Path: utzoo!attcan!utgpu!watmath!maytag!watstat!dmurdoch
From: dmurdoch@watstat.waterloo.edu (Duncan Murdoch)
Newsgroups: comp.lang.pascal
Subject: Re: Saving screen images to disk, can you help?
Message-ID: <397@maytag.waterloo.edu>
Date: 21 Aug 89 13:09:06 GMT
References: <5425@decvax.dec.com> <4487@druhi.ATT.COM>
Sender: daemon@maytag.waterloo.edu
Reply-To: dmurdoch@watstat.waterloo.edu (Duncan Murdoch)
Organization: U. of Waterloo, Ontario
Lines: 28

In article <4487@druhi.ATT.COM> boc@druhi.ATT.COM (Ocinneide) writes:
>In article <5425@decvax.dec.com>, f0057@uafhp.uucp (James E. Ward) writes:
>> 
>> 
>> A few days ago, I posted a brief request for help in this newsgroup.  I guess
>> it was too brief!  What I need is techniques for saving screen images to disk
>> files using Turbo Pascal 5.0!  I am doing a bit of graphics/animation and need
>> to be able to save part of or all of the screen to disk.  Let me know if you
>> can help, okay?
>> 
>> James E. Ward
>> f0057@uafhp.uucp		Use this address or be bounced!
>
>The Graphic Screen Ram on a PC or Compatible starts at segment $B800. Once your image is being displayed on the screen you need to copy the appropriate memory segments to your file. I believe for CGA 4-Color Graphics mode you need to copy 16K bytes start
i
>ng at this segment. Something like this should do it...

It's much safer to use Getimage and Putimage from the Graph unit.  They'll
work on any display that you have a BGI driver for, and can save any 
rectangular region on the screen.  (Well, almost any.  There was a bug that
made them ignore requests to save/restore a single line of pixels, but
it may have been fixed in 5.0 or 5.5.)  Be sure to use ImageSize to work
out how much space is needed; you can't just multiply rows by columns by depth
and get the right number.

To save to a file, just use BlockWrite after Getimage.

Duncan Murdoch