| 摘要 |
PURPOSE: To enable a screen composition process with a small hardware quantity as to the screen composition controller which puts plural screens, displayed overlapping with each other, together and displays the composite screen while performing mode conversion processes. CONSTITUTION: The screen composition control unit, consisting of a 1st selecting means 3 which selects one of video memories corresponding to screens and converting means 4 which are provided corresponding to the mode conversion processes, is equipped with an arithmetic means 5 which performs a mode conversion process for image data outputted by the 1st selecting means 3, a 2nd selecting means 6 which selects one of conversion data outputted by the converting means 4, a 1st control means 7 which judges whether or not a process pixel read out of each video memory is transparent and controls the selecting process of the 1st selecting means 3 according to the judgement result and hierarchical structure information on the screens, and a 2nd control means 8 which controls the selecting process of the 2nd selecting means 5 according to the output value of the 1st control means 7 and mode information on the respective screens. |
