Question

有没有办法在Linux下获取当前焦点窗口的Geometry？我只需要窗口当前具有焦点或位于桌面顶部的位置（x和y）和大小（宽度和高度）。

我想在QT应用程序中使用此信息来拍摄此窗口的屏幕截图。

Answer 1

显然，解决该问题的第一步是确定当前焦点的窗口。为此，您可以使用Xlib的XGetInputFocus()功能。之后，使用XGetWindowAttributes()获取窗口的位置和大小（甚至还有关于窗口的更多信息）。

Answer 2

您可以使用libxdo

/**
 * Like xdo_get_focused_window, but return the first ancestor-or-self window *
 * having a property of WM_CLASS. This allows you to get the "real" or
 * top-level-ish window having focus rather than something you may not expect
 * to be the window having focused.
 *
 * @param window_ret Pointer to a window where the currently-focused window
 *   will be stored.
 */
int xdo_get_focused_window_sane(const xdo_t *xdo, Window *window_ret);


/**
 * Get a window's size.
 *
 * @param wid the window to query
 * @param width_ret pointer to unsigned int where the width is stored.
 * @param height_ret pointer to unsigned int where the height is stored.
 */
int xdo_get_window_size(const xdo_t *xdo, Window wid, unsigned int *width_ret,
                        unsigned int *height_ret);

Answer 3

谢谢@Striezel，您的反馈意见指出了我正确的方向。在调查您的解决方案后，我会遇到这篇文章：Xlib: XGetWindowAttributes always returns 1x1?

稍微调整了@Doug的答案我已经跟进，这似乎按预期工作：

Window getToplevelParent(Display* display, Window window)
{
    Window parentWindow;
    Window rootWindow;
    Window* childrenWindows;
    unsigned int numberOfChildren;

    while (1) {
        if (XQueryTree(display, window, &rootWindow, &parentWindow, &childrenWindows,
                       &numberOfChildren) == 0) {
            qCritical("ImageGrabber::getToplevelParent: XQueryTree Error");
            return 0;
        }
        if (childrenWindows) {
            XFree(childrenWindows);
        }
        if (window == rootWindow || parentWindow == rootWindow) {
            return window;
        } else {
            window = parentWindow;
        }
    }
}

QRect ImageGrabber::getActiveWindowRect()
{

    Display* display = XOpenDisplay(NULL);
    Window focusWindow, parentOfFocusedWindow;
    XWindowAttributes attrributes;
    int revert;

    XGetInputFocus(display, &focusWindow, &revert);
    parentOfFocusedWindow = getToplevelParent(display, focusWindow);
    if (!parentOfFocusedWindow) {
        qCritical("ImageGrabber::getActiveWindowRect: Unable to get window, returning screen.");
        return getCurrectScreenRect();
    }

    XGetWindowAttributes(display, parentOfFocusedWindow, &attrributes);
    return QRect(attrributes.x, attrributes.y, attrributes.width, attrributes.height);
}

如何在C ++中获取Linux上当前关注窗口的几何？

3 个答案: