禁用JFrame中的背景绘图以正确显示Aero（DWM）效果

问题描述

我在Java窗口上使用Windows Vista / 7的DWM功能时遇到问题。我想让我的画面背景使用Aero风格。执行此操作的Windows API由 dwmapi 库中的函数 DwmExtendFrameIntoClientArea 提供。我已经设法通过JNA正确调用该程序，它完成了它应该做的事情（你可以看到，例如在调整框架大小时，在下一次重绘之前，你会看到尚未绘制的区域中的适当的空气动力效果，看附图。）

I'm having problems using the DWM functionality of Windows Vista/7 on Java windows. I want to make the background of my frame use the Aero style. The Windows API to do so is provide by the function DwmExtendFrameIntoClientArea in the dwmapi library. I've managed to call the procedure properly via JNA, and it does what it is supposed to do (You can see that for example when resizing the frame, before the next repaint you see the proper aero effects in the area not yet painted, see the attached image).

但在某处（我无法弄清楚在哪里）背景画在Aero效果上并且效果会丢失。

But somewhere (I can't figure out where) a background is painted over the Aero effect and the effect is lost.

我已经尝试过：

• 使用自定义 ContentPane 将不透明度设置为 false


• 设置的不透明度> LayeredPane 和 RootPane 为假


• 使用 Frame 代替 JFrame


• 设置 JFrame / <$的背景颜色c $ c> ContentPane 为黑/完全透明


• 使用 setLayersOpaque 及其自定义变体，请参阅第一个答案了解更多详情

• Using a custom ContentPane with opacity set to false
• Setting the opacity of the LayeredPane and the RootPane to false
• Using a Frame instead of a JFrame
• Set the background color of the JFrame/ContentPane to black/fully transparent
• Use setLayersOpaque and a custom variant thereof, see first answer for more details

到目前为止，我无法回答cceed删除该背景。这是AWT / Swing的限制吗？如何删除该背景或正确使用Aero效果？

So far I could not succeed removing that background. Is it a limitation of AWT/Swing? How can I remove that background or use the Aero effect properly?

非常感谢您的帮助。

这里是没有任何内容的框架的屏幕截图，将RootPane，LayeredPane和ContentPane的不透明度设置为false。我在调整大小时快速完成了。您会看到效果已正确应用于Java尚未绘制的区域。

Here a screenshot of a frame without any contents, having set the opacity of the RootPane, LayeredPane and ContentPane to false. I did it quickly while resizing. You see that the effect is properly applied to the area Java did not yet paint on.

（作为新用户，我无法直接发布图片...）

http://i55.tinypic.com/v614qo.png (As a new user I cannot post the image directly...)

经过进一步调查后，我发现了以下奇怪的行为。如果窗口大小为150x150或更低，则内容将以透明方式显示。这对于普通窗口组件来说非常小问题。如果通过覆盖 paint（）方法直接在框架上绘制，则所有内容都是半透明的。此外，坐标系似乎稍微偏离，它显示为 JFrame 的零点设置为窗口的实际零点。因此，Swing尝试绘制实际上窗口边界所在的区域，然后当然不可见。

Upon further investigation I came across the following odd behavior. If the window size is 150x150 or below the contents are displayed transparently. This is very glitchy for normal window components. If you paint directly on the frame by overriding the paint() method everything is drawn semi-transparent. Additionally the coordinate system seems to be a little off, it appears as the zero point of the JFrame is set to the actual zero point of the window. Thus Swing tries to paint to areas where actually the window border is located, which then of course is not visible.

看到这个截图：

这是我使用的代码。

需要 jna .jar 和 platform.jar 。可从JNA主页获取。

Requires jna.jar and platform.jar. Available from the JNA homepage.

