Path: utzoo!utgpu!watmath!watcgl!ksbooth
From: ksbooth@watcgl.waterloo.edu (Kelly Booth)
Newsgroups: comp.graphics
Subject: Re: the word "bitmap"
Message-ID: <7549@watcgl.waterloo.edu>
Date: 4 Jan 89 17:59:27 GMT
References: <8568@pasteur.Berkeley.EDU>
Reply-To: ksbooth@watcgl.waterloo.edu (Kelly Booth)
Organization: U. of Waterloo, Ontario
Lines: 21

In article <8568@pasteur.Berkeley.EDU> ph@miro.Berkeley.EDU (Paul Heckbert) writes:
>I've been troubled lately to see people using the word "bitmap" to mean
>a grayscale or color image.  As long as I can remember, however, "bitmap"
>has meant a ONE BIT PER PIXEL, black and white image.
>
>Where is this new, (and I believe) incorrect usage coming from?

(a)  You are correct that "bitmap" often means single-bit-per-pixel.

(b)  The more general usage appears in the Guibas-Stolfi TOG 1:3 paper
from 1982.  "bitmaps: arrays of discrete intensity/color values".

In skimming through the article again, I cannot find a place where
"bitmap" is defined exactly (the quote above is not definitive because
"discrete" could be taken as 0-1, finessing the issue in question,
though I'm sure it is intended to mean discrete in precisely the sense
used in Paul Heckbert's posting a few days ago).  But in section 5.1,
it is stated that the descriptor for a bitmap includes the depth
(number of bits per pixel).  Elsewhere in the article most of the
examples seem to assume only 0-1 valued pixels, but there are numerous
allusions to pixels having depth other than 1.