VTKPythonAlgorithmBase for custom annotations

Dear devs,

Can one use the VTKPythonAlgorithmBase class to create annotation filters, i.e. show additional descriptive text? I have managed to open a table in a separate window, but never to show a text in the same window.

I have a feeling there should be a connection to the PrintSelf function and the ostream to achieve this, is it so? Any help is deeply appreciated.


You may want to precise what you are trying to achieve.

As an execrcise, I am trying to write a PV plugin in python, that would create an annotation filter, i.e. show a text at the top of the render view window. The problem is that instead of a string I get a table in the Spread Sheet view. I also compared the python implementation with existing c++ filters, and the only thing that was different is that c++ filters have the PrintSelf function, while python filters do not.

A filter indicate it’s producing data that should rendered as text by adding a hint. If your filter is producing a table with a single row/column with the string to be rendered as text in the render view, the following hint should do the trick.

@smhint.xml("<OutputPort index='0'  name='Output-0'  type='text' />")
class Foo(VTKPythonAlgorithmBase):

Dear Mathieu, dear Utkarsh,

I’m sorry, but I still cannot get it right. I have added the hint as you suggested, yet I still get no text in the render view, but a table in a separate window. Here is my code:

@smproperty.input(name="InputDataSet", port_index=0)
@smhint.xml("<OutputPort index='0' name='output-0' type='text' />")
class ExampleTwoInputFilter(VTKPythonAlgorithmBase):
	def __init__(self):
		VTKPythonAlgorithmBase.__init__(self, nInputPorts=1, 
                     nOutputPorts=1, outputType="vtkTable")

	def FillInputPortInformation(self, port, info):
		info.Set(self.INPUT_REQUIRED_DATA_TYPE(), "vtkDataObject")
		return 1

	def RequestData(self, request, inInfoVec, outInfoVec):
		output = vtkTable.GetData(outInfoVec, 0)

		data = vtk.vtkStringArray()
		data.InsertNextValue("this is inserted text")

		return 1

Upon loading the plugin, I create a sphere from source and apply this filter.

Once again, any help is deeply appreciated, thank you.

Here is a Python text source that work out of the box.

    @smhint.xml("<OutputPort index='0'  name='Output-0'  type='text' />")
    class PythonText(VTKPythonAlgorithmBase):
        """This is dummy VTKPythonAlgorithmBase subclass that
        simply puts out a Text"""
        def __init__(self):
            from paraview.modules.vtkPVVTKExtensionsDefault import vtkPVTextSource
            self._realAlgorithm = vtkPVTextSource()

        def RequestData(self, request, inInfo, outInfo):
            from vtkmodules.vtkCommonDataModel import vtkTable
            output = vtkTable.GetData(outInfo, 0)
            return 1

        def SetText(self, text):