[ quesa-Bugs-907874 ] Picking on Windows does not match Mac

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Bugs item #907874, was opened at 2004-03-01 21:35
Message generated for change (Tracker Item Submitted) made by Item Submitter
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Dair Grant (grantd)
Assigned to: Nobody/Anonymous (nobody)
Summary: Picking on Windows does not match Mac

Initial Comment:
Joe Strout wrote:

There's a bug with picking in Win32, where in order to get the 
correct result, you have to adjust the window coordinates passed in 
by a certain scale factor that varies from machine to machine.  My 
guess is that this relates somehow to the resolution of the screen. 
Perhaps we're somewhere using pixels where we should be using 
points,  or vice versa.

We've found more information about the odd picking bug on Win32.  
In order to get the pick to work correctly, you have to apply a 
scaling factor that depends on both the screen size and the view 
size and position.  In RB code, it looks like this:

   #If TargetWin32
   x2 = x * Screen(0).width / Rb3DSpace1.width - Rb3DSpace1.left
   y2 = y * Screen(0).height / Rb3DSpace1.height - 
Rb3DSpace1.top
   #Else
   x2 = x // All works as expected on the Mac
   y2 = y
   #Endif

   // (and then pass x2, y2 to the picking function)


So, for both X and Y, we have to multiply by the ratio of the screen 
size to view size, and then subtract off the top/left of the view (so 
that the coordinates are now relative to the view rather than the 
window).

On the Mac none of that is necessary; we just pass in window 
coordinates and it works.

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