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Java > Open Source Codes > JSci > awt > PieChart


1 package JSci.awt;
2
3 import java.awt.*;
4
5 /**
6 * A pie chart AWT component.
7 * @version 1.2
8 * @author Mark Hale
9 */
10 public class PieChart extends CategoryGraph2D {
11         /**
12         * Total value of pie.
13         */
14         private float pieTotal;
15         /**
16         * Slice colors.
17         */
18         protected Color sliceColor[]={Color.blue,Color.green,Color.red,Color.yellow,Color.cyan,Color.lightGray,Color.magenta,Color.orange,Color.pink};
19         /**
20         * Constructs a pie chart.
21         */
22         public PieChart(CategoryGraph2DModel cgm) {
23                 super(cgm);
24                 dataChanged(new GraphDataEvent(model));
25         }
26         /**
27         * Implementation of GraphDataListener.
28         * Application code will not use this method explicitly, it is used internally.
29         */
30         public void dataChanged(GraphDataEvent e) {
31                 model.firstSeries();
32                 final int len=model.seriesLength();
33                 pieTotal=0.0f;
34                 for(int i=0;i<len;i++)
35                         pieTotal+=model.getValue(i);
36                 if(len>sliceColor.length) {
37                         Color tmp[]=sliceColor;
38                         sliceColor=new Color[len];
39                         System.arraycopy(tmp,0,sliceColor,0,tmp.length);
40                         for(int i=tmp.length;i<sliceColor.length;i++)
41                                 sliceColor[i]=sliceColor[i-tmp.length];
42                 }
43                 rescale();
44         }
45         /**
46         * Sets the slice color of the nth slice.
47         * @param n the index of the slice.
48         * @param c the slice color.
49         */
50         public final void setColor(int n,Color c) {
51                 sliceColor[n]=c;
52         }
53         /**
54         * Gets the slice color of the nth slice.
55         * @param n the index of the slice.
56         */
57         public final Color getColor(int n) {
58                 return sliceColor[n];
59         }
60         /**
61         * Reshapes the PieChart to the specified bounding box.
62         */
63         public final void setBounds(int x,int y,int width,int height) {
64                 super.setBounds(x,y,width,height);
65                 rescale();
66         }
67         /**
68         * Rescales the PieChart.
69         */
70         protected final void rescale() {
71                 origin.x=getSize().width/2;
72                 origin.y=getSize().height/2;
73                 redraw();
74         }
75         /**
76         * Paint the graph.
77         */
78         protected void offscreenPaint(Graphics g) {
79                 final int width=2*(origin.x-axisPad);
80                 final int height=2*(origin.y-axisPad);
81                 final double xRadius=0.4*width;
82                 final double yRadius=0.4*height;
83 // slices
84 int angle=0;
85                 model.firstSeries();
86                 final int n = model.seriesLength();
87                 if(n > 0) {
88                         for(int i=0; i<n-1; i++) {
89                                 g.setColor(sliceColor[i]);
90                                 int arcAngle=Math.round(model.getValue(i)*360.0f/pieTotal);
91                                 g.fillArc(axisPad,axisPad,width,height,angle,arcAngle);
92                                 angle+=arcAngle;
93                         }
94                         g.setColor(sliceColor[n-1]);
95                         g.fillArc(axisPad,axisPad,width,height,angle,360-angle);
96                 }
97 // border
98 g.setColor(getForeground());
99                 g.drawArc(axisPad,axisPad,width,height,0,360);
100 // labels
101 final int strHalfHeight=g.getFontMetrics().getHeight()/2;
102                 double dAngle=0.0;
103                 g.setColor(getForeground());
104                 for(int i=0; i<n; i++) {
105                         double dHalfArcAngle=model.getValue(i)*Math.PI/pieTotal;
106                         dAngle+=dHalfArcAngle;
107             String JavaDoc str = model.getCategory(i);
108             int strHalfWidth=g.getFontMetrics().stringWidth(str)/2;
109             g.drawString(str,origin.x-strHalfWidth+(int)(xRadius*Math.cos(dAngle)),origin.y+strHalfHeight-(int)(yRadius*Math.sin(dAngle)));
110                         dAngle+=dHalfArcAngle;
111                 }
112         }
113 }
114
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