[test] Add long-dashed-lines to exercise _cairo_box_intersects_line_segment().

Draw a few rectangles whose vertices are outside the bounds of the
surface, but whose segments cross the surface. This exercises the new
dashed stroker optimisation which tries to determine whether the line
segment is visible.

1 files changed, 75 insertions, 0 deletions

diff --git a/test/long-dashed-lines.c b/test/long-dashed-lines.c
new file mode 100644
index 00000000..fce6d796
--- /dev/null
+++ b/test/long-dashed-lines.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright © 2008 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
+ * the author not be used in advertising or publicity pertaining to
+ * distribution of the software without specific, written prior
+ * permission. The author makes no representations about the
+ * suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL THE AUTHOR. 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: Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+#include "cairo-test.h"
+
+static cairo_test_draw_function_t draw;
+
+cairo_test_t test = {
+    "long-dashed-lines",
+    "Exercises _cairo_box_intersects_line_segment()",
+    60, 60,
+    draw
+};
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    int i;
+    double dashes[] = {6, 3};
+
+    cairo_set_source_rgb (cr, 1, 1, 1);
+    cairo_paint (cr);
+
+    /* partially visible rectangle... */
+    cairo_rectangle (cr, -0.5, -0.5, 61, 61);
+
+    /* rectangles with intersecting segments... */
+    cairo_save (cr);
+    cairo_translate (cr, 30, 30);
+    for (i = 0; i < 4; i++) {
+	cairo_rotate (cr, M_PI / 4);
+	cairo_rectangle (cr, -37, -15, 74, 30);
+    }
+    cairo_restore (cr);
+
+    /* completely invisible rectangle */
+    cairo_rectangle (cr, -5, -5, 70, 70);
+
+    cairo_set_dash (cr, dashes, sizeof (dashes) / sizeof (dashes[0]), 0.);
+    cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
+    cairo_set_line_join (cr, CAIRO_LINE_JOIN_BEVEL);
+    cairo_set_source_rgb (cr, 0, 0, 0);
+    cairo_stroke (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+int
+main (void)
+{
+    return cairo_test (&test);
+}
+