vtkScalarBarActor

Section: Visualization Toolkit Rendering Classes

Usage

vtkScalarBarActor creates a scalar bar with annotation text. A scalar bar is a legend that indicates to the viewer the correspondence between color value and data value. The legend consists of a rectangular bar made of rectangular pieces each colored a constant value. Since vtkScalarBarActor is a subclass of vtkActor2D, it is drawn in the image plane (i.e., in the renderer's viewport) on top of the 3D graphics window.

To use vtkScalarBarActor you must associate a vtkScalarsToColors (or subclass) with it. The lookup table defines the colors and the range of scalar values used to map scalar data. Typically, the number of colors shown in the scalar bar is not equal to the number of colors in the lookup table, in which case sampling of the lookup table is performed.

Other optional capabilities include specifying the fraction of the viewport size (both x and y directions) which will control the size of the scalar bar and the number of annotation labels. The actual position of the scalar bar on the screen is controlled by using the vtkActor2D::SetPosition() method (by default the scalar bar is centered in the viewport). Other features include the ability to orient the scalar bar horizontally of vertically and controlling the format (printf style) with which to print the labels on the scalar bar. Also, the vtkScalarBarActor's property is applied to the scalar bar and annotation (including layer, and compositing operator).

Set the text property/attributes of the title and the labels through the vtkTextProperty objects associated to this actor.

To create an instance of class vtkScalarBarActor, simply invoke its constructor as follows

  obj = vtkScalarBarActor

Methods

The class vtkScalarBarActor has several methods that can be used. They are listed below. Note that the documentation is translated automatically from the VTK sources, and may not be completely intelligible. When in doubt, consult the VTK website. In the methods listed below, obj is an instance of the vtkScalarBarActor class.