vtkXYPlotActor

Section: Visualization Toolkit Hybrid Classes

Usage

vtkXYPlotActor creates an x-y plot of data from one or more input data sets or field data. The class plots dataset scalar values (y-axis) against the points (x-axis). The x-axis values are generated by taking the point ids, computing a cumulative arc length, or a normalized arc length. More than one input data set can be specified to generate multiple plots. Alternatively, if field data is supplied as input, the class plots one component against another. (The user must specify which component to use as the x-axis and which for the y-axis.)

To use this class to plot dataset(s), you must specify one or more input datasets containing scalar and point data. You'll probably also want to invoke a method to control how the point coordinates are converted into x values (by default point ids are used).

To use this class to plot field data, you must specify one or more input data objects with its associated field data. You'll also want to specify which component to use as the x-axis and which to use as the y-axis. Note that when plotting field data, the x and y values are used directly (i.e., there are no options to normalize the components).

Once you've set up the plot, you'll want to position it. The PositionCoordinate defines the lower-left location of the x-y plot (specified in normalized viewport coordinates) and the Position2Coordinate define the upper-right corner. (Note: the Position2Coordinate is relative to PositionCoordinate, so you can move the vtkXYPlotActor around the viewport by setting just the PositionCoordinate.) The combination of the two position coordinates specifies a rectangle in which the plot will lie.

Optional features include the ability to specify axes labels, label format and plot title. You can also manually specify the x and y plot ranges (by default they are computed automatically). The Border instance variable is used to create space between the boundary of the plot window (specified by PositionCoordinate and Position2Coordinate) and the plot itself.

The font property of the plot title can be modified through the TitleTextProperty attribute. The font property of the axes titles and labels can be modified through the AxisTitleTextProperty and AxisLabelTextProperty attributes. You may also use the GetXAxisActor2D or GetYAxisActor2D methods to access each individual axis actor to modify their font properties. In the same way, the GetLegendBoxActor method can be used to access the legend box actor to modify its font properties.

There are several advanced features as well. You can assign per curve properties (such as color and a plot symbol). (Note that each input dataset and/or data object creates a single curve.) Another option is to add a plot legend that graphically indicates the correspondance between the curve, curve symbols, and the data source. You can also exchange the x and y axes if you prefer you plot orientation that way.

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

  obj = vtkXYPlotActor

Methods

The class vtkXYPlotActor 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 vtkXYPlotActor class.