Add utility functions needed for rect-based event targeting

Add utility functions needed for rect-based event targeting
(computing the percentage overlap of two rectangles and
computing the distance between a point and the center
line of a rect).

BUG=306178

Review URL: https://codereview.chromium.org/26900004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228916 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 77 insertions, 0 deletions

diff --git a/ui/views/rect_based_targeting_utils_unittest.cc b/ui/views/rect_based_targeting_utils_unittest.cc
new file mode 100644
index 0000000..61e63e5
--- /dev/null
+++ b/ui/views/rect_based_targeting_utils_unittest.cc
@@ -0,0 +1,77 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/views/rect_based_targeting_utils.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gfx/rect.h"
+
+namespace views {
+
+TEST(RectBasedTargetingUtils, UsePointBasedTargeting) {
+  gfx::Rect rect_1(gfx::Point(-22, 30), gfx::Size(1, 1));
+  gfx::Rect rect_2(gfx::Point(0, 0), gfx::Size(34, 55));
+  gfx::Rect rect_3(gfx::Point(12, 12), gfx::Size(1, 0));
+  gfx::Rect rect_4(gfx::Point(12, 120), gfx::Size(0, 0));
+
+  EXPECT_TRUE(UsePointBasedTargeting(rect_1));
+  EXPECT_FALSE(UsePointBasedTargeting(rect_2));
+  EXPECT_FALSE(UsePointBasedTargeting(rect_3));
+  EXPECT_FALSE(UsePointBasedTargeting(rect_4));
+}
+
+TEST(RectBasedTargetingUtils, PercentCoveredBy) {
+  gfx::Rect rect_1(gfx::Point(0, 0), gfx::Size(300, 120));
+  gfx::Rect rect_2(gfx::Point(20, 10), gfx::Size(30, 90));
+  gfx::Rect rect_3(gfx::Point(160, 50), gfx::Size(150, 85));
+  gfx::Rect rect_4(gfx::Point(20, 55), gfx::Size(0, 15));
+  float error = 0.001f;
+
+  // Passing in identical rectangles.
+  EXPECT_FLOAT_EQ(1.0f, PercentCoveredBy(rect_1, rect_1));
+
+  // |rect_1| completely contains |rect_2|.
+  EXPECT_FLOAT_EQ(0.075f, PercentCoveredBy(rect_1, rect_2));
+  EXPECT_FLOAT_EQ(1.0f, PercentCoveredBy(rect_2, rect_1));
+
+  // |rect_2| and |rect_3| do not intersect.
+  EXPECT_FLOAT_EQ(0.0f, PercentCoveredBy(rect_2, rect_3));
+
+  // |rect_1| and |rect_3| have a nonzero area of intersection which
+  // is smaller than the area of either rectangle.
+  EXPECT_NEAR(0.272f, PercentCoveredBy(rect_1, rect_3), error);
+  EXPECT_NEAR(0.768f, PercentCoveredBy(rect_3, rect_1), error);
+
+  // |rect_4| has no area.
+  EXPECT_FLOAT_EQ(0.0f, PercentCoveredBy(rect_2, rect_4));
+  EXPECT_FLOAT_EQ(0.0f, PercentCoveredBy(rect_4, rect_2));
+}
+
+TEST(RectBasedTargetingUtils, DistanceSquaredFromCenterLineToPoint) {
+  gfx::Rect rect_1(gfx::Point(0, 0), gfx::Size(10, 10));
+  gfx::Rect rect_2(gfx::Point(20, 0), gfx::Size(80, 10));
+  gfx::Rect rect_3(gfx::Point(0, 20), gfx::Size(10, 20));
+
+  gfx::Point point_1(5, 5);
+  gfx::Point point_2(25, 5);
+  gfx::Point point_3(11, 15);
+  gfx::Point point_4(33, 44);
+
+  // The point lies on the center line of the rect.
+  EXPECT_EQ(0, DistanceSquaredFromCenterLineToPoint(point_1, rect_1));
+  EXPECT_EQ(0, DistanceSquaredFromCenterLineToPoint(point_2, rect_2));
+
+  // Distance from a point to the left/top endpoint of a rect's center line.
+  EXPECT_EQ(400, DistanceSquaredFromCenterLineToPoint(point_1, rect_2));
+  EXPECT_EQ(800, DistanceSquaredFromCenterLineToPoint(point_2, rect_3));
+  EXPECT_EQ(296, DistanceSquaredFromCenterLineToPoint(point_3, rect_2));
+
+  // Distance from a point to the center point of a square.
+  EXPECT_EQ(136, DistanceSquaredFromCenterLineToPoint(point_3, rect_1));
+
+  // Distance from a point to the bottom endpoint of a rect's center line.
+  EXPECT_EQ(865, DistanceSquaredFromCenterLineToPoint(point_4, rect_3));
+}
+
+}  // namespace views