virtual void get_output_size(unsigned *width, unsigned *height, unsigned *virtual_width, unsigned *virtual_height) const;
virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height);
private:
virtual void get_output_size(unsigned *width, unsigned *height, unsigned *virtual_width, unsigned *virtual_height) const;
virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height);
private: