[vtkusers] Re: Displaying string as labels - how to? (Roger Blum)

[scsrsao at leeds.ac.uk]

Hi Roger,

 I can think about two thinks you could do... the first one in case you only
want to set up some sort of title or description that doesn't need to be moved
when objects rotate in the render window... for this, you could something like:

	titleMapper = vtkTextMapper::New();
	  titleMapper->SetInput("your title");

	titleActor = vtkTextActor::New();
	  titleActor->SetMapper(titleMapper);
	  titleActor->GetTextProperty()->SetFontSize(24);
	 
titleActor->GetPositionCoordinate()->SetCoordinateSystemToNormalizedViewport();
	  titleActor->GetPositionCoordinate()->SetValue(0.4,0.93);

 On the other hand, if you want to make labels to move together with an object
you have associated to, then you need something more elavorated... the common
example (or at least the one I know) is to build 3d axes... the code should be
something like this:

	//initialize axis stuff
	xAxis = vtkArrowSource::New();

	xAxisMapper = vtkPolyDataMapper::New();
	  xAxisMapper->SetInput(xAxis->GetOutput());

	xAxisActor = vtkActor::New();
	  xAxisActor->SetMapper(xAxisMapper);
	  xAxisActor->GetProperty()->SetColor(1,0,0);

	xLabel = vtkCaptionActor2D::New();
	  xLabel->SetCaption("X");
	  xLabel->SetAttachmentPoint(0.8,0,0);
	  xLabel->LeaderOff();
	  xLabel->BorderOff();
	  xLabel->SetPosition(0,0);

	yAxis = vtkArrowSource::New();

	yAxisMapper = vtkPolyDataMapper::New();
	  yAxisMapper->SetInput(yAxis->GetOutput());

	yAxisActor = vtkActor::New();
	  yAxisActor->SetMapper(yAxisMapper);
	  yAxisActor->RotateZ(90);
	  yAxisActor->GetProperty()->SetColor(0,1,0);

	yLabel = vtkCaptionActor2D::New();
	  yLabel->SetCaption("Y");
	  yLabel->SetAttachmentPoint(0,0.7,0);
	  yLabel->LeaderOff();
	  yLabel->BorderOff();
	  yLabel->SetPosition(0,0);

	zAxis = vtkArrowSource::New();

	zAxisMapper = vtkPolyDataMapper::New();
	  zAxisMapper->SetInput(zAxis->GetOutput());

	zAxisActor = vtkActor::New();
	  zAxisActor->SetMapper(zAxisMapper);
	  zAxisActor->RotateY(-90);
	  zAxisActor->GetProperty()->SetColor(0,0,0.8);

	zLabel = vtkCaptionActor2D::New();
	  zLabel->SetCaption("Z");
	  zLabel->SetAttachmentPoint(0,0,1);
	  zLabel->LeaderOff();
	  zLabel->BorderOff();
	  zLabel->SetPosition(0,0);


	Axes3D = vtkPropAssembly::New();
	  Axes3D->AddPart(xAxisActor);
	  Axes3D->AddPart(xLabel);
	  Axes3D->AddPart(yAxisActor);
	  Axes3D->AddPart(yLabel);
	  Axes3D->AddPart(zAxisActor);
	  Axes3D->AddPart(zLabel);

	axesCam = vtkCamera::New();
	  axesCam->ParallelProjectionOn();

	axesRen = vtkRenderer::New();
	  axesRen->InteractiveOff();
	  axesRen->SetActiveCamera(axesCam);
	  axesRen->SetViewport(0,0.80,0.15,0.95);
	  axesRen->SetLayer(1);
	  axesRen->AddActor(Axes3D);
	  axesRen->ResetCameraClippingRange();


Hope it helps...
Rodolfo

> ------------------------------
>
> Message: 4
> Date: Sat, 26 Aug 2006 20:49:35 -1000
> From: "Roger Blum" <roger_blum at swissonline.ch>
> Subject: [vtkusers] Displaying string as labels - how to?
> To: vtkusers at public.kitware.com
> Message-ID: <ecrf9p$rao$1 at sea.gmane.org>
>
> Hi vtk users,
>
> I have a couple of points, a scalar value for each point and 1 to 4 strings
> describing each point. How can I display the strings at the point location
> (I am using vtk 5.0.0 with Tcl)?
>
> I have tried to use vtkPolyData (with a vtkStringArray containing the Labels
> in vtkPointData), but a vtkStringArray can not be added to vtkPointData.
>
> Is the vtkLabeledDataMapper the right thing to use for what I want to do? Is
> there a better way to do it?
>
> Thanks in advance for your help,
> Roger
>
>
>
>
>
>
> ------------------------------