透明背景 JFrame Linux 上的动画 [英] Animation on Transparent-background JFrame Linux

问题描述

我想为 Frame(或 JFrame)创建一个完全透明的背景，并让它显示一个透明的动画.我设法让它在 Windows 7 x64 上运行，但相同的代码不能在我的 Linux (Lubuntu x64 15.04) 上运行.

I want to create a fully transparent background for a Frame (or JFrame) and have it show a transparent animation. I managed to get it working in Windows 7 x64 but the same code does not run on my Linux (Lubuntu x64 15.04).

下面的代码显示了我想要实现的目标——只需复制 &粘贴它.我只想让小矩形在屏幕上移动而不留下任何痕迹.

The code below shows what I'm trying to achieve--just copy & paste it. I just want the little rectangle to move across the screen without leaving a trail.

static int  a   = 0;

public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setUndecorated(true);
    f.setBackground(new Color(0, 0, 0, 0));
    f.setVisible(true);
    f.setSize(512, 512);
    f.add(new JPanel() {
        @Override
        public void paintComponent(Graphics gr) {
            Graphics2D g = (Graphics2D)gr;
            g.setBackground(new Color(0, 0, 0, 0));
            g.clearRect(0, 0, 512, 512);
            g.drawRect(a, a++, 2, 2);
        }
    });

    while(true) {
        try {
            Thread.sleep(30);
        } catch(InterruptedException e) {
            e.printStackTrace();
        }
        f.repaint();
    }
}

我想要实现的目标(如 Windows 中所示)以及我在 Lubuntu 15.04 中得到的结果:

What I want to achieve (as shown in Windows) and what I get with Lubuntu 15.04:

        

        

我只想看到小方块移动，就像 Windows 7 上显示的那样——我不想看到踪迹.

I just want to see the little square move just like what's shown on Windows 7--I don't want to see a trail.

请不要给我 Oracle 的透明度和窗口文档的链接——我已经看了三次.

Please don't give me the link of Oracle's transparency and window documentation--I've gone over it all thrice.

我的尝试:

• Graphics2D 的透明空间的copyArea()".(这曾经适用于 AFAIK，但不再适用)
• 玻璃板
• AlphaComposite
• setPaint()

请先测试您的想法/代码.我已经尝试过很多这应该有效"的东西，但似乎没有……非常感谢所有帮助.

Please please just test out your thoughts/code first. A lot of the "this should work" stuff I have already tried and does not seem to... All help is greatly appreciated.

推荐答案

基本上这个问题是操作系统相关的.适用于 Windows 的方法不适用于 Linux，反之亦然.

Basically this issue is OS-related. What works for Windows will not work for Linux and vice versa.

由于某种原因，Linux 在设置 BufferStrategy 时只允许动画每像素透明度.但是，此解决方案在 Windows 上失败.因此，我提出了以下代码，它根据操作系统选择正确的算法:

For some reason, Linux only allows animated per-pixel-transparency when setting up a BufferStrategy. However, this solution fails on Windows. As a result I have come up with the following code which picks the correct algorithm based on the OS:

static int a = 0;

public static void main(String[] args) {
    JFrame f = new JFrame();
    JPanel p = new JPanel() {
        @Override
        public void paintComponent(Graphics g) {
            Graphics2D g2d = (Graphics2D) g;
            g2d.setBackground(new Color(255, 255, 255, 0));
            g2d.clearRect(0, 0, f.getWidth(), f.getHeight());
            g2d.drawRect(a, a++, 2, 2);
        }
    };
    f.add(p);
    f.setUndecorated(true);
    f.setBackground(new Color(255, 255, 255, 0));
    f.setSize(512, 512);
    f.setVisible(true);
    f.createBufferStrategy(2);

    BufferStrategy bs = f.getBufferStrategy();
    while (true) {
        try {
            Thread.sleep(33);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        if (System.getProperty("os.name").contains("indows ")) {
            p.repaint();
        } else {
            Graphics g = null;
            do {
                try {
                    g = bs.getDrawGraphics();
                    p.update(g);
                } finally {
                    g.dispose();
                }
                bs.show();
            } while (bs.contentsLost());
            Toolkit.getDefaultToolkit().sync();
        }
    }
}

此代码适用于我的 Windows 7 x64 和 Lubuntu 15.04 x64.请亲自试用此代码，看看它是否适合您.我自己没有Mac，所以如果有人愿意为我测试一下，我将非常感激.如果对任何人都不起作用，请告诉我.

This code works for my Windows 7 x64 and my Lubuntu 15.04 x64. Please try out this code out yourself and see if it works for you. I myself don't own a Mac so if someone would please test it for me I would be very grateful. If it does not work for anyone, please let me know.

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