diff --git a/libweston/vertex-clipping.c b/libweston/vertex-clipping.c
index 1ef840b9..319b35ee 100644
--- a/libweston/vertex-clipping.c
+++ b/libweston/vertex-clipping.c
@@ -291,13 +291,21 @@ clip_polygon_bottom(struct clip_context *ctx, const struct polygon8 *src,
 	return ctx->vertices - dst;
 }
 
-/* General purpose polygon clipping algorithm based on Sutherland-Hodgman:
+/* General purpose clipping function. Compute the boundary vertices of the
+ * intersection of a 'polygon' and a clipping 'box'. 'polygon' points to an
+ * array of 4 vertices defining a convex polygon of any winding order. 'box'
+ * points to an array of 2 vertices where the values of the 1st vertex are less
+ * than or equal to the values of the 2nd vertex. Up to 8 resulting vertices,
+ * using 'polygon' winding order, are written to 'vertices'. The return value is
+ * the number of vertices created.
+ *
+ * Based on Sutherland-Hodgman algorithm:
  * https://www.codeguru.com/cplusplus/polygon-clipping/
  */
-WESTON_EXPORT_FOR_TESTS int
-clipper_clip(const struct clipper_vertex polygon[4],
-	     const struct clipper_vertex box[2],
-	     struct clipper_vertex *restrict vertices)
+static int
+clip(const struct clipper_vertex polygon[4],
+     const struct clipper_vertex box[2],
+     struct clipper_vertex *restrict vertices)
 {
 	struct clip_context ctx;
 	struct polygon8 p, tmp;
@@ -386,7 +394,7 @@ clipper_quad_clip(struct clipper_quad *quad,
 
 	/* Then use our general purpose clipping algorithm:
 	 */
-	n = clipper_clip(quad->polygon, box, vertices);
+	n = clip(quad->polygon, box, vertices);
 
 	if (n < 3)
 		return 0;
diff --git a/libweston/vertex-clipping.h b/libweston/vertex-clipping.h
index 1308fecc..a88ff5c8 100644
--- a/libweston/vertex-clipping.h
+++ b/libweston/vertex-clipping.h
@@ -39,20 +39,6 @@ struct clipper_quad {
 	bool axis_aligned;
 };
 
-/*
- * General purpose clipping function. Compute the boundary vertices of the
- * intersection of a 'polygon' and a clipping 'box'. 'polygon' points to an
- * array of 4 vertices defining a convex polygon of any winding order. 'box'
- * points to an array of 2 vertices where the values of the 1st vertex are less
- * than or equal to the values of the 2nd vertex. Up to 8 resulting vertices,
- * using 'polygon' winding order, are written to 'vertices'. The return value is
- * the number of vertices created.
- */
-int
-clipper_clip(const struct clipper_vertex polygon[4],
-	     const struct clipper_vertex box[2],
-	     struct clipper_vertex *restrict vertices);
-
 /*
  * Initialize a 'quad' clipping context. 'polygon' points to an array of 4
  * vertices defining a convex quadrilateral of any winding order. Call
diff --git a/tests/vertex-clip-test.c b/tests/vertex-clip-test.c
index bea3be30..8983d2eb 100644
--- a/tests/vertex-clip-test.c
+++ b/tests/vertex-clip-test.c
@@ -77,94 +77,6 @@ assert_vertices(const struct clipper_vertex *clipped, int clipped_n,
 	}
 }
 
