在半透明框架/面板/组件上重新涂漆。 [英] Re-paint on translucent frame/panel/component.

问题描述

我正在尝试在OSX上创建一个带有Java的半透明窗口，并向其添加 JLabel 。

此 JLabel 每秒更改一次文字....

然而，该组件没有重新粉刷。

如何解决这个问题？

我发现

  import java.awt.AlphaComposite; 
 import java.awt.Color; 
 import java.awt.Dimension; 
 import java.awt.EventQueue; 
 import java.awt.Font; 
 import java.awt.FontMetrics; 
 import java.awt.Graphics; 
 import java.awt.Graphics2D; 
 import java.awt.RenderingHints; 
 import java.awt.event.ActionEvent; 
 import java.awt.event.ActionListener; 
 import java.awt.image.BufferedImage; 
 import java.text.SimpleDateFormat; 
 import java.util.Date; 
 import javax.swing.JFrame; 
 import javax.swing.JPanel; 
 import javax.swing.Timer; 
 
 public class Translucent extends JPanel实现ActionListener {
 
 private static final int W = 300; 
 private static final int H = 100; 
 private static final Font font = 
 new Font（Serif，Font.PLAIN，48）; 
 private static final SimpleDateFormat df = 
 new SimpleDateFormat（HH：mm：ss）; 
 private final Date now = new Date（）; 
 private final Timer timer = new Timer（1000，this）; 
私有BufferedImage时间; 
 private Graphics2D timeG; 
 
 public Translucent（）{
 super（true）; 
 this.setPreferredSize（new Dimension（W，H））; 
 timer.start（）; 
} 
 
 @Override 
 protected void paintComponent（Graphics g）{
 Graphics2D g2d =（Graphics2D）g; 
 g2d.setRenderingHint（
 RenderingHints.KEY_ANTIALIASING，
 RenderingHints.VALUE_ANTIALIAS_ON）; 
 int w = this.getWidth（）; 
 int h = this.getHeight（）; 
 g2d.setComposite（AlphaComposite.Clear）; 
 g2d.fillRect（0,0，w，h）; 
 g2d.setComposite（AlphaComposite.Src）; 
 g2d.setPaint（g2d.getBackground（））; 
 g2d.fillRect（0,0，w，h）; 
 renderTime（g2d）; 
 int w2 = time.getWidth（）/ 2; 
 int h2 = time.getHeight（）/ 2; 
 g2d.setComposite（AlphaComposite.SrcOver）; 
 g2d.drawImage（时间，w / 2  -  w2，h / 2  -  h2，null）; 
} 
 
 private void renderTime（Graphics2D g2d）{
 g2d.setFont（font）; 
 String s = df.format（now）; 
 FontMetrics fm = g2d.getFontMetrics（）; 
 int w = fm.stringWidth（s）; 
 int h = fm.getHeight（）; 
 if（time == null&& timeG == null）{
 time = new BufferedImage（w，h，BufferedImage.TYPE_INT_ARGB）; 
 timeG = time.createGraphics（）; 
 timeG.setRenderingHint（
 RenderingHints.KEY_ANTIALIASING，
 RenderingHints.VALUE_ANTIALIAS_ON）; 
 timeG.setFont（font）; 
} 
 timeG.setComposite（AlphaComposite.Clear）; 
 timeG.fillRect（0,0，w，h）; 
 timeG.setComposite（AlphaComposite.Src）; 
 timeG.setPaint（Color.green）; 
 timeG.drawString（s，0，fm.getAscent（））; 
} 
 
 private static void create（）{
 JFrame f = new JFrame（）; 
 f.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）; 
 f.setBackground（new Color（0f，0f，0f，0.3f））; 
 f.setUndecorated（true）; 
 f.add（new Translucent（））; 
 f.pack（）; 
 f.setLocationRelativeTo（null）; 
 f.setVisible（true）; 
} 
 
 @Override 
 public void actionPerformed（ActionEvent e）{
 now.setTime（System.currentTimeMillis（））; 
 this.repaint（）; 
} 
 
 public static void main（String [] args）{
 EventQueue.invokeLater（new Runnable（）{
 @Override 
 public void run （）{
 create（）; 
} 
}）; 
} 
} 
  

I'm trying to create a translucent window with Java on OSX and add a JLabel to it.

