如何使用jna在java中获得chrome进程的句柄

30byixjq  于 2021-07-03  发布在  Java
关注(0)|答案(1)|浏览(472)

我是jna新手,我需要使用java和jna拍摄chrome窗口的截图,我已经有了使用以下代码拍摄给定窗口截图的功能:

public BufferedImage capture(WinDef.HWND hWnd) {

    WinDef.HDC hdcWindow = User32.INSTANCE.GetDC(hWnd);
    WinDef.HDC hdcMemDC = GDI32.INSTANCE.CreateCompatibleDC(hdcWindow);

    WinDef.RECT bounds = new WinDef.RECT();
    User32Extra.INSTANCE.GetClientRect(hWnd, bounds);

    int width = bounds.right - bounds.left;
    int height = bounds.bottom - bounds.top;

    WinDef.HBITMAP hBitmap = GDI32.INSTANCE.CreateCompatibleBitmap(hdcWindow, width, height);

    WinNT.HANDLE hOld = GDI32.INSTANCE.SelectObject(hdcMemDC, hBitmap);
    GDI32Extra.INSTANCE.BitBlt(hdcMemDC, 0, 0, width, height, hdcWindow, 0, 0, WinGDIExtra.SRCCOPY);

    GDI32.INSTANCE.SelectObject(hdcMemDC, hOld);
    GDI32.INSTANCE.DeleteDC(hdcMemDC);

    WinGDI.BITMAPINFO bmi = new WinGDI.BITMAPINFO();
    bmi.bmiHeader.biWidth = width;
    bmi.bmiHeader.biHeight = -height;
    bmi.bmiHeader.biPlanes = 1;
    bmi.bmiHeader.biBitCount = 32;
    bmi.bmiHeader.biCompression = WinGDI.BI_RGB;

    Memory buffer = new Memory(width * height * 4);
    GDI32.INSTANCE.GetDIBits(hdcWindow, hBitmap, 0, height, buffer, bmi, WinGDI.DIB_RGB_COLORS);

    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    image.setRGB(0, 0, width, height, buffer.getIntArray(0, width * height), 0, width);

    GDI32.INSTANCE.DeleteObject(hBitmap);
    User32.INSTANCE.ReleaseDC(hWnd, hdcWindow);

    return image;

}

然后使用以下代码保存BuffereImage:

BufferedImage image;

     WinDef.HWND hWnd = User32.INSTANCE.FindWindow(null, "notepad - untitled");
                image = capture(hWnd);
                File outputfile = new File("image.jpg");
                try {
                    ImageIO.write(image, "jpg", outputfile);
                } catch (IOException e) {
                    e.printStackTrace();
                }

这适用于某些应用程序,例如记事本,但不适用于chrome,对于chrome,它只是抛出一个非法参数异常,因为程序试图捕获宽度和高度基本为0的屏幕截图,因为找不到进程,所以完全异常如下:

Exception in thread "JavaFX Application Thread" java.lang.IllegalArgumentException: Allocation size must be greater than zero
at com.sun.jna.Memory.<init>(Memory.java:111)
at de.xliquid.stadiarpc.Main.capture(Main.java:103)
at de.xliquid.stadiarpc.Main$1.run(Main.java:56)
at com.sun.javafx.scene.KeyboardShortcutsHandler.processAccelerators(KeyboardShortcutsHandler.java:347)
at com.sun.javafx.scene.KeyboardShortcutsHandler.dispatchBubblingEvent(KeyboardShortcutsHandler.java:163)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$KeyHandler.process(Scene.java:3964)
at javafx.scene.Scene$KeyHandler.access$1800(Scene.java:3910)
at javafx.scene.Scene.impl_processKeyEvent(Scene.java:2040)
at javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2501)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:217)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:149)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleKeyEvent$357(GlassViewEventHandler.java:248)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:247)
at com.sun.glass.ui.View.handleKeyEvent(View.java:546)
at com.sun.glass.ui.View.notifyKey(View.java:966)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$152(WinApplication.java:177)
at java.lang.Thread.run(Thread.java:748)

我试着使用当前的chrome标题,但没有成功,我认为最好的解决方案是只获得chrome的第一个选项卡的句柄。遗憾的是,我真的不知道从哪里开始。有人能告诉我我能做什么吗?提前谢谢。

ni65a41a

ni65a41a1#

jna的 WindowUtils 在这里上课是有帮助的。这个 getAllWindows() 方法将返回 List<DesktopWindow> 每个 DesktopWindow 示例包括标题(与chrome进程匹配)和 HWND 那扇Windows的把手。
这个 DesktopWindow 也有一个 Rectangle 使用位置和尺寸标注,因此您可以从桌面本身复制适当的尺寸标注,例如下面这个简单的一行:

BufferedImage screenShot = new Robot().createScreenCapture(rectangle);

这个问题的答案确定了拍摄整个窗口截图的多个其他选项;简单地替换 Rectangle 你从 DesktopWindow 适当地初始化(或者使用上面的代码和矩形的尺寸)。
或者,如果您不需要 WindowUtils 类,您可以更直接地使用winapi的 EnumWindows 函数直接迭代窗口并仅捕获所需的信息。这就是函数 WindowUtils 在内部使用,所以它的源代码将是一个很好的简化起点。

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