Path: utzoo!utgpu!water!watmath!clyde!att!ucbvax!decwrl!sun!hanami!landman
From: landman%hanami@Sun.COM (Howard A. Landman)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Mac II color graphics & animation questions
Message-ID: <60856@sun.uucp>
Date: 21 Jul 88 18:28:18 GMT
References: <210loganj@byuvax.bitnet> <1637@runx.ips.oz>
Sender: news@sun.uucp
Reply-To: landman@sun.UUCP (Howard A. Landman)
Organization: Sun Microsystems, Mountain View
Lines: 18

>In article <210loganj@byuvax.bitnet> loganj@byuvax.bitnet writes:
>>2.  We need to produce color graphics by scan lines (for raster devices),
>>    and doing this one pixel at a time is too slow.  Any suggestions?

In article <1637@runx.ips.oz> clubmac@runx.OZ (Australia's Largest Mac Users Group) writes:
>I'm no expect on Colour QuickDraw (until Apple Australia ship me mine!), but
>if you're going to change the colour of any pixel in a horizontal line, you
>may as well plot each pixel individually, changing the colour pixel by pixel.
>I would investigate the feasibility of only setting the pixel's colour if it
>has changed from the last pixel drawn. The test MAY be faster than setting the
>same colour.

You should also consider loop-unrolling.  Often the control is taking a
significant fraction of the time.

	Howard A. Landman
	landman@hanami.sun.com
	UUCP: sun!hanami!landman