Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ulowell!hawk!jkeegan
From: jkeegan@hawk.ulowell.edu (Jeff Keegan)
Newsgroups: comp.sys.mac.programmer
Subject: Offscreen Bitmap / MultiFinder
Message-ID: <14226@swan.ulowell.edu>
Date: 18 Jul 89 05:29:38 GMT
Sender: news@swan.ulowell.edu
Reply-To: jkeegan@hawk.ulowell.edu (Jeff Keegan)
Organization: University of Lowell, CS Dept
Lines: 35

This is actually a two part question (I'm getting lazy)..

One -> I want to have a window with a scroll bar that scrolls a large bitmap
       horizontally. I want to create an off-screen bitmap (actually an
       off-screen GrafPtr with it's own bitmap) and draw to that, then do
       a copybits to the screen after receiving an update event or after
       doing a scrollrect. Is this the best way to do it? And how exactly do
       I obtain the offscreen bitmap? I imagine that I must have to allocate
       enough memory for the bitmap (with NewPtr most likely) and have the
       baseAddr field of the bitmap point at that.. But how do I determine
       exactly how bit that NewPtr value must be? I know that I want my
       big-bitmap to have 7200 pixels across and a "n" pixels down..
       (By the way, I am creating the GrafPtr by creating a pointer with
       NewPtr(sizeof(GrafPort));  and then calling OpenPort. I've set the
       rectangle size to the correct size with PortSize.. What else am I
       going to have to do?

Two -> Because I am going to have to display the time constantly in one of
       windows, I am going to have to make my application "multi-finder
       aware".. Exactly what does this consist of? (I know there's some
       routine called waitnextevent, but what else is there? And how can I
       make it known that my routine UpdateTime() has to be called every
       once in a while, even if I'm in the background?

Thanks in advance.

..Jeff Keegan

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| Jeff Keegan                | I clutch the wire fence until my fingers bleed |
| jkeegan@hawk.ulowell.edu   | A wound that will not heal                     |
|----------------------------| A heart that cannot feel                       |
| This space intentionally   | Hoping that the horror will receed             |
| left blank                 | Hoping that tomorrow we'll all be freed  -RUSH |
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