Use wtk.js vtkXMLPolyDataReader class to load data from XML string

Hello, I try to use the vtkXMLPolyDataReader in a javascript, but i don’t want to use a file, i receive a XML in a string : <?xml version="1.0"?><VTKFile type="PolyData" version="0.1" byte_order="LittleEndian" header_type="UInt32" compressor="vtkZLibDataCompressor"><PolyData><Piece NumberOfPoints="38496" NumberOfVerts="0" NumberOfLines="0" NumberOfStrips="0" NumberOfPolys="53488">...

How I can load this data in the vtkXMLPolyDataReader . I try vtkXMLPolyDataReader.loadData(xml_string); but it does not seem to work. Many thanks for your help.

Patrick

[ZbindenJoel]

Hi @daker and thanks for pointing me in the right direction.

After some more research I figured as much from its name, but being rather new to JavaScript I needed some more time to understand it.

I tried to convert my string to an ArrayBuffer using encodedString = TextEncoder().encode(XMLString) as explained here on SO and calling parseAsArrayBuffer with encodedString.buffer, but got yet another error now stating Invalid data type null expecting PolyData

Am I creating my ArrayBuffer correctly? (edit: Yes!)

Edit: I did create my ArrayBuffer correctly. The error was due to a call to the XMLPolyDataReader.loadData() function that should not have been there.

For anyone struggling, here’s the lines of code to transform the XML string to a vtkActor with all its associated parts:

// get an actor and mapper
const actor = vtk.Rendering.Core.vtkActor.newInstance();
const mapper = vtk.Rendering.Core.vtkMapper.newInstance();
// instantiate the xml reader
const reader = vtk.IO.XML.vtkXMLPolyDataReader.newInstance();
// connect actor <-- mapper <-- reader
actor.setMapper(mapper);
mapper.setInputConnection(reader.getOutputPort());

// set source for reader and load data
mesh_xml_buffer = new TextEncoder("latin1").encode(mesh_xml_string).buffer;
reader.parseAsArrayBuffer(mesh_xml_buffer);

[daker]

@ZbindenJoel parseAsArrayBuffer needs an ArrayBuffer to work not a string