ABSTRACT
This chapter is about a fundamental mechanism for rendering bitmaps called a blit, short for bit block transfer. The Windows GDI contains a blit function but DirectDraw provides its own versions, in the form of two functions named Blt() and BltFast(). A third variation, called BltBatch(), was announced but never implemented. Another rendering technique is called an overlay. Overlays are like a transparent media which can be placed over an image and then removed, restoring the original. Overlays have been implemented inconsistently in the video hardware, and for this reason they are not discussed.
