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From: jimm@amiga.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: Layers Lib./Clipping
Message-ID: <1968@amiga.amiga.UUCP>
Date: Thu, 3-Dec-87 21:28:34 EST
Article-I.D.: amiga.1968
Posted: Thu Dec  3 21:28:34 1987
Date-Received: Sun, 6-Dec-87 21:50:39 EST
References: <8712010903.AA22789@cory.Berkeley.EDU> <1897@cadovax.UUCP>
Reply-To: jimm@amiga.UUCP (Jim Mackraz)
Organization: Commodore-Amiga Inc., 16795 Lark Ave. Suite 106, Los Gatos CA 95030
Lines: 29


WIndow rastport has layer, and clips always, but not all graphics calls
clip.  I think Ellipse/Circle are the only ones, think text is OK,
but some people believe that your rendering has to be at least ball-park
near the window/region.

As for not using Intuition, be sure to distinguish between input/interaction
roles and output.  You might want to open a screen and a backdrop window
to get a layer (and LayerInfo) set up, but never use gadgets, IntuiMessages
or the like again.  It's easier to do this than to figure out LayerInfo
stuff.  It';s also nice to prototype progs with Intuition, so you can
use debug windows, etc.  You can fake double-buffer and the whole nine yards.

Question was also about Layers vs. Algorithmic Clipping.  Well, layers is
algorithmic, too, eh?  Dale consistently traded ROM space for speed, if
that is any comfort.  His job was more general than normal, checking for
smart refresh and superbitmap on every call, and so on, but, again, it
is often nice to put off this part of the puzzle until later.  I find
that if I tune too much before I start, I don't always finish.  Use the
easy path, (Grasshopper) and trust your instincts to keep your options
open for performance mods.

Too bad about ellipses, though.  Draw 'em off screen and blit 'em in.

Why do I get the feeling that everyone is working on a MacDraw clone?
Whose got the hot rounded rect primitive?

	jimm
	I and I Computing