| Re: cursor return in graphics window [message #20852 is a reply to message #20851] |
Thu, 27 July 2000 00:00   |
Eric Williams
Messages: 14
Registered: April 1997
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Junior Member |
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Thanks David,
That did the trick. I actually have to rewrite this program because it
sucks and I want to do it with widgets. I have your programming book and
hope that will be the instruction I need to learn enough widgets to do
it efficiently.
Thanks for your help.
Eric
In article <MPG.13ea1f2b94d66170989b74@news.frii.com>,
davidf@dfanning.com (David Fanning) wrote:
> Whoops, I wrote:
>
>> Eric Williams (eric@astro.wesleyan.edu) writes:
>>
>>> I am trying to use cursor to return the coordinates of a mouse click
>>> in
>>> a graphics window. In fact I am trying to do it twice, back to back,
>>> and
>>> am running in to the problem that one mouse click is being read by
>>> both
>>> cursor calls. I want to select two points with the mouse in the
>>> graphics
>>> window but since one mouse click is being read by both cursor calls I
>>> am
>>> getting the same coordinates for each. I have tried playing with the
>>> wait keyword in cursor but that doesn't seem to make a difference.
>>>
>>> Any suggestions? I am doing this on a Mac right now but have the same
>>> problem on my Solaris boxes.
>>
>> Actually, I think your problem is that you are going through
>> your event handler twice on the *first* mouse click. Once
>> on the down event, and once on the up event. Since you weren't
>> anticipating this, you think you are getting the same
>> position from two clicks. You could modify your event
>> handler to look only for button DOWN events (event.type = 0).
>
> Sorry. I just *assumed* scientific programmers use widgets.
> I realize after reading my mail the past couple of days that
> this is a bad assumption. :-)
>
> The problem here is that default behaviour of the CURSOR
> is to be in the WAIT mode. *But* if the cursor button
> is depressed, the default behaviour is to be in a NOWAIT
> mode. On fast computers (I.e., any purchased in the past
> 10 years or so) it is impossible to punch the button fast
> enough not to get at least a couple of events generated.
>
> The solution is to simply set the DOWN keyword on the
> Cursor command.
>
> Cheers,
>
> David
--
------------
Eric Williams - Van Vleck Observatory, Wesleyan University
eric@astro.wesleyan.edu
(860) 685-3664
http://www.astro.wesleyan.edu
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