[vtkusers] Scalar bar with discrete values

[John Platt]

Hi Karl,

I made 3 additions to vtkScalarBarActor some time ago...

    1. Set a ceiling on the text font size.
    2. Allow a different title to be used when the legend is horizontal.
    3. Supply discrete labels.

The extend class is attached - it may require updating for your VTK version.

HTH

John.

----- Original Message ----- 
  From: Karl Merkley 
  To: VTK 
  Sent: Friday, February 24, 2012 3:04 PM
  Subject: Re: [vtkusers] Scalar bar with discrete values


  Setting the number of labels does help but it doesn't give me the discrete values on the scalar bar.    For example, if I have three discrete values .4, .5, 1.25.   The scalar bar displays .4 .825, 1.25.    The .825 appears to be just average of the minimum and the maximum for the three value case.


  Looking the source code for vtkScalarBarActor::AllocateAndSizeLabels(...), it looks like the interior values of scalar bar are a function of  the range and the number of labels.  There is no way to specify the discrete values.    It looks like I will have to subclass vtkScalarBarActor and overload AllocateAndSizeLabels.  Fortunately, it is a virtual method!


     -- Karl


  On Feb 23, 2012, at 2:33 AM, Jothybasu Selvaraj wrote:


    You could do that by

    //For 10 labels
    scalarBar->SetMaximumNumberOfColors(10);
    scalarBar->SetNumberOfLabels(10);

    Jothy


    On Thu, Feb 23, 2012 at 12:10 AM, Karl Merkley <karl at elemtech.com> wrote:


      I have a set of discrete values (thicknesses) that I want to describe with a scalar bar.   Each color has exactly one value associated with it.   When I set up my scalar bar it has a range defined by each color.    Is there a way to get a single label drawn at the center of the color range instead of labels at the tops and bottoms of each range?

       Thanks,
          Karl






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    -- 

    Jothy



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  Karl Merkley, Ph.D.


  Elemental Technologies, Inc.
  Computational Simulation Software, LLC
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