Keypress Help

[J. Landman Gay]

On 4/18/05 1:48 PM, Scott Rossi wrote:

> Howdy List:
> 
> Still looking for options to reliably detect keypress events on Windows with
> Rev.  Recap: keyUp messages are immediately sent regardless of whether a
> pressed key is released.  Same happens with keyDown and rawKeyDown.  Even
> the keysDown() function doesn't seem to help here since it apparently
> alternates between returning the pressed key/s and empty.
> 
> I now have to go explain to a client why I was unable to get their demo
> working correctly on a test system.  This is majorly irritating since key
> events work as expected on MacOS.
> 
> How can one reliably tell on Windows when a key is pressed versus when it is
> released?

Are you sure you don't have your operating systems backwards? ;) In my 
experience, it has always been Mac OS that doesn't generate accurate 
keyUp messages. Windows has always worked for me. That is an OS 
limitation, as Macs send keyup immediately after keydown, regardless of 
the physical state of the key itself. Or at least, that's how it has 
always been in the past.

At any rate, I wrote a work-around for it, which should work just as 
well on Windows as it does on Macs. You'll have to alter the script to 
suit your own needs, but basically I had to implement a checking loop 
after a key was depressed. I used a rawKeyDown to start the actions I 
needed to do, and added "checkKey whichKey,theBtn" to the rawKeyDown 
handler. That started the loop. Then this handler managed the rest of it:

on checkKey whichKey,theBtn
   -- see if "f" or "r" key has been released; Macs don't generate
   -- accurate keyUp msgs so we need to use a loop check
   put charToNum(whichKey) into theKey
   if theKey is not in keysDown() then -- key is released
     repeat for each line i in the pendingmessages
       if i contains "checkKey" then cancel (item 1 of i)
     end repeat
     send "mouseUp" to btn theBtn
   else
     send "checkKey whichKey,theBtn" to me in 200 milliseconds
   end if
end checkKey

In my case, I only needed to check for the keys "r" or "f", but you 
could alter this to check for whatever keys you need, or all of them.

I didn't have any trouble with the keysdown() function returning 
incorrectly. That may be because I allowed some time between checks, but 
I don't know for sure.

-- 
Jacqueline Landman Gay         |     jacque at hyperactivesw.com
HyperActive Software           |     http://www.hyperactivesw.com