Explicit animation support

ui/gfx/compositor/layer_animation_sequence.cc

+// Copyright (c) 2011 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/gfx/compositor/layer_animation_sequence.h"
+
+#include <algorithm>
+
+#include "base/debug/trace_event.h"
+#include "ui/gfx/compositor/layer_animation_delegate.h"
+#include "ui/gfx/compositor/layer_animation_element.h"
+
+namespace ui {
+
+LayerAnimationSequence::LayerAnimationSequence()
+    : is_cyclic_(false),
+      last_element_(0) {
+}
+
+LayerAnimationSequence::LayerAnimationSequence(LayerAnimationElement* element)
+    : is_cyclic_(false),
+      last_element_(0) {
+  AddElement(element);
+}
+
+LayerAnimationSequence::~LayerAnimationSequence() {
+}
+
+void LayerAnimationSequence::Progress(base::TimeDelta elapsed,
+                                      LayerAnimationDelegate* delegate) {
+  TRACE_EVENT0("LayerAnimationSequence", "Progress");
+  if (elements_.size() == 0 || duration_ == base::TimeDelta())
+    return;
+
+  // If delta = elapsed - last_start_ is huge, we can skip ahead by complete
+  // loops to save time.
+  base::TimeDelta delta = elapsed - last_start_;
+  int64 k = delta.ToInternalValue() / duration_.ToInternalValue() - 1;
+  if (k > 0) {
+    last_start_ += base::TimeDelta::FromInternalValue(
+        k * duration_.ToInternalValue());
+  }
+
+  size_t current_index = last_element_ % elements_.size();
+  while ((is_cyclic_ || last_element_ < elements_.size()) &&
+         (last_start_ + elements_[current_index]->duration() < elapsed)) {
+    // Let the element we're passing finish.
+    elements_[current_index]->Progress(1.0, delegate);
+    last_start_ += elements_[current_index]->duration();
+    ++last_element_;
+    current_index = last_element_ % elements_.size();
+  }
+
+  if (is_cyclic_ || last_element_ < elements_.size()) {
+    double t = 1.0;
+    if (elements_[current_index]->duration() > base::TimeDelta()) {
+      t = (elapsed - last_start_).InMillisecondsF() /
+          elements_[current_index]->duration().InMillisecondsF();
+    }
+    elements_[current_index]->Progress(t, delegate);
+  }
+
+  if (!is_cyclic_ && elapsed == duration_) {
+    last_element_ = 0;
+    last_start_ = base::TimeDelta::FromMilliseconds(0);
+  }
+}

[sky, 2011/10/20 16:33:03]

Do you want something like:
if (is_cyclic_)
  last_element_ = last_element_ % elements_.size();
Otherwise I think Abort is problematic.

+
+void LayerAnimationSequence::Abort() {
+  while (last_element_ < elements_.size()) {
+    elements_[last_element_]->Abort();
+    ++last_element_;
+  }
+  last_element_ = 0;
+  last_start_ = base::TimeDelta::FromMilliseconds(0);
+}
+
+void LayerAnimationSequence::AddElement(LayerAnimationElement* element) {
+  // Update duration and properties.
+  duration_ += element->duration();
+  properties_.insert(element->properties().begin(),
+                     element->properties().end());
+  elements_.push_back(element);
+}
+
+bool LayerAnimationSequence::HasCommonProperty(
+    const LayerAnimationElement::AnimatableProperties& other) const {
+  LayerAnimationElement::AnimatableProperties intersection;
+  std::insert_iterator<LayerAnimationElement::AnimatableProperties> ii(
+      intersection, intersection.begin());
+  std::set_intersection(properties_.begin(), properties_.end(),
+                        other.begin(), other.end(),
+                        ii);
+  return intersection.size() > 0;
+}
+
+}  // namespace ui