jpeg_loader

2019年6月21日2021年6月19日

このオブジェクトはJPEG画像ファイルをピクセルのarray2dに読み込みます。

このオブジェクトを使用したい場合は、DLIB_JPEG_SUPPORTを定義する必要があります。libjpegライブラリにリンクするようにビルド環境を設定する必要もあります。ただし、CMakeとdlibのデフォルトのCMakeLists.txtファイルを使用すると、自動的にセットアップされます。

#include <dlib / image_io.h>

    class jpeg_loader : noncopyable
    {
        /*!
            INITIAL VALUE
                Defined by the constructors

            WHAT THIS OBJECT REPRESENTS
                This object represents a class capable of loading JPEG image files.
                Once an instance of it is created to contain a JPEG file from
                disk you can obtain the image stored in it via get_image().
        !*/

    public:

        jpeg_loader( 
            const char* filename 
        );
        /*!
            ensures
                - loads the JPEG file with the given file name into this object
            throws
                - std::bad_alloc
                - image_load_error
                  This exception is thrown if there is some error that prevents
                  us from loading the given JPEG file.
        !*/

        jpeg_loader( 
            const std::string& filename 
        );
        /*!
            ensures
                - loads the JPEG file with the given file name into this object
            throws
                - std::bad_alloc
                - image_load_error
                  This exception is thrown if there is some error that prevents
                  us from loading the given JPEG file.
        !*/

        jpeg_loader( 
            const dlib::file& f 
        );
        /*!
            ensures
                - loads the JPEG file with the given file name into this object
            throws
                - std::bad_alloc
                - image_load_error
                  This exception is thrown if there is some error that prevents
                  us from loading the given JPEG file.
        !*/

        ~jpeg_loader(
        );
        /*!
            ensures
                - all resources associated with *this has been released
        !*/

        bool is_gray(
        ) const;
        /*!
            ensures
                - if (this object contains a grayscale image) then
                    - returns true
                - else
                    - returns false
        !*/
        
        bool is_rgb(
        ) const;
        /*!
            ensures
                - if (this object contains a 3 channel RGB image) then
                    - returns true
                - else
                    - returns false
        !*/

        template<
            typename image_type 
            >
        void get_image( 
            image_type& img
        ) const;
        /*!
            requires
                - image_type == an image object that implements the interface defined in
                  dlib/image_processing/generic_image.h 
            ensures
                - loads the JPEG image stored in this object into img
        !*/

    };