Drawing starts at the current X-position and at a Y-position defined as a row offset below the current Y-position. Data is supplied as a series of bytes and a count of the bits to be drawn. The handling routine cannot assume that unused bits at the end of the stream are set to 0. Bits are drawn from left to right. The high-order bit of each byte is the leftmost-image bit. The 1 bits are foreground and the 0 bits are background. Note that this function does not affect the current position.