import com.sun.jna.Function;
import com.sun.jna.Native;
import com.sun.jna.NativeLibrary;
import com.sun.jna.Structure;
import com.sun.jna.platform.win32.WinDef.HWND;
import com.sun.jna.platform.win32.WinNT.HRESULT;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.UIManager;

public class AeroFrame extends JFrame {

    public AeroFrame() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JLabel label = new JLabel("Testlabel");
        label.setOpaque(false);

        add(label);

        pack();

        enableAeroEffect();
    }

    private void enableAeroEffect() {
        NativeLibrary dwmapi = NativeLibrary.getInstance("dwmapi");
        HWND aeroFrameHWND = new HWND(Native.getWindowPointer(this));
        MARGINS margins = new MARGINS();
        margins.cxLeftWidth = -1;
        margins.cxRightWidth = -1;
        margins.cyBottomHeight = -1;
        margins.cyTopHeight = -1;
        //DwmExtendFrameIntoClientArea(HWND hWnd, MARGINS *pMarInset)
        //http://msdn.microsoft.com/en-us/library/aa969512%28v=VS.85%29.aspx
        Function extendFrameIntoClientArea = dwmapi.getFunction("DwmExtendFrameIntoClientArea");
        HRESULT result = (HRESULT) extendFrameIntoClientArea.invoke(HRESULT.class,
                new Object[] { aeroFrameHWND, margins});
        if(result.intValue()!=0)
            System.err.println("Call to DwmExtendFrameIntoClientArea failed.");
    }

    /**
     * http://msdn.microsoft.com/en-us/library/bb773244%28v=VS.85%29.aspx
     */
    public class MARGINS extends Structure implements Structure.ByReference {
            public int cxLeftWidth;
            public int cxRightWidth;
            public int cyTopHeight;
            public int cyBottomHeight;
    }

    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
            JFrame.setDefaultLookAndFeelDecorated(true);

        } catch (Exception e) {
            e.printStackTrace();
        }
        new AeroFrame().setVisible(true);
    }

}

推荐答案

好问题。

最明显的答案是

WindowUtils.setWindowOpaque(this, false);

这为您提供了所需的视觉效果，但遗憾的是，您无法点击窗口！

That gives you the visual effects you want but unfortunately prevents you from being able to click on the Window!

我尝试的第二件事是覆盖paint（）方法以执行与 Window.paint（）当 opaque 标志设置为false时。那没有做任何事情。

The second thing I tried was to override the paint() method to perform the same actions that Window.paint() does when the opaque flag is set to false. That didn't do anything.

然后我尝试使用Reflection。将 Window.opaque 反射设置为true会产生与使用 WindowUtils 相同的结果。

Then I tried using Reflection. Reflectively setting Window.opaque to true gave the same results as using WindowUtils.

最后，我尝试将此添加到 enableAeroEffect（）：

Finally, I tried adding this to enableAeroEffect():

Method m = null;
try {
    m = Window.class.getDeclaredMethod("setLayersOpaque", Component.class, Boolean.TYPE);
    m.setAccessible(true);
    m.invoke(null, this, false);
} catch ( Exception e ) {
    //TODO: handle errors correctly
} finally {
    if ( m != null ) {
        m.setAccessible(false);
    }
}

这很有效！窗口仍然可以正确响应鼠标事件，但不会绘制背景。绘图有点毛躁，但应该让你上路。

This worked! The Window still responds properly to mouse events, but the background isn't drawn. The drawing is a bit glitchy, but should get you on your way.

显然它很脆弱，因为它依赖于Reflection。如果我是你，我会看看 Window.setLayersOpaque（） 做什么，然后尝试以不同的方式复制它不依赖于反射。

Obviously it's fragile since it relies on Reflection. If I were you, I'd take a look at what Window.setLayersOpaque() does, and try to replicate that in a way that doesn't rely on Reflection.

编辑：在检查 setLayersOpaque 方法时，它似乎真的归结为禁用透明组件的双缓冲。从您的 enableAeroEffect（）方法调用此方法，然后就可以了：

Edit: On inspection of the setLayersOpaque method, it really seems to boil down to disabling double-buffering on the transparent components. Call this method from your enableAeroEffect() method and you're on your way:

//original source: Sun, java/awt/Window.java, setLayersOpaque(Component, boolean)
private static void setLayersTransparent(JFrame frame) {
    JRootPane root = frame.getRootPane();
    root.setOpaque(false);
    root.setDoubleBuffered(false);

    Container c = root.getContentPane();
    if (c instanceof JComponent) {
        JComponent content = (JComponent) c;
        content.setOpaque(false);
        content.setDoubleBuffered(false);
    }
    frame.setBackground(new Color(0, 0, 0, 0));
}

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