diff --git a/examples/cluster.c b/examples/cluster.c
index 9097054..a453064 100644
--- a/examples/cluster.c
+++ b/examples/cluster.c
@@ -158,14 +158,16 @@ static void draw_mfd(cairo_t *cr,
     cairo_stroke(cr);
 }
 
-static void draw_gauge_cluster_bg(Pixmap buf,
-                                  Display *display,
-                                  int screen,
+static void draw_gauge_cluster_bg(hexagram_window *window,
                                   double width,
                                   double height) {
     cairo_surface_t *sfc;
     cairo_t *cr;
 
+    Pixmap buf       = window->bg;
+    Display *display = window->display;
+    int screen       = window->screen;
+
     sfc = cairo_xlib_surface_create(display, buf, DefaultVisual(display, screen), width, height);
     cairo_xlib_surface_set_size(sfc, width, height);
 
@@ -259,7 +261,7 @@ int main(int argc, char **argv) {
     /*
      * Draw the background layer
      */
-    draw_gauge_cluster_bg(bg, display, screen, width, height);
+    draw_gauge_cluster_bg(window, width, height);
 
     hexagram_window_show(window);