1 files changed, 99 insertions, 0 deletions
diff --git a/gfx/2d/unittest/TestCairo.cpp b/gfx/2d/unittest/TestCairo.cpp
new file mode 100644
index 0000000000..4ed7ad4d4a
--- /dev/null
+++ b/gfx/2d/unittest/TestCairo.cpp
@@ -0,0 +1,99 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+#include "cairo.h"
+
+#include "gtest/gtest.h"
+
+namespace mozilla {
+namespace layers {
+
+static void TryCircle(double centerX, double centerY, double radius) {
+  printf("TestCairo:TryArcs centerY %f, radius %f\n", centerY, radius);
+
+  cairo_surface_t* surf =
+      cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 8, 21);
+  ASSERT_TRUE(surf != nullptr);
+
+  cairo_t* cairo = cairo_create(surf);
+  ASSERT_TRUE(cairo != nullptr);
+
+  cairo_set_antialias(cairo, CAIRO_ANTIALIAS_NONE);
+  cairo_arc(cairo, 0.0, centerY, radius, 0.0, 6.2831853071795862);
+  cairo_fill_preserve(cairo);
+
+  cairo_surface_destroy(surf);
+  cairo_destroy(cairo);
+}
+
+TEST(Cairo, Simple)
+{
+  TryCircle(0.0, 0.0, 14.0);
+  TryCircle(0.0, 1.0, 22.4);
+  TryCircle(1.0, 0.0, 1422.4);
+  TryCircle(1.0, 1.0, 3422.4);
+  TryCircle(-10.0, 1.0, -2);
+}
+
+TEST(Cairo, Bug825721)
+{
+  // OK:
+  TryCircle(0.0, 0.0, 8761126469220696064.0);
+  TryCircle(0.0, 1.0, 8761126469220696064.0);
+
+  // OK:
+  TryCircle(1.0, 0.0, 5761126469220696064.0);
+
+  // This was the crash in 825721.  Note that centerY has to be non-zero,
+  // and radius has to be not only large, but in particular range.
+  // 825721 has a band-aid fix, where the crash is inevitable, but does
+  // not fix the cause.  The same code crashes in cairo standalone.
+  TryCircle(0.0, 1.0, 5761126469220696064.0);
+}
+
+TEST(Cairo, Bug1063486)
+{
+  double x1, y1, x2, y2;
+  const double epsilon = .01;
+
+  cairo_surface_t* surf = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 1, 1);
+  ASSERT_TRUE(surf != nullptr);
+
+  cairo_t* cairo = cairo_create(surf);
+  ASSERT_TRUE(cairo != nullptr);
+
+  printf("Path 1\n");
+  cairo_move_to(cairo, -20, -10);
+  cairo_line_to(cairo, 20, -10);
+  cairo_line_to(cairo, 20, 10);
+  cairo_curve_to(cairo, 10, 10, -10, 10, -20, 10);
+  cairo_curve_to(cairo, -30, 10, -30, -10, -20, -10);
+
+  cairo_path_extents(cairo, &x1, &y1, &x2, &y2);
+
+  ASSERT_LT(std::abs(-27.5 - x1), epsilon);  // the failing coordinate
+  ASSERT_LT(std::abs(-10 - y1), epsilon);
+  ASSERT_LT(std::abs(20 - x2), epsilon);
+  ASSERT_LT(std::abs(10 - y2), epsilon);
+
+  printf("Path 2\n");
+  cairo_new_path(cairo);
+  cairo_move_to(cairo, 10, 30);
+  cairo_line_to(cairo, 90, 30);
+  cairo_curve_to(cairo, 30, 30, 30, 30, 10, 30);
+  cairo_curve_to(cairo, 0, 30, 0, 0, 30, 5);
+
+  cairo_path_extents(cairo, &x1, &y1, &x2, &y2);
+
+  ASSERT_LT(std::abs(4.019531 - x1), epsilon);  // the failing coordinate
+  ASSERT_LT(std::abs(4.437500 - y1), epsilon);
+  ASSERT_LT(std::abs(90. - x2), epsilon);
+  ASSERT_LT(std::abs(30. - y2), epsilon);
+
+  cairo_surface_destroy(surf);
+  cairo_destroy(cairo);
+}
+
+}  // namespace layers
+}  // namespace mozilla