Tag: color mask

Use of Color Mask Byte in HIRES

by Darrell Aldrich This is a brief description of the use of the color mask byte (Location 81210) for high re solution graphics in Apple Integer Basic. This mask specifies an 8 bit pattern of plottable X coordinates, with the pattern repeating itself every eight coordinates, going from left to right. The bits in this byte represent the colors violet and green, alternately. (See Figure 1). Suppose we want to mask off every other green bar on the screen as…