Logarithmic color maps and vtkScalarBarActor--help?

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Logarithmic color maps and vtkScalarBarActor--help?

Victor Putz

I'm trying to implement a model that displays a time series of data in an
animation.  The problem is that it reaches peak values early, which means
that if I recalibrate the color map every frame, the scale changes
dramatically, but if I use one color map for the whole series, it's pretty
much red all over 90% of the time.

The best answer would be to use a logarithmic scale, and it looks like
that's possible.  The VTK documentation either suggests using a
vtkLookupTable and SetScaleToLog10() or use the vtkLookupTable.

And if I set that, it seems to work.  Happy day!

The problem is the vtkScalarBarActor I'm using to display the scale for
the colors, and it doesn't like the logarithmic setup.  The documentation
says " if a vtkLogLookupTable is specified as the lookup table to use,
then the labels are created using a logarithmic scale," although under
vtkLogLookupTable, it says to use vtkLookupTable with SetScaleToLog10
instead.

Either way, my vtkScalarBarActor doesn't change its scale, and doesn't
look acurate  for the scale it shows.  Does anyone have example code out
there using a color map with a logarithmic scale and a vtkScalarBarActor
that looks correct?

Thanks,

-->VPutz

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