LegendScaleActor

Description¶

The vtkLegendScaleActor object is used to annotate the render window. Its basic goal is to provide an indication of the scale of the scene. Four axes surrounding the render window indicate (in a variety of ways) the scale of what the camera is viewing. An option also exists for displaying a scale legend.

The axes can be programmed either to display distance scales or x-y coordinate values. By default, the scales display a distance. However, if you know that the view is down the z-axis, the scales can be programmed to display x-y coordinate values.

Other languages

See (Cxx), (Java)

Question

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Code¶

LegendScaleActor.py

#!/usr/bin/env python3

# noinspection PyUnresolvedReferences
import vtkmodules.vtkInteractionStyle
# noinspection PyUnresolvedReferences
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.vtkCommonColor import vtkNamedColors
from vtkmodules.vtkCommonComputationalGeometry import vtkParametricEnneper
from vtkmodules.vtkFiltersSources import vtkParametricFunctionSource
from vtkmodules.vtkRenderingAnnotation import vtkLegendScaleActor
from vtkmodules.vtkRenderingCore import (
    vtkActor,
    vtkPolyDataMapper,
    vtkRenderer,
    vtkRenderWindow,
    vtkRenderWindowInteractor
)


def main():
    colors = vtkNamedColors()

    # The source will be a parametric function.
    src = vtkParametricEnneper()
    fn_src = vtkParametricFunctionSource()
    fn_src.SetParametricFunction(src)

    # Create a mapper and actor.
    mapper = vtkPolyDataMapper()
    fn_src >> mapper
    actor = vtkActor(mapper=mapper)
    actor.property.color = colors.GetColor3d('SandyBrown')

    # Create a renderer, render window, and interactor.
    renderer = vtkRenderer(background=colors.GetColor3d('MidnightBlue'))
    render_window = vtkRenderWindow(size=(600, 600), window_name='LegendScaleActor')
    render_window.AddRenderer(renderer)
    render_window_interactor = vtkRenderWindowInteractor()
    render_window_interactor.render_window = render_window

    legend_scale_actor = vtkLegendScaleActor()

    axes_prop = legend_scale_actor.axes_property
    axes_prop.color = colors.GetColor3d('Red')

    legend_scale_actor.top_axis.property = axes_prop
    legend_scale_actor.left_axis.property = axes_prop
    legend_scale_actor.bottom_axis.property = axes_prop

    # Add the actor to the scene.
    renderer.AddActor(actor)
    renderer.AddActor(legend_scale_actor)

    # Render and interact.
    render_window.Render()
    render_window_interactor.Start()


if __name__ == '__main__':
    main()