Constraining the pointer within a rect

[Jan Sælid]

This is just another addition to the suggestions. It is based on Tactile
medias dragsample stack.
Put it inside whatever object you want. Press and hold the mousebutton and
drag the mouse to activate it.
Change the mousedown, mouserelease and mouseup to any other handler you
want.
It is stable but there's still some minor flickering of the mouse cursor. At
least on windows...

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local constrain,boxL,boxR,boxT,boxB

ON mouseDown
    put item 1 of rect of me+4 into boxL -- change number 4 to suit your
needs
    put item 3 of rect of me-4 into boxR -- change 4
    put item 2 of rect of me+4 into boxT -- change 4
    put item 4 of rect of me-4 into boxB -- change 4
    put true into constrain
END mouseDown

ON mouseMove x,y
    IF not constrain THEN exit mouseMove
    set the screenmouseloc to \
            globalloc(min(boxR,max(boxL,(x))) & "," &
min(boxB,max(boxT,(y))))
END mouseMove

ON mouseUp
    put false into constrain
END mouseUp

ON mouseRelease
    mouseUp
END mouseRelease

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