/*
* @(#)BufferedUpdateStrategy.java 5.1
*
*/
package CH.ifa.draw.standard;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import CH.ifa.draw.framework.DrawingView;
import CH.ifa.draw.framework.Painter;
/**
* The BufferedUpdateStrategy implements an update
* strategy that first draws a view into a buffer
* followed by copying the buffer to the DrawingView.
* @see DrawingView
*/
public class BufferedUpdateStrategy
implements Painter {
/**
* The offscreen image
*/
transient private Image fOffscreen;
private int fImagewidth = -1;
private int fImageheight = -1;
/*
* Serialization support.
*/
private static final long serialVersionUID = 6489532222954612824L;
private int bufferedUpdateSerializedDataVersion = 1;
/**
* Draws the view contents.
*/
public void draw(Graphics g, DrawingView view) {
// create the buffer if necessary
Dimension d = view.getSize();
if ((fOffscreen == null) || (d.width != fImagewidth)
|| (d.height != fImageheight)) {
fOffscreen = view.createImage(d.width, d.height);
fImagewidth = d.width;
fImageheight = d.height;
}
// let the view draw on offscreen buffer
Graphics g2 = fOffscreen.getGraphics();
view.drawAll(g2);
g.drawImage(fOffscreen, 0, 0, view);
}
}