How to generate legend wise and custom pie chart

A pie chart (or a circle chart) is a circular statistical graphic which is divided into slices to illustrate numerical proportion. In a pie chart, the arc length of each slice (and consequently its central angle and area), is proportional to the quantity it represents.

jfreeChart-1.0.19.jar
jcommon-1.0.8.jar

The provided code consists of three Java classes that are part of a pie chart visualization application. Here's a breakdown of each class:

1. DemoData Class

package com.kartik.pie;

public class DemoData {

private String name;

private String description;

private double data;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getDescription() {

return description;

}

public void setDescription(String description) {

this.description = description;

}

public double getData() {

return data;

}

This is a simple data model that holds information for each slice of the pie chart. It has three attributes: name, description, and data.

Ø name: The name of the data item.

Ø description: A description of the data item (currently not utilized in the code).

Ø data: A double value representing the size of the pie slice.

Methods:

Ø Getters and setters for each field (getName(), setName(), getDescription(), setDescription(), getData(), and setData()).

2. CustomRingPlot Class

package com.kartik.pie;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics2D;

import java.awt.geom.Rectangle2D;

import org.jfree.chart.plot.PiePlotState;

import org.jfree.chart.plot.RingPlot;

import org.jfree.data.general.PieDataset;

import org.jfree.text.TextUtilities;

import org.jfree.ui.TextAnchor;

public class CustomRingPlot extends RingPlot {

/**

private static final long serialVersionUID = 1L;

private Font centerTextFont;

private Color centerTextColor;

private int total;

public CustomRingPlot(PieDataset dataset, Font centerTextFont,

Color centerTextColor) {

super(dataset);

this.centerTextFont = centerTextFont;

this.centerTextColor = centerTextColor;

}

public CustomRingPlot(PieDataset dataset, Font centerTextFont,

Color centerTextColor, int total) {

super(dataset);

this.centerTextFont = centerTextFont;

this.centerTextColor = centerTextColor;

this.total = total;

}

protected void drawItem(Graphics2D g2, int section, Rectangle2D dataArea,

PiePlotState state, int currentPass) {

super.drawItem(g2, section, dataArea, state, currentPass);

g2.setFont(this.centerTextFont);

g2.setPaint(Color.BLACK);

TextUtilities.drawAlignedString("Total Spendings", g2,

(float) dataArea.getCenterX(), (float) dataArea.getCenterY(),

TextAnchor.BOTTOM_CENTER);

g2.setPaint(this.centerTextColor);

g2.setFont(new Font(Font.SANS_SERIF, Font.HANGING_BASELINE, 14));

TextUtilities.drawAlignedString("$" + this.total, g2,

(float) dataArea.getCenterX(), (float) dataArea.getCenterY(),

TextAnchor.TOP_CENTER);

}

* protected void drawItem(Graphics2D g2, int section, Rectangle2D dataArea,

* PiePlotState state, int currentPass) { super.drawItem(g2, section,

* dataArea, state, currentPass); g2.setFont(this.centerTextFont);

* g2.setPaint(Color.BLACK);

* TextUtilities.drawAlignedString("Total Spendings", g2, (float)

* dataArea.getCenterX(), (float) dataArea.getCenterY(),

* TextAnchor.BOTTOM_CENTER); g2.setPaint(this.centerTextColor);

* g2.setFont(new Font(Font.SANS_SERIF, Font.HANGING_BASELINE, 14));

* TextUtilities.drawAlignedString("$", g2, (float) dataArea.getCenterX(),

* (float) dataArea.getCenterY(), TextAnchor.TOP_CENTER); }

}

This class extends RingPlot from the JFreeChart library to create a custom pie chart. It adds additional features such as custom text in the center of the ring plot (like total spendings).

Key Features:

Ø Custom Font and Color: The constructor accepts a dataset (PieDataset), a font for the center text, a color for the text, and the total value for display.

Ø Custom Rendering: The drawItem method is overridden to draw custom text at the center of the ring plot, showing the label "Total Spendings" and the total value.

Ø Item Drawing: It draws text using the TextUtilities.drawAlignedString() method, positioning it relative to the pie chart's center.

3. PieChartDemo2 Class

Code 3:

package com.kartik.pie;

import java.awt.BasicStroke;

import java.awt.Color;

import java.awt.Font;

import java.awt.GradientPaint;

import java.awt.Point;

import java.awt.geom.Rectangle2D;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.text.DecimalFormat;

import java.util.ArrayList;

import java.util.List;

import javax.swing.JPanel;

import org.jfree.chart.ChartPanel;

import org.jfree.chart.ChartUtilities;

import org.jfree.chart.JFreeChart;

import org.jfree.chart.labels.PieSectionLabelGenerator;

import org.jfree.chart.labels.StandardPieSectionLabelGenerator;

import org.jfree.chart.plot.RingPlot;

import org.jfree.chart.title.LegendTitle;

import org.jfree.data.general.DefaultPieDataset;

import org.jfree.data.general.PieDataset;

import org.jfree.ui.ApplicationFrame;

import org.jfree.ui.RectangleEdge;

import org.jfree.ui.RectangleInsets;

import org.jfree.ui.RefineryUtilities;

import org.jfree.util.Rotation;

/**

* A simple demonstration application showing how to create a pie chart using

* data from a {@link DefaultPieDataset}.

public class PieChartDemo2 extends ApplicationFrame {

private static int totalAmount=0;

/**

private static final long serialVersionUID = 1L;

private static int maxSize=0;

/**

* Default constructor.

