cc/trees/property_tree_builder.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/trees/property_tree_builder.h"
   6
   7 #include <map>
   8 #include <set>
   9
  10 #include "cc/base/math_util.h"
  11 #include "cc/layers/layer.h"
  12 #include "cc/layers/layer_impl.h"
  13 #include "cc/trees/layer_tree_host.h"
  14 #include "ui/gfx/geometry/point_f.h"
  15 #include "ui/gfx/geometry/vector2d_conversions.h"
  16
  17 namespace cc {
  18
  19 class LayerTreeHost;
  20
  21 namespace {
  22
  23 template <typename LayerType>
  24 struct DataForRecursion {
  25   TransformTree* transform_tree;
  26   ClipTree* clip_tree;
  27   OpacityTree* opacity_tree;
  28   LayerType* transform_tree_parent;
  29   LayerType* transform_fixed_parent;
  30   LayerType* render_target;
  31   int clip_tree_parent;
  32   int opacity_tree_parent;
  33   const LayerType* page_scale_layer;
  34   float page_scale_factor;
  35   float device_scale_factor;
  36   bool in_subtree_of_page_scale_application_layer;
  37   bool should_flatten;
  38   bool ancestor_clips_subtree;
  39   const gfx::Transform* device_transform;
  40   gfx::Vector2dF scroll_compensation_adjustment;
  41 };
  42
  43 template <typename LayerType>
  44 static LayerType* GetTransformParent(const DataForRecursion<LayerType>& data,
  45                                      LayerType* layer) {
  46   return layer->position_constraint().is_fixed_position()
  47              ? data.transform_fixed_parent
  48              : data.transform_tree_parent;
  49 }
  50
  51 template <typename LayerType>
  52 static ClipNode* GetClipParent(const DataForRecursion<LayerType>& data,
  53                                LayerType* layer) {
  54   const bool inherits_clip = !layer->parent() || !layer->clip_parent();
  55   const int id = inherits_clip ? data.clip_tree_parent
  56                                : layer->clip_parent()->clip_tree_index();
  57   return data.clip_tree->Node(id);
  58 }
  59
  60 template <typename LayerType>
  61 static bool HasPotentiallyRunningAnimation(LayerType* layer,
  62                                            Animation::TargetProperty property) {
  63   if (Animation* animation =
  64           layer->layer_animation_controller()->GetAnimation(property)) {
  65     return !animation->is_finished();
  66   }
  67   return false;
  68 }
  69
  70 template <typename LayerType>
  71 static bool RequiresClipNode(LayerType* layer,
  72                              const DataForRecursion<LayerType>& data,
  73                              int parent_transform_id,
  74                              bool is_clipped) {
  75   const bool render_surface_applies_clip =
  76       layer->render_surface() && is_clipped;
  77   const bool render_surface_may_grow_due_to_clip_children =
  78       layer->render_surface() && layer->num_unclipped_descendants() > 0;
  79
  80   if (!layer->parent() || layer->masks_to_bounds() || layer->mask_layer() ||
  81       render_surface_may_grow_due_to_clip_children)
  82     return true;
  83
  84   if (!render_surface_applies_clip)
  85     return false;
  86
  87   bool axis_aligned_with_respect_to_parent =
  88       data.transform_tree->Are2DAxisAligned(layer->transform_tree_index(),
  89                                             parent_transform_id);
  90
  91   return !axis_aligned_with_respect_to_parent;
  92 }
  93
  94 template <typename LayerType>
  95 static bool LayerClipsSubtree(LayerType* layer) {
  96   return layer->masks_to_bounds() || layer->mask_layer();
  97 }
  98
  99 template <typename LayerType>
 100 void AddClipNodeIfNeeded(const DataForRecursion<LayerType>& data_from_ancestor,
 101                          LayerType* layer,
 102                          bool created_transform_node,
 103                          DataForRecursion<LayerType>* data_for_children) {
 104   ClipNode* parent = GetClipParent(data_from_ancestor, layer);
 105   int parent_id = parent->id;
 106
 107   bool ancestor_clips_subtree =
 108       data_from_ancestor.ancestor_clips_subtree || layer->clip_parent();
 109
 110   data_for_children->ancestor_clips_subtree = false;
