Drawer
/*
* Drawer.java
*
* Created on June 8, 2007, 11:52 PM
*
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
*/
package dyno.swing.beans;
import java.awt.AlphaComposite;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Rectangle;
import javax.swing.JComponent;
/**
* 该类是个辅助类，目的是实现动画状态时透明图像及组件的移动效果
* 像是一个抽屉，放应用程序的组件
*
* @author William Chen
*/
class Drawer extends JComponent {
//目前抽屉抽开比例，同时是透明度值
private double ratio = 1.0;
//目前是否处于动画状态
private boolean animating;
//应用程序的组件
private JComponent content;
//保存有应用程序组件的虚屏图像
private Image offImage;
/** Creates a new instance of Drawer */
Drawer(double r, JComponent comp) {
this.ratio = r;
this.content = comp;
add(comp);
setLayout(null);
}
int getContentHeight() {
return content.getHeight();
}
int getContentWidth() {
return content.getWidth();
}
void setContentWidth(int w){
Rectangle bounds=content.getBounds();
bounds.width=w;
content.setBounds(bounds);
}
void setRatio(double ratio) {
this.ratio = ratio;
repaint();
}
double getRatio() {
return this.ratio;
}
//覆盖父类的paintChildren
protected void paintChildren(Graphics g) {
if (animating) {
//动画状态画出当前透明的应用程序组件以及抽拉状态
Graphics2D g2d = (Graphics2D) g;
g2d.setComposite(AlphaComposite.getInstance(
AlphaComposite.SRC_OVER, (float) ratio));
g2d.drawImage(getOffImage(), 0, getHeight() - content.getHeight(),
this);
} else {
//普通状态简单使用容器缺省的渲染
super.paintChildren(g);
}
}
void clearOffImage() {
offImage = null;
}
void setAnimating(boolean animating) {
this.animating = animating;
}
//创建应用程序组件的虚屏图像
private Image getOffImage() {
if (offImage == null) {
int contentWidth = content.getWidth();
int contentHeight = content.getHeight();
if (offImage == null) {
offImage = createImage(contentWidth, contentHeight);
Graphics g = offImage.getGraphics();
//使用Renderer机制
content.paint(g);
}
}
return offImage;
}
}