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 "ui/gfx/geometry/r_tree_base.h" 6 7 #include <algorithm> 8 9 #include "base/logging.h" 10 11 12 // Helpers -------------------------------------------------------------------- 13 14 namespace { 15 16 // Returns a Vector2d to allow us to do arithmetic on the result such as 17 // computing distances between centers. 18 gfx::Vector2d CenterOfRect(const gfx::Rect& rect) { 19 return rect.OffsetFromOrigin() + 20 gfx::Vector2d(rect.width() / 2, rect.height() / 2); 21 } 22 23 } 24 25 namespace gfx { 26 27 28 // RTreeBase::NodeBase -------------------------------------------------------- 29 30 RTreeBase::NodeBase::~NodeBase() { 31 } 32 33 void RTreeBase::NodeBase::RecomputeBoundsUpToRoot() { 34 RecomputeLocalBounds(); 35 if (parent_) 36 parent_->RecomputeBoundsUpToRoot(); 37 } 38 39 RTreeBase::NodeBase::NodeBase(const Rect& rect, NodeBase* parent) 40 : rect_(rect), 41 parent_(parent) { 42 } 43 44 void RTreeBase::NodeBase::RecomputeLocalBounds() { 45 } 46 47 // RTreeBase::RecordBase ------------------------------------------------------ 48 49 RTreeBase::RecordBase::RecordBase(const Rect& rect) : NodeBase(rect, NULL) { 50 } 51 52 RTreeBase::RecordBase::~RecordBase() { 53 } 54 55 void RTreeBase::RecordBase::AppendIntersectingRecords( 56 const Rect& query_rect, Records* matches_out) const { 57 if (rect().Intersects(query_rect)) 58 matches_out->push_back(this); 59 } 60 61 void RTreeBase::RecordBase::AppendAllRecords(Records* matches_out) const { 62 matches_out->push_back(this); 63 } 64 65 scoped_ptr<RTreeBase::NodeBase> 66 RTreeBase::RecordBase::RemoveAndReturnLastChild() { 67 return scoped_ptr<NodeBase>(); 68 } 69 70 int RTreeBase::RecordBase::Level() const { 71 return -1; 72 } 73 74 75 // RTreeBase::Node ------------------------------------------------------------ 76 77 RTreeBase::Node::Node() : NodeBase(Rect(), NULL), level_(0) { 78 } 79 80 RTreeBase::Node::~Node() { 81 } 82 83 scoped_ptr<RTreeBase::Node> RTreeBase::Node::ConstructParent() { 84 DCHECK(!parent()); 85 scoped_ptr<Node> new_parent(new Node(level_ + 1)); 86 new_parent->AddChild(scoped_ptr<NodeBase>(this)); 87 return new_parent.Pass(); 88 } 89 90 void RTreeBase::Node::AppendIntersectingRecords( 91 const Rect& query_rect, Records* matches_out) const { 92 // Check own bounding box for intersection, can cull all children if no 93 // intersection. 94 if (!rect().Intersects(query_rect)) 95 return; 96 97 // Conversely if we are completely contained within the query rect we can 98 // confidently skip all bounds checks for ourselves and all our children. 99 if (query_rect.Contains(rect())) { 100 AppendAllRecords(matches_out); 101 return; 102 } 103 104 // We intersect the query rect but we are not are not contained within it. 105 // We must query each of our children in turn. 106 for (Nodes::const_iterator i = children_.begin(); i != children_.end(); ++i) 107 (*i)->AppendIntersectingRecords(query_rect, matches_out); 108 } 109 110 void RTreeBase::Node::AppendAllRecords(Records* matches_out) const { 111 for (Nodes::const_iterator i = children_.begin(); i != children_.end(); ++i) 112 (*i)->AppendAllRecords(matches_out); 113 } 114 115 void RTreeBase::Node::RemoveNodesForReinsert(size_t number_to_remove, 116 Nodes* nodes) { 117 DCHECK_LE(number_to_remove, children_.size()); 118 119 std::partial_sort(children_.begin(), 120 children_.begin() + number_to_remove, 121 children_.end(), 122 &RTreeBase::Node::CompareCenterDistanceFromParent); 123 124 // Move the lowest-distance nodes to the returned vector. 