Overriding the update() Method: Example5Applet

Here is the code that draws the sine waves. The applet itself is shown above. Note that the animation is now a lot smoother. The code for the entire applet can be found in Example5Applet.java.

    /**
     * Paint a frame of animation.
     */
    public void update(Graphics g) {
	Color bg = getBackground();
	Dimension d = size();
	int h = d.height / 2;
	for (int x = 0 ; x < d.width ; x++) {
	    int y1 = (int)((1.0 + Math.sin((x - frame) * 0.05)) * h);
	    int y2 = (int)((1.0 + Math.sin((x + frame) * 0.07)) * h);

	    if (y1 > y2) {
		int t = y1;
		y1 = y2;
		y2 = t;
	    }
	    g.setColor(bg);
	    g.drawLine(x, 0, x, y1);
	    g.drawLine(x, y2, x, d.height);
	    g.setColor(Color.black);
	    g.drawLine(x, y1, x, y2);
	}
    }