Graphic Bit-Blt Copy Under Mask
Original Publication Date: 1985-Nov-01
Included in the Prior Art Database: 2005-Feb-19
Bit-Boundary Block Transfer (Bit-blt) operations require two rectangular windows to determine source and destination areas. When odd-shaped figures are to be copied into a frame buffer, difficulties may arise. If the source object has nearby objects, the unwanted data may be copied into the destination. Copying arbitrarily shaped objects may be attempted by piecewise copies. Such an approach may be very complicated and time consuming. An additional problem is that the background of the source is conventionally copied also. It is desirable to copy an arbitrary object in a straightforward and rapid manner. This disclosure describes a system for making bit-blt copy operations of arbitrary shapes within a frame buffer using masks contained in planes of the frame buffer.