International Business Machines Corporation

Narendra Maganlal Desai

Michael Terrell Vanover

Ashutosh Misra

Neal Richard Marion

John A Voltin

Irene Beattie

Seetharam Gundu Rao

Raju Bala Showry Pudota

Smoother transitions between changing cursor images which are less stressful to the interactive user of a computer controlled display are provided by apparatus for changing the cursor image, including a frame buffer for storing the display screen image as a pixel array, a separate display buffer for storing the current cursor image as a pixel array, together with apparatus for storing an alternate cursor image as a pixel array during the display of the current cursor image, and means for replacing the current cursor image with the alternate cursor image. In raster scan apparatus for maintaining screen images in the frame buffer on said display screen, there are means for effecting the replacement of said cursor images during a vertical blanking period in said raster scanning.

Computer controlled interactive display with dual cursor image storage for a smooth transition during cursor image change

Apparatus and methods for selectively controlling by window the number of overlay planes, the number of overlay palettes, and the overlay/underlay plane masks in a graphics video display system. A logic/multiplex control translates overlay and underlay data patterns from a multiple plane VRAM (Video Random Access Memory), referenced to the graphics system frame buffer, into window specific patterns. The window related translation is conveyed to conventional RAMDACs (Random Access Memory Digital-to-Analog Converters) for raster scan synchronized digital-to-analog conversion. The translation as provided by the controller is responsive to data selectively and dynamically written into a random access memory, thus providing translation of overlay/underlay data into window distinct and selective overlay/underlay palette functions.

Selective control of window related overlays and underlays

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Round Rock, TX, United States of America

Narendra Maganlal Desai