Constraining the pointer within a rect

[Scott Morrow]

I found that using a "send in time" structure to check the mouseLoc  
rather than waiting for the mouseMove message was slightly more  
reliable (OSX) and better kept it from going outside the bounding area.

on MouseTrap
    -- keep the mouse pointer inside the window
     if the optionkey is NOT "down" then -- but overide this behavior  
with the "optionKey"
         put item 1 of globalLoc(the mouseLoc) into x
         put item 2 of globalLoc(the mouseLoc) into y
         put the top of this stack into tTopEdge
         put the bottom of this stack into tBottomEdge
         put the right of this stack into tRightEdge
         put the left of this stack into tLeftEdge
         if x < tLeftEdge then put tLeftEdge +1 into x
         if x > tRightEdge then put tRightEdge -1 into x
         if y < tTopEdge then put tTopEdge +1 into y
         if y > tBottomEdge then put tBottomEdge-1 into y
         set the screenmouseloc to x,y
     end if
   send MouseTrap to me in 40 millisec
end MouseTrap


-Scott Morrow

Elementary Software
(Now with 20% less chalk dust !)
web     http://elementarysoftware.com/
email   scott at elementarysoftware.com

-----------------------------------------------------------------

On Aug 17, 2006, at 8:40 AM, Howard Bornstein wrote:

> This script seems to work with adequate performance:
>
> on mousemove mh,mv
>  if the hilite of btn "constrain" is true then
>
>    if mh <= the left of fld "container" then
>      set the screenmouseloc to the globalloc of (the left of fld
> "container", mv)
>    end if
>
>    if mh >= the right of fld "container" then
>      set the screenmouseloc to the globalloc of (the right of fld
> "container", mv)
>    end if
>
>    if mv <= the top of fld "container" then
>      set the screenmouseloc to the globalloc of (mh,the top of fld
> "container")
>    end if
>
>    if mv >= the bottom of fld "container" then
>      set the screenmouseloc to the globalloc of (mh,the bottom of fld
> "container")
>    end if
>
>  end if
> end mousemove
>
>
> Note two things:
>
> 1) The button "Constrain" needs to be within the field "Container"  
> or you'll
> never be able to get out. :-)
>
> 2) It is possible to move the mouse out of the rect for brief  
> moments, but
> then it pops back into the rectangle. I'm assuming it's a function of
> slipping out between a mousemove scan.
>
>
>
> -- 
> Regards,
>
> Howard Bornstein
> -----------------------
> www.designeq.com
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