palettebased

Palettebased is a term used to describe techniques and systems that use a color palette to represent image colors by indexing into that palette rather than storing full color values for every pixel. In practice, a palettebased approach stores a palette as a list of colors (for example, RGB triplets) and an image as a grid of indices into that list. The final display maps each index to its corresponding color.

Historically, palettebased methods were essential for memory and bandwidth efficiency in early computer graphics and video hardware. Many systems operated in indexed color modes with palettes of 256 colors or fewer. GIF images and many early games used a single global palette; PNG supports palette-based images through color type 3.

Techniques and variants include palette-based quantization, where a full-color image is reduced to a fixed palette, often using algorithms such as median cut or k-means. Adaptive palettes can be generated per image or scene, and some systems employ multiple palettes for different regions or layers. Dithering is commonly used to mitigate the perceptual limitations of a limited palette.

Advantages of palettebased approaches include lower memory usage, reduced bandwidth, and compatibility with hardware that only supports indexed colors. Disadvantages include restricted color fidelity, potential color shifts when editing or animating palettes, and added complexity in palette management.

See also: color quantization, indexed color, dithering, GIF, PNG, VGA.