Java创建透明与任意形状窗口
一： Java 2D图形基础知识
自从Java Swing发布以来，Java的图形能力得到了很大的提升，JDK6的高级版本开始支持创
建自定义形状的JFrame，结合Java 2D图形的相关API，可以实现任意形状JFrame的创建。当
前JAVA 2提供可以创建的基本形状如下：
当前Java提供的对2D图形的主要操作有裁剪和路径覆盖，适当的运用Java 2D与Swing的其
他相关API，可以创建出任意形状的JFrame。
二：API支持透明和自定义形状
从JDK6的release 10开始支持设置透明和自定义形状，支持的对象有Swing的JFrame, JDialog,
AWT的Frame.以及所以继承java.awt.Window的子类。
Windows的透明效果又分为两类，简单的透明效果和基于像素位的透明效果。简单透明效果使
用alpha来设置所有的象素位，值越小越透明，最小值是完全透明，最大值代表完全不透明
（opaque）windows, 基于像素为的透明效果需要通过以下API来启用：
AWTUtilities.setWindowOpaque (frame, false);
对于透明度和形状的设定都是通过Java的反射机制完成调用，在JDK的官方网站有一个很好的Demo里面有个AWTUtilitiesWrappe类是一个很好的示例.
三：一个可以改变自身形状与透明效果的JFrame
程序的主要功能是选择你想要的形状，然后点击【OK】按钮，应用程序的窗口随之改变
点击【Cancel】按钮将推出程序，移动鼠标到窗口上面，可以拖动窗口程序。
涉及到Swing组件有JFrame, JPanel, JButton, JComboBox
组件的位置放置使用了绝对定位的方式，需要调用setLayout(null)来声明绝对定位方式
程序启动的运行效果如下：
选择 Circle并点击【OK】按钮以后的效果如下：
选择 Area并点击【OK】按钮以后的效果如下：
主要的代码为JCustomFrame
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Shape;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.geom.Area;
import java.awt.geom.Ellipse2D;
import java.awt.geom.RoundRectangle2D;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
public class JCustomFrame extends JFrame {
/**
* gloomy fish
*/
private static final long serialVersionUID = -523336873755438297L;
private Shape shape;
private float alpha = 1f;
private Dimension arcSize = new Dimension(50, 50);
protected static final int CIRCLE_TYPE = 1;
protected static final int RECTANGEL_TYPE = 0;
protected static final int AREA_TYPE = 2;
public JCustomFrame() {
setUndecorated(true);
setVisible(true);
setListenersForEffects();
}
public JCustomFrame(int width, int height) {
this();
setSize(width, height);
}
public JCustomFrame(Shape shape, int width, int height) {
this(width, height);
setShape(shape);
}
public void setShape(Shape shape) {
this.shape = shape;
}
public JCustomFrame(float alpha, Shape shape, int width, int height) {
this(shape, width, height);
setAlpha(alpha);
}
public void setAlpha(float alpha) {
this.alpha = alpha;
}
private void setListenersForEffects() {
//It is important to upadate visual effect on form resize.
addComponentListener(new ComponentAdapter() {
@Override
public void componentResized(ComponentEvent evt) {
updateFrameEffects();
}
});
}
/**
* This updates visual effects like SHAPE form and transparency. You have to
* update also <b>shape</b> property or it paints old shape ( if you resize
* frame without resize shape .. )
*/
public void updateFrameEffects() {
updateShape();
try {
AWTUtilitiesWrapper.setWindowShape(this, shape);
if (shape != null) {
AWTUtilitiesWrapper.setWindowOpacity(this, alpha);
}
} catch (Exception ex) {
Logger.getLogger(JCustomFrame.class.getName()).log(Level.SEVERE, null, ex);
}
}
public void updateShape() {
if(shape == null) {
shape = new RoundRectangle2D.Double(0d, 0d, getWidth(), getHeight(), arcSize.width, arcSize.height);
}
}
public void updateShape(int type) {
if(type == RECTANGEL_TYPE) {
shape = new RoundRectangle2D.Double(0d, 0d, getWidth(), getHeight(), arcSize.width, arcSize.height);
} else if(type == CIRCLE_TYPE) {
shape = new Ellipse2D.Double(0, 0,400, 400);
} else if(type == AREA_TYPE) {
Shape circle1 = new Ellipse2D.Double(0, 0,400, 400);
Shape circle2 = new Ellipse2D.Double(200, 100,400, 400);
Area area1 = new Area(circle1);
Area area2 = new Area(circle2);
area1.subtract(area2);
shape = area1;
}
}
public void center() {
Toolkit tk = Toolkit.getDefaultToolkit();
Dimension screenSize = tk.getScreenSize();
int screenHeight = screenSize.height;
int screenWidth = screenSize.width;
this.setLocation((screenWidth - this.getWidth()) / 2, (screenHeight - this.getHeight()) / 2);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
try {
// com.sun.java.swing.plaf.windows.WindowsLookAndFeel
UIManager.setLookAndFeel("com.sun.java.swing.plaf.motif.MotifLookAndFeel");
} catch (Exception e) {
}
/*These are simple custom panel generated with vidual editor of Netbeans
don't care about it, take a look only to ImagePanel inherit ( why?...)
*/
// Cool transparent Frame
final JCustomFrame customFrame = new JCustomFrame();
customFrame.setLayout(new BorderLayout());
// create custom JPanel
final JImagePanel panel = new JImagePanel();
java.net.URL image1 = this.getClass().getResource("ball.jpg");
try {
panel.setImage(ImageIO.read(image1));
panel.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if(e.getActionCommand().equals("OK")) {
System.out.println("Transfer now......");
customFrame.updateShape(panel.getSelectedIndex());
if(panel.getSelectedIndex() == CIRCLE_TYPE) {
customFrame.setSize(400, 400);
} else if(panel.getSelectedIndex() == AREA_TYPE) {
customFrame.setSize(400, 399); // force layout Manager re-computation
} else {
customFrame.setSize(400, 300);
}
} else if(e.getActionCommand().equals("Cancel")) {
System.out.println("System Exit......");
customFrame.setVisible(false);
customFrame.dispose();
System.exit(0);
}
}
});
} catch (IOException e) {
e.printStackTrace();
}
DragBarHandler dragHandle = new DragBarHandler(customFrame);
customFrame.add(panel, BorderLayout.CENTER);
customFrame.add(dragHandle, BorderLayout.NORTH);
customFrame.setTitle("Ttranslucency JFrame");
customFrame.setSize(400, 300);
customFrame.setAlpha(0.8f);
customFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
customFrame.center();
}
});
}
}
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