SETTING PAINT MODE

The paint mode determines how objects are drawn in a window. By default, new output
to a window overwrites any preexisting contents. However, it is possible to have new
objects XORed onto the window by using setXORMode( ), as follows:
void setXORMode(Color xorColor)
Here, xorColor specifies the color that will be XORed to the window when an object is
drawn. The advantage of XOR mode is that the new object is always guaranteed to be
visible no matter what color the object is drawn over.
To return to overwrite mode, call setPaintMode( ), shown here:
void setPaintMode( )
In general, you will want to use overwrite mode for normal output, and XOR mode for
special purposes. For example, the following program displays cross hairs that track
the mouse pointer. The cross hairs are XORed onto the window and are always visible,
no matter what the underlying color is.

// Demonstrate XOR mode.
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
/*


*/
public class XOR extends Applet {
int chsX=100, chsY=100;
public XOR() {
addMouseMotionListener(new MouseMotionAdapter() {
public void mouseMoved(MouseEvent me) {
int x = me.getX();
int y = me.getY();
chsX = x-10;
chsY = y-10;
repaint();
}
});
}
public void paint(Graphics g) {
g.drawLine(0, 0, 100, 100);
g.drawLine(0, 100, 100, 0);
g.setColor(Color.blue);
g.drawLine(40, 25, 250, 180);
g.drawLine(75, 90, 400, 400);
g.setColor(Color.green);
g.drawRect(10, 10, 60, 50);
g.fillRect(100, 10, 60, 50);
g.setColor(Color.red);
g.drawRoundRect(190, 10, 60, 50, 15, 15);
g.fillRoundRect(70, 90, 140, 100, 30, 40);
g.setColor(Color.cyan);
g.drawLine(20, 150, 400, 40);
g.drawLine(5, 290, 80, 19);
// xor cross hairs
g.setXORMode(Color.black);
g.drawLine(chsX-10, chsY, chsX+10, chsY);

g.drawLine(chsX, chsY-10, chsX, chsY+10);
g.setPaintMode();
}
}