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Path: utzoo!mnetor!seismo!rochester!ur-tut!dpvc
From: dpvc@ur-tut.UUCP (David Cervone)
Newsgroups: comp.sys.amiga
Subject: Re: proportional gadgets
Message-ID: <1244@ur-tut.UUCP>
Date: Tue, 28-Apr-87 17:38:44 EDT
Article-I.D.: ur-tut.1244
Posted: Tue Apr 28 17:38:44 1987
Date-Received: Thu, 30-Apr-87 03:19:03 EDT
References: <3294@jade.BERKELEY.EDU>
Reply-To: dpvc@tut.cc.rochester.edu.UUCP (Davide Cervone)
Organization: Univ. of Rochester Computing Center
Lines: 55

In article <3294@jade.BERKELEY.EDU> spencer@eris.BERKELEY.EDU (Randy Spencer) writes:
>                                                             I am 
>working on that word processing project and I can't seem to figure 
>out how to let the user press in that area outside that gadgets knob
>and have the mouse button repeat.  I want to let the use scroll down
>by pressing the mouse button down with the pointer near the bottom,
>but now it only moves one window per click.
>
>If there are any ideas out there, please fill me in on them...
>
>-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>Randy Spencer      P.O. Box 4542   Berkeley  CA  94704        (415)284-4740 

Well, here's an idea:  you set the GADGIMMEDIATE flag in the scroll gadget,
then, when the gadget is hit, you get the message right away.  When you receive
the message, check to see if the KNOBHIT flag is set.  If it is, ignore the
hit and wait for the gadget to be releases (you also have RELVERIFY set, as
usual).  If KNOBHIT is not set, then the user has hit in one of the other
areas of the gadget.  You can tell which by comparing the current knob
position to the previous position (which you have stored in a variable
somewhere; you could use the input event's MouseX and MouseY fields, but
that becomes complicated, as the knob has ALREADY been moved, and isn't were
it used to be).  When you know which way to move, scroll that direction.  
You've probably already gotten this far without me, but here's the trick:
when you've finished with your scroll, check to see if the SELECTED flag is
set in the scroll gadget's Flag field.  If it is, the user is still holding 
down the button, so you should continue to scroll.  When he lets go, SELECTED
will no longer be set, so you stop scrolling and go back to waiting for more 
messages.  If the scrolling happens too fast (it never does, though), you 
could call Delay() to slow it down a bit.  When the user lets go, you will 
still receive a RELVERIFY message for the gadget.  When you get a RELVERY
you should check for KNOBHIT.  If it was hit, then process the scroll as though
the user moved the knob (that's what he did).  If KNOBHIT is not set, then
ignore the event, since you've already taken care of it above.

I thank that shoudl work.  If not, I have done it, and I acn go back and 
look to see in more detail what I did.

Someone asked a question about MOUSEBUTTON messages and perportional gadgets
a while back, and I just remembered something about that.  If you have a
RELVERIFY gadget, and the user presses the gadget, then moves the mouse
away from the gadget (it becomes de-selected), and then lets go, you get
a mouse up message.  If he lets go over the gadget, you get the RELVERIFY
message.  In this way, you can get a mouse up with no mouse down.  I don't
remember whether the gadget also has to be GADGIMMEDIATE, or whether it 
makes any difference.  I think it does.  I'll have to go back and try it 
out again...

Anyway, hope this is useful to someone.

Davide P. Cervone
University of Rochester
DPVC@UORDBV.BITNET
dpvc@tut.cc.rochester.edu
dpvc@ur-tut.UUCP