Palette tool laser prototype.

ash/common/system/chromeos/palette/tools/laser_pointer_points.cc

Index: ash/common/system/chromeos/palette/tools/laser_pointer_points.cc
diff --git a/ash/common/system/chromeos/palette/tools/laser_pointer_points.cc b/ash/common/system/chromeos/palette/tools/laser_pointer_points.cc
new file mode 100644
index 0000000000000000000000000000000000000000..29d15dd2f5911d4d46f76fe3cdda4fe9eccac210
--- /dev/null
+++ b/ash/common/system/chromeos/palette/tools/laser_pointer_points.cc
@@ -0,0 +1,83 @@
+// Copyright 2016 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 "ash/common/system/chromeos/palette/tools/laser_pointer_points.h"
+
+#include <limits>
+
+namespace ash {
+
+LaserPointerPoints::LaserPointerPoints(base::TimeDelta life_duration)
+    : life_duration_(life_duration) {}
+
+LaserPointerPoints::~LaserPointerPoints() {}
+
+void LaserPointerPoints::AddPoint(const gfx::Point& point) {
+  LaserPoint new_point;
+  new_point.location = point;
+  new_point.creation_time = base::Time::Now();
+  points_.push_back(new_point);
+  ClearOldPoints();
+}
+
+void LaserPointerPoints::Clear() {
+  points_.clear();
+}
+
+gfx::Rect LaserPointerPoints::GetBoundingBox() {
+  gfx::Point min_point(INT_MAX, INT_MAX);

[jdufault, 2016/08/19 01:02:08]

std::numeric_limits<int64_t>::max() (or whatever the right generic type is)

[sammiequon, 2016/08/19 20:28:46]

Done.

+  gfx::Point max_point(INT_MIN, INT_MIN);
+  for (auto it = points_.begin(); it != points_.end(); it++) {

[jdufault, 2016/08/19 01:02:08]

for (const LaserPoint& point : points_)

[sammiequon, 2016/08/19 20:28:46]

Done.

+    min_point = gfx::Point(std::min(it->location.x(), min_point.x()),
+                           std::min(it->location.y(), min_point.y()));
+    max_point = gfx::Point(std::max(it->location.x(), max_point.x()),
+                           std::max(it->location.y(), max_point.y()));
+  }
+  return gfx::BoundingRect(min_point, max_point);
+}
+
+LaserPointerPoints::LaserPoint LaserPointerPoints::GetOldest() const {
+  DCHECK(!IsEmpty());
+  return points_.front();
+}
+
+LaserPointerPoints::LaserPoint LaserPointerPoints::GetMostRecent() const {
+  DCHECK(!IsEmpty());
+  return points_.back();
+}
+
+bool LaserPointerPoints::IsEmpty() const {
+  return points_.empty();
+}
+
+int LaserPointerPoints::GetNumberOfPoints() const {
+  return points_.size();
+}
+
+std::deque<LaserPointerPoints::LaserPoint>::const_iterator
+LaserPointerPoints::PointsStart() const {
+  return points_.cbegin();
+}
+
+std::deque<LaserPointerPoints::LaserPoint>::const_iterator
+LaserPointerPoints::PointsEnd() const {
+  return points_.cend();
+}
+
+void LaserPointerPoints::ClearOldPoints() {

[jdufault, 2016/08/19 01:02:08]

This only gets called after a point has been added so instead of the if
(!points_.empty()) add a DCHECK(!points_.empty())

[sammiequon, 2016/08/19 20:28:46]

Done.

+  if (!points_.empty()) {
+    LaserPoint newest = points_.back();
+    auto it = points_.begin();

[jdufault, 2016/08/19 01:02:08]

What about

  auto it = std::find_if(points_.begin(), points_.end(),
                [](p) {
                  return newest.creation_time - p.creation_time <
                         life_duration;
                });
  points_.erase(points_.begin(), it);

If you don't like that approach, then please cleanup the for loop so that there
is no empty if block - or maybe convert it to a while (condition) { ++it }
block?

[sammiequon, 2016/08/19 20:28:46]

Done.

+    for (; it != points_.end(); ++it) {
+      if (newest.creation_time - it->creation_time > life_duration_) {
+      } else {
+        // Since the points are sorted by time we can end the loop early once
+        // the condition fails.
+        break;
+      }
+    }
+    points_.erase(points_.begin(), it);
+  }
+}
+}  // namespace ash