125 nodes->insert( 126 nodes->end(), children_.begin(), children_.begin() + number_to_remove); 127 children_.weak_erase(children_.begin(), children_.begin() + number_to_remove); 128 } 129 130 scoped_ptr<RTreeBase::NodeBase> RTreeBase::Node::RemoveChild( 131 NodeBase* child_node, Nodes* orphans) { 132 DCHECK_EQ(this, child_node->parent()); 133 134 scoped_ptr<NodeBase> orphan(child_node->RemoveAndReturnLastChild()); 135 while (orphan) { 136 orphans->push_back(orphan.release()); 137 orphan = child_node->RemoveAndReturnLastChild(); 138 } 139 140 Nodes::iterator i = std::find(children_.begin(), children_.end(), child_node); 141 DCHECK(i != children_.end()); 142 children_.weak_erase(i); 143 144 return scoped_ptr<NodeBase>(child_node); 145 } 146 147 scoped_ptr<RTreeBase::NodeBase> RTreeBase::Node::RemoveAndReturnLastChild() { 148 if (children_.empty()) 149 return scoped_ptr<NodeBase>(); 150 151 scoped_ptr<NodeBase> last_child(children_.back()); 152 children_.weak_erase(children_.end() - 1); 153 last_child->set_parent(NULL); 154 return last_child.Pass(); 155 } 156 157 RTreeBase::Node* RTreeBase::Node::ChooseSubtree(NodeBase* node) { 158 DCHECK(node); 159 // Should never be called on a node at equal or lower level in the tree than 160 // the node to insert. 161 DCHECK_GT(level_, node->Level()); 162 163 // If we are a parent of nodes on the provided node level, we are done. 164 if (level_ == node->Level() + 1) 165 return this; 166 167 // Precompute a vector of expanded rects, used by both LeastOverlapIncrease 168 // and LeastAreaEnlargement. 169 Rects expanded_rects; 170 expanded_rects.reserve(children_.size()); 171 for (Nodes::iterator i = children_.begin(); i != children_.end(); ++i) 172 expanded_rects.push_back(UnionRects(node->rect(), (*i)->rect())); 173 174 Node* best_candidate = NULL; 175 // For parents of leaf nodes, we pick the node that will cause the least 176 // increase in overlap by the addition of this new node. This may detect a 177 // tie, in which case it will return NULL. 178 if (level_ == 1) 179 best_candidate = LeastOverlapIncrease(node->rect(), expanded_rects); 180 181 // For non-parents of leaf nodes, or for parents of leaf nodes with ties in 182 // overlap increase, we choose the subtree with least area enlargement caused 183 // by the addition of the new node. 184 if (!best_candidate) 185 best_candidate = LeastAreaEnlargement(node->rect(), expanded_rects); 186 187 DCHECK(best_candidate); 188 return best_candidate->ChooseSubtree(node); 189 } 190 191 size_t RTreeBase::Node::AddChild(scoped_ptr<NodeBase> node) { 192 DCHECK(node); 193 // Sanity-check that the level of the child being added is one less than ours. 194 DCHECK_EQ(level_ - 1, node->Level()); 195 node->set_parent(this); 196 set_rect(UnionRects(rect(), node->rect())); 197 children_.push_back(node.release()); 198 return children_.size(); 199 } 200 201 scoped_ptr<RTreeBase::NodeBase> RTreeBase::Node::Split(size_t min_children, 202 size_t max_children) { 203 // We should have too many children to begin with. 204 DCHECK_EQ(max_children + 1, children_.size()); 205 206 // Determine if we should split along the horizontal