[vtk-developers] Re: Your checkin

Charles Law charles.law at kitware.com
Mon Jan 22 11:13:17 EST 2001


At 04:33 PM 1/19/01 -0500, you wrote:
>I noticed you changed the image api. Will this affect any of our internal 
>filters?
>
>Bill

Yes and No.

Elimination of EnlargeOutputUpdateExtent:
I intend to remove the EnlargeOutputUpdateExtent method completely.  Right 
now it only has a legacy warning around it.  This does change some filter 
internals.  In the future,  the Execute() (no parameters) method should be 
overridden and it should set its own output extent and allocate it own 
scalars (just like graphics).  I changed all of the sources in VTK to use 
this approach. Take a look at vtkDEMReader for an example.

Elimination of ImageToStructuredPoints:
All filters will have to take vtkImageData instead of 
vtkStructuredPoints.  This is not a big change because right now structured 
points is an empty subclass of vtkImageData.  The primary role of 
vtkImageToStrucutredPoints was to crop the image if the source returned a 
larger extent.  This is now vtkImageData's responsibility, and the 
consuming filter has to indicate that it wants only the extent 
requested.  It does this with the method 
"vtkDataObject::RequestExactExtentOn()".  Since many superclasses do this 
for you (i.e. vtkDataSetToDataSetFitler),  most filters can ignore this method.

Also, we may want to change all the structured points sources to generate 
vtkImageData.

Charles.




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