// 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" 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 ); 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); } 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_