Piechart.java.

• By Anand Jain
• July 17, 2000

Listing 2. Piechart.java.

import java.awt.*;
import java.applet.*;
import java.util.*;


public class Piechart extends Applet {
	

	Image buffer;      // used for double buffering
	Graphics gContext; // used for double buffering

	Label lblChartTitle;
	String []lblLegend = new String[16];
	Slice []slice = new Slice[16];
	Color backGroundColor = Color.white;
	Color []color = {	new Color(43,14,114),
	new Color(238,156,104),        	
	Color.blue, new Color(223,23,122),
	new Color(0,143,224),
	new Color(242,155,190),
	new Color(247,198,0),
	new Color(127,196,36),
	new Color(253,252,155),
	new Color(186,112,164),
	new Color(121,197,161),
	new Color(143,86,68),
	new Color(116,195,242),
	Color.yellow, new Color(0,146,64),
	new Color(245,198,144) }; // colors
	int numOfSlices;
	int biggestNumberIndx=0;
	public final int MAXSLICES = 16;
	final int chartBase = 360;
	final int legendRectStartPosx=5;
	final int legendRectStartPosy=215;
	final int legendLblStartPosx=20;
	final int legendLblStartPosy=225;
	int [] intPercent = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
	// for disp. in chart
	int legendLabelMaxLength = 8;
	int xLegendDistance = 102;
	int yLegendDistance = 15;
	int intTotal = 0; // total number of items recd.
	int [] intValue  	= {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
	// values picked up from the html page
	int [] intDegree  = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
	// converted values

	static int sliceno=0;


	public void init() {

		String chartTitle;

		chartTitle = getParameter("TITLE");

        lblChartTitle = new Label(chartTitle,Label.CENTER);
        // center align
        if(lblChartTitle==null) lblChartTitle= new Label(" ");
              lblChartTitle.setBounds(0,0,25,400);
              add(lblChartTitle);

              readParams(); // reads the parameters from html file

	} // init()


	// getting the <params> from the applet
	private void readParams() {

		String tmpChartValues;
		for(numOfSlices =0;numOfSlices < MAXSLICES;numOfSlices++) {
			tmpChartValues = getParameter("SLICE"+(numOfSlices+1));
			if(tmpChartValues.trim().equals("")) break;
			// get out if read all values

			int indexOf = tmpChartValues.indexOf("-");
			String strValue = tmpChartValues.substring(0,indexOf);

			lblLegend[numOfSlices] = new String(
        tmpChartValues.substring(indexOf+1,tmpChartValues.length()));
			float floatValue = (new Float(strValue)).floatValue();
			intValue[numOfSlices] = (int)(floatValue*10000); 	
			// converting float to int.

			// but preserving decimals

			// by multiplying by 10000
							intTotal = intValue[numOfSlices] + intTotal;
		}

		allocSlices(); // find out the share of each slice

	}

	private void allocSlices() {
			// getting the index of the biggest value
		for(int i =0;i <numOfSlices;i++) {
			if(intValue[biggestNumberIndx] < intValue[i]) {
					biggestNumberIndx = i;
			}
		}

		int tmp=0;
		int tmp1=0;
		for(int i =0;i <numOfSlices;i++) {
		// allocating values - % and 360 both
			if(i != biggestNumberIndx) { // if not biggest then process
				float ftmp = (float) (chartBase * intValue[i]) / intTotal ;
				float fpercent = (float) (100 * intValue[i]) / intTotal ;

				intDegree[i] 	= Math.round(ftmp);
				intPercent[i] = Math.round(fpercent);
				tmp = tmp+intDegree[i];
				tmp1=tmp1+intPercent[i];

			}
			else {
				float ftmp = (float) (chartBase * intValue[i]) / intTotal ;
			}
		}

		intDegree[biggestNumberIndx] = chartBase - tmp;
		// remaining allocating to the biggest value
		intPercent[biggestNumberIndx] = 100-tmp1;
// remaining % allocating to the biggest value

		int startAngle=0;

		for(int i =0;i <numOfSlices;i++) {
			slice[i] = new Slice(startAngle,intDegree[i],color[i].darker());
			startAngle= startAngle+intDegree[i];
		}
	}


	public void start() {
		buffer = createImage(400, 300);  // used for double buffering
		gContext = buffer.getGraphics(); // used for double buffering
		gContext.setColor(backGroundColor);
		gContext.fillRect(0,0,400,300);
		gContext.setColor(Color.lightGray);
		gContext.fillOval(76,110,250,99); // shadow

		gContext.setColor(Color.black);
		gContext.fillOval(75,101,250,100); // baseline

    drawSlices();      // draw slices
       drawLegends();  // draw legends

	} // start()

	private void drawSlices() {
		for(int j=30; j>0; j-){
			Slice.setDimensions(75,70+j,250,100);
			for(int i =0;i <numOfSlices;i++) {
				slice[i].draw(gContext);
				// drawing the 'depth' of each slice
			}
		}

		for(int i =0;i <numOfSlices;i++) {
			slice[i].draw(gContext,color[i]);
			// drawing the brighter version on the top
		}

	}	private void drawLegends() {
		sliceno=0;
		String tmpString;
		final int MAXLEGENDS_HORIZ=4, MAXLEGENDS_VERT=4;

		for(int i =0; i< MAXLEGENDS_HORIZ;i++) {
			for(int j =1; j<= MAXLEGENDS_VERT;j++) {
				//drawing the legends
					if(sliceno >= numOfSlices) break;
					slice[sliceno].drawRect(new Rectangle(
                                   legendRectStartPosx+(i*xLegendDistance),
                                                      legendRectStartPosy+(
                                     j*yLegendDistance),10,10), gContext);
					gContext.setColor(Color.black);
					tmpString = lblLegend[sliceno] ;
					int lengthofString = tmpString.length();
					tmpString = tmpString.substring(0,(
                                  lengthofString >legendLabelMaxLength?
                                 legendLabelMaxLength : lengthofString));
				gContext.drawString(tmpString+" 
                    (" + intPercent[sliceno] +"%)", legendLblStartPosx+
          (i*xLegendDistance),legendLblStartPosy+(j*yLegendDistance));
		sliceno++;
			}
			if(sliceno >= numOfSlices) break;
		}
	}


	public void paint(Graphics g) {
		g.drawImage(buffer,0,0,this);
	} // paint()


	public void stop() {	} // stop()


}