Fix covering of composited notifications (#96)

[i3/i3lock] / xcb.c

diff --git a/xcb.c b/xcb.c
index e0b78111a06b3347371cd72ba88972bb462d64c4..73ebb7e63490d4f0996b99bb93fbf07650fd7e47 100644 (file)
--- a/xcb.c
+++ b/xcb.c
@@ -11,6 +11,7 @@
 #include <xcb/xcb_image.h>
 #include <xcb/xcb_atom.h>
 #include <xcb/xcb_aux.h>
+#include <xcb/composite.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdbool.h>
@@ -106,6 +107,29 @@ xcb_window_t open_fullscreen_window(xcb_connection_t *conn, xcb_screen_t *scr, c
     uint32_t mask = 0;
     uint32_t values[3];
     xcb_window_t win = xcb_generate_id(conn);
+    xcb_window_t parent_win = scr->root;
+
+    /* Check whether the composite extension is available */
+    const xcb_query_extension_reply_t *extension_query = NULL;
+    xcb_generic_error_t *error = NULL;
+    xcb_composite_get_overlay_window_cookie_t cookie;
+    xcb_composite_get_overlay_window_reply_t *composite_reply = NULL;
+
+    extension_query = xcb_get_extension_data(conn, &xcb_composite_id);
+    if (extension_query && extension_query->present) {
+        /* When composition is used, we need to use the composite overlay
+         * window instead of the normal root window to be able to cover
+         * composited windows */
+        cookie = xcb_composite_get_overlay_window(conn, scr->root);
+        composite_reply = xcb_composite_get_overlay_window_reply(conn, cookie, &error);
+
+        if (!error && composite_reply) {
+            parent_win = composite_reply->overlay_win;
+        }
+
+        free(composite_reply);
+        free(error);
+    }
 
     if (pixmap == XCB_NONE) {
         mask |= XCB_CW_BACK_PIXEL;
@@ -127,8 +151,8 @@ xcb_window_t open_fullscreen_window(xcb_connection_t *conn, xcb_screen_t *scr, c
 
     xcb_create_window(conn,
                       XCB_COPY_FROM_PARENT,
-                      win,       /* the window id */
-                      scr->root, /* parent == root */
+                      win, /* the window id */
+                      parent_win,
                       0, 0,
                       scr->width_in_pixels,
                       scr->height_in_pixels, /* dimensions */