Abstract: A compressive coding device converts three color components of pixel data from the RGB presentation to the YCbCr presentation according to a mapping rule. Converted pixel data are subsequently subjected to irreversible compressive coding, thus producing compressive coded data. Pixel data ascribed to transparency control are converted to a prescribed value out of a mapping range according to the mapping rule. Compressive coded data are supplied to a visual display control device, in which they are decoded and reproduced into original pixel data of the first color presentation. Compressive coded data corresponding to pixel data ascribed to transparency control are rendered with a prescribed color in the RGB presentation which is designated as transparency in advance or not rendered on screen. Thus, it is possible to precisely perform the transparency control without causing a reduction of the compression factor regardless of the irreversible compressive coding and decoding.

Abstract: A compressive coding device converts three color components of pixel data from the RGB presentation to the YCbCr presentation according to a mapping rule. Converted pixel data are subsequently subjected to irreversible compressive coding, thus producing compressive coded data. Pixel data ascribed to transparency control are converted to a prescribed value out of a mapping range according to the mapping rule. Compressive coded data are supplied to a visual display control device, in which they are decoded and reproduced into original pixel data of the first color presentation. Compressive coded data corresponding to pixel data ascribed to transparency control are rendered with a prescribed color in the RGB presentation which is designated as transparency in advance or not rendered on screen. Thus, it is possible to precisely perform the transparency control without causing a reduction of the compression factor regardless of the irreversible compressive coding and decoding.

Abstract: An image display device is constructed by a display memory, a sprite attribute table, a sprite rendering processor and an animation execution engine. The display memory stores image data to be displayed on a display. The sprite attribute table stores attribute data representing a display attribute of a sprite which is a component of the image data. The sprite rendering processor executes a drawing process for reflecting image data of the sprite to the image data stored in the display memory according to the attribute data stored in the sprite attribute table. The animation execution engine reads an animation execution program including both attribute data to be transferred and a table write command of the attribute data from an external memory, and executes the animation execution program to transfer the attribute data to the sprite attribute table according to the table write command.