Cursor Display on Raster Graphic Devices
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
In general, cross-hair, rectangular (or other) cursors are drawn on single buffered raster displays by operating on bits in the bit plane(s) using one of the following functions: . XOR cursor bits with bit plane(s) . OR (set) cursor bits with bit plane(s), i.e., 'all 1's' cursor . AND NOT (reset) cursor bits with bit plane(s), i.e., 'all d's cursor When the cursor is deleted and/or moved, the pels (picture elements) of the picture in the bit planes must be restored. Currently there are two alternatives: 1. Re-draw the picture 2. Save the bits in the cursor positions before drawing the cursor, and restore them when the cursor is deleted. [Note that for the XOR cursor, simply XORing it into the bit plane a second time will restore the picture.