Question

JAVA - Write a program that prompts the user (at the command line) for 4 positive integers, then draws a pie chart in a window. Convert the numbers to percentages of the numbers’ total sum; color each segment differently; use Arc2D. No text fields (other than the window title) are required. Provide a driver in a separate source file to test your class.

Please use the following:

java.lang.Object

java.awt.Graphics

java.awt.Graphics2D

Take note of the following:

setPaint

setStroke

fill

// imports

public class PieChartPanel extends JPanel {

// attributes

// constructor

public void paintComponent(Graphics g) {

super.paintComponent (g);

Graphics2D g2d = ( Graphics2D ) g;

...

}

There should be a paintComponent method that calls its parent

Answer 1

CODE:

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.util.Scanner;

import javax.swing.JComponent;
import javax.swing.JFrame;

// class to store the value and color mapping of the
// pie segment(slices)
class Segment {
   double value;
   Color color;

   // constructor
   public Segment(double value, Color color) {
       this.value = value;
       this.color = color;
   }
}

class pieChartComponent extends JComponent {

   private static final long serialVersionUID = 1L;
   Segment[] Segments;

   // Parameterized constructor
   // create 4 segments of the pie chart
   pieChartComponent(int v1, int v2, int v3, int v4) {
       Segments = new Segment[] { new Segment(v1, Color.black), new Segment(v2, Color.green), new Segment(v3, Color.yellow),
               new Segment(v4, Color.red) };
   }

   // function responsible for calling the worker method drawPie
   public void paint(Graphics g) {
       drawPie((Graphics2D) g, getBounds(), Segments);
   }

   // worker function for creating the percentage wise slices of the pie chart
  
   void drawPie(Graphics2D g, Rectangle area, Segment[] Segments) {
       double total = 0.0D;
       // fin the total of the all the inputs provided by the user
       for (int i = 0; i < Segments.length; i++) {
           total += Segments[i].value;
       }
      
       // Initialization
       double curValue = 0.0D;
       int strtAngle = 0;
       // iterate till all the segments are covered
       for (int i = 0; i < Segments.length; i++) {
           // compute start angle, with percentage
           strtAngle = (int) (curValue * 360 / total);
           // find the area angle of the segment
           int arcAngle = (int) (Segments[i].value * 360 / total);

           g.setColor(Segments[i].color);
           g.fillArc(area.x, area.y, area.width, area.height, strtAngle, arcAngle);
           curValue += Segments[i].value;
       }
   }
}

public class Graphic_Pie2D {
   public static void main(String[] argv) {

       System.out.println("Pleae provide 4 values, to create the pie chart");
       Scanner input = new Scanner(System.in);
       int v1, v2, v3, v4;
       v1 = input.nextInt();
       v2 = input.nextInt();
       v3 = input.nextInt();
       v4 = input.nextInt();
      
       // create a JFrame with title
       JFrame frame = new JFrame("Pie Chart");
       frame.getContentPane().add(new pieChartComponent(v1,v2,v3,v4));
       frame.setSize(500, 300);
       frame.setVisible(true);

   }
}

RESULT: