[test] Add degenerate-curve-to

Andrea Canciani (ranma42) pointed out a second bug in the curve-to as
line-to optimisation, that is a curve starting and finishing on the same
point is not necessarily degenerate. This test case exercises 5 different
curves that start and end on the same point.

5 files changed, 106 insertions, 0 deletions

diff --git a/test/Makefile.am b/test/Makefile.am
index b7942834..7e42789f 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -291,6 +291,8 @@ REFERENCE_IMAGES = \
 	degenerate-arc.ps3.ref.png \
 	degenerate-arc.ref.png \
 	degenerate-arc.xlib.ref.png \
+	degenerate-curve-to.ref.png \
+	degenerate-curve-to.ps.xfail.png \
 	degenerate-dash.ps.xfail.png \
 	degenerate-dash.ref.png \
 	degenerate-path.ps.argb32.xfail.png \
diff --git a/test/Makefile.sources b/test/Makefile.sources
index b468bf26..3acc2559 100644
--- a/test/Makefile.sources
+++ b/test/Makefile.sources
@@ -44,6 +44,7 @@ test_sources = \
 	dash-state.c					\
 	dash-zero-length.c				\
 	degenerate-arc.c				\
+	degenerate-curve-to.c				\
 	degenerate-dash.c				\
 	degenerate-path.c				\
 	degenerate-pen.c				\
diff --git a/test/degenerate-curve-to.c b/test/degenerate-curve-to.c
new file mode 100644
index 00000000..a081a3bb
--- /dev/null
+++ b/test/degenerate-curve-to.c
@@ -0,0 +1,103 @@
+/*
+ * Copyright © 2005 Red Hat, Inc.
+ * Copyright © 2009 Chris Wilson
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of
+ * Red Hat, Inc. not be used in advertising or publicity pertaining to
+ * distribution of the software without specific, written prior
+ * permission. Red Hat, Inc. makes no representations about the
+ * suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * RED HAT, INC. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL RED HAT, INC. BE LIABLE FOR ANY SPECIAL,
+ * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+ * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Author: Carl D. Worth <cworth@cworth.org>
+ *         Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+#include "cairo-test.h"
+
+#define SIZE 30
+
+/* Another attempt at avoiding unnecessary splines was made, where
+ * a curve-to that ended on the same point as it began were discarded.
+ */
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_set_source_rgb (cr, 1.0, 1.0, 1.0); /* white */
+    cairo_paint (cr);
+
+    cairo_set_line_width (cr, 1.0);
+    cairo_set_line_cap (cr, CAIRO_LINE_CAP_BUTT);
+    cairo_set_line_join (cr, CAIRO_LINE_JOIN_BEVEL);
+    cairo_set_source_rgb (cr, 0.0, 0.0, 0.0); /* black */
+
+    /* entirely degenerate */
+    cairo_move_to (cr,
+		    2.5, 2.5);
+    cairo_curve_to (cr,
+		    2.5, 2.5,
+		    2.5, 2.5,
+		    2.5, 2.5);
+    cairo_stroke (cr);
+
+    /* horizontal */
+    cairo_move_to (cr,
+		     5.5, 2.5);
+    cairo_curve_to (cr,
+		    22.0, 2.5,
+		    -0.5, 2.5,
+		     5.5, 2.5);
+    cairo_stroke (cr);
+
+    /* vertical */
+    cairo_move_to (cr,
+		    7.5,  0.0);
+    cairo_curve_to (cr,
+		    7.5, 11.0,
+		    7.5,  0.0,
+		    7.5,  0.0);
+    cairo_stroke (cr);
+
+    cairo_translate (cr, 15, 0);
+
+    /* horizontal/vertical */
+    cairo_move_to (cr,
+		     5.5,  0.5);
+    cairo_curve_to (cr,
+		    -0.5,  0.5,
+		     5.5, 10.5,
+		     5.5,  0.5);
+
+    cairo_translate (cr, 10, 0);
+
+    /* vertical/horizontal */
+    cairo_move_to (cr,
+		     5.5,  0.0);
+    cairo_curve_to (cr,
+		     5.5, 11.0,
+		    10.5,  0.0,
+		     5.5,  0.0);
+    cairo_stroke (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (degenerate_curve_to,
+	    "Test optimization treating degenerate curve_to as line_to",
+	    "path", /* keywords */
+	    NULL, /* requirements */
+	    40,
+	    5,
+	    NULL, draw)
diff --git a/test/degenerate-curve-to.ps.xfail.png b/test/degenerate-curve-to.ps.xfail.png
new file mode 100644
index 00000000..a8e221e7
--- /dev/null
+++ b/test/degenerate-curve-to.ps.xfail.png
diff --git a/test/degenerate-curve-to.ref.png b/test/degenerate-curve-to.ref.png
new file mode 100644
index 00000000..353f08d3
--- /dev/null
+++ b/test/degenerate-curve-to.ref.png