diff --git a/src/Makefile.am b/src/Makefile.am
index 71aa02674..fb0ccbb5d 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -112,6 +112,8 @@ libmutter_la_SOURCES =				\
 	core/boxes.c				\
 	core/boxes-private.h			\
 	meta/boxes.h				\
+	core/meta-border.c			\
+	core/meta-border.h			\
 	compositor/clutter-utils.c		\
 	compositor/clutter-utils.h		\
 	compositor/cogl-utils.c			\
diff --git a/src/backends/meta-barrier-private.h b/src/backends/meta-barrier-private.h
index 8e1d223de..8c711172c 100644
--- a/src/backends/meta-barrier-private.h
+++ b/src/backends/meta-barrier-private.h
@@ -26,6 +26,8 @@
 #ifndef META_BARRIER_PRIVATE_H
 #define META_BARRIER_PRIVATE_H
 
+#include "core/meta-border.h"
+
 G_BEGIN_DECLS
 
 #define META_TYPE_BARRIER_IMPL            (meta_barrier_impl_get_type ())
@@ -67,14 +69,7 @@ G_END_DECLS
 struct _MetaBarrierPrivate
 {
   MetaDisplay *display;
-
-  int x1;
-  int y1;
-  int x2;
-  int y2;
-
-  MetaBarrierDirection directions;
-
+  MetaBorder border;
   MetaBarrierImpl *impl;
 };
 
diff --git a/src/backends/meta-barrier.c b/src/backends/meta-barrier.c
index f5422ee1b..a1e1180fe 100644
--- a/src/backends/meta-barrier.c
+++ b/src/backends/meta-barrier.c
@@ -61,19 +61,20 @@ meta_barrier_get_property (GObject    *object,
       g_value_set_object (value, priv->display);
       break;
     case PROP_X1:
-      g_value_set_int (value, priv->x1);
+      g_value_set_int (value, priv->border.line.a.x);
       break;
     case PROP_Y1:
-      g_value_set_int (value, priv->y1);
+      g_value_set_int (value, priv->border.line.a.y);
       break;
     case PROP_X2:
-      g_value_set_int (value, priv->x2);
+      g_value_set_int (value, priv->border.line.b.x);
       break;
     case PROP_Y2:
-      g_value_set_int (value, priv->y2);
+      g_value_set_int (value, priv->border.line.b.y);
       break;
     case PROP_DIRECTIONS:
-      g_value_set_flags (value, priv->directions);
+      g_value_set_flags (value,
+                         meta_border_get_allows_directions (&priv->border));
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
@@ -95,19 +96,20 @@ meta_barrier_set_property (GObject      *object,
       priv->display = g_value_get_object (value);
       break;
     case PROP_X1:
-      priv->x1 = g_value_get_int (value);
+      priv->border.line.a.x = g_value_get_int (value);
       break;
     case PROP_Y1:
-      priv->y1 = g_value_get_int (value);
+      priv->border.line.a.y = g_value_get_int (value);
       break;
     case PROP_X2:
-      priv->x2 = g_value_get_int (value);
+      priv->border.line.b.x = g_value_get_int (value);
       break;
     case PROP_Y2:
-      priv->y2 = g_value_get_int (value);
+      priv->border.line.b.y = g_value_get_int (value);
       break;
     case PROP_DIRECTIONS:
-      priv->directions = g_value_get_flags (value);
+      meta_border_set_allows_directions (&priv->border,
+                                         g_value_get_flags (value));
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
@@ -166,7 +168,8 @@ meta_barrier_constructed (GObject *object)
   MetaBarrier *barrier = META_BARRIER (object);
   MetaBarrierPrivate *priv = barrier->priv;
 
-  g_return_if_fail (priv->x1 == priv->x2 || priv->y1 == priv->y2);
+  g_return_if_fail (priv->border.line.a.x == priv->border.line.b.x ||
+                    priv->border.line.a.y == priv->border.line.b.y);
 
