cros: Laser pointer fades out on release, do not cover palette.

ash/laser/laser_pointer_points.cc

 // 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/laser/laser_pointer_points.h"
 
 #include <algorithm>
 #include <limits>
 
 namespace ash {
 
 LaserPointerPoints::LaserPointerPoints(base::TimeDelta life_duration)
     : life_duration_(life_duration) {}
 
 LaserPointerPoints::~LaserPointerPoints() {}
 
 void LaserPointerPoints::AddPoint(const gfx::Point& point) {
+  base::Time current_time = base::Time::Now();
+  // If the collection is empty, set the latest time to the time of the first
+  // added point.
+  if (IsEmpty())
+    collection_latest_time_ = current_time;

[jdufault, 2016/09/23 23:59:19]

We should always be updating collection_latest_time_, otherwise the logic in
MoveForwardInTime will use a stale value.

[sammiequon, 2016/09/26 19:30:38]

Done.

   LaserPoint new_point;
   new_point.location = point;
-  new_point.creation_time = base::Time::Now();
+  new_point.creation_time = current_time;
   points_.push_back(new_point);
+  MoveForwardInTime(current_time);
+}
+
+void LaserPointerPoints::MoveForwardInTime() {
+  collection_latest_time_ = base::Time::Now();

[jdufault, 2016/09/23 23:59:19]

Call MoveFowardInTime(base::Time::Now())

[sammiequon, 2016/09/26 19:30:38]

Done.

   ClearOldPoints();
 }
 
+void LaserPointerPoints::MoveForwardInTime(const base::Time& new_latest_time) {

[jdufault, 2016/09/23 23:59:19]

Rename one of the MoveForwardInTime methods so they are not overloaded.

[sammiequon, 2016/09/26 19:30:38]

Done.

+  collection_latest_time_ = new_latest_time;
+  ClearOldPoints();
+}
+
 void LaserPointerPoints::Clear() {
   points_.clear();
 }
 
 gfx::Rect LaserPointerPoints::GetBoundingBox() {
   if (IsEmpty())
     return gfx::Rect();
 
   gfx::Point min_point = GetOldest().location;
   gfx::Point max_point = GetOldest().location;
   for (const LaserPoint& point : points_) {
     min_point.SetToMin(point.location);
     max_point.SetToMax(point.location);
   }
   return gfx::BoundingRect(min_point, max_point);
 }
 
 LaserPointerPoints::LaserPoint LaserPointerPoints::GetOldest() const {
   DCHECK(!IsEmpty());
   return points_.front();
 }
 
 LaserPointerPoints::LaserPoint LaserPointerPoints::GetNewest() const {
   DCHECK(!IsEmpty());
   return points_.back();
 }
 
+base::Time LaserPointerPoints::GetCollectionLatestTime() const {
+  return collection_latest_time_;
+}
+
+base::Time LaserPointerPoints::GetCollectionEarliestTime() const {
+  return collection_latest_time_ - life_duration_;
+}
+
 bool LaserPointerPoints::IsEmpty() const {
   return points_.empty();
 }
 
 int LaserPointerPoints::GetNumberOfPoints() const {
   return points_.size();
 }
 
 const std::deque<LaserPointerPoints::LaserPoint>&
 LaserPointerPoints::laser_points() {
   return points_;
 }
 
 void LaserPointerPoints::ClearOldPoints() {
-  DCHECK(!IsEmpty());
+  if (IsEmpty())

[jdufault, 2016/09/23 23:59:19]

Why do we need this if?

[sammiequon, 2016/09/26 19:30:38]

Done.

+    return;
+
   auto first_alive_point =
       std::find_if(points_.begin(), points_.end(), [this](LaserPoint& p) {
-        return GetNewest().creation_time - p.creation_time < life_duration_;
+        return collection_latest_time_ - p.creation_time < life_duration_;
       });
   points_.erase(points_.begin(), first_alive_point);
 }
 
 }  // namespace ash