Add support for calculating the position of the top controls in the cc layer.

cc/top_controls_manager.cc

Index: cc/top_controls_manager.cc
diff --git a/cc/top_controls_manager.cc b/cc/top_controls_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a390d9774b9a2771d2d6302c0f9e4fe4844e78d5
--- /dev/null
+++ b/cc/top_controls_manager.cc
@@ -0,0 +1,219 @@
+// Copyright 2012 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/bind.h"
+#include "base/compiler_specific.h"
+#include "base/logging.h"
+#include "base/message_loop.h"
+#include "base/time.h"
+#include "cc/layer_tree_impl.h"
+#include "cc/top_controls_animation.h"
+#include "ui/gfx/transform.h"
+#include "ui/gfx/vector2d_f.h"
+
+namespace cc {
+
+// static
+scoped_ptr<TopControlsManager> TopControlsManager::create(
+    TopControlsDelegate* delegate, bool enabled, float topControlsHeight) {
+  return make_scoped_ptr(new TopControlsManager(delegate, enabled,
+                                                topControlsHeight));
+}
+
+TopControlsManager::TopControlsManager(TopControlsDelegate* delegate,
+                                       bool enabled, float topControlsHeight)
+    : ALLOW_THIS_IN_INITIALIZER_LIST(weak_ptr_factory_(this)),
+      delegate_(delegate),
+      enabled_(enabled),
+      is_overlay_mode_(false),
+      top_controls_height_(topControlsHeight),
+      controls_top_offset_(0),
+      content_top_offset_(topControlsHeight),
+      top_controls_auto_hide_trigger_time_(-1),
+      previous_root_scroll_offset_(-1.f) {

[aelias_OOO_until_Jul13, 2012/12/19 08:31:18]

Use 0 here, not -1.

[Ted C, 2012/12/19 21:34:17]

I need some value to ensure it doesn't update while you are scrolling to prevent
jittery locations of the toolbar.  I updated this to use a separate boolean to
avoid muddling the logic between the two.

+  CHECK(delegate_);
+}
+
+TopControlsManager::~TopControlsManager() {
+}
+
+void TopControlsManager::updateDrawPositions() {
+  if (!enabled_ || !rootScrollLayer())
+    return;
+
+  // If the scroll position has changed underneath us (i.e. a javascript
+  // scroll), then simulate a scroll that covers the delta.
+  float scrollTotalY = rootScrollLayerTotalScrollY();
+  if (previous_root_scroll_offset_ >= 0
+      && scrollTotalY != previous_root_scroll_offset_) {
+    scrollBy(gfx::Vector2dF(0, scrollTotalY - previous_root_scroll_offset_));
+    startAnimationIfNecessary();
+    previous_root_scroll_offset_ = rootScrollLayerTotalScrollY();
+  }
+
+  float offsetTop = is_overlay_mode_ ? 0 : content_top_offset_;
+
+  // The two layers that need to be transformed are the clip layer and root
+  // scrollbar layers, which are the only two children of the root layer.
+  LayerImpl* rootLayer = delegate_->activeTree()->RootLayer();
+  for (size_t i = 0; i < rootLayer->children().size(); ++i) {
+    LayerImpl* childLayer = rootLayer->children()[i];
+    gfx::Transform transform;
+    transform.Translate(0, offsetTop);
+    childLayer->setImplTransform(transform);
+  }
+
+  // TODO(tedchoc): Adjust fixed position layers as well.
+}
+
+void TopControlsManager::scrollBegin() {
+  resetAnimations();
+  previous_root_scroll_offset_ = -1;

[aelias_OOO_until_Jul13, 2012/12/19 08:31:18]

I don't think it's a good idea to have -1 as a magic invalid value.  Why not
just keep it in sync with the layerTreeImpl's value?