 111   bool has_unclipped_surface = false;
 112
 113   if (layer->has_render_surface()) {
 114     if (ancestor_clips_subtree && layer->num_unclipped_descendants() > 0)
 115       data_for_children->ancestor_clips_subtree = true;
 116     else if (!ancestor_clips_subtree && !layer->num_unclipped_descendants())
 117       has_unclipped_surface = true;
 118   } else {
 119     data_for_children->ancestor_clips_subtree = ancestor_clips_subtree;
 120   }
 121
 122   if (LayerClipsSubtree(layer))
 123     data_for_children->ancestor_clips_subtree = true;
 124
 125   if (has_unclipped_surface)
 126     parent_id = 0;
 127
 128   if (!RequiresClipNode(layer, data_from_ancestor, parent->data.transform_id,
 129                         data_for_children->ancestor_clips_subtree)) {
 130     // Unclipped surfaces reset the clip rect.
 131     data_for_children->clip_tree_parent = parent_id;
 132   } else if (layer->parent()) {
 133     // Note the root clip gets handled elsewhere.
 134     LayerType* transform_parent = data_for_children->transform_tree_parent;
 135     if (layer->position_constraint().is_fixed_position() &&
 136         !created_transform_node) {
 137       transform_parent = data_for_children->transform_fixed_parent;
 138     }
 139     ClipNode node;
 140     node.data.clip = gfx::RectF(
 141         gfx::PointF() + layer->offset_to_transform_parent(), layer->bounds());
 142     node.data.transform_id = transform_parent->transform_tree_index();
 143     node.data.target_id =
 144         data_for_children->render_target->transform_tree_index();
 145     node.owner_id = layer->id();
 146
 147     data_for_children->clip_tree_parent =
 148         data_for_children->clip_tree->Insert(node, parent_id);
 149   }
 150
 151   layer->set_clip_tree_index(
 152       has_unclipped_surface ? 0 : data_for_children->clip_tree_parent);
 153
 154   // TODO(awoloszyn): Right now when we hit a node with a replica, we reset the
 155   // clip for all children since we may need to draw. We need to figure out a
 156   // better way, since we will need both the clipped and unclipped versions.
 157 }
 158
 159 template <typename LayerType>
 160 bool AddTransformNodeIfNeeded(
 161     const DataForRecursion<LayerType>& data_from_ancestor,
 162     LayerType* layer,
 163     DataForRecursion<LayerType>* data_for_children) {
 164   const bool is_root = !layer->parent();
 165   const bool is_page_scale_application_layer =
 166       layer->parent() && layer->parent() == data_from_ancestor.page_scale_layer;
 167   const bool is_scrollable = layer->scrollable();
 168   const bool is_fixed = layer->position_constraint().is_fixed_position();
 169
 170   const bool has_significant_transform =
 171       !layer->transform().IsIdentityOr2DTranslation();
 172
 173   const bool has_potentially_animated_transform =
 174       HasPotentiallyRunningAnimation(layer, Animation::TRANSFORM);
 175
 176   const bool has_animated_transform =
 177       layer->layer_animation_controller()->IsAnimatingProperty(
 178           Animation::TRANSFORM);
 179
 180   const bool has_surface = !!layer->render_surface();
 181
 182   bool requires_node = is_root || is_scrollable || has_significant_transform ||
 183                        has_potentially_animated_transform || has_surface ||
 184                        is_fixed || is_page_scale_application_layer;
 185
 186   LayerType* transform_parent = GetTransformParent(data_from_ancestor, layer);
 187
 188   int parent_index = 0;
 189   if (transform_parent)
 190     parent_index = transform_parent->transform_tree_index();
 191
 192   int source_index = parent_index;
 193
 194   gfx::Vector2dF source_offset;
 195   if (transform_parent) {
 196     if (layer->scroll_parent()) {
 197       LayerType* source = layer->parent();
 198       source_offset += source->offset_to_transform_parent();
 199       source_index = source->transform_tree_index();
 200     } else if (!is_fixed) {
 201       source_offset = transform_parent->offset_to_transform_parent();
 202     } else {
 203       if (data_from_ancestor.transform_tree_parent !=
 204           data_from_ancestor.transform_fixed_parent) {
