Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!batcomputer!cornell!rochester!pt.cs.cmu.edu!h.gp.cs.cmu.edu!kem
From: kem@h.gp.cs.cmu.edu (Kenneth Mohnkern)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: if there is ... at [xx,yy]
Message-ID: <12511@pt.cs.cmu.edu>
Date: 28 Mar 91 14:36:08 GMT
References: <12497@pt.cs.cmu.edu> <17959@crdgw1.crd.ge.com>
Organization: Carnegie-Mellon University, CS/RI
Lines: 42

I ask:
) I guess HC2.0's "there is" doesn't have the ability to check if 
) there's an object at a certain point. 
)  [...]
) 				I'd like to look at a specific 
) location and see if there's a button there without looking at
) every button and comparing its loc with the desired loc.
) 
) I know if there's a cool way to do this I'll find it here.
) 

Bill Leue answers:
) It's pretty easy.  First, find out if the object exists.  Next, if
) it exists, get its location properties and test them against your
) requirements.
) 
) if there is a <object)  then
)   get the TopLeft of <object) 
)   -- or some other location property
)   if it is <your coordinates)  then
)     -- the object exists at the desired location
)   else
)     -- it exists, but not at the desired location
)   end if
) else
)   -- it doesn't exist at all
) end if
) 
) -Bill Leue
) leue@crd.ge.com

Thanks, Bill, but I'm looking for a way to see if there's an object at a 
certain location. Rather than starting with finding a certain object and 
checking its loc, I'd like to start with a loc and see if there's an object 
there. I'm not looking for a certain object. I'm looking at a point on the
card, seeing whether or not it's an empty space.

I suppose I could put the location in a variable and check every object's
loc against it. That could be time consuming if there are a lot of obj's.
-- 

ken mohnkern#the robotics institute#carnegie mellon univ#pittsburgh pa