The analysis and evaluation techniques of a gamut mapping technique, which can reflect the determination result of the quality of gamut mapping in the gamut mapping technique, are demanded. Hence, a color distribution information file and image file are loaded, initial 3D object data is generated based on color distribution data, and initial image object data is generated based on image data. The image object data and 3D object data are displayed on a monitor. When the user inputs a message, a process corresponding to the input message is executed, and the updated image object data and 3D object data are displayed on the monitor.