This JLabel changes its text every second....

However the component is not repainting well.

How can I solve this problem?

I've found the these articles, but I can't figure out how to solve it.

If possible, please paste the fixing source code, here's mine:

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JLabel;
import java.awt.Color;
import java.awt.Font;
import java.util.Timer;
import java.util.TimerTask;

public class Translucent {
    public static void main( String [] args ) {

        JFrame frame = new JFrame();

        frame.setBackground( new Color( 0.0f,0.0f,0.0f,0.3f));

        final JLabel label =  new JLabel("Hola");
        label.setFont( new Font( label.getFont().getFamily(), Font.PLAIN, 46 ) );
        label.setForeground( Color.white );

        frame.add( label );
        frame.pack();
        frame.setLocationRelativeTo( null );
        frame.setVisible( true );

        Timer timer = new Timer();
        timer.schedule( new TimerTask(){
            int i = 0;
            public void run() {
                label.setText("Hola "+ i++ );
            }
        }, 0, 1000 );


    }   
}

解决方案

I've had some luck extending JLabel and implementing Icon to get a translucent component working the way I want. You can see the result of various rule combinations in this AlphaCompositeDemo. The example below is 100% white atop 50% black.

Addendum: Note how this example composites opaque text on a clear offscreen background over the translucent frame background.

Addendum: Here's a way to make the whole frame translucent. Unfortunately, it dims the content, too.

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;

public class Translucent extends JPanel implements ActionListener {

    private static final int W = 300;
    private static final int H = 100;
    private static final Font font =
        new Font("Serif", Font.PLAIN, 48);
    private static final SimpleDateFormat df =
        new SimpleDateFormat("HH:mm:ss");
    private final Date now = new Date();
    private final Timer timer = new Timer(1000, this);
    private BufferedImage time;
    private Graphics2D timeG;

    public Translucent() {
        super(true);
        this.setPreferredSize(new Dimension(W, H));
        timer.start();
    }

    @Override
    protected void paintComponent(Graphics g) {
        Graphics2D g2d = (Graphics2D) g;
        g2d.setRenderingHint(
            RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);
        int w = this.getWidth();
        int h = this.getHeight();
        g2d.setComposite(AlphaComposite.Clear);
        g2d.fillRect(0, 0, w, h);
        g2d.setComposite(AlphaComposite.Src);
        g2d.setPaint(g2d.getBackground());
        g2d.fillRect(0, 0, w, h);
        renderTime(g2d);
        int w2 = time.getWidth() / 2;
        int h2 = time.getHeight() / 2;
        g2d.setComposite(AlphaComposite.SrcOver);
        g2d.drawImage(time, w / 2 - w2, h / 2 - h2, null);
    }

    private void renderTime(Graphics2D g2d) {
        g2d.setFont(font);
        String s = df.format(now);
        FontMetrics fm = g2d.getFontMetrics();
        int w = fm.stringWidth(s);
        int h = fm.getHeight();
        if (time == null && timeG == null) {
            time = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
            timeG = time.createGraphics();
            timeG.setRenderingHint(
                RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
            timeG.setFont(font);
        }
        timeG.setComposite(AlphaComposite.Clear);
        timeG.fillRect(0, 0, w, h);
        timeG.setComposite(AlphaComposite.Src);
        timeG.setPaint(Color.green);
        timeG.drawString(s, 0, fm.getAscent());
    }

    private static void create() {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setBackground(new Color(0f, 0f, 0f, 0.3f));
        f.setUndecorated(true);
        f.add(new Translucent());
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        now.setTime(System.currentTimeMillis());
        this.repaint();
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                create();
            }
        });
    }
}

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