gridSnap Function

[Marielle Lange]

Hi TJ,

Funny, I wrote something similar a week ago, to move a box to a given  
day in a calendar display. That looks pretty much equivalent to me.

on MoveDayHiliteBox pLoc
   if not within(field "Calendar", pLoc) then exit MoveDayHiliteBox
   put 20 into tXGrid  --- This is the width of a grid cell
   put 21 into tYGrid --- This is the height of a grid cell
   --- This is to implement a small grid system, such that points  
aref forced on a grid
   put item 1 of pLoc into tX
   put item 2 of pLoc into tY
   put (trunc((tX - (tXGrid/2)) / tXGrid) * tXGrid) into tX
   put (trunc((tY - (tYGrid/2)) / tYGrid) * tYGrid) into tY
   set the topleft of graphic "Hilite" to (tX,tY)
   set the visible of graphic "Hilite" to true
end MoveDayHiliteBox

That's true... I have  date handling functions in that stack I should  
post on the web one of these days... As I think about it, it is now  
on the web:
<http://revolution.lexicall.org/wiki/tiki-index.php? 
page=RevolutionSnippetDates>
(you can use the "backlinks" drop down menu to get to the snippets page)

Marielle

> Hey everyone,
>   Thought I'd contribute a simple function Im using in my current  
> project.
> Someone may find it useful.
>   Basically it "snaps" the mouseloc passed to it based on a given  
> grid size
> similar to countless programs where you have the ability to snap  
> objects to
> a grid. You can have non-square grids by using diffrent gridX and  
> gridY
> values
>  The way I use the function is that when I move objects by user  
> interaction
> I just pass the desired location through this function first. for  
> example -
> "Set the loc of myObject to checksnap(the mouseloc,10,10)"
>  I also refer to a previously declared global variable gAlignGrid,  
> that
> stores a boolean value of whether or not the grid is turned on. You  
> can just
> eliminate the first line of the function if you dont need it.
>  function checkSnap mloc, gridX, gridY
>  if not gAlignGrid then return mloc
>  put trunc(item 1 of mloc/gridX) into xfactor
>  put trunc(item 2 of mloc/gridY) into yfactor
>  if item 1 of mloc >= xfactor * gridX + gridX/2 then add 1 to xfactor
>  if item 2 of mloc >= yfactor * gridY + gridY/2 then add 1 to yfactor
>  return round(xfactor * gridX ) & "," & round(yfactor * gridY)
> end checkSnap
>  Feel free to post any enhancements or more efficient methods of  
> doing this
> :)
>  - TJ


Marielle Lange (PhD),  Psycholinguist

Alternative emails: mlange at blueyonder.co.uk, M.Lange at ed.ac.uk
Homepage:  http://homepages.lexicall.org/mlange/
Lexicall: http://lexicall.org
Revolution-education: http://revolution.lexicall.org