* @param title the frame title.

public PieChartDemo2(String title) {

super(title);

setContentPane(createDemoPanel());

}

/**

* @return A sample dataset.

private static PieDataset createDataset() {

DefaultPieDataset dataset = new DefaultPieDataset();

/*dataset.setValue("one", new Double(43.2));

dataset.setValue("two", new Double(10.0));

dataset.setValue("three", new Double(27.5));

dataset.setValue("four", new Double(17.5));

dataset.setValue("five", new Double(11.0));

dataset.setValue("six", new Double(19.4));

dataset.setValue("seven", new Double(43.2));*/

List<DemoData> data=setData();

totalAmount=sumOfValue(data);

dataset=getdata(data);

return dataset;

}

private static DefaultPieDataset getdata(List<DemoData> data){

DefaultPieDataset dataSet=new DefaultPieDataset();

for (DemoData demoData : data) {

dataSet.setValue(demoData.getName(), demoData.getData());

}

return dataSet;

}

private static int sumOfValue(List<DemoData> data){

int sum=0;

for (DemoData demoData : data) {

sum+=demoData.getData();

}

return sum;

}

private static List<DemoData> setData(){

List<DemoData> list=new ArrayList<DemoData>();

DemoData one=new DemoData();

one.setName("ONE");

one.setData( new Double(43.2));

list.add(one);

DemoData two=new DemoData();

two.setName("TWO");

two.setData(new Double(10.0));

list.add(two);

DemoData three=new DemoData();

three.setName("THREE");

three.setData( new Double(27.5));

list.add(three);

DemoData four=new DemoData();

four.setName("FOUR");

four.setData( new Double(17.5));

list.add(four);

DemoData five=new DemoData();

five.setName("FIVE");

five.setData( new Double(11.0));

list.add(five);

DemoData six=new DemoData();

six.setName("SIX");

six.setData( new Double(19.4));

list.add(six);

DemoData seven=new DemoData();

seven.setName("SEVEN");

seven.setData( new Double(9.2));

list.add(seven);

DemoData twenty=new DemoData();

twenty.setName("twentyOne");

twenty.setData( new Double(65.0));

list.add(twenty);

return list;

}

private static JFreeChart createChart(PieDataset dataset) {

//RingPlot plot = new RingPlot(dataset);

RingPlot plot = null;

//PiePlot plot = (PiePlot) chart.getPlot();

// plot = (RingPlot) chart.getPlot();

plot = new CustomRingPlot((PieDataset)dataset, new Font(Font.SANS_SERIF, Font.BOLD, 13), Color.BLUE,totalAmount);

JFreeChart chart = new JFreeChart("", JFreeChart.DEFAULT_TITLE_FONT,

plot, true);

chart.setBackgroundPaint(new GradientPaint(new Point(100, 100),

Color.WHITE, new Point(100, 100), Color.WHITE));

plot.setNoDataMessage("No data available");

plot.setDirection(Rotation.ANTICLOCKWISE);

plot.setSectionDepth(0.50D); //this is required for circle radios

plot.setBaseSectionOutlineStroke(new BasicStroke(0.5f));

plot.setCircular(true);

plot.setSeparatorsVisible(false); //this is required otherwise inside circle lot of straight line will come

plot.setForegroundAlpha(1.0f); //this is required to display deep color inside pie chart

plot.setOutlinePaint(null); //this is required for circle border if comment this line

plot.setShadowPaint(null);

plot.setOuterSeparatorExtension(50);

plot.setInnerSeparatorExtension(50);

plot = setSectionPaintColors(plot);

LegendTitle legend = chart.getLegend();

legend.setPosition(RectangleEdge.RIGHT);//this is also required to display legend label

//legend.setFrame(BlockBorder.NONE); //this is required legend border if you need otherwise comments this line

Rectangle2D r2DD = new Rectangle2D.Double(0, 0, 5, 15);

plot.setLegendItemShape(r2DD);

/*StandardPieSectionLabelGenerator standardPieSectionLabelGenerator = new StandardPieSectionLabelGenerator(("{0}:{2}"),NumberFormat.getNumberInstance(), new DecimalFormat("0.0%"));

plot.setLabelGenerator(standardPieSectionLabelGenerator);*/

@SuppressWarnings("unchecked")

