More send in time

[Jan Schenkel]

--- Ken Norris <pixelbird at interisland.net> wrote:
> Howdy,
> 
> I'm still having problems understanding 'send in
> time'
> 
> I want to send continuous messages to scroll a field
> while the cursor is
> within a graphic while the mouse is down. It's been
> reiterated a number of
> times that it's not a good idea to use 'mouseWithin'
> or  'mouseStillDown' or
> 'while the mouse..' or 'until the mouse..' in Rev.
> 
> As an example, here's how I would write it in a
> normal HyperTalk structure:
> 
> on mouseDown
>   repeat until the mouse is up
>     if the mouse is within graphic 1 then
>        set the vScroll of fld 1 to (the vScroll of
> fld 1) - 1
>     else beep
>   end repeat
> end mouseDown
> 
> How should I rewrite this to get the exact same
> effect with a 'send in time'
> construct?
> 
> 

Hi Ken,

How about this script : 

--

constant kInterval = 20
local sTracking

on mouseDown
  put true into sTracking
  send "Do1Scroll" to me in kInterval milliseconds
end mouseDown

on mouseUp
  put false into sTracking
end mouseUp

on mouseRelease
  put false into sTracking
end mouseRelease

on Do1Scroll
  if sTracking then
    if the mouseLoc is within graphic 1 then
      set the vScroll of fld 1 to \
         (the vScroll of fld 1) - 1
    else beep
    send "Do1Scroll" to me in kInterval milliseconds
  end if
end Do1Scroll

--

Explanation:
- on mouseDown, the scrolling cycle starts
- on mouseUp or mouseRelease, the scrolling cycle ends
- Do1Scroll fires itself with a 20 ms delay, but will
do nothing if the scrolling cycle has ended, by
checking the content of the script local sTracking.

Hope this helped,

Jan Schenkel.

=====
"As we grow older, we grow both wiser and more foolish at the same time."  (La Rochefoucauld)

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