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From: haitex@pnet01.cts.com (Wade Bickel)
Newsgroups: comp.sys.amiga
Subject: Re: Layers Lib./Clipping
Message-ID: <2069@crash.cts.com>
Date: Wed, 2-Dec-87 14:16:09 EST
Article-I.D.: crash.2069
Posted: Wed Dec  2 14:16:09 1987
Date-Received: Sun, 6-Dec-87 08:47:09 EST
Sender: news@crash.cts.com
Organization: People-Net [pnet01], El Cajon, CA
Lines: 44

dillon@CORY.BERKELEY.EDU (Matt Dillon) writes:
>>          I am about to deal with the issue of clipping in the
>>      program I am working on, and would like some advice on how
>>      to go about it.  I have been told that by using the Layers
>>      Library functions I can do this, but my reading has neither
>>      confirmed nor denied this.
>>
>>          By clipping I mean that I would like to be able to pass the
>>      drawing functions lines whose endpoints may not be within the
>
>	All windows created with OpenWindow() automatically use the
>layers library and clip.  The rastport in the screen structure does not
>use the layers library and thus does not clip.  Usually one opens a 
>custom screen, then a backdrop window, rendering into the window.
>
>	The simple drawing functions will clip completely, but I have
>found that the more complex ones can't handle x/y values greater than
>about 4096, so you still need to be a little careful.
>
>					-Matt


        Thanks for the info Matt.  Howerver, I am not using intuition. I
      have tried, and do not believe it is possible for my application.
      However I still need to incorporate clipping.  I have a RastPort
      already set up, and would like to simply prevent it from drawing
      out into ?? memory when my points are out of bounds.  I do not want
      to utilize the Layers Library to actually create the Display, as
      I would like to avoid system copper list management as much as 
      possible.

        Also, can anyone give me any idea of the processing costs of 
      implementing Layers Lib. clipping.  I am working with 3-D images
      and must clip in Z space anyway.  Will the Layers functions be
      faster/slower than algorithmically croping the images?

                                        Thanks again,

                                                        Wade.


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