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From: cutler@reed.UUCP (Steven J. Russell)
Newsgroups: comp.sys.mac,net.sources.mac
Subject: Macintosh programming.  Help!
Message-ID: <4501@reed.UUCP>
Date: Mon, 10-Nov-86 22:21:05 EST
Article-I.D.: reed.4501
Posted: Mon Nov 10 22:21:05 1986
Date-Received: Tue, 11-Nov-86 07:57:50 EST
Organization: Reed College, Portland OR
Lines: 33
Keywords: scrolling,growing,updating,Printer Drivers,in LightSpeed Pascal
Xref: mnetor comp.sys.mac:9 net.sources.mac:1263

I have a few questions pertaining to programming on the Macintosh in Pascal
(specifically LightSpeed Pascal).

          1. How do you get graphics to scroll smoothly?  I have a procedure
                  that draws graphics, and I want to get it to scroll.  I have
                  my scroll bars, and windows, etc.  Should I keep an offscreen
                  bitmap and scroll by CopyBits, or should I draw the image
                  each time.  Also, is there some formula that figures out what
                  a control's MaxValue should be when the image is bigger than
                  the window can show?  Source might be helpful.

          2. How do I update quickly?  This might be part of question 1.  Is
                  there any particular method that would update just the update
                  region instead of the whole image?  Source would be helpful.

          3. I seem to be having trouble with handling grows.  The trouble
                  seems to be with not erasing the scroll bars when enlarging
                  and not drawing them right when reducing by small amount.
                  How do you do this?

Thanks for any help (particularly source code) that you can lend me.  If you
have source, it would be most helpful in Pascal, but I will get by if it is in
C.  Even just the concepts behind scrolling, etc. would be of a great help.

One last question...

Has anyone written a Printer Driver in LightSpeed Pascal or LightSpeed C?  If
you have, I would be very interested in hearing about it, especially if it is
like the ImageWriter driver (dialog boxes, etc.).

Thanks for your help.

Steven J. Russell