How to SendEvent properly?

[RangerCD]

I'm trying to maximize a window with xproto.SendEvent, just like command wmctrl -ir xxxxxx -b add,maximized_vert,maximized_horz:

func X11Atom(X *xgb.Conn, name string) (xproto.Atom, error) {
	reply, err := xproto.InternAtom(X, false, uint16(len(name)), name).Reply()
	if err != nil {
		return 0, err
	}
	return reply.Atom, nil
}

func MaximizeWindow(window xproto.Window) error {
	setup := xproto.Setup(X)
	root := setup.DefaultScreen(X).Root

	stateAtom, err := X11Atom(X, "_NET_WM_STATE")
	if err != nil {
		return err
	}
	maxHorzAtom, err := X11Atom(X, "_NET_WM_STATE_MAXIMIZED_HORZ")
	if err != nil {
		return err
	}
	maxVertAtom, err := X11Atom(X, "_NET_WM_STATE_MAXIMIZED_VERT")
	if err != nil {
		return err
	}

	err = xproto.SendEventChecked(X, false, root, xproto.EventMaskSubstructureRedirect|xproto.EventMaskSubstructureNotify,
		xproto.ClientMessageEvent{
			Sequence: 0,
			Format:   32,
			Window:   window,
			Type:     stateAtom,
			Data: xproto.ClientMessageDataUnionData32New([]uint32{
				1, // _NET_WM_STATE_ADD
				uint32(maxHorzAtom),
				uint32(maxVertAtom),
				0,
				0,
			}),
		}.String()).Check()
	if err != nil {
		return err
	}
	X.Sync()

	return nil
}

I'm pretty sure window is the correct one, but nothing happened to that window, So I have to implement this with C:

/*
#cgo linux pkg-config: x11

#include <string.h>
#include <X11/Xlib.h>
#include <X11/Xatom.h>

int MaximizeWindow(Display *display, Window window) {
	Atom stateAtom = XInternAtom(display, "_NET_WM_STATE", False);
	Atom maxHorzAtom = XInternAtom(display, "_NET_WM_STATE_MAXIMIZED_HORZ", False);
	Atom maxVertAtom = XInternAtom(display, "_NET_WM_STATE_MAXIMIZED_VERT", False);

	XEvent e;
	memset(&e, 0, sizeof(e));
	e.xclient.type = ClientMessage;
	e.xclient.window = window;
	e.xclient.message_type = stateAtom;
	e.xclient.format = 32;
	e.xclient.data.l[0] = 1; // _NET_WM_STATE_ADD
	e.xclient.data.l[1] = maxHorzAtom;
	e.xclient.data.l[2] = maxVertAtom;
	e.xclient.data.l[3] = 0;
	e.xclient.data.l[4] = 0;

	XSendEvent(display, DefaultRootWindow(display), False,
		SubstructureRedirectMask | SubstructureNotifyMask, &e);

	XSync(display, False);

	return 0;
}

*/
import "C"

func MaximizeWindow(window xproto.Window) error {
	display := C.XOpenDisplay(nil)
	defer C.XCloseDisplay(display)
	C.MaximizeWindow(display, C.ulong(window))

	return nil
}

And it works just fine.
I've checked window event with xprop -spy -id xxxxxx, nothing comes in with golang version. But with C version, there is an event:

_NET_WM_STATE(ATOM) = _NET_WM_STATE_MAXIMIZED_VERT, _NET_WM_STATE_MAXIMIZED_HORZ, _NET_WM_STATE_FOCUSED

So I think there must be something wrong with previous golang version.
I've tried both SendEvent and SendEventChecked, with Reply() or Check(), still not working.
But I couldn't find anything helpful on the Internet, any idea?

[jezek]

@RangerCD Please, could you provide an minimal example program, which can be compiled and toy with to debug your problem? Something like create-window example and you can add maximize/restore to some key press. And if we make it work (the go way, not using C/XLib), this example could be added to examples for future references.

In meantime I would suggest to check it, how the XLib doest the maximization, I think (not really sure) it uses xcb under the hood and from that you can figure out how to do it using xgb, cause both use the same xproto function calls. If there is a bug in xgb, more faster to debug it is to have the same example done in raw xcb (not XLib), so we can see what is transferred to X server and debug (something like I did here).

ps: maybe this xcb example in this issue helps.