 205         source_offset = data_from_ancestor.transform_tree_parent
 206                             ->offset_to_transform_parent();
 207         source_index =
 208             data_from_ancestor.transform_tree_parent->transform_tree_index();
 209       }
 210       source_offset += data_from_ancestor.scroll_compensation_adjustment;
 211     }
 212   }
 213
 214   if (layer->IsContainerForFixedPositionLayers() || is_root)
 215     data_for_children->transform_fixed_parent = layer;
 216   data_for_children->transform_tree_parent = layer;
 217
 218   if (layer->IsContainerForFixedPositionLayers() || is_fixed)
 219     data_for_children->scroll_compensation_adjustment = gfx::Vector2dF();
 220
 221   if (!requires_node) {
 222     data_for_children->should_flatten |= layer->should_flatten_transform();
 223     gfx::Vector2dF local_offset = layer->position().OffsetFromOrigin() +
 224                                   layer->transform().To2dTranslation();
 225     gfx::Vector2dF source_to_parent;
 226     if (source_index != parent_index) {
 227       gfx::Transform to_parent;
 228       data_from_ancestor.transform_tree->ComputeTransform(
 229           source_index, parent_index, &to_parent);
 230       source_to_parent = to_parent.To2dTranslation();
 231     }
 232     layer->set_offset_to_transform_parent(source_offset + source_to_parent +
 233                                           local_offset);
 234     layer->set_should_flatten_transform_from_property_tree(
 235         data_from_ancestor.should_flatten);
 236     layer->set_transform_tree_index(parent_index);
 237     return false;
 238   }
 239
 240   data_for_children->transform_tree->Insert(TransformNode(), parent_index);
 241
 242   TransformNode* node = data_for_children->transform_tree->back();
 243   layer->set_transform_tree_index(node->id);
 244
 245   node->data.scrolls = is_scrollable;
 246   node->data.flattens_inherited_transform = data_for_children->should_flatten;
 247
 248   // Surfaces inherently flatten transforms.
 249   data_for_children->should_flatten =
 250       layer->should_flatten_transform() || has_surface;
 251   node->data.target_id =
 252       data_from_ancestor.render_target->transform_tree_index();
 253   node->data.content_target_id =
 254       data_for_children->render_target->transform_tree_index();
 255   DCHECK_NE(node->data.target_id, -1);
 256   node->data.is_animated = has_animated_transform;
 257
 258   float post_local_scale_factor = 1.0f;
 259   if (is_root) {
 260     node->data.post_local = *data_from_ancestor.device_transform;
 261     post_local_scale_factor = data_from_ancestor.device_scale_factor;
 262   }
 263
 264   if (is_page_scale_application_layer)
 265     post_local_scale_factor *= data_from_ancestor.page_scale_factor;
 266
 267   if (has_surface && !is_root) {
 268     node->data.needs_sublayer_scale = true;
 269     node->data.layer_scale_factor = data_from_ancestor.device_scale_factor;
 270     if (data_from_ancestor.in_subtree_of_page_scale_application_layer)
 271       node->data.layer_scale_factor *= data_from_ancestor.page_scale_factor;
 272   }
 273
 274   if (is_root) {
 275     node->data.post_local.Scale(post_local_scale_factor,
 276                                 post_local_scale_factor);
 277   } else {
 278     node->data.post_local_scale_factor = post_local_scale_factor;
 279     node->data.source_offset = source_offset;
 280     node->data.source_node_id = source_index;
 281     node->data.update_post_local_transform(layer->position(),
 282                                            layer->transform_origin());
 283   }
 284
 285   if (!layer->scroll_parent()) {
 286     node->data.scroll_offset =
 287         gfx::ScrollOffsetToVector2dF(layer->CurrentScrollOffset());
 288   }
 289
 290   node->data.local = layer->transform();
 291   node->data.update_pre_local_transform(layer->transform_origin());
 292
 293   node->data.needs_local_transform_update = true;
 294   data_from_ancestor.transform_tree->UpdateTransforms(node->id);
 295
 296   layer->set_offset_to_transform_parent(gfx::Vector2dF());
 297
 298   // Flattening (if needed) will be handled by |node|.