 #if defined(HAVE_NATIVE_BACKEND)
   if (META_IS_BACKEND_NATIVE (meta_get_backend ()))
diff --git a/src/backends/native/meta-barrier-native.c b/src/backends/native/meta-barrier-native.c
index 8f81d3440..c6a6be6c1 100644
--- a/src/backends/native/meta-barrier-native.c
+++ b/src/backends/native/meta-barrier-native.c
@@ -93,126 +93,18 @@ next_serial (void)
   return barrier_serial;
 }
 
-typedef struct _Vector2
-{
-  float x, y;
-} Vector2;
-
-static float
-vector2_cross_product (Vector2 a, Vector2 b)
-{
-  return a.x * b.y - a.y * b.x;
-}
-
-static Vector2
-vector2_add (Vector2 a, Vector2 b)
-{
-  return (Vector2) {
-    .x = a.x + b.x,
-    .y = a.y + b.y,
-  };
-}
-
-static Vector2
-vector2_subtract (Vector2 a, Vector2 b)
-{
-  return (Vector2) {
-    .x = a.x - b.x,
-    .y = a.y - b.y,
-  };
-}
-
-static Vector2
-vector2_multiply_constant (float c, Vector2 a)
-{
-  return (Vector2) {
-    .x = c * a.x,
-    .y = c * a.y,
-  };
-}
-
-typedef struct _Line2
-{
-  Vector2 a;
-  Vector2 b;
-} Line2;
-
-static gboolean
-lines_intersect (Line2 *line1, Line2 *line2, Vector2 *intersection)
-{
-  Vector2 p = line1->a;
-  Vector2 r = vector2_subtract (line1->b, line1->a);
-  Vector2 q = line2->a;
-  Vector2 s = vector2_subtract (line2->b, line2->a);
-  float rxs;
-  float sxr;
-  float t;
-  float u;
-
-  /*
-   * The line (p, r) and (q, s) intersects where
-   *
-   *   p + t r = q + u s
-   *
-   * Calculate t:
-   *
-   *   (p + t r) × s = (q + u s) × s
-   *   p × s + t (r × s) = q × s + u (s × s)
-   *   p × s + t (r × s) = q × s
-   *   t (r × s) = q × s - p × s
-   *   t (r × s) = (q - p) × s
-   *   t = ((q - p) × s) / (r × s)
-   *
-   * Using the same method, for u we get:
-   *
-   *   u = ((p - q) × r) / (s × r)
-   */
-
-  rxs = vector2_cross_product (r, s);
-  sxr = vector2_cross_product (s, r);
-
-  /* If r × s = 0 then the lines are either parallel or collinear. */
-  if (fabs ( rxs) < DBL_MIN)
-    return FALSE;
-
-  t = vector2_cross_product (vector2_subtract (q, p), s) / rxs;
-  u = vector2_cross_product (vector2_subtract (p, q), r) / sxr;
-
-
-  /* The lines only intersect if 0 ≤ t ≤ 1 and 0 ≤ u ≤ 1. */
-  if (t < 0.0 || t > 1.0 || u < 0.0 || u > 1.0)
-    return FALSE;
-
-  *intersection = vector2_add (p, vector2_multiply_constant (t, r));
-
-  return TRUE;
-}
-
 static gboolean
 is_barrier_horizontal (MetaBarrier *barrier)
 {
-  return barrier->priv->y1 == barrier->priv->y2;
+  return meta_border_is_horizontal (&barrier->priv->border);
 }
 
