Method and system for independent control of multiple windows in a graphics display system

A frame buffer to be utilized in displaying an image in a graphics display system, said frame buffer comprising:

• at least one color plane, wherein said at least one color plane comprises a first plurality of pixels, and wherein said at least one color plane comprises a rendered image for display on a display screen;
• at least one overlay plane, wherein said at least one overlay plane comprises a second plurality of pixels, and wherein said second plurality of pixels supersedes at least a portion of said first plurality of pixels on said display screen;
• a first window identification plane associated with said at least one color plane, wherein said first window identification plane defines at least a first window for displaying at least a portion of said first plurality of pixels;
• and
• a second window identification plane associated with said at least one overlay plane, wherein said second window plane defines at least a second window, and wherein said first and second window identification planes provide for independent control of said at least first and second windows such that when said first and second plurality of pixels are displayed within said at least first and second windows, said portion of first plurality of pixels which are superseded by said second plurality of pixels may be updated during display of said second plurality of pixels.

A graphics display system for displaying an image on a display device, said graphics display system comprises:

• means for specifying a first window within a first portion of a display screen of said display device, whereby said first window is associated with a first plurality of pixel;
• means for specifying intensity data for said first plurality of pixels for an underlying image within said first window, wherein each of said first plurality of pixels within said first window has a first window identifier associated therewith;
• means for specifying a second window within a second portion of said display screen, whereby said second window is associated with a second plurality of pixels, and whereby a only portion of said second window overlies a portion of said first window;
• means for specifying intensity data for said second plurality of pixels for an overlying image within said second window, wherein each of said second plurality of pixels within said second window has a second window identifier associated therewith and wherein selected pixels among said second plurality of pixels supersede particular pixels among said first plurality of pixels within said displayed image;
• means for storing said intensity data for all of said first and second plurality of pixels and said first and second window identifiers for said overlying and underlying images in separate locations in a single frame buffer including said superseded pixels among said first plurality of pixels;
• and
• means for displaying an overall image comprised of said underlying image and said overlying image superimposed over at least a portion of said underlying image by utilizing said intensity data and said first and second window identifiers from said single frame buffer, wherein said first and second window identifiers provide for independent control of said first and second windows so that said first plurality of pixels can be updated during display of said overall image.