stroke: Do not initialise the pen if will not use it

The pen is only used for ensuring that we generate consist vertices
around a fan used for end-capping or line-joining when set to ROUND.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 19 insertions, 11 deletions

diff --git a/src/cairo-path-stroke-polygon.c b/src/cairo-path-stroke-polygon.c
index 5d121fac8..7978af027 100644
--- a/src/cairo-path-stroke-polygon.c
+++ b/src/cairo-path-stroke-polygon.c
@@ -163,6 +163,8 @@ add_fan (struct stroker *stroker,
 {
     int start, stop, step, i, npoints;
 
+    assert (stroker->pen.num_vertices);
+
     if (clockwise) {
 	step  = 1;
 
@@ -1357,16 +1359,21 @@ _cairo_path_fixed_stroke_to_polygon (const cairo_path_fixed_t	*path,
     stroker.ctm_det_positive =
 	_cairo_matrix_compute_determinant (ctm) >= 0.0;
 
-    status = _cairo_pen_init (&stroker.pen,
-		              style->line_width / 2.0,
-			      tolerance, ctm);
-    if (unlikely (status))
-	return status;
-
-    /* If the line width is so small that the pen is reduced to a
-       single point, then we have nothing to do. */
-    if (stroker.pen.num_vertices <= 1)
-	return CAIRO_STATUS_SUCCESS;
+    stroker.pen.num_vertices = 0;
+    if (path->has_curve_to ||
+	style->line_join == CAIRO_LINE_JOIN_ROUND ||
+	style->line_cap == CAIRO_LINE_CAP_ROUND) {
+	status = _cairo_pen_init (&stroker.pen,
+				  style->line_width / 2.0,
+				  tolerance, ctm);
+	if (unlikely (status))
+	    return status;
+
+	/* If the line width is so small that the pen is reduced to a
+	   single point, then we have nothing to do. */
+	if (stroker.pen.num_vertices <= 1)
+	    return CAIRO_STATUS_SUCCESS;
+    }
 
     stroker.has_current_face = FALSE;
     stroker.has_first_face = FALSE;
@@ -1396,7 +1403,8 @@ _cairo_path_fixed_stroke_to_polygon (const cairo_path_fixed_t	*path,
 
     _cairo_contour_fini (&stroker.cw.contour);
     _cairo_contour_fini (&stroker.ccw.contour);
-    _cairo_pen_fini (&stroker.pen);
+    if (stroker.pen.num_vertices)
+	_cairo_pen_fini (&stroker.pen);
 
 #if DEBUG
     {