Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!usc!apple!keith
From: keith@Apple.COM (Keith Rollin)
Newsgroups: comp.sys.mac.programmer
Subject: Re: turning on a pixel
Message-ID: <34169@apple.Apple.COM>
Date: 21 Aug 89 04:35:42 GMT
References: <6294@hubcap.clemson.edu>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 38

In article <6294@hubcap.clemson.edu> mikeoro@hubcap.clemson.edu (Michael K O'Rourke) writes:
>I am writing a graphics program that turns on many pixels one at a time
>by calculating some mathematical eqns. (kind of a fractal).  It presently
>is using :
>
>moveto(x,y);
>lineto(x,y);
>
>to turn on a pixel.  Is there some quicker way to do this from pascal?

I usually use PaintRect(r), where r is (x,y,x+1,y+1), just so I don't have to
make 2 calls through the Dispatcher. I've also heard that MoveTo/Line(0,0) is
particularly optimized, but I don't know if, internally, that's different from
what you are doing.

>The program is horribly slow right now and it needs to be speeded up.
>For instance, does someone have a quick assembly routine that will turn
>on a pixel?  I'd be willing to convert to LSC so that i could use the 
>inline assembly if it would really improve speed.

Do you know for sure that it's QuickDraw that's slowing you down? I was just
working on a program that did a lot of intense calculations and single-pixel
plotting. After my first pass at writing it (in MacApp, of course), I turned
on the Performance tools to see where I could speed things up. *MUCH* to my
surprise, almost no time was spent in QuickDraw. This was even after I was
doing a lot of plotting, setting and changing of ports and gDevices, Color
Manager calls, and region manipulations. It turned out that 85-90% of the time 
was spent in my calculations.

Of course, this is just my own experience, and may not apply to yours. You may
be plotting a bunch of X/Y pairs, and not be performing any calculations at
all...
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"Argue for your Apple, and sure enough, it's yours" - Keith Rollin, Contusions