 static gboolean
 is_barrier_blocking_directions (MetaBarrier         *barrier,
                                 MetaBarrierDirection directions)
 {
-  /* Barriers doesn't block parallel motions. */
-  if (is_barrier_horizontal (barrier))
-    {
-      if ((directions & (META_BARRIER_DIRECTION_POSITIVE_Y |
-                         META_BARRIER_DIRECTION_NEGATIVE_Y)) == 0)
-        return FALSE;
-    }
-  else
-    {
-      if ((directions & (META_BARRIER_DIRECTION_POSITIVE_X |
-                         META_BARRIER_DIRECTION_NEGATIVE_X)) == 0)
-        return FALSE;
-    }
-
-  return (barrier->priv->directions & directions) != directions;
+  return meta_border_is_blocking_directions (&barrier->priv->border,
+                                             directions);
 }
 
 static void
@@ -224,31 +116,16 @@ dismiss_pointer (MetaBarrierImplNative *self)
   priv->state = META_BARRIER_STATE_LEFT;
 }
 
-static Line2
-barrier_to_line (MetaBarrier *barrier)
-{
-  return (Line2) {
-    .a = (Vector2) {
-      .x = MIN (barrier->priv->x1, barrier->priv->x2),
-      .y = MIN (barrier->priv->y1, barrier->priv->y2),
-    },
-    .b = (Vector2) {
-      .x = MAX (barrier->priv->x1, barrier->priv->x2),
-      .y = MAX (barrier->priv->y1, barrier->priv->y2),
-    },
-  };
-}
-
 /*
  * Calculate the hit box for a held motion. The hit box is a 2 px wide region
  * in the opposite direction of every direction the barrier blocks. The purpose
  * of this is to allow small movements without receiving a "left" signal. This
  * heuristic comes from the X.org pointer barrier implementation.
  */
-static Line2
+static MetaLine2
 calculate_barrier_hit_box (MetaBarrier *barrier)
 {
-  Line2 hit_box = barrier_to_line (barrier);
+  MetaLine2 hit_box = barrier->priv->border.line;
 
   if (is_barrier_horizontal (barrier))
     {
@@ -273,7 +150,8 @@ calculate_barrier_hit_box (MetaBarrier *barrier)
 }
 
 static gboolean
-is_within_box (Line2 box, Vector2 point)
+is_within_box (MetaLine2   box,
+               MetaVector2 point)
 {
   return (point.x >= box.a.x && point.x < box.b.x &&
           point.y >= box.a.y && point.y < box.b.y);
@@ -288,8 +166,8 @@ maybe_release_barrier (gpointer key,
   MetaBarrierImplNativePrivate *priv =
     meta_barrier_impl_native_get_instance_private (self);
   MetaBarrier *barrier = priv->barrier;
-  Line2 *motion = user_data;
-  Line2 hit_box;
+  MetaLine2 *motion = user_data;
+  MetaLine2 hit_box;
 
   if (priv->state != META_BARRIER_STATE_HELD)
     return;
@@ -297,8 +175,10 @@ maybe_release_barrier (gpointer key,
   /* Release if we end up outside barrier end points. */
   if (is_barrier_horizontal (barrier))
     {
-      if (motion->b.x > MAX (barrier->priv->x1, barrier->priv->x2) ||
-          motion->b.x < MIN (barrier->priv->x1, barrier->priv->x2))
+      if (motion->b.x > MAX (barrier->priv->border.line.a.x,
+                             barrier->priv->border.line.b.x) ||
+          motion->b.x < MIN (barrier->priv->border.line.a.x,
+                             barrier->priv->border.line.b.x))
         {
           dismiss_pointer (self);
           return;
@@ -306,8 +186,10 @@ maybe_release_barrier (gpointer key,
     }
   else
     {
-      if (motion->b.y > MAX (barrier->priv->y1, barrier->priv->y2) ||
-          motion->b.y < MIN (barrier->priv->y1, barrier->priv->y2))
+      if (motion->b.y > MAX (barrier->priv->border.line.a.y,
+                             barrier->priv->border.line.b.y) ||
+          motion->b.y < MIN (barrier->priv->border.line.a.y,
+                             barrier->priv->border.line.b.y))
         {
           dismiss_pointer (self);
           return;
@@ -330,7 +212,7 @@ maybe_release_barriers (MetaBarrierManagerNative *manager,
                         float                     x,
                         float                     y)
 {
-  Line2 motion = {
+  MetaLine2 motion = {
     .a = {
       .x = prev_x,
       .y = prev_y,
@@ -350,7 +232,7 @@ typedef struct _MetaClosestBarrierData
 {
   struct
   {
-    Line2                       motion;
+    MetaLine2                   motion;
     MetaBarrierDirection        directions;
   } in;
 
