Focus follows pointer rewrite

TODO.md

@@ -1,4 +1,3 @@
-- Rewrite `focus_follows_pointer` by using a root sized input only window mapped and unmapped via enter notify events.
 - Rewrite `find_neighbor` based on the distances between the windows sides (more intuitive).
 - Focus history.
 - Command line completion for *bspc*.

bspwm.c

@@ -62,6 +62,11 @@ void setup(void)
     screen_height = screen->height_in_pixels;
     root_depth = screen->root_depth;
 
+    uint32_t mask = XCB_CW_EVENT_MASK;
+    uint32_t values[] = {XCB_EVENT_MASK_POINTER_MOTION};
+    motion_recorder = xcb_generate_id(dpy);
+    xcb_create_window(dpy, XCB_COPY_FROM_PARENT, motion_recorder, root, 0, 0, screen_width, screen_height, 0, XCB_WINDOW_CLASS_INPUT_ONLY, XCB_COPY_FROM_PARENT, mask, values);
+
     xcb_atom_t net_atoms[] = {ewmh->_NET_SUPPORTED,
                               ewmh->_NET_DESKTOP_NAMES,
                               ewmh->_NET_NUMBER_OF_DESKTOPS,
@@ -124,8 +129,6 @@ void setup(void)
     ewmh_update_current_desktop();
     rule_head = rule_tail = NULL;
     frozen_pointer = make_pointer_state();
-    last_focused_window = XCB_NONE;
-    save_pointer_position(&last_pointer_position);
     split_mode = MODE_AUTOMATIC;
     visible = true;
     exit_status = 0;
@@ -240,6 +243,7 @@ int main(int argc, char *argv[])
     if (status_fifo != NULL)
         fclose(status_fifo);
     xcb_ewmh_connection_wipe(ewmh);
+    xcb_destroy_window(dpy, motion_recorder);
     free(ewmh);
     xcb_flush(dpy);
     xcb_disconnect(dpy);

bspwm.h

@@ -5,7 +5,7 @@
 
 #define ROOT_EVENT_MASK        (XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT | XCB_EVENT_MASK_SUBSTRUCTURE_NOTIFY)
 #define CLIENT_EVENT_MASK      (XCB_EVENT_MASK_PROPERTY_CHANGE)
-#define CLIENT_EVENT_MASK_FFP  (XCB_EVENT_MASK_PROPERTY_CHANGE | XCB_EVENT_MASK_ENTER_WINDOW | XCB_EVENT_MASK_POINTER_MOTION)
+#define CLIENT_EVENT_MASK_FFP  (XCB_EVENT_MASK_PROPERTY_CHANGE | XCB_EVENT_MASK_ENTER_WINDOW)
 
 xcb_connection_t *dpy;
 int default_screen, screen_width, screen_height;
@@ -31,8 +31,7 @@ rule_t *rule_head;
 rule_t *rule_tail;
 
 pointer_state_t *frozen_pointer;
-xcb_window_t last_focused_window;
-xcb_point_t last_pointer_position;
+xcb_window_t motion_recorder;
 xcb_atom_t compton_shadow;
 
 int exit_status;

events.c

@@ -39,7 +39,7 @@ void handle_event(xcb_generic_event_t *evt)
             enter_notify(evt);
             break;
         case XCB_MOTION_NOTIFY:
-            motion_notify(evt);
+            motion_notify();
             break;
         default:
             break;
@@ -234,20 +234,22 @@ void enter_notify(xcb_generic_event_t *evt)
     PRINTF("enter notify %X %d %d\n", win, e->mode, e->detail);
 
     if (e->mode != XCB_NOTIFY_MODE_NORMAL
-            || (last_pointer_position.x = e->root_x && last_pointer_position.y == e->root_y))
+            || (mon->desk->focus != NULL && mon->desk->focus->client->window == win))
         return;
 
