[wxVTK] Fwd: [ wxvtk-Bugs-2025027 ] incorrect SetEventInformationFlipY() in OnMouseWheel()

[Mathieu M. <mat...@gm...>]

Fixed in CVS HEAD:

$ cvs ci -m"BUG: Fix [ wxvtk-Bugs-2025027 ] incorrect
SetEventInformationFlipY() in OnMouseWheel(), thanks to Mu Shang for
patch"
         ~/Projects/wxVTK
Checking in src/wxVTKRenderWindowInteractor.cxx;
/cvsroot/wxvtk/wxVTK/src/wxVTKRenderWindowInteractor.cxx,v  <--
wxVTKRenderWindowInteractor.cxx
new revision: 1.37; previous revision: 1.36
done


---------- Forwarded message ----------
From: SourceForge.net <no...@so...>
Date: Tue, Jul 22, 2008 at 10:06 PM
Subject: [ wxvtk-Bugs-2025027 ] incorrect SetEventInformationFlipY()
in OnMouseWheel()
To: no...@so...


Bugs item #2025027, was opened at 2008-07-22 16:06
Message generated for change (Tracker Item Submitted) made by Item Submitter
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=669338&aid=2025027&group_id=114757

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: shang (mshang)
Assigned to: Nobody/Anonymous (nobody)
Summary: incorrect SetEventInformationFlipY() in OnMouseWheel()

Initial Comment:
The current (incorrect) code in OnMouseWheel() is:

'''
 //Set vtk event information ... The numebr of wheel rotations is stored in
 //the x varible.  y varible is zero
 SetEventInformationFlipY(event.GetWheelRotation() / event.GetWheelDelta(), 0,
                          event.ControlDown(), event.ShiftDown(),
'\0', 0, NULL);
'''


And the correct code should be:
'''
 SetEventInformationFlipY(event.GetX(), event.GetY(),
                          event.ControlDown(), event.ShiftDown(),
'\0', 0, NULL);
'''


I don't know why the incorrect code was written like that, but it

1. does not conform to the implementation in
vtkWin32RenderWindowInteractor, vtkXRenderWindowInteractor,
vtkCocoaGLView, vtkCarbonRenderWindowInteractor, etc.

2. breaks many interactor styles that rely on the difference between
the current event coordinate and the previous event coordinate:
Consider this:
The user is moving an actor by holding down middle button(mouse wheel
button) in vtkInteractorStyleTrackballActor. He accidentally rotates
the mouse wheel and the coordinates are set to (1,0) or similar. Then
in the next mouse move event the event handler calculates the
difference between the current coordinates with the previous
coordinates - the difference would be big and it move the actor out of
the visible scene.


----------------------------------------------------------------------

You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=669338&aid=2025027&group_id=114757



-- 
Mathieu