Class ContourPlot

src/org/opensourcephysics/display2d/ContourPlot.java:24–720

ContourPlot draws a contour plot of a scalar field. Contour uses code from the Surface Plotter package by Yanto Suryono. @author Wolfgang Christian @version 1.0

 * @version 1.0
 */
public class ContourPlot implements Plot2D {
  private GridData griddata;
  private Color lineColor = new Color(0, 64, 0);  // dark green
  private boolean visible = true;
  private int contour_lines = 12;                 // number of contour lines
  private boolean showContourLines = true;
  private boolean showColoredLevels = true;       // fill with colors
  private double contour_stepz;                   // contour spacing
  private int[] xpoints = new int[8];
  private int[] ypoints = new int[8];
  private int[] contour_x = new int[8];
  private int[] contour_y = new int[8];
  private double[] delta = new double[4];
  private double[] intersection = new double[4];
  private double[][] contour_vertex = new double[4][3];
  private ContourAccumulator accumulator = new ContourAccumulator();
  private double zmin = 0, zmax = 1.0;            // the range for contour levels
  private boolean autoscaleZ = true;
  private boolean symmetricZ=false;
  protected ZExpansion zMap = null;
  protected ColorMapper colorMap = new ColorMapper(contour_lines, zmin, zmax, ColorMapper.SPECTRUM);
  private Color[] contourColors = new Color[contour_lines+2];
  private double[][] internalData = new double[1][1];
  private int ampIndex = 0;                       // amplitude index
  private int nx = 0, ny = 0;
  private int maxGridSize = 48;
  protected boolean interpolateLargeGrids = true; // interpolates a large grid onto a smaller grid to speed the computation of contour lines

  /**
   * Constructs a ContourPlot without any data.
   *
   */
  public ContourPlot() {}

  /**
   * Constructs a ContourPlot that renders the given GridData.
   *
   * @param  _griddata data storage
   */
  public ContourPlot(GridData _griddata) {
    griddata = _griddata;
    if(griddata==null) {
      return;
    }
    nx = (interpolateLargeGrids&&(griddata.getNx()>maxGridSize)) ? 32 : griddata.getNx();
    ny = (interpolateLargeGrids&&(griddata.getNy()>maxGridSize)) ? 32 : griddata.getNy();
    internalData = new double[nx][ny];
    update();
  }

  /**
   * Gets the x coordinate for the given index.
   *
   * @param i int
   * @return double the x coordinate
   */
  @Override
public double indexToX(int i) {