Subject: Re: Dragging Lines in a Field

[Tariel Gogoberidze]

>>Does anybody have a solution for dragging lines up and down in a field to
>> resort them?
>>Thanks,

>Ray Horsley
>Developer, LinkIt! Software


As a reply

Rich
Payne Sparkman Mfg.
shop at paynesparkman.com

Posted a script that  allows to drag lines inside  the field.

Posted a script that  allows to drag lines inside  the field.

I tested  the script and  it works, but  unfortunately after  intensive
use it  eventually  crushes MC v 2.4.2, at least  on my computer (Mac OS
9.1 G3 350, 512 Meg RAM). One of the symptoms is that MouseStillDown
handler begins to indefinitely  calling itself  even long  after  the
mouse is UP (indefinite recursion, if I'm not messing up the terms). It
keeps  calling MouseStillDown  until  the mouse is  clicked outside  the
field.  So, I blocked this behavior with "click  at -100,100" at the end
 of the  handler. This  stopped MouseStillDown to continue working 
after mouseup  but  MC  2.4 still crushes, through less frequently.
Without having  exact recipe I think this has something  to  do with new
async behavior of mouse function


"The "mouse" function is now async rather than event based as in
previous releases.  This means that "the mouse" will only return
"down" if the mouse is actually down at the exact instant the function
checks it."

So,  I modified  script  a little (see below) and now it seems to be 
stable in  all versions of MC. 
note:  I'm sure  it can be done in more efficient way, but I cooked it
very  quickly and  my  goal was  to just stabilize the script in MC  2.4.2

Local VertiMouse,MyTop,MyLeft,linHt,CurLinPtr,moveTxt,Actionflag

## you can set  any margin for fld and  have it with or without 
vertical  scrollbar
## button should have  "showBorder" = false and name "DragLineBtn"
## field has  list behavior.

on mouseDown
  put "false"  into  Actionflag
  pass mousedown
end mouseDown


on mousestillDown
  if Actionflag is "false"  then -- MouseStillDown should work only once
this way...
    put the ClickLine into CkLn
    put value(the ClickLine) into moveTxt
    if moveTxt is empty then exit mousestillDown
    delete line (word 2 of CkLn) of me
    set the label of button "DragLineBtn" to MoveTxt
    put the textHeight of me into linHt
    ## f you want  custom cursor while  dragging, create one and
activate lines below
    --set the cursor to (the id of image  "DragLineImg" of grp "DragLineGrp")
   -- set the lockcursor to true

    put 4 into  MyTune
    ## Would love  to know why but on my computer it needs this correction
    ## to let button fit exactly in Field boundaries. Put 0 into MyTune
if your
    ##  OS/computer  will not require correction

    set the borderWidth of button "DragLineBtn" to the margins of me - MyTune
    put the top of me into MyTop
    put (the left of me) + MyTune into MyLeft
    if the vScrollbar of me is "true" then
      set the width of button "DragLineBtn" to (the width of me) - (the
scrollbarWidth of me) - (MyTune*2)
    else
      set the width of button "DragLineBtn" to (the width of me) - (MyTune*2)
    end if
    set the height of button "DragLineBtn" to LinHt
    set the topLeft of button "DragLineBtn" to MyLeft,MyTop
    set the visible of button "DragLineBtn" to true
    --
    put "true"  into  Actionflag -- so it never do it again while the
mouse is down
    Send "dragLine" to me in 1 milliseconds
    --
  end if
end  mouseStillDown

on dragLine
  if  the mouse is up  then -- get out and exit
    -- repeat for each line L in the pendingMessages
    -- cancel (item 1 of L) -- not needed actually
    -- end repeat
    set the visible of button "DragLineBtn" to false
    put ((VertiMouse - MyTop) div linHt)+1 into CurLinPtr
    if the scroll of me > 0 then
      add (the scroll of me div LinHt)  to CurLinPtr
    end if
    if CurLinPtr > (number of lines in me) then
      put cr&moveTxt after the last line of me
      select the last line of me
    else
      put MoveTxt & cr before line CurLinPtr of me
      select line CurLinPtr of me
    end if
    set the lockcursor to false
    exit  dragline
  end if
  --
  put the MouseV into VertiMouse
  put the scroll of me into temp
  if VertiMouse < MyTop then
    put MyTop into VertiMouse
    subtract LinHt from temp
  end if
  if VertiMouse > the bottom of me then
    put the bottom of me into VertiMouse
    add LinHt to temp
  end if
  set the scroll of me to temp
  set the topLeft of button "DragLineBtn" to MyLeft,VertiMouse-(LinHt
div 2)
  ---
  send dragline to me in 10 milliseconds -- is 10 Milliseconds OK?
end dragline

Best regards
Tariel Gogoberidze