@@ -371,8 +253,7 @@ update_closest_barrier (gpointer key,
     meta_barrier_impl_native_get_instance_private (self);
   MetaBarrier *barrier = priv->barrier;
   MetaClosestBarrierData *data = user_data;
-  Line2 barrier_line;
-  Vector2 intersection;
+  MetaVector2 intersection;
   float dx, dy;
   float distance_2;
 
@@ -391,17 +272,9 @@ update_closest_barrier (gpointer key,
 
   /* Check if the motion intersects with the barrier, and retrieve the
    * intersection point if any. */
-  barrier_line = (Line2) {
-    .a = {
-      .x = barrier->priv->x1,
-      .y = barrier->priv->y1
-    },
-    .b = {
-      .x = barrier->priv->x2,
-      .y = barrier->priv->y2
-    },
-  };
-  if (!lines_intersect (&barrier_line, &data->in.motion, &intersection))
+  if (!meta_line2_intersects_with (&barrier->priv->border.line,
+                                   &data->in.motion,
+                                   &intersection))
     return;
 
   /* Calculate the distance to the barrier and keep track of the closest
@@ -570,9 +443,9 @@ clamp_to_barrier (MetaBarrierImplNative *self,
   if (is_barrier_horizontal (barrier))
     {
       if (*motion_dir & META_BARRIER_DIRECTION_POSITIVE_Y)
-        *y = barrier->priv->y1;
+        *y = barrier->priv->border.line.a.y;
       else if (*motion_dir & META_BARRIER_DIRECTION_NEGATIVE_Y)
-        *y = barrier->priv->y1;
+        *y = barrier->priv->border.line.a.y;
 
       priv->blocked_dir = *motion_dir & (META_BARRIER_DIRECTION_POSITIVE_Y |
                                          META_BARRIER_DIRECTION_NEGATIVE_Y);
@@ -582,9 +455,9 @@ clamp_to_barrier (MetaBarrierImplNative *self,
   else
     {
       if (*motion_dir & META_BARRIER_DIRECTION_POSITIVE_X)
-        *x = barrier->priv->x1;
+        *x = barrier->priv->border.line.a.x;
       else if (*motion_dir & META_BARRIER_DIRECTION_NEGATIVE_X)
-        *x = barrier->priv->x1;
+        *x = barrier->priv->border.line.a.x;
 
       priv->blocked_dir = *motion_dir & (META_BARRIER_DIRECTION_POSITIVE_X |
                                          META_BARRIER_DIRECTION_NEGATIVE_X);
diff --git a/src/backends/x11/meta-barrier-x11.c b/src/backends/x11/meta-barrier-x11.c
index 1a813c43d..054e5cdc6 100644
--- a/src/backends/x11/meta-barrier-x11.c
+++ b/src/backends/x11/meta-barrier-x11.c
@@ -107,6 +107,7 @@ meta_barrier_impl_x11_new (MetaBarrier *barrier)
   MetaDisplay *display = barrier->priv->display;
   Display *dpy;
   Window root;
+  unsigned int allowed_motion_dirs;
 
   if (display == NULL)
     {
@@ -121,12 +122,14 @@ meta_barrier_impl_x11_new (MetaBarrier *barrier)
   dpy = display->xdisplay;
   root = DefaultRootWindow (dpy);
 
