From ede5a54355559ffe9d48888b92677f231068dda0 Mon Sep 17 00:00:00 2001
From: Julien Danjou <julien@danjou.info>
Date: Mon, 6 Oct 2008 11:42:02 +0200
Subject: [PATCH] event: handle background changes

Signed-off-by: Julien Danjou <julien@danjou.info>
---
 awesome.c      |  3 ++-
 common/xutil.c | 17 +++++++++++++++++
 common/xutil.h |  2 ++
 event.c        |  4 +---
 property.c     | 30 ++++++++++++++++++++++++++++++
 5 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/awesome.c b/awesome.c
index 937b8656..2ff811b0 100644
--- a/awesome.c
+++ b/awesome.c
@@ -484,7 +484,8 @@ main(int argc, char **argv)
         {
             XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT | XCB_EVENT_MASK_SUBSTRUCTURE_NOTIFY
                 | XCB_EVENT_MASK_ENTER_WINDOW | XCB_EVENT_MASK_LEAVE_WINDOW
-                | XCB_EVENT_MASK_STRUCTURE_NOTIFY,
+                | XCB_EVENT_MASK_STRUCTURE_NOTIFY
+                | XCB_EVENT_MASK_PROPERTY_CHANGE,
             globalconf.cursor[CurNormal]
         };
 
diff --git a/common/xutil.c b/common/xutil.c
index 8f262b4b..40891daa 100644
--- a/common/xutil.c
+++ b/common/xutil.c
@@ -427,4 +427,21 @@ xutil_cursor_new(xcb_connection_t *conn, unsigned int cursor_font)
     return cursor;
 }
 
+/** Convert a root window a physical screen ID.
+ * \param connection The connection to the X server.
+ * \param root Root window.
+ * \return A physical screen number.
+ */
+int
+xutil_root2screen(xcb_connection_t *connection, xcb_window_t root)
+{
+    xcb_screen_iterator_t iter;
+    int phys_screen = 0;
+
+    for(iter = xcb_setup_roots_iterator(xcb_get_setup(connection));
+        iter.rem && iter.data->root != root; xcb_screen_next(&iter), ++phys_screen);
+
+    return phys_screen;
+}
+
 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=80
diff --git a/common/xutil.h b/common/xutil.h
index cec59aa3..269daf33 100644
--- a/common/xutil.h
+++ b/common/xutil.h
@@ -143,5 +143,7 @@ xutil_screen_get(xcb_connection_t *c, int screen)
     return s;
 }
 
+int xutil_root2screen(xcb_connection_t *, xcb_window_t);
+
 #endif
 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=80
diff --git a/event.c b/event.c
index b6187391..3b517976 100644
--- a/event.c
+++ b/event.c
@@ -511,7 +511,6 @@ event_handle_maprequest(void *data __attribute__ ((unused)),
     xcb_query_pointer_reply_t *qp_r = NULL;
     xcb_get_geometry_cookie_t geom_c;
     xcb_get_geometry_reply_t *geom_r;
-    xcb_screen_iterator_t iter;
 
     wa_c = xcb_get_window_attributes_unchecked(connection, ev->window);
 
@@ -554,8 +553,7 @@ event_handle_maprequest(void *data __attribute__ ((unused)),
         }
 
 
-        for(iter = xcb_setup_roots_iterator(xcb_get_setup(connection)), phys_screen = 0;
-            iter.rem && iter.data->root != geom_r->root; xcb_screen_next(&iter), ++phys_screen);
+        phys_screen = xutil_root2screen(connection, geom_r->root);
 
         if(globalconf.xinerama_is_active
            && (qp_r = xcb_query_pointer_reply(connection, qp_c, NULL)))
diff --git a/property.c b/property.c
index 4b795a5e..d2ece640 100644
--- a/property.c
+++ b/property.c
@@ -321,6 +321,32 @@ property_handle_xembed_info(void *data __attribute__ ((unused)),
     return 0;
 }
 
+static int
+property_handle_xrootpmap_id(void *data __attribute__ ((unused)),
+                             xcb_connection_t *connection,
+                             uint8_t state,
+                             xcb_window_t window,
+                             xcb_atom_t name,
+                             xcb_get_property_reply_t *reply)
+{
+    if(globalconf.xinerama_is_active)
+        for(int screen = 0; screen < globalconf.nscreen; screen++)
+        {
+            wibox_array_t *w = &globalconf.screens[screen].wiboxes;
+            for(int i = 0; i < w->len; i++)
+                w->tab[i]->need_update = true;
+        }
+    else
+    {
+        int screen = xutil_root2screen(connection, window);
+        wibox_array_t *w = &globalconf.screens[screen].wiboxes;
+        for(int i = 0; i < w->len; i++)
+            w->tab[i]->need_update = true;
+    }
+
+    return 0;
+}
+
 void a_xcb_set_property_handlers(void)
 {
     /* init */
@@ -347,6 +373,10 @@ void a_xcb_set_property_handlers(void)
                              property_handle_net_wm_strut_partial, NULL);
     xcb_property_set_handler(&globalconf.prophs, _NET_WM_ICON, UINT_MAX,
                              property_handle_net_wm_icon, NULL);
+
+    /* background change */
+    xcb_property_set_handler(&globalconf.prophs, _XROOTPMAP_ID, 1,
+                             property_handle_xrootpmap_id, NULL);
 }
 
 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=80