Add support for rect-based event targeting in views

ui/views/rect_based_targeting_utils.cc

Index: ui/views/rect_based_targeting_utils.cc
diff --git a/ui/views/rect_based_targeting_utils.cc b/ui/views/rect_based_targeting_utils.cc
new file mode 100644
index 0000000000000000000000000000000000000000..eff91f2e0080de072e86ca12f98488a47d3cbbb9
--- /dev/null
+++ b/ui/views/rect_based_targeting_utils.cc
@@ -0,0 +1,54 @@
+// Copyright (c) 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"
+
+namespace views {
+
+namespace {
+
+// The positive distance from |pos| to the nearest endpoint of the interval
+// [start, end] is returned if |pos| lies within the interval, otherwise
+// 0 is returned.
+int DistanceToInterval(int pos, int start, int end) {
+  if (pos < start)
+    return start - pos;
+  if (pos > end)
+    return pos - end;
+  return 0;
+}
+
+}  // namespace
+
+bool UsePointBasedTargeting(const gfx::Rect& rect) {
+  return rect.width() == 1 && rect.height() == 1;
+}
+
+float PercentCoveredBy(const gfx::Rect& rect_1, const gfx::Rect& rect_2) {
+  gfx::Rect intersection(rect_1);
+  intersection.Intersect(rect_2);
+  int intersection_area = intersection.size().GetArea();
+  int rect_1_area = rect_1.size().GetArea();
+  return rect_1_area ? (float)intersection_area / (float)rect_1_area : 0;

[sky, 2013/10/08 20:01:12]

use c++ casts, eg static_cast<float> ...

[tdanderson, 2013/10/09 21:42:06]

Done.

+}
+
+int DistanceSquaredFromCenterLineToPoint(const gfx::Point& point,
+                                         const gfx::Rect& rect) {
+  gfx::Point center_point = rect.CenterPoint();
+  int dx = center_point.x() - point.x();
+  int dy = center_point.y() - point.y();
+
+  if (rect.width() > rect.height()) {
+    dx = DistanceToInterval(point.x(),
+                            rect.x() + (rect.height() / 2),
+                            rect.right() - (rect.height() / 2));
+  } else {
+    dy = DistanceToInterval(point.y(),
+                            rect.y() + (rect.width() / 2),
+                            rect.bottom() - (rect.width() / 2));
+  }
+  return (dx * dx) + (dy * dy);
+}
+
+}  // namespace views