Cell Animation
Now that we have presented an overview of the image APIs, we can put together an interesting
applet that will display a sequence of animation cells. The animation cells are taken from a
single image that can arrange the cells in a grid specified via the rows and cols <param>
tags. Each cell in the image is snipped out in a way similar to that used in the TileImage
example earlier. We obtain the sequence in which to display the cells from the sequence
<param> tag. This is a comma-separated list of cell numbers that is zero-based and proceeds
across the grid from left to right, top to bottom.
Once the applet has parsed the <param> tags and loaded the source image, it cuts the
image into a number of small subimages. Then, a thread is started that causes the images
to be displayed according to the order described in sequence. The thread sleeps for enough
time to maintain the framerate. Here is the source code:
/ Animation example.
import java.applet.*;
import java.awt.*;
import java.awt.image.*;
import java.util.*;
public class Animation extends Applet implements Runnable {
Image cell[];
final int MAXSEQ = 64;
int sequence[];
int nseq;
int idx;
int framerate;
boolean stopFlag;
private int intDef(String s, int def) {
int n = def;
if (s != null)
try {
n = Integer.parseInt(s);
} catch (NumberFormatException e) {
System.out.println("Number Format Exception");
}
return n;
}
public void init() {
framerate = intDef(getParameter("framerate"), 5);
int tilex = intDef(getParameter("cols"), 1);
int tiley = intDef(getParameter("rows"), 1);
cell = new Image[tilex*tiley];
StringTokenizer st = new
StringTokenizer(getParameter("sequence"), ",");
sequence = new int[MAXSEQ];
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