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Mail Archives: djgpp/1997/08/20/08:29:47

From: "Hargreaves, Shawn" <shawnh AT probe DOT co DOT uk>
To: "'djgpp AT delorie DOT com'" <djgpp AT delorie DOT com>
Subject: Re: dirty stuff
Date: Wed, 20 Aug 97 13:24:00 PDT
Message-ID: <33FB53A4@relay.probe.co.uk>
Encoding: 27 TEXT

Alan Poppleton writes:
> What do people mean when they talk about dirty stuff when discussing
> graphics?  For example 'dirty rectangles'.

Dirty rectangles are a commonly used technique for reducing the amount
of screen space that needs to be updated when displaying animations.
In many situations, only a small part of the screen will change from one
frame to the next, and well-written graphics routines will exploit this
coherency by only bothering to redraw the areas that have changed,
ie. the regions that are "dirty" and need to be updated with the new
image...

> Also what is this 'foo' variable that keeps cropping up everywhere?

'foo' is a commonly used name for almost anything (variables, functions,
files, etc) where the name itself doesn't matter, for example as a
placeholder to use in example code or documentation. When someone
tells you to type "strcpy(foo, bar)", they don't mean literally to type   
in
the string foo, but insert whatever name is relevant to your situation
instead.

See   
http://www.lysator.liu.se/hackdict/split2/metasyntactic_variable.html.

 Shawn Hargreaves.

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