diff --git a/zathura/utils.c b/zathura/utils.c
index 44a74db..8352d7f 100644
--- a/zathura/utils.c
+++ b/zathura/utils.c
@@ -311,117 +311,150 @@ running_under_wsl(void)
   return result;
 }
 
-
-
-
-
 typedef struct zathura_point_s
 {
   double x;
   double y;
 } zathura_point_t;
 
-int cmp_point(const zathura_point_t* a, const zathura_point_t* b){
+static int
+cmp_point(const void* va, const void* vb) {
+  const zathura_point_t* a = va;
+  const zathura_point_t* b = vb;
+
   return a->x == b->x && a->y == b->y ? 0 : -1;
 }
-int cmp_double(const double* x, const double* y){
+
+static int
+cmp_double(const void* vx, const void* vy) {
+  const double* x = vx;
+  const double* y = vy;
+
   return *x == *y ? 0 : (*x > *y ? 1 : -1);
 }
-int cmp_rectangle(const zathura_rectangle_t* r1, const zathura_rectangle_t* r2){
-  return
-    (r1->x1 == r2->x1 &&
-     r1->x2 == r2->x2 &&
-     r1->y1 == r2->y1 &&
-     r1->y2 == r2->y2
-    ) ? 0 : -1;
-}
-girara_compare_function_t gcmp_double = (girara_compare_function_t)cmp_double;
-girara_compare_function_t gcmp_point = (girara_compare_function_t)cmp_point;
-girara_compare_function_t gcmp_rectangle = (girara_compare_function_t)cmp_rectangle;
 
-bool girara_list_append_unique(girara_list_t* l, girara_compare_function_t cmp, void* item){
-  if(girara_list_find(l, cmp, item))
+static int
+cmp_rectangle(const void* vr1, const void* vr2) {
+  const zathura_rectangle_t* r1 = vr1;
+  const zathura_rectangle_t* r2 = vr2;
+
+  return (r1->x1 == r2->x1 && r1->x2 == r2->x2 && r1->y1 == r2->y1 &&
+          r1->y2 == r2->y2)
+           ? 0
+           : -1;
+}
+
+
+static bool
+girara_list_append_unique(girara_list_t* l, girara_compare_function_t cmp, void* item) {
+  if (girara_list_find(l, cmp, item) != NULL) {
     return false;
+  }
+
   girara_list_append(l, item);
   return true;
 }
 
-void rectangle_to_points(const zathura_rectangle_t* rect, girara_list_t* list){
+static void
+rectangle_to_points(void* vrect, void* vlist) {
+  const zathura_rectangle_t* rect = vrect;
+  girara_list_t* list = vlist;
+
   zathura_point_t* p1 = g_try_malloc0(sizeof(zathura_point_t));
   zathura_point_t* p2 = g_try_malloc0(sizeof(zathura_point_t));
   zathura_point_t* p3 = g_try_malloc0(sizeof(zathura_point_t));
   zathura_point_t* p4 = g_try_malloc0(sizeof(zathura_point_t));
-  if(p1==NULL || p2==NULL || p3==NULL || p4==NULL)
+  if (p1 == NULL || p2 == NULL || p3 == NULL || p4 == NULL) {
+    g_free(p4);
+    g_free(p3);
+    g_free(p2);
+    g_free(p1);
     return;
+  }
+
   *p1 = (zathura_point_t) { rect->x1, rect->y1 };
   *p2 = (zathura_point_t) { rect->x1, rect->y2 };
   *p3 = (zathura_point_t) { rect->x2, rect->y1 };
   *p4 = (zathura_point_t) { rect->x2, rect->y2 };
-  if(!girara_list_append_unique(list, gcmp_point, (void*) p1))
+
+  if (!girara_list_append_unique(list, cmp_point, p1)) {
     g_free(p1);
-  if(!girara_list_append_unique(list, gcmp_point, (void*) p2))
+  }
+  if (!girara_list_append_unique(list, cmp_point, p2)) {
     g_free(p2);
-  if(!girara_list_append_unique(list, gcmp_point, (void*) p3))
+  }
+  if (!girara_list_append_unique(list, cmp_point, p3)) {
     g_free(p3);
-  if(!girara_list_append_unique(list, gcmp_point, (void*) p4))
+  }
+  if (!girara_list_append_unique(list, cmp_point, p4)) {
     g_free(p4);
+  }
 }
 
