inherit window icon from embedded (Xembed) application

* This is largely taken from tabbed's "icon" patch (cf. xseticon()):
  https://tools.suckless.org/tabbed/patches/icon/
* I found that some applications that show their icon flawlessly in the WM
  won't work (neither in st, nor in tabbed).
  This was the case with SciTECO, but it could be resolved
  by reordering some statements.
* Once the embedded application terminates, we try to remove the icon again.
  `xprop` confirms that this worked.
  Unfortunately, Awesome WM will continue to show the old icon, which
  is probably an Awesome WM bug.
  Perhaps we should therefore apply this patch on top of netwmicon (FIXME):
  https://st.suckless.org/patches/netwmicon/

1 files changed, 49 insertions, 0 deletions

diff --git a/x.c b/x.c
index 6d5f1a7..ca4c57e 100644
--- a/x.c
+++ b/x.c
@@ -197,6 +197,7 @@ static void destroynotify(XEvent *e);
 static void sendxembed(long msg, long detail, long d1, long d2);
 static Bool gettextprop(Window w, Atom atom, char *text, unsigned int size);
 static void updatetitle(Window win);
+static void updateicon(Window win);
 
 static void run(void);
 static void usage(void);
@@ -525,6 +526,7 @@ propnotify(XEvent *e)
 {
 	XPropertyEvent *xpev;
 	Atom clipboard = XInternAtom(xw.dpy, "CLIPBOARD", 0);
+	Atom wmicon = XInternAtom(xw.dpy, "_NET_WM_ICON", 0);
 
 	xpev = &e->xproperty;
 	if (xpev->state == PropertyNewValue &&
@@ -534,6 +536,9 @@ propnotify(XEvent *e)
 	} else if (xpev->state != PropertyDelete && xpev->atom == XA_WM_NAME &&
 	           embed == xpev->window) {
 		updatetitle(embed);
+	} else if ((xpev->atom == wmicon || xpev->state == PropertyNewValue && xpev->atom == XA_WM_HINTS) &&
+	           embed == xpev->window) {
+		updateicon(embed);
 	}
 }
 
@@ -778,6 +783,7 @@ createnotify(XEvent *e)
 	XSelectInput(xw.dpy, embed, PropertyChangeMask | StructureNotifyMask | EnterWindowMask);
 
 	updatetitle(embed);
+	updateicon(embed);
 
 	XMapWindow(xw.dpy, embed);
 	sendxembed(XEMBED_EMBEDDED_NOTIFY, 0, xw.win, 0);
@@ -854,6 +860,46 @@ updatetitle(Window win)
 }
 
 void
+updateicon(Window win)
+{
+	Atom ret_type;
+	XWMHints *wmh, *cwmh;
+	int ret_format;
+	unsigned long ret_nitems, ret_nleft;
+	long offset = 0L;
+	unsigned char *data = NULL;
+
+	Atom wmicon = XInternAtom(xw.dpy, "_NET_WM_ICON", 0);
+	XDeleteProperty(xw.dpy, xw.win, wmicon);
+
+	wmh = XGetWMHints(xw.dpy, xw.win);
+	wmh->flags &= ~(IconPixmapHint | IconMaskHint);
+	wmh->icon_pixmap = wmh->icon_mask = None;
+
+	if (win) {
+		if (XGetWindowProperty(xw.dpy, win, wmicon, offset, LONG_MAX, False,
+		                       XA_CARDINAL, &ret_type, &ret_format, &ret_nitems,
+		                       &ret_nleft, &data) == Success &&
+		    ret_type == XA_CARDINAL && ret_format == 32) {
+			XChangeProperty(xw.dpy, xw.win, wmicon, XA_CARDINAL, 32,
+			                PropModeReplace, data, ret_nitems);
+		} else if ((cwmh = XGetWMHints(xw.dpy, win)) && cwmh->flags & IconPixmapHint) {
+			wmh->flags |= IconPixmapHint;
+			wmh->icon_pixmap = cwmh->icon_pixmap;
+			if (cwmh->flags & IconMaskHint) {
+				wmh->flags |= IconMaskHint;
+				wmh->icon_mask = cwmh->icon_mask;
+			}
+			XFree(cwmh);
+		}
+	}
+
+	XSetWMHints(xw.dpy, xw.win, wmh);
+	XFree(wmh);
+	XFree(data);
+}
+
+void
 xresize(int col, int row)
 {
 	win.tw = col * win.cw;
@@ -1826,6 +1872,9 @@ void
 unmap(XEvent *ev)
 {
 	if (embed == ev->xunmap.window) {
+		/* FIXME: restore the previous window title? */
+		/* FIXME: Does not remove the icon */
+		updateicon(0);
 		embed = 0;
 		XRaiseWindow(xw.dpy, xw.win);
 		XSetInputFocus(xw.dpy, xw.win, RevertToParent, CurrentTime);