Editing Vtk/ColorLookupTablea (section)

===Brute Force Definition of Color Table===
As is illustrated by the following snapshot of the full VisTrails builder window, the same user-defined color table can be injected into the VisTrails rendering pipeline by using VisTrail's ''vtkLookupTable'' module.
* In the left-hand "Modules" segment of the VisTrails builder window, find the ''vtkLookupTable'' module and drag it into the pipeline segment of the window.
* Link the standard output from the ''vtkLookupTable'' module to the appropriate input channel of the ''vtkPolyDataMapper'' module, as shown.
* Click on (''i.e.,'' select) the ''vtkLookupTable'' module then locate and drag/drop the following Methods into the "Set Methods" segment of right-hand window:
** One instance of the ''SetNumberOfColors'' method. 
** Eight instances of the ''SetTableValue'' method.
** <font color="red">CAUTION:</font> After dropping (approximately) the third instance of ''SetTableValue'' into the "Set Methods" window, you will likely discover that the window is completely filled (as illustrated in the screen shot, below) but that VisTrails does not activate scrolling.  Hence, it isn't possible to ''drop'' the fourth instance of the method ''below'' the third instance.  What VisTrails expects you to do, instead, is ''drop'' all subsequent instances of the ''SetTableValue'' method onto the header bar at the top of the window segment that reads, "Set Methods."  VisTrails will then insert each additional method into its proper location, at the end of the stack of activated methods.
* In keeping with the above-provided example Lookup Table, type in the following:
** Type the integer "8" into the ''SetNumberOfColors'' method window.
** In each instance of the ''SetTableValue'' method, (A) use the top "Integer" text window to label, in sequence, each color table value with the appropriate integer number, <math>~0 - 7</math>; and (B) use the four "Float" text windows to enter the assigned <font face="Courier">rgba</font> colors. 


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VisTrails Screen Snapshot
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[[Image:LookUpTableFullScreen.png|700px|Employing the vtkLookupTable Module]]
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The new Lookup Table that is now provided by VisTrail's ''vtkLookupTable'' module will be treated by the VisTrails pipeline as the ''default'' Lookup Table.  VTK will use this new color table when rendering the POLYGONS if it is instructed to refer to the ''default'' table.  This can be accomplished via an explicit instruction inside the user-provided input data file &#8212; as in Examples A, B, &amp; C from our accompanying [[vtk/SimpleCubeTutorial|"Simple Cube" tutorial]] &#8212; or by activating the "SetLookupTableName" method in the ''vtkPolyDataReader'' module and typing the string "default" into the provided text window.  This discussion should be considered a supplement to our [[vtk/SimpleCubeTutorial#Other_Knobs_to_Twist|related discussion on switching between different color tables]].