 299   layer->set_should_flatten_transform_from_property_tree(false);
 300
 301   data_for_children->scroll_compensation_adjustment +=
 302       layer->ScrollCompensationAdjustment() - node->data.scroll_snap;
 303
 304   node->owner_id = layer->id();
 305
 306   return true;
 307 }
 308
 309 bool IsAnimatingOpacity(Layer* layer) {
 310   return HasPotentiallyRunningAnimation(layer, Animation::OPACITY) ||
 311          layer->OpacityCanAnimateOnImplThread();
 312 }
 313
 314 bool IsAnimatingOpacity(LayerImpl* layer) {
 315   return HasPotentiallyRunningAnimation(layer, Animation::OPACITY);
 316 }
 317
 318 template <typename LayerType>
 319 void AddOpacityNodeIfNeeded(
 320     const DataForRecursion<LayerType>& data_from_ancestor,
 321     LayerType* layer,
 322     DataForRecursion<LayerType>* data_for_children) {
 323   const bool is_root = !layer->parent();
 324   const bool has_transparency = layer->opacity() != 1.f;
 325   const bool has_animated_opacity = IsAnimatingOpacity(layer);
 326   bool requires_node = is_root || has_transparency || has_animated_opacity;
 327
 328   int parent_id = data_from_ancestor.opacity_tree_parent;
 329
 330   if (!requires_node) {
 331     layer->set_opacity_tree_index(parent_id);
 332     data_for_children->opacity_tree_parent = parent_id;
 333     return;
 334   }
 335
 336   OpacityNode node;
 337   node.owner_id = layer->id();
 338   node.data = layer->opacity();
 339   data_for_children->opacity_tree_parent =
 340       data_for_children->opacity_tree->Insert(node, parent_id);
 341   layer->set_opacity_tree_index(data_for_children->opacity_tree_parent);
 342 }
 343
 344 template <typename LayerType>
 345 void BuildPropertyTreesInternal(
 346     LayerType* layer,
 347     const DataForRecursion<LayerType>& data_from_parent) {
 348   DataForRecursion<LayerType> data_for_children(data_from_parent);
 349   if (layer->render_surface())
 350     data_for_children.render_target = layer;
 351
 352   bool created_transform_node =
 353       AddTransformNodeIfNeeded(data_from_parent, layer, &data_for_children);
 354   AddClipNodeIfNeeded(data_from_parent, layer, created_transform_node,
 355                       &data_for_children);
 356
 357   if (data_from_parent.opacity_tree)
 358     AddOpacityNodeIfNeeded(data_from_parent, layer, &data_for_children);
 359
 360   if (layer == data_from_parent.page_scale_layer)
 361     data_for_children.in_subtree_of_page_scale_application_layer = true;
 362
 363   for (size_t i = 0; i < layer->children().size(); ++i) {
 364     if (!layer->child_at(i)->scroll_parent())
 365       BuildPropertyTreesInternal(layer->child_at(i), data_for_children);
 366   }
 367
 368   if (layer->scroll_children()) {
 369     for (LayerType* scroll_child : *layer->scroll_children()) {
 370       BuildPropertyTreesInternal(scroll_child, data_for_children);
 371     }
 372   }
 373
 374   if (layer->has_replica())
 375     BuildPropertyTreesInternal(layer->replica_layer(), data_for_children);
 376 }
 377
 378 }  // namespace
 379
 380 template <typename LayerType>
 381 void BuildPropertyTreesTopLevelInternal(LayerType* root_layer,
 382                                         const LayerType* page_scale_layer,
 383                                         float page_scale_factor,
