Color index conversion system in graphic display device

Claim 1

In a color graphic display device having a plurality of frame memories, apparatus for copying color index data read out from at least one designated area of a first frame memory into at least one designated area of a second frame memory in oder to convert color information on screen color index data which are read out from said plurality of frame memories, comprising: frame editing means adapted for controlling copy and edit operations among said frame memories, and for providing a group number determined in accordance with a combination of areas between a copy source memory of said first frame memory and a copy designation memory of said second frame memory, and for providing write enable/disable data which represents a write enable/disable state of said plurality of frame memories; first register means, coupled to said frame editing means, for holding said group number output from said frame editing means; second register means, coupled to said frame editing means, for holding said write enable/disable data output from said frame editing means; read only memory means, coupled to said plurality of frame memories and to said first register means and to said frame editing means, for storing conversion color index data at a plurality of addresses, and for receiving, as address data, linked data comprising said group number output from said first register means and the color index data output from said plurality of frame memories; and writing means, coupled to said frame editing means, for receiving from said frame editing means data read out from said read only memory means, and for writing said data to said plurality of frame memories as converted color index data.