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// Copyright 2014 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 "cc/animation/scrollbar_animation_controller.h"
#include <algorithm>
#include "base/time/time.h"
namespace cc {
ScrollbarAnimationController::ScrollbarAnimationController(
ScrollbarAnimationControllerClient* client,
base::TimeDelta delay_before_starting,
base::TimeDelta duration)
: client_(client),
delay_before_starting_(delay_before_starting),
duration_(duration),
is_animating_(false),
currently_scrolling_(false),
scroll_gesture_has_scrolled_(false),
weak_factory_(this) {
}
ScrollbarAnimationController::~ScrollbarAnimationController() {
}
void ScrollbarAnimationController::Animate(base::TimeTicks now) {
if (!is_animating_)
return;
if (last_awaken_time_.is_null())
last_awaken_time_ = now;
float progress = AnimationProgressAtTime(now);
RunAnimationFrame(progress);
if (is_animating_) {
delayed_scrollbar_fade_.Cancel();
client_->SetNeedsScrollbarAnimationFrame();
}
}
float ScrollbarAnimationController::AnimationProgressAtTime(
base::TimeTicks now) {
base::TimeDelta delta = now - last_awaken_time_;
float progress = delta.InSecondsF() / duration_.InSecondsF();
return std::max(std::min(progress, 1.f), 0.f);
}
void ScrollbarAnimationController::DidScrollBegin() {
currently_scrolling_ = true;
}
void ScrollbarAnimationController::DidScrollUpdate() {
StopAnimation();
delayed_scrollbar_fade_.Cancel();
// As an optimization, we avoid spamming fade delay tasks during active fast
// scrolls. But if we're not within one, we need to post every scroll update.
if (!currently_scrolling_)
PostDelayedFade();
else
scroll_gesture_has_scrolled_ = true;
}
void ScrollbarAnimationController::DidScrollEnd() {
if (scroll_gesture_has_scrolled_) {
PostDelayedFade();
scroll_gesture_has_scrolled_ = false;
}
currently_scrolling_ = false;
}
void ScrollbarAnimationController::PostDelayedFade() {
delayed_scrollbar_fade_.Reset(
base::Bind(&ScrollbarAnimationController::StartAnimation,
weak_factory_.GetWeakPtr()));
client_->PostDelayedScrollbarFade(delayed_scrollbar_fade_.callback(),
delay_before_starting_);
}
void ScrollbarAnimationController::StartAnimation() {
delayed_scrollbar_fade_.Cancel();
is_animating_ = true;
last_awaken_time_ = base::TimeTicks();
client_->SetNeedsScrollbarAnimationFrame();
}
void ScrollbarAnimationController::StopAnimation() {
is_animating_ = false;
}
} // namespace cc
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