bitmap

graphics, file format A data file or structure which

corresponds bit for bit with an image displayed on a

screen, probably in the same format as it would be stored in

the display's video memory or maybe as a device independentbitmap. A bitmap is characterised by the width and height of

the image in pixels and the number of bits per pixel which

determines the number of shades of grey or colours it can

represent. A bitmap representing a coloured image (a

"pixmap") will usually have pixels with between one and

eight bits for each of the red, green, and blue components,

though other colour encodings are also used. The green

component sometimes has more bits that the other two to cater

for the human eye's greater discrimination in this component.

See also vector graphics, image formats.

(1996-09-21)