Pie Chart : Chart « Advanced Graphics « Java






Pie Chart

Pie Chart
 
import java.awt.*;
import java.util.*;

import javax.swing.*;

import no.geosoft.cc.geometry.Geometry;
import no.geosoft.cc.graphics.*;



/**
 * G demo program. Demonstrates:
 *
 * <ul>
 * <li>A rudimentary pie chart class
 * <li>Annotation techniques
 * <li>Example geometry generation
 * </ul>
 * 
 * @author <a href="mailto:jacob.dreyer@geosoft.no">Jacob Dreyer</a>
 */   
public class Demo16 extends JFrame
{
  public Demo16()
  {
    super ("G Graphics Library - Demo 16");    
    setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
    
    // Create the graphic canvas
    GWindow window = new GWindow();
    getContentPane().add (window.getCanvas());
    
    // Create scane with default viewport and world extent settings
    GScene scene = new GScene (window);

    GStyle pieStyle = new GStyle();
    pieStyle.setFont (new Font ("Dialog", Font.BOLD, 18));
    pieStyle.setLineStyle (GStyle.LINESTYLE_INVISIBLE);
    pieStyle.setForegroundColor (new Color (255, 255, 255));
    
    PieChart pieChart = new PieChart (250, 250, 200);
    pieChart.setStyle (pieStyle);

    pieChart.addSector (0.20, "Canada", getStyle());
    pieChart.addSector (0.10, "USA",    getStyle());
    pieChart.addSector (0.25, "Spain",  getStyle());
    pieChart.addSector (0.35, "China",  getStyle());
    pieChart.addSector (0.10, "Chile",  getStyle());

    scene.add (pieChart);
    
    pack();
    setSize (new Dimension (500, 500));
    setVisible (true);
  }


  
  private GStyle getStyle()
  {
    GStyle style = new GStyle();
    style.setBackgroundColor (new Color (Color.HSBtoRGB ((float)Math.random(), 0.4f, 0.8f)));
    return style;
  }
  
    

  private class PieChart extends GObject
  {
    private int         x0_, y0_;
    private int         radius_;
    private Collection  sectors_;
    
    
    PieChart (int x0, int y0, int radius)
    {
      x0_      = x0;
      y0_      = y0;
      radius_  = radius;
      sectors_ = new ArrayList();
    }


    void addSector (double fraction, String text, GStyle style)
    {
      sectors_.add (new Sector (fraction, text, style));
    }
    
    
    public void draw()
    {
      removeSegments();

      // Loop through the sectors and draw the graphics for each
      double angle0 = 0.0;
      for (Iterator i = sectors_.iterator(); i.hasNext(); ) {
        Sector sector = (Sector) i.next();

        //
        // Geometry for the sector itself
        //
        GSegment segment = new GSegment();
        addSegment (segment);
        segment.setStyle (sector.style);

        double angle1 = angle0 + sector.fraction * Math.PI * 2.0;

        int[] sectorGeometry = Geometry.createSector (x0_, y0_, radius_,
                                                      angle0, angle1);

        segment.setGeometry (sectorGeometry);
        angle0 = angle1;

        //
        // Add annotation. Create an invisible line from the sector center
        // thorugh the center of the arc and out and associated annotation
        // with this line.
        //
        double[] p0 = new double[3];
        double[] p1 = new double[3];

        int nPoints = sectorGeometry.length / 2;
        int pointNo = (nPoints - 2) / 2;
        
        p1[0] = sectorGeometry[pointNo * 2 + 0];
        p1[1] = sectorGeometry[pointNo * 2 + 1];
        p1[2] = 0.0;

        double[] sectorCenter = Geometry.computePointOnLine (x0_, y0_,
                                                             p1[0], p1[1],
                                                             0.5);
        p0[0] = sectorCenter[0];
        p0[1] = sectorCenter[1];
        p0[2] = 0.0;

        // Ensure line extends far out of the sector
        Geometry.extendLine (p0, p1, 1000.0);
        
        GSegment annotationLine = new GSegment();
        addSegment (annotationLine);

        annotationLine.setGeometry ((int) p0[0], (int) p0[1],
                                    (int) p1[0], (int) p1[1]);

        // Add the percentage text
        int percent = (int) Math.round (sector.fraction * 100.0);
        GText text = new GText (percent + "%", GPosition.FIRST);
        annotationLine.addText (text);

        // Add the label to the same geometry point as the percentage;
        // It will be adjusted so it doesn't overlap
        text = new GText (sector.label, GPosition.FIRST);
        annotationLine.addText (text);
      }
    }
  }

  

  private class Sector
  {
    public double  fraction;
    public String  label;
    public GStyle  style;

    public Sector (double fraction, String label, GStyle style)
    {
      this.fraction = fraction;
      this.label    = label;
      this.style    = style;
    }
  }
  


  public static void main (String[] args)
  {
    new Demo16();
  }
}

           
         
  








G-PieChart.zip( 214 k)

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