创建一个模糊的Transperent JPanel

Question

我正在试图将一个子类创建为JLabel，我将其命名为BlurPanel。我希望这个类像任何普通的swing容器一样行事，只有它默认有一个透明的背景，即（setOpaque（false）），它必须模糊父框架的背景。到目前为止，我已经设法模糊BufferedImages并调整它们的大小，但是当使用标准的摆动布局管理器时，我很难将帧图像裁剪到BlurPanels位置。有没有人有一个好的策略来做到这一点？也许这可以在不复制底层图片的情况下完成？

Answer 1

使用GlassPane卢克

import java.awt.BorderLayout; 
import java.awt.Color; 
import java.awt.Graphics; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.awt.event.FocusEvent; 
import java.awt.event.FocusListener; 
import java.awt.event.MouseAdapter; 

import javax.swing.JButton; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.JTextField; 
import javax.swing.Timer; 
import javax.swing.WindowConstants; 

/** 
* Glass pane used to blur the content of the window. 
* 
* @author SMedvynskyy 
*/ 
@SuppressWarnings("serial") 
public class SplashGlassPane extends JPanel implements FocusListener { 

    /** 
    * Creates new GlassPane. 
    */ 
    public SplashGlassPane() { 
     addMouseListener(new MouseAdapter() {}); 
     addMouseMotionListener(new MouseAdapter() {}); 
     addFocusListener(this); 
     setOpaque(false); 
     setFocusable(true); 
     setBackground(new Color(0, 0, 0, 190)); 
    } 

    @Override 
    public final void setVisible(boolean v) { 
     // Make sure we grab the focus so that key events don't go astray. 
     if (v) { 
      requestFocus(); 
     } 
     super.setVisible(v); 
    } 

    // Once we have focus, keep it if we're visible 
    @Override 
    public final void focusLost(FocusEvent fe) { 
     if (isVisible()) { 
      requestFocus(); 
     } 
    } 

    /** 
    * {@inheritDoc} 
    */ 
    @Override 
    public final void paint(Graphics g) { 
     final Color old = g.getColor(); 
     g.setColor(getBackground()); 
     g.fillRect(0, 0, getSize().width, getSize().height); 
     g.setColor(old); 
     super.paint(g); 
    } 

    @Override 
    public void focusGained(FocusEvent fe) { 
     // nothing to do 
    } 

    public static void main(String[] args) { 
     final JFrame frm = new JFrame("Test blurring"); 
     frm.add(new JTextField("It's first component"), BorderLayout.NORTH); 
     frm.add(new JTextField("It's second component"), BorderLayout.SOUTH); 
     final JButton btn = new JButton("Start blur"); 
     btn.addActionListener(new ActionListener() { 

      @Override 
      public void actionPerformed(ActionEvent e) { 
       frm.getGlassPane().setVisible(true); 
       final Timer t = new Timer(5000, new ActionListener() { 

        @Override 
        public void actionPerformed(ActionEvent e) { 
         frm.getGlassPane().setVisible(false); 
        } 
       }); 
       t.setRepeats(false); 
       t.start(); 
      } 
     }); 
     frm.add(btn); 
     frm.setSize(500, 400); 
     frm.setGlassPane(new SplashGlassPane()); 

     frm.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); 
     frm.setVisible(true); 
    } 
}