 384                                         float device_scale_factor,
 385                                         const gfx::Rect& viewport,
 386                                         const gfx::Transform& device_transform,
 387                                         PropertyTrees* property_trees) {
 388   DataForRecursion<LayerType> data_for_recursion;
 389   data_for_recursion.transform_tree = &property_trees->transform_tree;
 390   data_for_recursion.clip_tree = &property_trees->clip_tree;
 391   data_for_recursion.opacity_tree = &property_trees->opacity_tree;
 392   data_for_recursion.transform_tree_parent = nullptr;
 393   data_for_recursion.transform_fixed_parent = nullptr;
 394   data_for_recursion.render_target = root_layer;
 395   data_for_recursion.clip_tree_parent = 0;
 396   data_for_recursion.opacity_tree_parent = -1;
 397   data_for_recursion.page_scale_layer = page_scale_layer;
 398   data_for_recursion.page_scale_factor = page_scale_factor;
 399   data_for_recursion.device_scale_factor = device_scale_factor;
 400   data_for_recursion.in_subtree_of_page_scale_application_layer = false;
 401   data_for_recursion.should_flatten = false;
 402   data_for_recursion.ancestor_clips_subtree = true;
 403   data_for_recursion.device_transform = &device_transform;
 404
 405   data_for_recursion.transform_tree->clear();
 406   data_for_recursion.clip_tree->clear();
 407   data_for_recursion.opacity_tree->clear();
 408
 409   ClipNode root_clip;
 410   root_clip.data.clip = viewport;
 411   root_clip.data.transform_id = 0;
 412   data_for_recursion.clip_tree_parent =
 413       data_for_recursion.clip_tree->Insert(root_clip, 0);
 414   BuildPropertyTreesInternal(root_layer, data_for_recursion);
 415   property_trees->needs_rebuild = false;
 416
 417   // The transform tree is kept up-to-date as it is built, but the
 418   // combined_clips stored in the clip tree aren't computed during tree
 419   // building.
 420   property_trees->transform_tree.set_needs_update(false);
 421   property_trees->clip_tree.set_needs_update(true);
 422 }
 423
 424 void PropertyTreeBuilder::BuildPropertyTrees(
 425     Layer* root_layer,
 426     const Layer* page_scale_layer,
 427     float page_scale_factor,
 428     float device_scale_factor,
 429     const gfx::Rect& viewport,
 430     const gfx::Transform& device_transform,
 431     PropertyTrees* property_trees) {
 432   // TODO(enne): hoist this out of here
 433   if (!property_trees->needs_rebuild)
 434     return;
 435
 436   BuildPropertyTreesTopLevelInternal(
 437       root_layer, page_scale_layer, page_scale_factor, device_scale_factor,
 438       viewport, device_transform, property_trees);
 439 }
 440
 441 void PropertyTreeBuilder::BuildPropertyTrees(
 442     LayerImpl* root_layer,
 443     const LayerImpl* page_scale_layer,
 444     float page_scale_factor,
 445     float device_scale_factor,
 446     const gfx::Rect& viewport,
 447     const gfx::Transform& device_transform,
 448     PropertyTrees* property_trees) {
 449   BuildPropertyTreesTopLevelInternal(
 450       root_layer, page_scale_layer, page_scale_factor, device_scale_factor,
 451       viewport, device_transform, property_trees);
 452 }
 453
 454 }  // namespace cc