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// Copyright 2013 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/top_controls_manager.h"
#include <algorithm>
#include "base/logging.h"
#include "base/time.h"
#include "cc/keyframed_animation_curve.h"
#include "cc/layer_tree_impl.h"
#include "cc/timing_function.h"
#include "cc/top_controls_manager_client.h"
#include "ui/gfx/transform.h"
#include "ui/gfx/vector2d_f.h"
namespace cc {
namespace {
// These constants were chosen empirically for their visually pleasant behavior.
// Contact tedchoc@chromium.org for questions about changing these values.
const float kShowHideThreshold = 0.5f;
const int64 kShowHideMaxDurationMs = 175;
}
// static
scoped_ptr<TopControlsManager> TopControlsManager::Create(
TopControlsManagerClient* client, float top_controls_height) {
return make_scoped_ptr(new TopControlsManager(client, top_controls_height));
}
TopControlsManager::TopControlsManager(TopControlsManagerClient* client,
float top_controls_height)
: client_(client),
animation_direction_(NO_ANIMATION),
in_scroll_gesture_(false),
top_controls_height_(top_controls_height),
controls_top_offset_(0),
content_top_offset_(top_controls_height),
previous_root_scroll_offset_(0.f),
scroll_start_offset_(0.f) {
CHECK(client_);
}
TopControlsManager::~TopControlsManager() {
}
void TopControlsManager::ScrollBegin() {
ResetAnimations();
in_scroll_gesture_ = true;
scroll_start_offset_ = RootScrollLayerTotalScrollY() + controls_top_offset_;
}
gfx::Vector2dF TopControlsManager::ScrollBy(
const gfx::Vector2dF pending_delta) {
if (pending_delta.y() == 0)
return pending_delta;
float scroll_total_y = RootScrollLayerTotalScrollY();
if (in_scroll_gesture_ && pending_delta.y() > 0 && controls_top_offset_ == 0)
scroll_start_offset_ = scroll_total_y;
else if (in_scroll_gesture_ &&
((pending_delta.y() > 0 && scroll_total_y < scroll_start_offset_) ||
(pending_delta.y() < 0 &&
scroll_total_y > scroll_start_offset_ + top_controls_height_))) {
return pending_delta;
}
ResetAnimations();
return ScrollInternal(pending_delta);
}
gfx::Vector2dF TopControlsManager::ScrollInternal(
const gfx::Vector2dF pending_delta) {
float scroll_total_y = RootScrollLayerTotalScrollY();
float scroll_delta_y = pending_delta.y();
float previous_controls_offset = controls_top_offset_;
float previous_content_offset = content_top_offset_;
controls_top_offset_ -= scroll_delta_y;
controls_top_offset_ = std::min(
std::max(controls_top_offset_, -top_controls_height_), 0.f);
// To determine if the scroll delta should be applied to the content position
// as well, we check the following:
// 1.) Scrolling down the page and the content position isn't already at 0.
// This case handles corrections where the page content shifts outside of
// the knowledge of the top controls manager.
// 2.) Scrolling either direction while the root scroll layer is scrolled to
// the very top.
if ((scroll_delta_y > 0 && content_top_offset_ > 0) || scroll_total_y <= 0) {
float content_scroll_delta_y = scroll_delta_y;
if (content_scroll_delta_y > 0)
content_scroll_delta_y -= previous_controls_offset - controls_top_offset_;
content_top_offset_ -= content_scroll_delta_y;
}
content_top_offset_ = std::max(
std::min(content_top_offset_,
controls_top_offset_ + top_controls_height_), 0.f);
gfx::Vector2dF applied_delta(
0.f, previous_content_offset - content_top_offset_);
if (previous_controls_offset != controls_top_offset_ ||
previous_content_offset != content_top_offset_) {
client_->setNeedsRedraw();
client_->setActiveTreeNeedsUpdateDrawProperties();
}
return pending_delta - applied_delta;
}
void TopControlsManager::ScrollEnd() {
StartAnimationIfNecessary();
previous_root_scroll_offset_ = RootScrollLayerTotalScrollY();
in_scroll_gesture_ = false;
}
void TopControlsManager::Animate(base::TimeTicks monotonic_time) {
if (!top_controls_animation_ || !client_->haveRootScrollLayer())
return;
double time = (monotonic_time - base::TimeTicks()).InMillisecondsF();
float new_offset = top_controls_animation_->getValue(time);
gfx::Vector2dF scroll_vector(0.f, -(new_offset - controls_top_offset_));
ScrollInternal(scroll_vector);
client_->setNeedsRedraw();
if (IsAnimationCompleteAtTime(monotonic_time))
ResetAnimations();
}
void TopControlsManager::ResetAnimations() {
if (top_controls_animation_)
top_controls_animation_.reset();
animation_direction_ = NO_ANIMATION;
}
float TopControlsManager::RootScrollLayerTotalScrollY() {
return client_->rootScrollLayerTotalScrollY();
}
void TopControlsManager::SetupAnimation(AnimationDirection direction) {
top_controls_animation_ = KeyframedFloatAnimationCurve::create();
double start_time =
(base::TimeTicks::Now() - base::TimeTicks()).InMillisecondsF();
top_controls_animation_->addKeyframe(
FloatKeyframe::create(start_time, controls_top_offset_,
scoped_ptr<TimingFunction>()));
float max_ending_offset =
(direction == SHOWING_CONTROLS ? 1 : -1) * top_controls_height_;
top_controls_animation_->addKeyframe(
FloatKeyframe::create(start_time + kShowHideMaxDurationMs,
controls_top_offset_ + max_ending_offset,
EaseTimingFunction::create()));
animation_direction_ = direction;
}
void TopControlsManager::StartAnimationIfNecessary() {
float scroll_total_y = RootScrollLayerTotalScrollY();
if (controls_top_offset_ != 0
&& controls_top_offset_ != -top_controls_height_) {
AnimationDirection show_controls =
controls_top_offset_ >= -(top_controls_height_ * kShowHideThreshold) ?
SHOWING_CONTROLS : HIDING_CONTROLS;
if (!top_controls_animation_ || animation_direction_ != show_controls) {
SetupAnimation(show_controls);
client_->setNeedsRedraw();
}
}
}
bool TopControlsManager::IsAnimationCompleteAtTime(base::TimeTicks time) {
if (!top_controls_animation_)
return true;
double time_ms = (time - base::TimeTicks()).InMillisecondsF();
float new_offset = top_controls_animation_->getValue(time_ms);
if ((animation_direction_ == SHOWING_CONTROLS && new_offset >= 0) ||
(animation_direction_ == HIDING_CONTROLS
&& new_offset <= -top_controls_height_)) {
return true;
}
return false;
}
} // namespace cc
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