Frame Buffer Architecture of Raster Displays

True-Color Frame Buffers

• Each pixel requires at least 3 bytes. One byte for each primary color.
• Sometimes combined with a look-up table per primary
• Each pixel can be one of 2^24 colors
• Worry about your Endians

Indexed-Color Frame Buffers

• Each pixel uses one byte
• Each byte is an index into a color map
• If the color map is not updated synchronously then Color-map flashing may occcur.
• Color-map Animations
• Each pixel may be one of 2^24 colors, but only 256 color be displayed at a time

High-Color Frame Buffers

• Popular PC/(SVGA) standard
• Each pixel can be one of 2^15 colors
• Can exhibit worse quantization effects than Indexed-color

Specialty Frame Buffers

• Non-RGB color models (YUV) or 4-2-2
• True color plus an Overlay
• Older 4-bit per pixel models [I,R,G,B]