+  allowed_motion_dirs =
+    meta_border_get_allows_directions (&barrier->priv->border);
   priv->xbarrier = XFixesCreatePointerBarrier (dpy, root,
-                                               barrier->priv->x1,
-                                               barrier->priv->y1,
-                                               barrier->priv->x2,
-                                               barrier->priv->y2,
-                                               barrier->priv->directions,
+                                               barrier->priv->border.line.a.x,
+                                               barrier->priv->border.line.a.y,
+                                               barrier->priv->border.line.b.x,
+                                               barrier->priv->border.line.b.y,
+                                               allowed_motion_dirs,
                                                0, NULL);
 
   g_hash_table_insert (display->xids, &priv->xbarrier, barrier);
diff --git a/src/core/meta-border.c b/src/core/meta-border.c
new file mode 100644
index 000000000..cc996fef3
--- /dev/null
+++ b/src/core/meta-border.c
@@ -0,0 +1,154 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/*
+ * Copyright (C) 2015 Red Hat
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ * Written by:
+ *     Jonas Ådahl <jadahl@gmail.com>
+ */
+
+#include "config.h"
+
+#include "core/meta-border.h"
+
+#include <math.h>
+
+static inline float
+meta_vector2_cross_product (const MetaVector2 a,
+                            const MetaVector2 b)
+{
+  return a.x * b.y - a.y * b.x;
+}
+
+static inline MetaVector2
+meta_vector2_add (const MetaVector2 a,
+                  const MetaVector2 b)
+{
+  return (MetaVector2) {
+    .x = a.x + b.x,
+    .y = a.y + b.y,
+  };
+}
+
+static inline MetaVector2
+meta_vector2_multiply_constant (const float       c,
+                                const MetaVector2 a)
+{
+  return (MetaVector2) {
+    .x = c * a.x,
+    .y = c * a.y,
+  };
+}
+
+gboolean
+meta_line2_intersects_with (const MetaLine2 *line1,
+                            const MetaLine2 *line2,
+                            MetaVector2     *intersection)
+{
+  MetaVector2 p = line1->a;
+  MetaVector2 r = meta_vector2_subtract (line1->b, line1->a);
+  MetaVector2 q = line2->a;
+  MetaVector2 s = meta_vector2_subtract (line2->b, line2->a);
+  float rxs;
+  float sxr;
+  float t;
+  float u;
+
+  /*
+   * The line (p, r) and (q, s) intersects where
+   *
+   *   p + t r = q + u s
+   *
+   * Calculate t:
+   *
+   *   (p + t r) × s = (q + u s) × s
+   *   p × s + t (r × s) = q × s + u (s × s)
+   *   p × s + t (r × s) = q × s
+   *   t (r × s) = q × s - p × s
+   *   t (r × s) = (q - p) × s
+   *   t = ((q - p) × s) / (r × s)
+   *
+   * Using the same method, for u we get:
+   *
+   *   u = ((p - q) × r) / (s × r)
+   */
+
+  rxs = meta_vector2_cross_product (r, s);
+  sxr = meta_vector2_cross_product (s, r);
+
+  /* If r × s = 0 then the lines are either parallel or collinear. */
+  if (fabs (rxs) < DBL_MIN)
+    return FALSE;
+
+  t = meta_vector2_cross_product (meta_vector2_subtract (q, p), s) / rxs;
+  u = meta_vector2_cross_product (meta_vector2_subtract (p, q), r) / sxr;
+
+  /* The lines only intersect if 0 ≤ t ≤ 1 and 0 ≤ u ≤ 1. */
+  if (t < 0.0 || t > 1.0 || u < 0.0 || u > 1.0)