 // transform a rectangle into multiple new ones according a grid of points 
-void cut_rectangle(const zathura_rectangle_t* rect, girara_list_t* points,
-		   girara_list_t* rectangles){
+static void
+cut_rectangle(const zathura_rectangle_t* rect, girara_list_t* points, girara_list_t* rectangles) {
   // Lists of ordred relevant points
-  girara_list_t* xs = girara_sorted_list_new2(gcmp_double, g_free);
-  girara_list_t* ys = girara_sorted_list_new2(gcmp_double, g_free);
-  
+  girara_list_t* xs = girara_sorted_list_new2(cmp_double, g_free);
+  girara_list_t* ys = girara_sorted_list_new2(cmp_double, g_free);
+
   double* rX2 = g_try_malloc(sizeof(double));
   double* rY2 = g_try_malloc(sizeof(double));
-  if(rX2 == NULL || rY2 == NULL)
-    return;
+  if (rX2 == NULL || rY2 == NULL) {
 
-  *rX2 = (double)rect->x2;
-  *rY2 = (double)rect->y2;
+    return;
+  }
+
+  *rX2 = rect->x2;
+  *rY2 = rect->y2;
   girara_list_append(xs, rX2);
   girara_list_append(ys, rY2);
 
   GIRARA_LIST_FOREACH(points, zathura_point_t*, i_pt, pt)
-  if(pt->x > rect->x1 && pt->x < rect->x2){
-    double* v = g_try_malloc(sizeof(double));
-    if(v == NULL) return;
-    *v = (double) pt->x;
-    if(!girara_list_append_unique(xs, gcmp_double, v))
-      g_free(v);
-  }
-  if(pt->y > rect->y1 && pt->y < rect->y2){
-    double* v = g_try_malloc(sizeof(double));
-    if(v == NULL) return;
-    *v = (double) pt->y;
-    if(!girara_list_append_unique(ys, gcmp_double, v))
-      g_free(v);
-  }
+    if (pt->x > rect->x1 && pt->x < rect->x2) {
+      double* v = g_try_malloc(sizeof(double));
+      if (v == NULL) {
+        return;
+      }
+      *v = pt->x;
+      if (!girara_list_append_unique(xs, cmp_double, v)) {
+        g_free(v);
+      }
+    }
+    if (pt->y > rect->y1 && pt->y < rect->y2) {
+      double* v = g_try_malloc(sizeof(double));
+      if (v == NULL) {
+        return;
+      }
+      *v = pt->y;
+      if (!girara_list_append_unique(ys, cmp_double, v)) {
+        g_free(v);
+      }
+    }
   GIRARA_LIST_FOREACH_END(points, zathura_point_t*, i_pt, pt);
-  
+
   double x = rect->x1;
   GIRARA_LIST_FOREACH(xs, double*, ix, cx)
-  double y = rect->y1;
-  GIRARA_LIST_FOREACH(ys, double*, iy, cy)
-    zathura_rectangle_t* r = g_try_malloc(sizeof(zathura_rectangle_t));
-  *r = (zathura_rectangle_t) {x, y, *cx, *cy};
-  y = *cy;
-  girara_list_append_unique(rectangles, gcmp_rectangle, r);
-  GIRARA_LIST_FOREACH_END(ys, double*, iy, cy);
-  x = *cx;
+    double y = rect->y1;
+    GIRARA_LIST_FOREACH(ys, double*, iy, cy)
+      zathura_rectangle_t* r = g_try_malloc(sizeof(zathura_rectangle_t));
+      *r = (zathura_rectangle_t) {x, y, *cx, *cy};
+      y = *cy;
+      girara_list_append_unique(rectangles, cmp_rectangle, r);
+    GIRARA_LIST_FOREACH_END(ys, double*, iy, cy);
+    x = *cx;
   GIRARA_LIST_FOREACH_END(xs, double*, ix, cx);
 
   girara_list_free(xs);
   girara_list_free(ys);
 }
 
-girara_list_t* flatten_rectangles(girara_list_t* rectangles){
+girara_list_t*
+flatten_rectangles(girara_list_t* rectangles) {
   girara_list_t* new_rectangles = girara_list_new2(g_free);
   girara_list_t* points = girara_list_new2(g_free);
-  girara_list_foreach(rectangles, (girara_list_callback_t) rectangle_to_points, points);
-  
+  girara_list_foreach(rectangles, rectangle_to_points, points);
+
   GIRARA_LIST_FOREACH(rectangles, zathura_rectangle_t*, i, r)
     cut_rectangle(r, points, new_rectangles);
   GIRARA_LIST_FOREACH_END(rectangles, zathura_rectangle_t*, i, r);