Class FunctionDrawer

src/org/opensourcephysics/display/FunctionDrawer.java:26–257

FunctionDrawer draws a function from xmin to xmax. The function will be evaluated at every screen pixel unless the domain is set using the initialize method. @author Wolfgang Christian @author Joshua Gould @version 1.0

 * @version 1.0
 */
public class FunctionDrawer implements Drawable, Measurable, Function {
  protected double[] xrange = new double[2];
  protected double[] yrange = new double[2];
  protected int numpts = 0;
  protected GeneralPath generalPath = new GeneralPath();
  protected Function function;
  protected boolean filled = false;
  protected boolean measured = false; // set to true if function has been initialized.
  public Color color = Color.black;
  public boolean functionChanged = false;
  protected boolean enabled = true;

  public void setEnabled(boolean b) {
	  enabled = b;
  }
  /**
   * Constructs a FunctionDrawer with optimum resolution.
   *
   * @param   f the function that will be drawn.
   */
  public FunctionDrawer(Function f) {
    function = f;
  }

  /**
   * Creates the function drawer and initialzies the domain with the given values.
   * @param f Function
   * @param xmin double
   * @param xmax double
   * @param numpts int
   * @param filled boolean  fills the area under the curve with the drawing color when true
   */
  public FunctionDrawer(Function f, double xmin, double xmax, int numpts, boolean filled) {
    this(f);
    initialize(xmin, xmax, numpts, filled);
  }

  /**
   * Evaluates the function.
   * @param x
   * @return value of the function
   */
  @Override
  public double evaluate(double x) {
    return function.evaluate(x);
  }

  /**
   * Initialize the function range and the number of display points.
   * @param xmin  the beginning value of the range.
   * @param xmax  the ending value for the range
   * @param numpts the number of points to display
   * @param filled fills the area under the curve with the drawing color when true
   */
  public void initialize(double xmin, double xmax, int numpts, boolean filled) {
    if(numpts<1) {
      return;
    }