Pinch/Zoom Infrastructure & Plumbing CL

cc/layers/scrollbar_layer_impl_base.cc

 // 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/layers/scrollbar_layer_impl_base.h"
 
 #include <algorithm>
-#include "cc/layers/layer.h"
+#include "cc/trees/layer_tree_impl.h"
 #include "ui/gfx/rect_conversions.h"
 
 namespace cc {
 
 ScrollbarLayerImplBase::ScrollbarLayerImplBase(
     LayerTreeImpl* tree_impl,
     int id,
     ScrollbarOrientation orientation,
-    bool is_left_side_vertical_scrollbar)
+    bool is_left_side_vertical_scrollbar,
+    bool is_overlay)
     : LayerImpl(tree_impl, id),
-      scroll_layer_id_(Layer::INVALID_ID),
-      is_overlay_scrollbar_(false),
+      scroll_layer_(NULL),
+      clip_layer_(NULL),
+      is_overlay_scrollbar_(is_overlay),
       thumb_thickness_scale_factor_(1.f),
       current_pos_(0.f),
       maximum_(0),
       orientation_(orientation),
       is_left_side_vertical_scrollbar_(is_left_side_vertical_scrollbar),
       vertical_adjust_(0.f),
       visible_to_total_length_ratio_(1.f) {}
 
+ScrollbarLayerImplBase::~ScrollbarLayerImplBase() {

[aelias_OOO_until_Jul13, 2014/01/16 03:44:04]

This should make sure to call RemoveScrollbar() to avoid leaving dangling
pointers.

[wjmaclean, 2014/01/16 15:07:32]

Done.

+}
+
 void ScrollbarLayerImplBase::PushPropertiesTo(LayerImpl* layer) {
   LayerImpl::PushPropertiesTo(layer);
+  DCHECK(layer->ToScrollbarLayer());
+  layer->ToScrollbarLayer()->set_is_overlay_scrollbar(is_overlay_scrollbar_);
+  PushScrollClipPropertiesTo(layer);
+}
+
+void ScrollbarLayerImplBase::PushScrollClipPropertiesTo(LayerImpl* layer) {
+  DCHECK(layer->ToScrollbarLayer());
+  layer->ToScrollbarLayer()->SetScrollLayerById(ScrollLayerId());
+  layer->ToScrollbarLayer()->SetClipLayerById(ClipLayerId());
 }
 
 ScrollbarLayerImplBase* ScrollbarLayerImplBase::ToScrollbarLayer() {
   return this;
 }
 
+void ScrollbarLayerImplBase::SetScrollLayerById(int id) {
+  LayerImpl* scroll_layer = layer_tree_impl()->LayerById(id);
+  if (scroll_layer_ == scroll_layer)
+    return;
+
+  if (scroll_layer_)
+    scroll_layer_->RemoveScrollbar(this);
+  scroll_layer_ = scroll_layer;
+  if (scroll_layer_)
+    scroll_layer_->AddScrollbar(this);
+}
+
+void ScrollbarLayerImplBase::SetClipLayerById(int id) {
+  LayerImpl* clip_layer = layer_tree_impl()->LayerById(id);
+  if (clip_layer_ == clip_layer)
+    return;
+
+  if (clip_layer_)
+    clip_layer_->RemoveScrollbar(this);
+  clip_layer_ = clip_layer;
+  if (clip_layer_)
+    clip_layer_->AddScrollbar(this);

[aelias_OOO_until_Jul13, 2014/01/16 03:44:04]

It's weird that the clip layer is getting called AddScrollbar just like the
scroll layer even though the semantic relationship is very different.  What does
the clip layer need this for?  Isn't it enough for the scrollbar to have one-way
knowledge of the clip?

[wjmaclean, 2014/01/16 15:07:32]

The scrollbar should not have to rely on polling the clip layer to know when
changes have occurred. Thereforefore both the scroll layer and the scroll clip
layer will push notifications to any registered scrollbars when relevant
geometry changes.

+}
+
 gfx::Rect ScrollbarLayerImplBase::ScrollbarLayerRectToContentRect(
     const gfx::RectF& layer_rect) const {
   // Don't intersect with the bounds as in LayerRectToContentRect() because
   // layer_rect here might be in coordinates of the containing layer.
   gfx::RectF content_rect = gfx::ScaleRect(layer_rect,
       contents_scale_x(),
       contents_scale_y());
   return gfx::ToEnclosingRect(content_rect);
 }
 
@@ skipping 123 matching lines @@
             ? bounds().width() - thumb_thickness
             : thumb_thickness_adjustment,
         thumb_offset,
         thumb_thickness - thumb_thickness_adjustment,
         thumb_length);
   }
 
   return ScrollbarLayerRectToContentRect(thumb_rect);
 }
 
+void ScrollbarLayerImplBase::ScrollbarParametersDidChange() {
+  if (!clip_layer_ || !scroll_layer_)
+    return;
+
+  scroll_layer_->SetScrollbarPosition(this, clip_layer_);
+}
+
 }  // namespace cc