[vtkusers] How to color a line

[R K Shyam Prakash]

Patrick,
		To add scalar values you can use the following code. The
code is in java.

	int numCells = polydata.GetNumberOfCells(); //number of cells in
your polydata

	vtkIntArray newScalars = new vtkIntArray();  //You can use any
subclass of vtkDataArray here
	newScalars.SetNumberOfTuples(numCells); //I am setting cell
scalars here. You can change it to point scalars as well
	newScalars.SetNumberOfComponents(1); //# of components can vary
based on your requirements

	//iterate over number of cells in the polydata
	for (int i = 0; i < numCells; i++) {
		//set the scalar value
		newScalars.InsertComponent(i, 0, 0);
	}

	//create a lookup table and set it to the scalars
	vtkLookupTable scalarLUT = new vtkLookupTable();
	scalarLUT.SetTableValue(255, 1, 0, 0, 1.0); //I am setting red
color for a scalar value 255
	scalarLUT.SetTableValue(0, 0, 0, 1.0, 1.0); //I am setting blue
color for a scalar value 0
	newScalars.SetLookupTable(scalarLUT);

	//set the scalar to the polydata (cell scalars)
	data.GetCellData().SetScalars(newScalars);

--Shyam


> -----Original Message-----
> From: vtkusers-bounces at vtk.org 
> [mailto:vtkusers-bounces at vtk.org] On Behalf Of Patrick (Peng) Cheng
> Sent: Thursday, July 29, 2004 11:11 PM
> To: R K Shyam Prakash; 'vtkusers'
> Subject: Re: RE: [vtkusers] How to color a line
> 
> 
> hi,
> Sorry I didn't say it clearly. 
> I mean I want to color the line with different colors.
> These colors will be determined by the scalar values at each 
> point. I don't know how to add the scalar values into the 
> polydata as in my code. I know the polydatamapper have method 
> like : ScalarVisibilityOn() and SetLookupTable() once I have 
> put the scalar value into the polydata, I think it will work. right?
> ---------------------------
> Patrick (Peng) Cheng
> Biomedical Engineering
> University of Iowa
> Tel:(319) 400-7442
> Email: peng-cheng at uiowa.edu
> 
> ===========2004-07-29 11:08:25 You wrote in your letter:==============
> 
> >Patrick,
> >		Look at the example /Examples/Medical/Cxx/Medical3.cxx.
> >You can use SetTableValue to specify the color.
> >
> >--Shyam
> >
> >> -----Original Message-----
> >> From: vtkusers-bounces at vtk.org
> >> [mailto:vtkusers-bounces at vtk.org] On Behalf Of Patrick (Peng) Cheng
> >> Sent: Thursday, July 29, 2004 10:50 PM
> >> To: vtkusers
> >> Subject: [vtkusers] How to color a line
> >> 
> >> 
> >> Hi,
> >> I have the following code to draw a tube in the scene.
> >> The tube is of the same color. Now I have some scalar values
> >> at each point How do I use something like lookup table to 
> >> color the line according to the scalar values. Thanks a lot
> >> 
> >> 	vtkPolyData *data = vtkPolyData::New();
> >> 	data->SetPoints(points); // points is vtkPoints
> >> 	data->SetLines(line);	 // line is vtkCellArray
> >> 	
> >> 	vtkCleanPolyData *clean = vtkCleanPolyData::New();
> >> 	clean->SetInput(data);
> >> 	
> >> 	vtkTubeFilter *tube = vtkTubeFilter::New();
> >> 	tube->SetInput(clean->GetOutput());
> >> 	tube->SetRadius(0.6);
> >> 	tube->SetNumberOfSides(6);
> >> 	tube->SetVaryRadiusToVaryRadiusOff();
> >> 	
> >> 	vtkPolyDataMapper *mapper = vtkPolyDataMapper::New();
> >> 	mapper->SetInput(tube->GetOutput());
> >> 	
> >> 	vtkProperty *pro = vtkProperty::New();
> >> 	pro->SetColor(1,0,0);
> >> 	
> >> 	vtkActor *actor = vtkActor::New();
> >> 	actor->SetMapper(mapper);
> >> 	actor->SetProperty(pro);
> >> ---------------------------
> >> Patrick (Peng) Cheng
> >> Biomedical Engineering
> >> University of Iowa
> >> Tel:(319) 400-7442
> >> Email: peng-cheng at uiowa.edu
> >> 
> >> 
> >> 
> >> 
> >> _______________________________________________
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> >.
> 
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> 
> 
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