使用 Python xlib 在活动 X 窗口更改时获取通知

Question

我想监控在运行 X 的 Linux 系统上哪个窗口处于活动状态，以及该活动窗口何时调整大小或移动。我可以监视活动窗口（它保存在根窗口的_NET_ACTIVE_WINDOW 属性中，我可以在根窗口上注册PropertyNotify 事件以发现该属性何时更改）。但是，我不知道如何监视活动窗口以了解它是否被调整大小或移动。

import Xlib
import Xlib.display

disp = Xlib.display.Display()
Xroot = disp.screen().root
NET_ACTIVE_WINDOW = disp.intern_atom('_NET_ACTIVE_WINDOW')
Xroot.change_attributes(event_mask=Xlib.X.PropertyChangeMask)

while True:
    # loop until an event happens that we care about
    # we care about a change to which window is active
    # (NET_ACTIVE_WINDOW property changes on the root)
    # or about the currently active window changing
    # in size or position (don't know how to do this)
    event = disp.next_event()
    if (event.type == Xlib.X.PropertyNotify and
            event.atom == NET_ACTIVE_WINDOW):
        active = disp.get_input_focus().focus
        try:
            name = active.get_wm_class()[1]
        except TypeError:
            name = "unknown"
        print("The active window has changed! It is now", name)

有没有办法做到这一点？它可能涉及在当前活动窗口上侦听 ConfigureNotify 事件（并在该窗口变为活动时调用 change_attributes 以设置适当的掩码），但我无法让它工作。

（注意：我没有使用 Gtk，所以请不要使用 Gtk 解决方案。）

更新：有一个相当可疑的方法来检测窗口调整大小，通过观察活动窗口的_NET_WM_OPAQUE_REGION 属性值的变化（因为我正确接收到 PropertyChange 事件，虽然我没有t 接收 ConfigureNotify 事件）。但是，尚不清楚所有窗口管理器是否都设置了此属性，并且仅在窗口调整大小时才会更改；它不会随着窗口移动而改变（任何其他属性也不会改变）。

Answer 1

这样做的方法是在根窗口上选择SubstructureNotifyMask，然后读取所有ConfigureNotify事件并忽略那些不属于我们关心的窗口的事件，因此：

import Xlib
import Xlib.display

disp = Xlib.display.Display()
Xroot = disp.screen().root
NET_ACTIVE_WINDOW = disp.intern_atom('_NET_ACTIVE_WINDOW')
Xroot.change_attributes(event_mask=Xlib.X.PropertyChangeMask |
                        Xlib.X.SubstructureNotifyMask)

windows = []

while True:
    # loop until an event happens that we care about
    # we care about a change to which window is active
    # (NET_ACTIVE_WINDOW property changes on the root)
    # or about the currently active window changing
    # in size or position (ConfigureNotify event for
    # our window or one of its ancestors)
    event = disp.next_event()
    if (event.type == Xlib.X.PropertyNotify and
            event.atom == NET_ACTIVE_WINDOW):
        active = disp.get_input_focus().focus
        try:
            name = active.get_wm_class()[1]
        except TypeError:
            name = "unknown"
        print("The active window has changed! It is now", name)

        # Because an X window is not necessarily just what one thinks of
        # as a window (the window manager may add an invisible frame, and
        # so on), we record not just the active window but its ancestors
        # up to the root, and treat a ConfigureNotify on any of those
        # ancestors as meaning that the active window has been moved or resized
        pointer = active
        windows = []
        while pointer.id != Xroot.id:
            windows.append(pointer)
            pointer = pointer.query_tree().parent
    elif event.type == Xlib.X.ConfigureNotify and event.window in windows:
        print("Active window size/position is now", event.x, event.y,
              event.width, event.height)