[vtkusers] RGBA and vtkImagePlaneWidget

[Andre Gouws]

vtk users / developers ...


I am trying to get a vtkImagePlaneWidget to display the RGBA values 
passed to it in a vtkImageData object generated from a 176x256x256 MRI 
dataset. The vtkImageData object has all the properties I expect:

/
        vtkImageData (0x63f8dd0)
          Debug: Off
          Modified Time: 30087
          Reference Count: 3
          Registered Events: (none)
          Source: (none)
          Information: 0x63f8ee0
          Data Released: False
          Global Release Data: Off
          UpdateTime: 30088
          Release Data: Off
          UpdateExtent: Not Initialized
          UpdateExtent: 0, 175, 0, 255, 0, 255
          Update Number Of Pieces: 1
          Update Piece: 0
          Update Ghost Level: 0
          WholeExtent: 0, 175, 0, 255, 0, 255
          ExtentTranslator: (0x63f6e60)
          RequestExactExtent: Off
           Field Data:
            Debug: Off
            Modified Time: 30074
            Reference Count: 1
            Registered Events: (none)
            Number Of Arrays: 0
            Number Of Components: 0
            Number Of Tuples: 0
          Number Of Points: 11534336
          Number Of Cells: 11379375
          Cell Data:
            Debug: Off
            Modified Time: 30076
            Reference Count: 1
            Registered Events: (none)
            Number Of Arrays: 0
            Number Of Components: 0
            Number Of Tuples: 0
            Copy Flags: ( 1 1 1 1 1 )
            Scalars: (none)
            Vectors: (none)
            Normals: (none)
            TCoords: (none)
            Tensors: (none)
          Point Data:
            Debug: Off
            Modified Time: 30087
            Reference Count: 1
            Registered Events: (none)
            Number Of Arrays: 1
            Array 0 name = NULL
            Number Of Components: 4
            Number Of Tuples: 11534336
            Copy Flags: ( 0 1 1 1 1 )
            Scalars:
              Debug: Off
              Modified Time: 30083
              Reference Count: 1
              Registered Events: (none)
              Name: (none)
              Number Of Components: 4
              Number Of Tuples: 11534336
              Size: 46137344
              MaxId: 46137343
              LookupTable: (none)
              Array: 0x16a5b000
            Vectors: (none)
            Normals: (none)
            TCoords: (none)
            Tensors: (none)
          Bounds:
            Xmin,Xmax: (0.999946, 175.99)
            Ymin,Ymax: (0, 288.864)
            Zmin,Zmax: (0, 288.864)
          Compute Time: 0
          ScalarType: 3
          NumberOfScalarComponents: 4
          Spacing: (-0.999946, 1.1328, 1.1328)
          Origin: (175.99, 0, 0)
          Dimensions: (176, 256, 256)
          Increments: (4, 704, 180224)
          Extent: (0, 175, 0, 255, 0, 255)

/
.. this includes /NumberOfScalarComponents: 4 / ... these values 
correspond to the RGBA values of my dataset ...

e.g.  if I access:

            my_data_object.GetOutput().GetScalarComponentAsFloat    
(77,45,128,0) = 255.0
                                                                         
                                    (77,45,128,1) = 174.0
                                                                         
                                    (77,45,128,2) = 0.0
                                                                         
                                    (77,45,128,3) = 255.0

     ..... corresponding to RGBA value of 255,174,0,255 for the voxel at 
77,45,128 .... (right?)
   
           
Perhaps I don't understand the capabilities of the vtkImageplaneWidget 
... The vtkImagePlaneWidget seems to display the R (or first scalar 
component) as an intensity (0-255 greyscale) .. I have set up a routien 
to remap all rgba values to a defined lookuptable and then recalculate 
values in my data to map to this but it takes forever ...

Does the vtkImagePlaneWidget not have the ability to handle / map RGBA 
values?

I see this problem has been covered to some extent before (but I am not 
using ITK) .. 
http://public.kitware.com/pipermail/insight-users/2004-July/009412.html

Thanks in advance

Andre'

//