Method of electronically moving portions of several different images on a CRT screen

摘要

A method of electronically moving portions of several different images on a CRT screen includes the steps of: storing a first image in one section of an image memory, and storing a second image in a different section of the image memory; storing control bits in a control memory which define high and low priority viewports on the screen and correlate portions of the first and second images to the high and low priority viewports respectively; displaying, in response to the stored control bits, the entire portion of the image in the high priority viewport and only the non-overlapping portion of the image in the low priority viewport by transferring the image portions from the image memory to the screen with no frame buffer therebetween; modifying at least some of the stored control bits to change the priorities of the high and low priority viewports to low and high respectively; and repeating the displaying step, in response to the modified control bits, to display the entire portion of the image in the new high priority viewport and only the non-overlapping portion of the image in the new low priority viewport.