+}
+
+gfx::Vector2dF TopControlsManager::scrollBy(const gfx::Vector2dF pendingDelta) {
+  if (!enabled_)
+    return pendingDelta;
+
+  float scrollTotalY = rootScrollLayerTotalScrollY();
+  float scrollDeltaY = pendingDelta.y();
+
+  float previousControlsOffset = controls_top_offset_;
+  float previousContentOffset = content_top_offset_;
+  bool previousWasOverlay = is_overlay_mode_;
+
+  controls_top_offset_ -= scrollDeltaY;
+  controls_top_offset_ = std::min(
+      std::max(controls_top_offset_, -top_controls_height_), 0.f);
+
+  if (scrollTotalY > 0 || (scrollTotalY == 0
+      && content_top_offset_ < scrollDeltaY)) {
+    is_overlay_mode_ = true;
+    content_top_offset_ = 0;
+  } else if (scrollTotalY <= 0 && (scrollDeltaY < 0
+      || (scrollDeltaY > 0 && content_top_offset_ > 0))) {
+    is_overlay_mode_ = false;
+    content_top_offset_ -= scrollDeltaY;
+  }
+  content_top_offset_ = std::max(
+      std::min(content_top_offset_,
+               controls_top_offset_ + top_controls_height_), 0.f);
+
+  gfx::Vector2dF appliedDelta;
+  if (!previousWasOverlay)
+    appliedDelta.set_y(previousContentOffset - content_top_offset_);
+
+  if (is_overlay_mode_ != previousWasOverlay
+      || previousControlsOffset != controls_top_offset_
+      || previousContentOffset != content_top_offset_) {
+    delegate_->setNeedsRedraw();
+    delegate_->setNeedsUpdateDrawProperties();
+  }
+
+  return pendingDelta - appliedDelta;
+}
+
+void TopControlsManager::scrollEnd() {
+  if (!enabled_)
+    return;
+  startAnimationIfNecessary();
+  previous_root_scroll_offset_ = rootScrollLayerTotalScrollY();
+}
+
+void TopControlsManager::animate(base::TimeTicks monotonicTime) {
+  if (!enabled_)
+    return;
+
+  if (!top_controls_animation_ || !rootScrollLayer())
+    return;
+
+  double time = (monotonicTime - base::TimeTicks()).InSecondsF();
+  float newOffset = top_controls_animation_->scrollOffsetAtTime(monotonicTime);
+  gfx::Vector2dF scrollVector(0.f, -(newOffset - controls_top_offset_));
+  scrollBy(scrollVector);
+  delegate_->setNeedsRedraw();
+
+  if (top_controls_animation_->isAnimationCompleteAtTime(monotonicTime)) {
+    top_controls_animation_.reset();
+    startAnimationIfNecessary();
+  }
+}
+
+void TopControlsManager::resetAnimations() {
+  if (!enabled_)
+    return;
+  if (top_controls_animation_)
+    top_controls_animation_.reset();
+  top_controls_auto_hide_trigger_time_ = -1;
+}
+
+LayerImpl* TopControlsManager::rootScrollLayer() {
+  return delegate_->activeTree()->root_scroll_layer();
+}
+
+float TopControlsManager::rootScrollLayerTotalScrollY() {
+  LayerImpl* layer = rootScrollLayer();
+  if (!layer)
+    return 0;
+  gfx::Vector2dF scrollTotal = layer->scrollOffset() + layer->scrollDelta();
+  return scrollTotal.y();
+}
+
+void TopControlsManager::startAnimationIfNecessary() {
+  if (!enabled_)
+    return;
+
+  if (!is_overlay_mode_)
+    return;
+
+  float scrollTotalY;

[aelias_OOO_until_Jul13, 2012/12/19 08:31:18]

This may be uninitialized.  Just change it to:
float scrollTotalY = rootScrollLayerTotalScrollY();

[Ted C, 2012/12/19 21:34:17]

Done.

+  if (rootScrollLayer())
+    scrollTotalY = rootScrollLayerTotalScrollY();
+
+  if (controls_top_offset_ != 0
+      && controls_top_offset_ != -top_controls_height_) {
+    top_controls_animation_ = TopControlsAnimation::create(
+        controls_top_offset_,
+        top_controls_height_,
+        base::TimeTicks::Now(),
+        base::TimeDelta::FromMilliseconds(kShowHideMaxDurationMs));
+    top_controls_animation_->setDirection(
+        controls_top_offset_ >= -(top_controls_height_ * 0.75f));

[aelias_OOO_until_Jul13, 2012/12/19 08:31:18]

Promote 0.75f to a constant at the top of this file.

[Ted C, 2012/12/19 21:34:17]

Done.

+    delegate_->setNeedsRedraw();
+  } else if (controls_top_offset_ == 0 && scrollTotalY != 0) {
+    MessageLoop* loop = MessageLoop::current();
+    DCHECK(loop);
+    if (loop) {
+      int64 triggerTime = top_controls_auto_hide_trigger_time_ =
+          (base::TimeTicks::Now() - base::TimeTicks()).InMilliseconds();
+      loop->PostDelayedTask(
+          FROM_HERE,
+          base::Bind(&TopControlsManager::startAutoHideAnimation,
+                     weak_ptr_factory_.GetWeakPtr(), triggerTime),
+          base::TimeDelta::FromMilliseconds(kAutoHideDelayMs));
+    }
+  }
+}
+
+void TopControlsManager::startAutoHideAnimation(int64 triggeredTime) {
+  if (!enabled_)
+    return;
+
+  if (triggeredTime != top_controls_auto_hide_trigger_time_)
+    return;
+
+  top_controls_animation_ = TopControlsAnimation::create(
+      controls_top_offset_,
+      top_controls_height_,
+      base::TimeTicks::Now(),
+      base::TimeDelta::FromMilliseconds(kShowHideMaxDurationMs));
+  top_controls_animation_->setDirection(false);
+  delegate_->setNeedsRedraw();
+}
+
+}  // namespace cc