test: Add a couple of variants to line-width-overlap

The bug may be in only the fast-path, but future bugs may lie elsewhere.

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

test/Makefile.refs

@@ -690,6 +690,10 @@ REFERENCE_IMAGES = \
 	leaky-polygon.image16.ref.png \
 	leaky-polygon.ps.ref.png \
 	leaky-polygon.ref.png \
+	line-width-overlap-flipped.ref.png \
+	line-width-overlap-flopped.ref.png \
+	line-width-overlap-offset.ref.png \
+	line-width-overlap-rotated.ref.png \
 	line-width-overlap.ref.png \
 	line-width-scale.image16.ref.png \
 	line-width-scale.ps2.ref.png \

test/line-width-overlap.c

@@ -54,9 +54,9 @@ draw (cairo_t *cr, int width, int height)
 
     /* rectangle that is smaller than the line width in center of image */
     cairo_rectangle (cr,
-                     (SIZE - RECT_SIZE) / 2, 
                      (SIZE - RECT_SIZE) / 2,
-                     RECT_SIZE, 
+                     (SIZE - RECT_SIZE) / 2,
+                     RECT_SIZE,
                      RECT_SIZE);
 
     cairo_stroke (cr);
@@ -64,9 +64,86 @@ draw (cairo_t *cr, int width, int height)
     return CAIRO_TEST_SUCCESS;
 }
 
+/* and again slightly offset to trigger another path */
+static cairo_test_status_t
+draw_offset (cairo_t *cr, int width, int height)
+{
+    cairo_translate (cr, .5, .5);
+    return draw (cr, width, height);
+}
+
+static cairo_test_status_t
+draw_rotated (cairo_t *cr, int width, int height)
+{
+    cairo_translate (cr, SIZE/2, SIZE/2);
+    cairo_rotate (cr, M_PI/4);
+    cairo_translate (cr, -SIZE/2, -SIZE/2);
+
+    return draw (cr, width, height);
+}
+
+static cairo_test_status_t
+draw_flipped (cairo_t *cr, int width, int height)
+{
+    cairo_translate (cr, SIZE/2, SIZE/2);
+    cairo_scale (cr, -1, 1);
+    cairo_translate (cr, -SIZE/2, -SIZE/2);
+
+    return draw (cr, width, height);
+}
+
+static cairo_test_status_t
+draw_flopped (cairo_t *cr, int width, int height)
+{
+    cairo_translate (cr, SIZE/2, SIZE/2);
+    cairo_scale (cr, 1, -1);
+    cairo_translate (cr, -SIZE/2, -SIZE/2);
+
+    return draw (cr, width, height);
+}
+
+static cairo_test_status_t
+draw_dashed (cairo_t *cr, int width, int height)
+{
+    const double dashes[] = { 4 };
+    cairo_set_dash (cr, dashes, 1, 0);
+    cairo_set_line_cap (cr, CAIRO_LINE_CAP_BUTT);
+    return draw (cr, width, height);
+}
+
 CAIRO_TEST (line_width_overlap,
 	    "Test overlapping lines due to large line width",
 	    "stroke", /* keywords */
 	    NULL, /* requirements */
 	    SIZE, SIZE,
 	    NULL, draw)
+CAIRO_TEST (line_width_overlap_offset,
+	    "Test overlapping lines due to large line width",
+	    "stroke", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw_offset)
+CAIRO_TEST (line_width_overlap_rotated,
+	    "Test overlapping lines due to large line width",
+	    "stroke", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw_rotated)
+CAIRO_TEST (line_width_overlap_flipped,
+	    "Test overlapping lines due to large line width",
+	    "stroke", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw_flipped)
+CAIRO_TEST (line_width_overlap_flopped,
+	    "Test overlapping lines due to large line width",
+	    "stroke", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw_flopped)
+CAIRO_TEST (line_width_overlap_dashed,
+	    "Test overlapping lines due to large line width",
+	    "stroke", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw_dashed)