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From: john@felix.UUCP (John Gilbert)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: Hyper-Hackers Digest Vol. 1 #5
Message-ID: <13811@felix.UUCP>
Date: Mon, 23-Nov-87 20:17:54 EST
Article-I.D.: felix.13811
Posted: Mon Nov 23 20:17:54 1987
Date-Received: Sat, 28-Nov-87 07:41:49 EST
References: <34497@sun.uucp>
Sender: daemon@felix.UUCP
Reply-To: john@felix.UUCP (John Gilbert)
Organization: FileNet Corp., Costa Mesa, CA
Lines: 51

>Date: 	  Wed, 18 Nov 87 17:31:10 PST
>From: PUGH@NMFECC.ARPA
>Subject:   Visual Effects
>
>A bit of trivia:
>
>You can stack visual effect commands so that you get a series of effects.  A 
>good example is this:
>
>visual effect dissolve to inverse
>visual effect dissolve
>
>Check it out and see what happens.  The important questions are, is there a way 
>to turn off any visual effects that are queued, and can you tell if and/or 
>what visual effects are queued?
>
>Why do I care, you may ask?  I wanted to put a handler in my Home stack that
>would detect arrow key events and queue an effect for them, since they don't
>have any nice effect by default.  Well, that's where I found out that effects
>are cumulative.  I would like a string returned that tells what effects are
>queued, like "wipe slow to black, dissolve to inverse, scroll up" for that
>list of effects.  That wouldn't be too hard would it?  This way I could even
>trap effects I don't like.  Isn't that what object programming is all about?


I may have mis-understood when I played with these things, but I don't think
that the effects are "stacked".  It seems to me that a command like:

    visual effect dissolve to inverse

is executed immidiately, operating on the current card.  I believe this is
true for visual effects which go "to <some pattern>" other than a new
card.  I guess this includes to black, to white, to grey, to inverse.

On the other hand, setting the visual effect with:

   visual effect dissolve

with no target pattern specified is applied to movement to the next
card, as long as it is done within some (as yet completely understood by me)
scope of the script.  I usually do it right before I issue the 'go' command.
I am pretty sure the effect is lost if you set it and then exit the current
script (message handler?).  I know if I specify an effect and lock the screen,
or while the screen is locked, unlocking the screen does not use the effect.
I wish it would myself, as I find most of my movement involves locking the
screen.


--
John Gilbert
!trwrb!felix!john