or vertical axis. 207 std::vector<NodeBase*> vertical_sort(children_.get()); 208 std::vector<NodeBase*> horizontal_sort(children_.get()); 209 std::sort(vertical_sort.begin(), 210 vertical_sort.end(), 211 &RTreeBase::Node::CompareVertical); 212 std::sort(horizontal_sort.begin(), 213 horizontal_sort.end(), 214 &RTreeBase::Node::CompareHorizontal); 215 216 Rects low_vertical_bounds; 217 Rects low_horizontal_bounds; 218 BuildLowBounds(vertical_sort, 219 horizontal_sort, 220 &low_vertical_bounds, 221 &low_horizontal_bounds); 222 223 Rects high_vertical_bounds; 224 Rects high_horizontal_bounds; 225 BuildHighBounds(vertical_sort, 226 horizontal_sort, 227 &high_vertical_bounds, 228 &high_horizontal_bounds); 229 230 // Choose |end_index| such that both Nodes after the split will have 231 // min_children <= children_.size() <= max_children. 232 size_t end_index = std::min(max_children, children_.size() - min_children); 233 bool is_vertical_split = 234 SmallestMarginSum(min_children, 235 end_index, 236 low_horizontal_bounds, 237 high_horizontal_bounds) < 238 SmallestMarginSum(min_children, 239 end_index, 240 low_vertical_bounds, 241 high_vertical_bounds); 242 243 // Choose split index along chosen axis and perform the split. 244 const Rects& low_bounds( 245 is_vertical_split ? low_vertical_bounds : low_horizontal_bounds); 246 const Rects& high_bounds( 247 is_vertical_split ? high_vertical_bounds : high_horizontal_bounds); 248 size_t split_index = 249 ChooseSplitIndex(min_children, end_index, low_bounds, high_bounds); 250 251 const std::vector<NodeBase*>& sort( 252 is_vertical_split ? vertical_sort : horizontal_sort); 253 return DivideChildren(low_bounds, high_bounds, sort, split_index); 254 } 255 256 int RTreeBase::Node::Level() const { 257 return level_; 258 } 259 260 RTreeBase::Node::Node(int level) : NodeBase(Rect(), NULL), level_(level) { 261 } 262 263 // static 264 bool RTreeBase::Node::CompareVertical(const NodeBase* a, const NodeBase* b) { 265 const Rect& a_rect = a->rect(); 266 const Rect& b_rect = b->rect(); 267 return (a_rect.y() < b_rect.y()) || 268 ((a_rect.y() == b_rect.y()) && (a_rect.height() < b_rect.height())); 269 } 270 271 // static 272 bool RTreeBase::Node::CompareHorizontal(const NodeBase* a, const NodeBase* b) { 273 const Rect& a_rect = a->rect(); 274 const Rect& b_rect = b->rect(); 275 return (a_rect.x() < b_rect.x()) || 276 ((a_rect.x() == b_rect.x()) && (a_rect.width() < b_rect.width())); 277 } 278 279 // static 280 bool RTreeBase::Node::CompareCenterDistanceFromParent(const NodeBase* a, 281 const NodeBase* b) { 282 const NodeBase* p = a->parent(); 283 284 DCHECK(p); 285 DCHECK_EQ(p, b->parent()); 286 287 Vector2d p_center = CenterOfRect(p->rect()); 288 Vector2d a_center = CenterOfRect(a->rect()); 289 Vector2d b_center = CenterOfRect(b->rect()); 290 291 // We don't bother with square roots because we are only comparing the two 292 // values for sorting purposes. 