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 independent bitmap. 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.