The pel data is stored in the bitmap in the order that the coordinates appear on a display screen. That is, the pel in the lower-left corner is the first in the bitmap. Pels are scanned to the right, and upward, from that position. The bits of the first pel are stored, beginning with the most significant bits of the first byte. The data for pels in each scan line is packed together tightly, but all scan lines are padded at the end, so that each one begins on a ULONG boundary.