[Paraview-developers] PV widgets cleanup

[Berk Geveci]

On Monday, I will commit quite a few changes to paraview, mostly to 
cleanup some vtkPVWidget and sub-classes. In future, please keep the 
following in mind when developing/changing paraview widgets:

1. Initialize() is called once after the widget is created (cloned) and 
is responsible of anything that is done once at the beginning. For 
example, vtkPVInputMenu connects the current source as input in 
Initialize().

2. Reset() is called when the user clicks on Reset or when a source is 
selected ONLY if the widget has been modified (ModifiedFlag = 1). 
Reset() is not called when the widget is created. If Initialize() and 
Reset() has common code, it might be convenient to move it to another 
method.

3. Accept() is called when user clicks Accept (or when a widget changes 
if auto-accept is on) ONLY if the widget has been modified (ModifiedFlag 
= 1). Accept() should reset ModifiedFlag to 0. Accept() should also call 
Trace().

4. Select()/Deselect() are called when the source is selected/deselected 
and should do things like turning visibility of a 3d widget on/off or 
updating a menu.

Let me know if you run into strange widget behavior, specially when 3d 
widgets are concerned.

-Berk