-/* clipper_clip() tests: */
-
-static const struct vertex_clip_test_data clip_expected_data[] = {
-	/* Quad inside box. */
-	{
-		.box       = BOX (50.0f, 50.0f, 100.0f, 100.0f),
-		.polygon   = QUAD(51.0f, 51.0f,  99.0f,  99.0f),
-		.clipped   = QUAD(51.0f, 51.0f,  99.0f,  99.0f),
-		.clipped_n = 4,
-	},
-
-	/* Quad bottom edge outside of box. */
-	{
-		.box       = BOX (50.0f, 50.0f, 100.0f, 100.0f),
-		.polygon   = QUAD(51.0f, 51.0f,  99.0f, 101.0f),
-		.clipped   = QUAD(51.0f, 51.0f,  99.0f, 100.0f),
-		.clipped_n = 4,
-	},
-
-	/* Quad top edge outside of box. */
-	{
-		.box       = BOX (50.0f, 50.0f, 100.0f, 100.0f),
-		.polygon   = QUAD(51.0f, 49.0f,  99.0f,  99.0f),
-		.clipped   = QUAD(51.0f, 50.0f,  99.0f,  99.0f),
-		.clipped_n = 4,
-	},
-
-	/* Quad left edge outside of box. */
-	{
-		.box       = BOX (50.0f, 50.0f, 100.0f, 100.0f),
-		.polygon   = QUAD(49.0f, 51.0f,  99.0f,  99.0f),
-		.clipped   = QUAD(50.0f, 51.0f,  99.0f,  99.0f),
-		.clipped_n = 4,
-	},
-
-	/* Quad right edge outside of box. */
-	{
-		.box       = BOX (50.0f, 50.0f, 100.0f, 100.0f),
-		.polygon   = QUAD(51.0f, 51.0f, 101.0f,  99.0f),
-		.clipped   = QUAD(51.0f, 51.0f, 100.0f,  99.0f),
-		.clipped_n = 4,
-	},
-
-	/* Rotated quad with edges adjacent to box corners. */
-	{
-		.box       = BOX(50.0f, 50.0f, 100.0f, 100.0f),
-		.polygon   = {{ 25.0f, 75.0f}, {75.0f,  25.0f},
-			      {125.0f, 75.0f}, {75.0f, 125.0f}},
-		.clipped   = QUAD(50.0f, 50.0f, 100.0f, 100.0f),
-		.clipped_n = 4,
-	},
-
-	/* Rotated quad with edges cutting out box corners. */
-	{
-		.box       = BOX(50.0f, 50.0f, 100.0f, 100.0f),
-		.polygon   = {{ 37.5f,  75.0f}, { 75.0f,  37.5f},
-			      {112.5f,  75.0f}, { 75.0f, 112.5f}},
-		.clipped   = {{ 62.5f,  50.0f}, { 87.5f,  50.0f},
-			      {100.0f,  62.5f}, {100.0f,  87.5f},
-			      { 87.5f, 100.0f}, { 62.5f, 100.0f},
-			      { 50.0f,  87.5f}, { 50.0f,  62.5f}},
-		.clipped_n = 8,
-	},
-
-	/* Same as above using counter-clockwise winding. */
-	{
-		.box       = BOX(50.0f, 50.0f, 100.0f, 100.0f),
-		.polygon   = {{ 37.5f,  75.0f}, { 75.0f, 112.5f},
-			      {112.5f,  75.0f}, { 75.0f,  37.5f}},
-		.clipped   = {{ 62.5f,  50.0f}, { 50.0f,  62.5f},
-			      { 50.0f,  87.5f}, { 62.5f, 100.0f},
-			      { 87.5f, 100.0f}, {100.0f,  87.5f},
-			      {100.0f,  62.5f}, { 87.5f,  50.0f}},
-		.clipped_n = 8,
-	},
-};
-
-TEST_P(clip_expected, clip_expected_data)
-{
-	struct vertex_clip_test_data *tdata = data;
-	struct clipper_vertex clipped[8];
-	int clipped_n;
-
-	clipped_n = clipper_clip(tdata->polygon, tdata->box, clipped);
-
-	assert_vertices(clipped, clipped_n, tdata->clipped, tdata->clipped_n);
-}
-
 /* clipper_quad_clip() tests: */
 
 static const struct vertex_clip_test_data quad_clip_expected_data[] = {
@@ -661,6 +573,89 @@ static const struct vertex_clip_test_data quad_clip_expected_data[] = {
 		.clipped_n = 4,
 	},
 
