ld_->info_ptr_, png_transforms, 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 &&
|
|
color_type_ != PNG_COLOR_TYPE_GRAY_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);
|
|
}
|
|
|
|
if (bit_depth_ != 8 && bit_depth_ != 16)
|
|
{
|
|
fclose( fp );
|
|
png_destroy_read_struct( &( ld_->png_ptr_ ), &( ld_->info_ptr_ ), &( ld_->end_info_ ) );
|
|
throw image_load_error("png_loader: unsupported bit depth of " + cast_to_string(bit_depth_) + " in file " + std::string(filename));
|
|
}
|
|
|
|
ld_->row_pointers_ = png_get_rows( ld_->png_ptr_, ld_->info_ptr_ );
|
|
|
|
fclose( fp );
|
|
if ( ld_->row_pointers_ == NULL )
|
|
{
|
|
png_destroy_read_struct( &( ld_->png_ptr_ ), &( ld_->info_ptr_ ), &( ld_->end_info_ ) );
|
|
throw image_load_error(std::string("png_loader: parse error in file ") + filename);
|
|
}
|
|
}
|
|
|
|
// ----------------------------------------------------------------------------------------
|
|
|
|
}
|
|
|
|
#endif // DLIB_PNG_SUPPORT
|
|
|
|
#endif // DLIB_PNG_LOADER_CPp_
|
|
|