# ScalarBarWidget

VTKExamples/Python/Widgets/ScalarBarWidget

### Description

Display a movable and resizable scalar bar.

An example input file is uGridEx.vtk (folder Data at VTKData).

### Code

ScalarBarWidget.py

    #!/usr/bin/env python
    # -*- coding: utf-8 -*-
    #
    # by Panos Mavrogiorgos, email : pmav99 >a< gmail

    import vtk

    # The source file
    file_name = "uGridEx.vtk"

    # Create a custom lut. The lut is used both at the mapper and at the
    # scalar_bar
    lut = vtk.vtkLookupTable()
    lut.Build()

    # Read the source file.
    reader = vtk.vtkUnstructuredGridReader()
    reader.SetFileName(file_name)
    reader.Update()  # Needed because of GetScalarRange
    output = reader.GetOutput()
    scalar_range = output.GetScalarRange()

    mapper = vtk.vtkDataSetMapper()
    if vtk.VTK_MAJOR_VERSION <= 5:
        mapper.SetInput(output)
    else:
        mapper.SetInputData(output)
    mapper.SetScalarRange(scalar_range)
    mapper.SetLookupTable(lut)

    actor = vtk.vtkActor()
    actor.SetMapper(mapper)

    renderer = vtk.vtkRenderer()
    renderer.AddActor(actor)
    renderer.SetBackground(0.1, 0.2, 0.4)

    render_window = vtk.vtkRenderWindow()
    render_window.AddRenderer(renderer)
    render_window.SetSize(300, 300)

    interactor = vtk.vtkRenderWindowInteractor()
    interactor.SetRenderWindow(render_window)

    # create the scalar_bar
    scalar_bar = vtk.vtkScalarBarActor()
    scalar_bar.SetOrientationToHorizontal()
    scalar_bar.SetLookupTable(lut)

    # create the scalar_bar_widget
    scalar_bar_widget = vtk.vtkScalarBarWidget()
    scalar_bar_widget.SetInteractor(interactor)
    scalar_bar_widget.SetScalarBarActor(scalar_bar)
    scalar_bar_widget.On()

    interactor.Initialize()
    render_window.Render()
    interactor.Start()