Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!ncar!unmvax!tut.cis.ohio-state.edu!bloom-beacon!hermes!jpexg
From: jpexg@hermes.ai.mit.edu (John Purbrick)
Newsgroups: comp.sys.atari.st
Subject: Re: Atari ST Screen Dump Info Sought
Summary: How does a program "steal the alt-help"?
Message-ID: <3292@hermes.ai.mit.edu>
Date: 4 Mar 89 06:49:36 GMT
References: <3958@druhi.ATT.COM> <10597@pasteur.Berkeley.EDU>
Organization: MIT AI Lab, Cambridge, MA
Lines: 13

> ... for the Atari Laser Printer (SLM804) there's a screen dumper that
> steals the Alt-Help and outputs the correct data over the DMA to print
> to the laser printer...
> --Kenneth Soohoo	(soohoo@cory.Berkeley.Edu)

How does a program do this? Presumably terminate-and-stay-resident, but how
does it intercept keypresses?

A couple of years ago Moshe Braner (where's he gone?) posted a program which
did this but it shoved the screen into a reserved area of memory he called the
"barrel"; then you could dump the barrel to a Degas file. I'd like to try
writing a program which instead created a .TNY format screen file every time
alt-help was hit.