+    return FALSE;
+
+  *intersection = meta_vector2_add (p, meta_vector2_multiply_constant (t, r));
+
+  return TRUE;
+}
+
+gboolean
+meta_border_is_horizontal (MetaBorder *border)
+{
+  return border->line.a.y == border->line.b.y;
+}
+
+gboolean
+meta_border_is_blocking_directions (MetaBorder               *border,
+                                    MetaBorderMotionDirection directions)
+{
+  if (meta_border_is_horizontal (border))
+    {
+      if ((directions & (META_BORDER_MOTION_DIRECTION_POSITIVE_Y |
+                         META_BORDER_MOTION_DIRECTION_NEGATIVE_Y)) == 0)
+        return FALSE;
+    }
+  else
+    {
+      if ((directions & (META_BORDER_MOTION_DIRECTION_POSITIVE_X |
+                         META_BORDER_MOTION_DIRECTION_NEGATIVE_X)) == 0)
+        return FALSE;
+    }
+
+  return (~border->blocking_directions & directions) != directions;
+}
+
+unsigned int
+meta_border_get_allows_directions (MetaBorder *border)
+{
+  return ~border->blocking_directions &
+    (META_BORDER_MOTION_DIRECTION_POSITIVE_X |
+     META_BORDER_MOTION_DIRECTION_POSITIVE_Y |
+     META_BORDER_MOTION_DIRECTION_NEGATIVE_X |
+     META_BORDER_MOTION_DIRECTION_NEGATIVE_Y);
+}
+
+void
+meta_border_set_allows_directions (MetaBorder *border, unsigned int directions)
+{
+  border->blocking_directions =
+    ~directions & (META_BORDER_MOTION_DIRECTION_POSITIVE_X |
+                   META_BORDER_MOTION_DIRECTION_POSITIVE_Y |
+                   META_BORDER_MOTION_DIRECTION_NEGATIVE_X |
+                   META_BORDER_MOTION_DIRECTION_NEGATIVE_Y);
+}
diff --git a/src/core/meta-border.h b/src/core/meta-border.h
new file mode 100644
index 000000000..dd76db5c9
--- /dev/null
+++ b/src/core/meta-border.h
@@ -0,0 +1,84 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/*
+ * Copyright (C) 2015 Red Hat
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ * Written by:
+ *     Jonas Ådahl <jadahl@gmail.com>
+ */
+
+#ifndef META_BORDER_H
+#define META_BORDER_H
+
+#include <glib.h>
+
+typedef enum
+{
+  META_BORDER_MOTION_DIRECTION_POSITIVE_X = 1 << 0,
+  META_BORDER_MOTION_DIRECTION_POSITIVE_Y = 1 << 1,
+  META_BORDER_MOTION_DIRECTION_NEGATIVE_X = 1 << 2,
+  META_BORDER_MOTION_DIRECTION_NEGATIVE_Y = 1 << 3,
+} MetaBorderMotionDirection;
+
+typedef struct _MetaVector2
+{
+  float x;
+  float y;
+} MetaVector2;
+
+typedef struct _MetaLine2
+{
+  MetaVector2 a;
+  MetaVector2 b;
+} MetaLine2;
+
+typedef struct _MetaBorder
+{
+  MetaLine2 line;
+  MetaBorderMotionDirection blocking_directions;
+} MetaBorder;
+
+static inline MetaVector2
+meta_vector2_subtract (const MetaVector2 a,
+                       const MetaVector2 b)
+{
+  return (MetaVector2) {
+    .x = a.x - b.x,
+    .y = a.y - b.y,
+  };
+}
+
+gboolean
+meta_line2_intersects_with (const MetaLine2 *line1,
+                            const MetaLine2 *line2,
+                            MetaVector2     *intersection);
+
+gboolean
+meta_border_is_horizontal (MetaBorder *border);
+
+gboolean
+meta_border_is_blocking_directions (MetaBorder               *border,
+                                    MetaBorderMotionDirection directions);
+
+unsigned int
+meta_border_get_allows_directions (MetaBorder *border);
+
+void
+meta_border_set_allows_directions (MetaBorder *border, unsigned int directions);
+
+#endif /* META_BORDER_H */