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(11) | EP 0 482 746 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Multiple-window lookup table selection |
(57) A system for selecting from multiple palette lookup tables (LUTs) in a multiple-window
system without requiring extra planes in video memory for storing palette information.
X and Y position signals representing the current position on the screen are compared
with the X and Y minima and maxima of each of the defined windows to determine whether
the current position is within one or more windows. If the current position is within
two or more windows, the window with the highest priority, as stored in a programmable
priority register, is selected, and the lookup table is selected that is assigned
to that window by a programmable lookup table register. Successive groups of pixels
are processed in parallel to increase the speed of operation. |