plotproperties.java

一个一元曲线多项式数值演示例子

package numbercruncher.graphutils;

import java.awt.*;

/**
 * The properties of a function plot.
 */
public class PlotProperties {
  /** width */
  private int w;
  /** height */
  private int h;
  /** x-axis row */
  private int xAxisRow;
  /** y-axis column */
  private int yAxisCol;
  /** minimum x value */
  private float xMin;
  /** maximum x value */
  private float xMax;
  /** minimum y value */
  private float yMin;
  /** maximum y value */
  private float yMax;
  /** x delta per pixel */
  private float xDelta;
  /** y delta per pixel */
  private float yDelta;

  /**
   * Constructor.
   * @param xMin the minimum x value
   * @param xMax the maximum x value
   * @param yMin the minimum y value
   * @param yMax the maximum y value
   */
  public PlotProperties(float xMin, float xMax, float yMin, float yMax) {
    this.xMin = xMin;
    this.xMax = xMax;
    this.yMin = yMin;
    this.yMax = yMax;
  }

  /**
   * Return the minimum x value.
   * @return the minimum x value
   */
  public float getXMin() {
    return xMin;
  }

  /**
   * Return the maximum x value.
   * @return the maximum x value
   */
  public float getXMax() {
    return xMax;
  }

  /**
   * Return the minimum y value.
   * @return the minimum y value
   */
  public float getYMin() {
    return yMin;
  }

  /**
   * Return the maximum y value.
   * @return the maximum y value
   */
  public float getYMax() {
    return yMax;
  }

  /**
   * Return the x delta value.
   * @return the x delta value
   */
  public float getXDelta() {
    return xDelta;
  }

  /**
   * Return the y delta value.
   * @return the y delta value
   */
  public float getYDelta() {
    return yDelta;
  }

  /**
   * Return the width.
   * @return the width
   */
  public int getWidth() {
    return w;
  }

  /**
   * Return the height.
   * @return the height
   */
  public int getHeight() {
    return h;
  }

  /**
   * Return the x-axis row.
   * @return the row
   */
  public int getXAxisRow() {
    return xAxisRow;
  }

  /**
   * Return the y-axis column.
   * @return the column
   */
  public int getYAxisColumn() {
    return yAxisCol;
  }

  /**
   * Update the bounds values.
   * @param xMin the minimum x value
   * @param xMax the maximum x value
   * @param yMin the minimum y value
   * @param yMax the maximum y value
   */
  public void update(float xMin, float xMax, float yMin, float yMax) {
    this.xMin = xMin;
    this.xMax = xMax;
    this.yMin = yMin;
    this.yMax = yMax;
  }

  /**
   * Compute property values.
   * @param plotSize the plot panel size
   */
  void compute(Dimension plotSize) {
    w = plotSize.width;
    h = plotSize.height;

    xDelta = (xMax - xMin) / w;
    yDelta = (yMax - yMin) / h;

    xAxisRow = Math.round(yMax / yDelta);
    yAxisCol = Math.round( -xMin / xDelta);
  }
}