Write a program to develop a simple paint like program using the applet in java.
Program Code:
import java.awt.event.*;
import java.awt.*;
import java.applet.*;
import java.util.Vector;
public class DrawTest extends Applet
{
DrawPanel panel;
DrawControls controls;
public void init()
{
setLayout(new BorderLayout());
panel = new DrawPanel();
controls = new DrawControls(panel);
add("Center", panel);
add("South",controls);
}
public void destroy()
{
remove(panel);
remove(controls);
}
public static void main(String args[])
{
Frame f = new Frame("DrawTest");
DrawTest drawTest = new DrawTest();
drawTest.init();
drawTest.start();
f.add("Center", drawTest);
f.setSize(300, 300);
f.show();
}
public String getAppletInfo()
{
return "A simple drawing program.";
}
}
class DrawPanel extends Panel implements MouseListener, MouseMotionListener
{
public static final int LINES = 0;
public static final int POINTS = 1;
int mode = LINES;
Vector lines = new Vector();
Vector colors = new Vector();
int x1,y1;
int x2,y2;
public DrawPanel()
{
setBackground(Color.white);
addMouseMotionListener(this);
addMouseListener(this);
}
public void setDrawMode(int mode)
{
switch (mode)
{
case LINES:
case POINTS:
this.mode = mode;
break;
default:
throw new IllegalArgumentException();
}
}
public void mouseDragged(MouseEvent e)
{
e.consume();
switch (mode)
{
case LINES:
x2 = e.getX();
y2 = e.getY();
break;
case POINTS:
default:
colors.addElement(getForeground());
lines.addElement(new Rectangle(x1, y1, e.getX(), e.getY()));
x1 = e.getX();
y1 = e.getY();
break;
}
repaint();
}
public void mouseMoved(MouseEvent e)
{
}
public void mousePressed(MouseEvent e)
{
e.consume();
switch (mode)
{
case LINES:
x1 = e.getX();
y1 = e.getY();
x2 = -1;
break;
case POINTS:
default:
colors.addElement(getForeground());
lines.addElement(new Rectangle(e.getX(), e.getY(), -1, -1));
x1 = e.getX();
y1 = e.getY();
repaint();
break;
}
}
public void mouseReleased(MouseEvent e)
{
e.consume();
switch (mode)
{
case LINES:
colors.addElement(getForeground());
lines.addElement(new Rectangle(x1, y1, e.getX(), e.getY()));
x2 = -1;
break;
case POINTS:
default:
break;
}
repaint();
}
public void mouseEntered(MouseEvent e)
{
}
public void mouseExited(MouseEvent e)
{
}
public void mouseClicked(MouseEvent e)
{
}
public void paint(Graphics g)
{
int np = lines.size();
g.setColor(getForeground());
for (int i=0; i < np; i++)
{
Rectangle p = (Rectangle)lines.elementAt(i);
g.setColor((Color)colors.elementAt(i));
if (p.width != -1)
{
g.drawLine(p.x, p.y, p.width, p.height);
}
else
{
g.drawLine(p.x, p.y, p.x, p.y);
}
}
if (mode == LINES)
{
g.setColor(getForeground());
if (x2 != -1)
{
g.drawLine(x1, y1, x2, y2);
}
}
}
}
class DrawControls extends Panel implements ItemListener
{
DrawPanel target;
public DrawControls(DrawPanel target)
{
this.target = target;
setLayout(new FlowLayout());
setBackground(Color.lightGray);
target.setForeground(Color.red);
CheckboxGroup group = new CheckboxGroup();
Checkbox b;
add(b = new Checkbox(null, group, false));
b.addItemListener(this);
b.setForeground(Color.red);
add(b = new Checkbox(null, group, false));
b.addItemListener(this);
b.setForeground(Color.green);
add(b = new Checkbox(null, group, false));
b.addItemListener(this);
b.setForeground(Color.blue);
add(b = new Checkbox(null, group, false));
b.addItemListener(this);
b.setForeground(Color.pink);
add(b = new Checkbox(null, group, false));
b.addItemListener(this);
b.setForeground(Color.orange);
add(b = new Checkbox(null, group, true));
b.addItemListener(this);
b.setForeground(Color.black);
target.setForeground(b.getForeground());
Choice shapes = new Choice();
shapes.addItemListener(this);
shapes.addItem("Lines");
shapes.addItem("Points");
shapes.setBackground(Color.lightGray);
add(shapes);
}
public void paint(Graphics g)
{
Rectangle r = getBounds();
g.setColor(Color.lightGray);
g.draw3DRect(0, 0, r.width, r.height, false);
int n = getComponentCount();
for(int i=0; i<n; i++)
{
Component comp = getComponent(i);
if (comp instanceof Checkbox)
{
Point loc = comp.getLocation();
Dimension d = comp.getSize();
g.setColor(comp.getForeground());
g.drawRect(loc.x-1, loc.y-1, d.width+1, d.height+1);
}
}
}
public void itemStateChanged(ItemEvent e)
{
if (e.getSource() instanceof Checkbox)
{
target.setForeground(((Component)e.getSource()).getForeground());
}
else if (e.getSource() instanceof Choice)
{
String choice = (String) e.getItem();
if (choice.equals("Lines"))
{
target.setDrawMode(DrawPanel.LINES);
}
else if (choice.equals("Points"))
{
target.setDrawMode(DrawPanel.POINTS);
}
}
}
}
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