+	/* General purpose clipper tests: */
+
+	/* Quad inside box. */
+	{
+		.aligned   = false,
+		.box       = BOX (50.0f, 50.0f, 100.0f, 100.0f),
+		.polygon   = QUAD(51.0f, 51.0f,  99.0f,  99.0f),
+		.clipped   = QUAD(51.0f, 51.0f,  99.0f,  99.0f),
+		.clipped_n = 4,
+	},
+
+	/* Quad bottom edge outside of box. */
+	{
+		.aligned   = false,
+		.box       = BOX (50.0f, 50.0f, 100.0f, 100.0f),
+		.polygon   = QUAD(51.0f, 51.0f,  99.0f, 101.0f),
+		.clipped   = QUAD(51.0f, 51.0f,  99.0f, 100.0f),
+		.clipped_n = 4,
+	},
+
+	/* Quad top edge outside of box. */
+	{
+		.aligned   = false,
+		.box       = BOX (50.0f, 50.0f, 100.0f, 100.0f),
+		.polygon   = QUAD(51.0f, 49.0f,  99.0f,  99.0f),
+		.clipped   = QUAD(51.0f, 50.0f,  99.0f,  99.0f),
+		.clipped_n = 4,
+	},
+
+	/* Quad left edge outside of box. */
+	{
+		.aligned   = false,
+		.box       = BOX (50.0f, 50.0f, 100.0f, 100.0f),
+		.polygon   = QUAD(49.0f, 51.0f,  99.0f,  99.0f),
+		.clipped   = QUAD(50.0f, 51.0f,  99.0f,  99.0f),
+		.clipped_n = 4,
+	},
+
+	/* Quad right edge outside of box. */
+	{
+		.aligned   = false,
+		.box       = BOX (50.0f, 50.0f, 100.0f, 100.0f),
+		.polygon   = QUAD(51.0f, 51.0f, 101.0f,  99.0f),
+		.clipped   = QUAD(51.0f, 51.0f, 100.0f,  99.0f),
+		.clipped_n = 4,
+	},
+
+	/* Rotated quad with edges adjacent to box corners. */
+	{
+		.aligned   = false,
+		.box       = BOX(50.0f, 50.0f, 100.0f, 100.0f),
+		.polygon   = {{ 25.0f, 75.0f}, {75.0f,  25.0f},
+			      {125.0f, 75.0f}, {75.0f, 125.0f}},
+		.clipped   = QUAD(50.0f, 50.0f, 100.0f, 100.0f),
+		.clipped_n = 4,
+	},
+
+	/* Rotated quad with edges cutting out box corners. */
+	{
+		.aligned   = false,
+		.box       = BOX(50.0f, 50.0f, 100.0f, 100.0f),
+		.polygon   = {{ 37.5f,  75.0f}, { 75.0f,  37.5f},
+			      {112.5f,  75.0f}, { 75.0f, 112.5f}},
+		.clipped   = {{ 62.5f,  50.0f}, { 87.5f,  50.0f},
+			      {100.0f,  62.5f}, {100.0f,  87.5f},
+			      { 87.5f, 100.0f}, { 62.5f, 100.0f},
+			      { 50.0f,  87.5f}, { 50.0f,  62.5f}},
+		.clipped_n = 8,
+	},
+
+	/* Same as above using counter-clockwise winding. */
+	{
+		.aligned   = false,
+		.box       = BOX(50.0f, 50.0f, 100.0f, 100.0f),
+		.polygon   = {{ 37.5f,  75.0f}, { 75.0f, 112.5f},
+			      {112.5f,  75.0f}, { 75.0f,  37.5f}},
+		.clipped   = {{ 62.5f,  50.0f}, { 50.0f,  62.5f},
+			      { 50.0f,  87.5f}, { 62.5f, 100.0f},
+			      { 87.5f, 100.0f}, {100.0f,  87.5f},
+			      {100.0f,  62.5f}, { 87.5f,  50.0f}},
+		.clipped_n = 8,
+	},
+
 	/* Miscellaneous cases: */
 
 	/* Box intersects entire same size aligned quad. */