List<String> key=dataset.getKeys();

for (String string : key) {

if(string.length()>maxSize){

maxSize=string.length();

}

PieSectionLabelGenerator labelGenerator = new StandardPieSectionLabelGenerator("{2}{1}{0}", new DecimalFormat("0.00"), new DecimalFormat("0%") ){

private static final long serialVersionUID = 1L;

@SuppressWarnings("rawtypes")

@Override

protected Object[] createItemArray(PieDataset dataset, Comparable key) {

Object[] array = super.createItemArray(dataset, key);

Object[] array1 = new Object[array.length];

int count=0;

for (Object object : array) {

StringBuffer sss=new StringBuffer();

if(count == 1){

sss.append(object.toString());

sss=charSpace(sss,object.toString().length(),9);

}else if(count == 2){

sss=charDigit(sss,object.toString().length(),5);

sss.append(object.toString());

if(object.toString().length()==2){

sss=charSpaceDigit(sss,object.toString().length()+1,6);

}

else{

sss=charSpace(sss,object.toString().length(),6);

}

}else if(count == 0){

sss.append(object.toString().substring(0, 1).toUpperCase() + object.toString().substring(1,object.toString().length()).toLowerCase());

}else{

sss.append(object.toString());

}

array1[count] = sss.toString();

count++;

}

return array1;

}

};

plot.setLabelGenerator(null);

//plot.setLabelGenerator(labelGenerator); //this is required if you need display inside circle your description otherwise put null

plot.setLegendLabelGenerator(labelGenerator); //this is required to display legend label

chart.setPadding(new RectangleInsets(-6, 0, 0, 20)); //this is required for right side of legend space

chart.setBorderVisible(true);

chart.setBorderPaint(Color.WHITE);

chart.setBorderStroke(new BasicStroke(0.3f));

return chart;

}

/**

* Creates a panel for the demo (used by SuperDemo.java).

* @return A panel.

public static JPanel createDemoPanel() {

JFreeChart chart = createChart(createDataset());

try {

ChartUtilities.writeChartAsPNG(new FileOutputStream(new File("D:\\sampleChart.png")) , chart, 400, 300);

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

return new ChartPanel(chart);

}

private static RingPlot setSectionPaintColors(RingPlot plot) {

List<?> listOfData = plot.getDataset().getKeys();

String[] color = getColors();

if (color != null && color.length > 0) {

int count=0;

for (Object string : listOfData) {

plot.setSectionPaint((String)string,Color.decode(color[count]));

count++;

}

return plot;

}

private static String[] getColors() {

String[] colors ={"#41f46e", "#f47f41", "#5b2a44","#DF0096","#CF0096","#EE0096","#BBCCCC","#4286f4"};

return colors;

}

private static StringBuffer charSpace(StringBuffer sb,int datalength,int MaxSize){

if(datalength==MaxSize){

sb.append(" ");

return sb;

}else{

sb.append(" ");

return charSpace(sb,datalength+1,MaxSize);

}

private static StringBuffer charSpaceDigit(StringBuffer sb,int datalength,int MaxSize){

if(datalength==MaxSize){

sb.append(" ");

return sb;

}else{

sb.append(" ");

return charSpaceDigit(sb,datalength+1,MaxSize);

}

private static StringBuffer charDigit(StringBuffer sb,int datalength,int MaxSize){

if(datalength==2){

sb.append(" ");

return sb;

}

return sb;

}

/**

* Starting point for the demonstration application.

* @param args ignored.

public static void main(String[] args) {

PieChartDemo2 demo = new PieChartDemo2("Pie Chart Demo 1");

demo.pack();

RefineryUtilities.centerFrameOnScreen(demo);

demo.setVisible(true);

}

This class sets up the pie chart using JFreeChart and renders it using a dataset created with the DemoData class.

Key Features:

Ø createDataset(): This method creates a pie dataset by using data from DemoData instances. The dataset is populated with values like "ONE", "TWO", etc., each with its respective data.

Ø createChart(): This method builds the actual pie chart using a RingPlot, and it applies the CustomRingPlot for custom drawing.

ü It configures the look of the pie chart, including section depth, legend placement, and colors for different sections.

ü A custom label generator is used to space out the chart's sections and add specific formatting.

Ø setSectionPaintColors(): This method applies custom colors to each section of the pie chart. Colors are fetched from a predefined array of hex color codes.

Ø Main Method: The entry point for the application, where the pie chart is displayed in a Swing frame using ChartPanel and exported to a PNG file.

Enhancements and Customizations:

Custom Labels and Center Text: The ring chart has text at its center ("Total Spendings"), with additional data displayed in the legend. This enhances the user interface, providing quick summary information.
Color Customization: The pie chart sections are colored with custom colors for better visualization.
Exporting Chart to PNG: The chart can be exported as a PNG file by saving it to disk using ChartUtilities.writeChartAsPNG().

If you have specific questions, feel free to let me know!