[vtk-developers] Upcoming features, careful with CVS updates...

[Will Schroeder]

Okay, I'm checking in vtkWin32RenderWindowInteractor reflecting the new 
timer API. As I said, CreateTimer() and DestroyTimer() (the old methods) 
should be backward compatible although they are implemented differently now.
Will

Will Schroeder wrote:

> *Summary*:
> There are upcoming changes to VTK timers (which may affect interactor 
> styles); and the addition of timer-based widgets (e.g., 
> vtkBalloonWidget). Please delay CVS updates for a day or two while we 
> stabilize.
>
> *Details:*
> Dave Cole and I have been working on the timer methods found in 
> vtkRenderWindowInteractor. Originally, these methods implicitly 
> assumed that only one timer at a time was created, and they were only 
> used by subclasses of vtkInteractorStyle. However, we are beginning to 
> add widgets (like vtkHoverWidget and vtkBalloonWidget) that depend on 
> timers. (These widgets perform an action if the mouse pointer does not 
> move for a certain time and the pointer is over top of a vtkProp. For 
> example, a text string or caption associated with the vtkProp can be 
> popped up. Eventually we will have widgets that popup thumbnails 
> and/or hyperlinks.)
>
> Such widgets require that multiple timers run simultaneously, meaning 
> that timers must be distinguished by a timer id. Also, the 
> InvokeEvent() method must provide the timer id associated with the 
> event (e.g., vtkCommand::TimerEvent,(void*)&timerId);) so that 
> observers know whether an event is for them or not.
>
> While the code is fairly straightforward, it is a bit tricky to 
> simultaneously develop and thoroughly test the code on multiple 
> platforms (Win32, X, Carbon, Cocoa). We plan on checking the code in 
> stages starting early Tuesday or Wednesday (I will warn everybody). 
> Unfortunately  there may be some instability while we coordinate our 
> efforts which we will do our best to avoid.  I will give the all clear 
> once we believe everything is stable.
>
> Note that backward compatibility should be preserved: the old 
> CreateTimer(timerType)/DestroyTimer(void) methods are being augmented 
> by new methods that deal with timer ids 
> (timerId=CreateOneShotTimer(duration); 
> timerId=CreateRepeatingTimer(duration); ResetTimer(timerId) and 
> DestroyTimer(timerId)).
>
> Please let me know if you have concerns, suggestions, etc.
>
> Will
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