ui/gfx/animation/animation_container.cc

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/gfx/animation/animation_container.h"
   6
   7 #include "ui/gfx/animation/animation_container_element.h"
   8 #include "ui/gfx/animation/animation_container_observer.h"
   9
  10 using base::TimeDelta;
  11 using base::TimeTicks;
  12
  13 namespace gfx {
  14
  15 AnimationContainer::AnimationContainer()
  16     : last_tick_time_(base::TimeTicks::Now()), observer_(NULL) {
  17 }
  18
  19 AnimationContainer::~AnimationContainer() {
  20   // The animations own us and stop themselves before being deleted. If
  21   // elements_ is not empty, something is wrong.
  22   DCHECK(elements_.empty());
  23 }
  24
  25 void AnimationContainer::Start(AnimationContainerElement* element) {
  26   DCHECK(elements_.count(element) == 0);  // Start should only be invoked if the
  27                                           // element isn't running.
  28
  29   if (elements_.empty()) {
  30     last_tick_time_ = base::TimeTicks::Now();
  31     SetMinTimerInterval(element->GetTimerInterval());
  32   } else if (element->GetTimerInterval() < min_timer_interval_) {
  33     SetMinTimerInterval(element->GetTimerInterval());
  34   }
  35
  36   element->SetStartTime(last_tick_time_);
  37   elements_.insert(element);
  38 }
  39
  40 void AnimationContainer::Stop(AnimationContainerElement* element) {
  41   DCHECK(elements_.count(element) > 0);  // The element must be running.
  42
  43   elements_.erase(element);
  44
  45   if (elements_.empty()) {
  46     timer_.Stop();
  47     if (observer_)
  48       observer_->AnimationContainerEmpty(this);
  49   } else {
  50     TimeDelta min_timer_interval = GetMinInterval();
  51     if (min_timer_interval > min_timer_interval_)
  52       SetMinTimerInterval(min_timer_interval);
  53   }
  54 }
  55
  56 void AnimationContainer::Run() {
  57   // We notify the observer after updating all the elements. If all the elements
  58   // are deleted as a result of updating then our ref count would go to zero and
  59   // we would be deleted before we notify our observer. We add a reference to
  60   // ourself here to make sure we're still valid after running all the elements.
  61   scoped_refptr<AnimationContainer> this_ref(this);
  62
  63   TimeTicks current_time = base::TimeTicks::Now();
  64
  65   last_tick_time_ = current_time;
  66
  67   // Make a copy of the elements to iterate over so that if any elements are
  68   // removed as part of invoking Step there aren't any problems.
  69   Elements elements = elements_;
  70
  71   for (Elements::const_iterator i = elements.begin();
  72        i != elements.end(); ++i) {
  73     // Make sure the element is still valid.
  74     if (elements_.find(*i) != elements_.end())
  75       (*i)->Step(current_time);
  76   }
  77
  78   if (observer_)
  79     observer_->AnimationContainerProgressed(this);
  80 }
  81
  82 void AnimationContainer::SetMinTimerInterval(base::TimeDelta delta) {
  83   // This doesn't take into account how far along the current element is, but
  84   // that shouldn't be a problem for uses of Animation/AnimationContainer.
  85   timer_.Stop();
  86   min_timer_interval_ = delta;
  87   timer_.Start(FROM_HERE, min_timer_interval_, this, &AnimationContainer::Run);
  88 }
  89
  90 TimeDelta AnimationContainer::GetMinInterval() {
  91   DCHECK(!elements_.empty());
  92
  93   TimeDelta min;
  94   Elements::const_iterator i = elements_.begin();
  95   min = (*i)->GetTimerInterval();
  96   for (++i; i != elements_.end(); ++i) {
  97     if ((*i)->GetTimerInterval() < min)
  98       min = (*i)->GetTimerInterval();
  99   }
 100   return min;
 101 }
 102
 103 }  // namespace gfx