///////    PiePlot.java    ///////
import java.awt.*;

/** Draws a color pie chart given:
    n:     the number of items
    perc:  n percentages (must sum to 1)
    c:     n colors to use 
*/
class PiePlot extends Canvas
{   public PiePlot(int n, double[] perc, Color[] c)
    {   items = n; color = c;
        ang0 = new int[n];
        ang1 = new int[n];
        int start=0;
        for (int i=0; i < items; i++)
        {   if ( start >= 360 ) break;
            ang0[i] = start;
            ang1[i] = Math.max(2, (int)(360*perc[i]+0.5));
            if ( start + ang1[i] > 360 )
                ang1[i] = 360 - start;
            start += ang1[i];
        }
    }

    protected PiePlot() { }

    public void paint(Graphics g) // override
    {   int wd = getSize().width; 
        int ht = getSize().height;
        w = wd*4/5; h = (int)(w*ratio);
        if ( h > ht - 12 )           
        {   h = ht - 12; 
            w = (int)(h/ratio);     
        }
        x0 = ( wd - w )/4;       // left margin
        y0 = ht - h;             // headroom
        for (int i=0; i < items; i++)
        {   g.setColor(color[i]);  
            g.fillArc(x0, y0, w, h,
                      ang0[i], ang1[i]);
        }
    }
    protected int items; // no of sections
    protected Color[] color; // section colors
    protected int[] ang0; // starting angles
    protected int[] ang1; // section angles
    protected int x0=0, y0=0, w=0, h=0;  // area for oval pie
    protected double ratio = 0.62; // golden ratio
}