Draw a pie graph - Java 2D Graphics

Java examples for 2D Graphics:Ellipse

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Description

Draw a pie graph

Demo Code

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Arc2D;
import java.awt.geom.Ellipse2D;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Main extends JFrame {
  public Main() {
    super("Pie Graph");
    setSize(322, 322);/*from w w w  .j a v  a2  s  .co  m*/
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    PiePanel pie = new PiePanel(4);
    pie.addSlice(Color.green, 20F);
    pie.addSlice(Color.blue, 33F);
    pie.addSlice(Color.red, 12F);
    pie.addSlice(Color.yellow, 15F);
    add(pie);
    setVisible(true);
  }

  public static void main(String[] arguments) {
    Main pg = new Main();
  }
}

class PiePanel extends JPanel {
  private PieSlice[] slice;
  private int current = 0;
  private float totalSize = 0;
  private Color background;

  public PiePanel(int sliceCount) {
    slice = new PieSlice[sliceCount];
    background = getBackground();
  }

  public void addSlice(Color sColor, float sSize) {
    if (current <= slice.length) {
      slice[current] = new PieSlice(sColor, sSize);
      totalSize += sSize;
      current++;
    }
  }

  public void paintComponent(Graphics comp) {
    Graphics2D comp2D = (Graphics2D) comp;
    int width = getSize().width - 10;
    int height = getSize().height - 15;
    int xInset = 5;
    int yInset = 5;
    if (width < 5) {
      xInset = width;
    }
    if (height < 5) {
      yInset = height;
    }
    comp2D.setColor(background);
    comp2D.fillRect(0, 0, getSize().width, getSize().height);
    comp2D.setColor(Color.lightGray);
    Ellipse2D.Float pie = new Ellipse2D.Float(xInset, yInset, width, height);
    comp2D.fill(pie);
    float start = 0;
    for (PieSlice slice1 : slice) {
      float extent = slice1.size * 360F / totalSize;
      comp2D.setColor(slice1.color);
      Arc2D.Float drawSlice = new Arc2D.Float(xInset, yInset, width, height,
          start, extent, Arc2D.Float.PIE);
      start += extent;
      comp2D.fill(drawSlice);
    }
  }
}

class PieSlice {
  Color color = Color.lightGray;
  float size = 0;

  PieSlice(Color pColor, float pSize) {
    color = pColor;
    size = pSize;
  }
}

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