Palette (computing)
From Wikipedia, the free encyclopedia
| Color depth |
|---|
|
8-bit color |
| Related |
|
RGB color model |
A palette, in computer graphics, is a designated subset of the total range of colors supported by a computer graphics system. Each color in the palette is assigned a number, and for each pixel, one of these numbers is stored. This number determines the color of the pixel.
Graphics modes with low color depths (generally, from 4 to 8 bits) usually have a modifiable palette, also referred to as pseudocolor palette, that contains indices to the full palette of the display hardware. For instance, in the 256-color modes of the original VGA, each of the colors can be chosen from a total palette of 262,144 colors. Pseudocolor allows images comprising a small number of colours to be stored using a relatively modest amount of graphics memory.
Notable computer graphics systems extensively (or even exclusively) using pseudocolor palettes include EGA and VGA (for the IBM PC), the Atari ST and Amiga's OCS and AGA.
Some popular image file formats, such as PCX, GIF, BMP and TIFF allows indexed color modes, generally up to 16 or 256 (four or eight bits per pixel). In that kind of files, along with a header and the raw image data, also the palette map is stored, with up to 16 or 256 entries RGB color map. This is necessary due to the color map for a given image is arbitrary, and without this extra information, it is impossible that the image could render correctly.
A palette may also be a small window, or section of a window that's readily accessible for quick and frequent color choices.
