Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!usc!apple!dlyons
From: dlyons@Apple.COM (David A. Lyons)
Newsgroups: comp.sys.apple2
Subject: Re: offscreen grafports in Orca/Pascal
Message-ID: <43826@apple.Apple.COM>
Date: 10 Aug 90 02:33:08 GMT
References: <3980@rex.cs.tulane.edu>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 21

In article <3980@rex.cs.tulane.edu> lang@rex.cs.tulane.edu (Raymond Lang) writes:
>How do you set up an offscreen grafport in Orca/Pascal for an image
>that is larger than the screen (i.e., greater than 640 pixels across
>by 200 pixels in height)?

For general information about off-screen grafports, see "Math" and "DTS
Libraries and Tools" in Apple IIgs Source Code Sampler volume 2, and
the QuickDraw documentation.

In summary, you need to allocate memory for the off-screen pixel map,
open a new grafport by calling OpenPort on a 170-byte chunk of memory,
and use SetLocInfo to set up the locInfo record of your grafport to
refer to your pixel map.
-- 
David A. Lyons, Apple Computer, Inc.      |   DAL Systems
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