Composite.java Source code

Introduction

Here is the source code for Composite.java

Source

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;

import javax.swing.JApplet;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class Composite extends JApplet implements ItemListener {
    CompPanel comp;

    JLabel alphaLabel = new JLabel("Alphas");

    JLabel rulesLabel = new JLabel("Rules");

    JComboBox alphas = new JComboBox();

    JComboBox rules = new JComboBox();

    String alpha = "1.0";

    int rule = 0;

    public void init() {
        getContentPane().setLayout(new FlowLayout());
        getContentPane().add(alphaLabel);
        getContentPane().add(rulesLabel);

        alphas.addItem("1.0");
        alphas.addItem("0.75");
        alphas.addItem("0.50");
        alphas.addItem("0.25");
        alphas.addItem("0.0");
        alphas.addItemListener(this);
        getContentPane().add(alphas);

        rules.addItem("SRC");
        rules.addItem("DST_IN");
        rules.addItem("DST_OUT");
        rules.addItem("DST_OVER");
        rules.addItem("SRC_IN");
        rules.addItem("SRC_OVER");
        rules.addItem("SRC_OUT");
        rules.addItem("CLEAR");
        rules.addItemListener(this);
        getContentPane().add(rules);

        comp = new CompPanel();
        getContentPane().add(comp);

        validate();
    }

    public void itemStateChanged(ItemEvent e) {
        if (e.getStateChange() != ItemEvent.SELECTED) {
            return;
        }

        Object choice = e.getSource();
        if (choice == alphas) {
            alpha = (String) alphas.getSelectedItem();
        } else {
            rule = rules.getSelectedIndex();
        }
        comp.changeRule(alpha, rule);
    }

    public static void main(String s[]) {
        JFrame f = new JFrame("Composite");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
        JApplet applet = new Composite();
        f.getContentPane().add("Center", applet);
        applet.init();
        f.pack();
        f.setSize(new Dimension(300, 300));
        f.show();
    }
}

class CompPanel extends JPanel {

    AlphaComposite ac = AlphaComposite.getInstance(AlphaComposite.SRC);

    float alpha = 1.0f;

    public CompPanel() {
        setPreferredSize(new Dimension(250, 250));
    }

    public void changeRule(String a, int rule) {
        alpha = Float.valueOf(a).floatValue();
        ac = AlphaComposite.getInstance(getRule(rule), alpha);
        repaint();
    }

    public int getRule(int rule) {
        int alphaComp = 0;
        switch (rule) {
        case 0:
            alphaComp = AlphaComposite.SRC;
            break;
        case 1:
            alphaComp = AlphaComposite.DST_IN;
            break;
        case 2:
            alphaComp = AlphaComposite.DST_OUT;
            break;
        case 3:
            alphaComp = AlphaComposite.DST_OVER;
            break;
        case 4:
            alphaComp = AlphaComposite.SRC_IN;
            break;
        case 5:
            alphaComp = AlphaComposite.SRC_OVER;
            break;
        case 6:
            alphaComp = AlphaComposite.SRC_OUT;
            break;
        case 7:
            alphaComp = AlphaComposite.CLEAR;
            break;
        }
        return alphaComp;
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;

        Dimension d = getSize();
        int w = d.width;
        int h = d.height;

        BufferedImage buffImg = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
        Graphics2D gbi = buffImg.createGraphics();

        g2.setColor(Color.white);
        g2.fillRect(0, 0, d.width, d.height);

        int rectx = w / 4;
        int recty = h / 4;

        gbi.setColor(new Color(0.0f, 0.0f, 1.0f, 1.0f));
        gbi.fill(new Rectangle2D.Double(rectx, recty, 150, 100));
        gbi.setColor(new Color(1.0f, 0.0f, 0.0f, 1.0f));
        gbi.setComposite(ac);
        gbi.fill(new Ellipse2D.Double(rectx + rectx / 2, recty + recty / 2, 150, 100));

        g2.drawImage(buffImg, null, 0, 0);
    }
}