-    window_focus(win);
+    enable_motion_recorder();
 }
 
-void motion_notify(xcb_generic_event_t *evt)
+void motion_notify(void)
 {
-    xcb_motion_notify_event_t *e = (xcb_motion_notify_event_t *) evt;
-    xcb_window_t win = e->event;
+    PUTS("motion notify");
 
-    PRINTF("motion notify %X\n", win);
+    disable_motion_recorder();
 
-    window_focus(win);
+    xcb_window_t win = XCB_NONE;
+    get_pointed_window(&win);
+    if (win != XCB_NONE)
+        window_focus(win);
 }
 
 void handle_state(monitor_t *m, desktop_t *d, node_t *n, xcb_atom_t state, unsigned int action)

events.h

@@ -12,7 +12,7 @@ void configure_request(xcb_generic_event_t *);
 void client_message(xcb_generic_event_t *);
 void property_notify(xcb_generic_event_t *);
 void enter_notify(xcb_generic_event_t *);
-void motion_notify(xcb_generic_event_t *);
+void motion_notify(void);
 void handle_state(monitor_t *, desktop_t *, node_t *, xcb_atom_t, unsigned int);
 void grab_pointer(pointer_action_t);
 void track_pointer(int, int);

tree.c

@@ -196,8 +196,6 @@ void arrange(monitor_t *m, desktop_t *d)
     rect.y += m->top_padding + wg;
     rect.width -= m->left_padding + m->right_padding + wg;
     rect.height -= m->top_padding + m->bottom_padding + wg;
-    if (focus_follows_pointer)
-        save_pointer_position(&last_pointer_position);
     apply_layout(m, d, d->root, rect, rect);
 }
 
@@ -389,16 +387,10 @@ void focus_node(monitor_t *m, desktop_t *d, node_t *n, bool is_mapped)
     }
 
     if (focus_follows_pointer) {
-        save_pointer_position(&last_pointer_position);
-        if (n != mon->desk->focus) {
-            if (last_focused_window != XCB_NONE) {
-                uint32_t values[] = {CLIENT_EVENT_MASK_FFP};
-                xcb_change_window_attributes(dpy, last_focused_window, XCB_CW_EVENT_MASK, values);
-            }
-            uint32_t values[] = {CLIENT_EVENT_MASK};
-            xcb_change_window_attributes(dpy, n->client->window, XCB_CW_EVENT_MASK, values);
-            last_focused_window = n->client->window;
-        }
+        xcb_window_t win = XCB_NONE;
+        get_pointed_window(&win);
+        if (win != n->client->window)
+            enable_motion_recorder();
     }
 
     if (!is_tiled(n->client)) {

window.c

@@ -421,6 +421,15 @@ void save_pointer_position(xcb_point_t *pos)
     }
 }
 
+void get_pointed_window(xcb_window_t *win)
+{
+    xcb_query_pointer_reply_t *qpr = xcb_query_pointer_reply(dpy, xcb_query_pointer(dpy, root), NULL);
+    if (qpr != NULL) {
+        *win = qpr->child;
+        free(qpr);
+    }
+}
+
 void window_focus(xcb_window_t win)
 {
     window_location_t loc;
@@ -500,3 +509,14 @@ void toggle_visibility(void)
     if (visible)
         update_current();
 }
+
+void enable_motion_recorder(void)
+{
+    window_raise(motion_recorder);
+    window_show(motion_recorder);
+}
+
+void disable_motion_recorder(void)
+{
+    window_hide(motion_recorder);
+}

window.h

@@ -34,10 +34,12 @@ void window_lower(xcb_window_t);
 void window_set_visibility(xcb_window_t, bool);
 void window_hide(xcb_window_t);
 void window_show(xcb_window_t);
+void enable_motion_recorder(void);
+void disable_motion_recorder(void);
 void toggle_visibility(void);
 uint32_t get_border_color(client_t *, bool, bool);
 void update_floating_rectangle(client_t *);
-void save_pointer_position(xcb_point_t *);
+void get_pointed_window(xcb_window_t *);
 void list_windows(char *);
 
 #endif