293 return (a_center - p_center).LengthSquared() < 294 (b_center - p_center).LengthSquared(); 295 } 296 297 // static 298 void RTreeBase::Node::BuildLowBounds( 299 const std::vector<NodeBase*>& vertical_sort, 300 const std::vector<NodeBase*>& horizontal_sort, 301 Rects* vertical_bounds, 302 Rects* horizontal_bounds) { 303 Rect vertical_bounds_rect; 304 vertical_bounds->reserve(vertical_sort.size()); 305 for (std::vector<NodeBase*>::const_iterator i = vertical_sort.begin(); 306 i != vertical_sort.end(); 307 ++i) { 308 vertical_bounds_rect.Union((*i)->rect()); 309 vertical_bounds->push_back(vertical_bounds_rect); 310 } 311 312 Rect horizontal_bounds_rect; 313 horizontal_bounds->reserve(horizontal_sort.size()); 314 for (std::vector<NodeBase*>::const_iterator i = horizontal_sort.begin(); 315 i != horizontal_sort.end(); 316 ++i) { 317 horizontal_bounds_rect.Union((*i)->rect()); 318 horizontal_bounds->push_back(horizontal_bounds_rect); 319 } 320 } 321 322 // static 323 void RTreeBase::Node::BuildHighBounds( 324 const std::vector<NodeBase*>& vertical_sort, 325 const std::vector<NodeBase*>& horizontal_sort, 326 Rects* vertical_bounds, 327 Rects* horizontal_bounds) { 328 Rect vertical_bounds_rect; 329 vertical_bounds->reserve(vertical_sort.size()); 330 for (std::vector<NodeBase*>::const_reverse_iterator i = 331 vertical_sort.rbegin(); 332 i != vertical_sort.rend(); 333 ++i) { 334 vertical_bounds_rect.Union((*i)->rect()); 335 vertical_bounds->push_back(vertical_bounds_rect); 336 } 337 std::reverse(vertical_bounds->begin(), vertical_bounds->end()); 338 339 Rect horizontal_bounds_rect; 340 horizontal_bounds->reserve(horizontal_sort.size()); 341 for (std::vector<NodeBase*>::const_reverse_iterator i = 342 horizontal_sort.rbegin(); 343 i != horizontal_sort.rend(); 344 ++i) { 345 horizontal_bounds_rect.Union((*i)->rect()); 346 horizontal_bounds->push_back(horizontal_bounds_rect); 347 } 348 std::reverse(horizontal_bounds->begin(), horizontal_bounds->end()); 349 } 350 351 size_t RTreeBase::Node::ChooseSplitIndex(size_t start_index, 352 size_t end_index, 353 const Rects& low_bounds, 354 const Rects& high_bounds) { 355 DCHECK_EQ(low_bounds.size(), high_bounds.size()); 356 357 int smallest_overlap_area = UnionRects( 358 low_bounds[start_index], high_bounds[start_index]).size().GetArea(); 359 int smallest_combined_area = low_bounds[start_index].size().GetArea() + 360 high_bounds[start_index].size().GetArea(); 361 size_t optimal_split_index = start_index; 362 for (size_t p = start_index + 1; p < end_index; ++p) { 363 const int overlap_area = 364 UnionRects(low_bounds[p], high_bounds[p]).size().GetArea(); 365 const int combined_area = 366 low_bounds[p].size().GetArea() + high_bounds[p].size().GetArea(); 367 if ((overlap_area < smallest_overlap_area) || 368 ((overlap_area == smallest_overlap_area) && 369 (combined_area < smallest_combined_area))) { 370 smallest_overlap_area = overlap_area; 371 smallest_combined_area = combined_area; 372 optimal_split_index = p; 373 } 374 } 375 376 // optimal_split_index currently points at the last element in the first set, 377 // so advance it by 1 to point at the first element in the second set. 378 return optimal_split_index + 1; 379 } 380 381 // static 382 int RTreeBase::Node::SmallestMarginSum(size_t start_index, 383 size_t end_index, 384 const Rects& low_bounds, 385 const Rects& high_bounds) { 386 DCHECK_EQ(low_bounds.size(), high_bounds.size()); 387 DCHECK_LT(start_index, low_bounds.size()); 388 DCHECK_LE(start_index, end_index); 389 DCHECK_LE(end_index, low_bounds.size()); 390 Rects::const_iterator i(low_bounds.begin() + start_index); 391 Rects::const_iterator j(high_bounds.begin() + start_index); 392 int smallest_sum = i->width() + i->height() + j->width() + j->height(); 393 for (; i != (low_bounds.begin() + end_index); ++i, ++j) { 394 smallest_sum = std::min( 395 smallest_sum, i->width() + i->height() + j->width() + j->height()); 396 } 397 398 return smallest_sum; 399 } 400 401 void RTreeBase::Node::RecomputeLocalBounds() { 402 Rect bounds; 403 for (size_t i = 0; i < children_.size(); ++i) 404 bounds.Union(children_[i]->rect()); 405 406 set_rect(bounds); 407 } 408 409 int RTreeBase::Node::OverlapIncreaseToAdd(const Rect& rect, 410 const NodeBase* candidate_node, 411 const Rect& expanded_rect) const { 412 DCHECK(candidate_node); 413 414 // Early-out when |rect| is contained completely within |candidate|. 415 if (candidate_node->rect().Contains(rect)) 416 return 0; 417 418 int total_original_overlap = 0; 419 int total_expanded_overlap = 0; 420 421 // Now calculate overlap with all other rects in this node. 422 for (Nodes::const_iterator it = children_.begin(); 423 it != children_.end(); ++it) { 424 // Skip calculating overlap with the candidate rect. 425 if ((*it) == candidate_node) 426 continue; 427 NodeBase* overlap_node = (*it); 428 total_original_overlap += IntersectRects( 429 candidate_node->rect(), overlap_node->rect()).size().GetArea(); 430 Rect expanded_overlap_rect = expanded_rect; 431 expanded_overlap_rect.Intersect(overlap_node->rect()); 432 total_expanded_overlap += expanded_overlap_rect.size().GetArea(); 433 } 434 435 return total_expanded_overlap - total_original_overlap; 436 } 437 438 scoped_ptr<RTreeBase::NodeBase> RTreeBase::Node::DivideChildren( 439 const Rects& low_bounds, 440 const Rects& high_bounds, 441 const std::vector<NodeBase*>& sorted_children, 442 size_t split_index) { 443 DCHECK_EQ(low_bounds.size(), high_bounds.size()); 444 DCHECK_EQ(low_bounds.size(), sorted_children.size()); 445 DCHECK_LT(split_index, low_bounds.size()); 446 DCHECK_GT(split_index, 0U); 447 448 scoped_ptr<Node> sibling(new Node(level_)); 449 sibling->set_parent(parent()); 450 set_rect(low_bounds[split_index - 1]); 451 sibling->set_rect(high_bounds[split_index]); 452 453 // Our own children_ vector is unsorted, so we wipe it out and divide the 454 // sorted bounds rects between ourselves and our sibling. 455 children_.weak_clear(); 456 children_.insert(children_.end(), 457 sorted_children.begin(), 458 sorted_children.begin() + split_index); 459 sibling->children_.insert(sibling->children_.end(), 460 sorted_children.begin() + split_index, 461 sorted_children.end()); 462 463 for (size_t i = 0; i < sibling->children_.size(); ++i) 464 sibling->children_[i]->set_parent(sibling.get()); 465 466 return sibling.PassAs<NodeBase>(); 467 } 468 469 RTreeBase::Node* RTreeBase::Node::LeastOverlapIncrease( 470 const Rect& node_rect, 471 const Rects& expanded_rects) { 472 NodeBase* best_node = children_.front(); 473 int least_overlap_increase = 474 OverlapIncreaseToAdd(node_rect, children_[0], expanded_rects[0]); 475 for (size_t i = 1; i < children_.size(); ++i) { 476 int overlap_increase = 477 OverlapIncreaseToAdd(node_rect, children_[i], expanded_rects[i]); 478 if (overlap_increase < least_overlap_increase) { 479 least_overlap_increase = overlap_increase; 480 best_node = children_[i]; 481 } else if (overlap_increase == least_overlap_increase) { 482 // If we are tied at zero there is no possible better overlap increase, 483 // so we can report a tie early. 484 if (overlap_increase == 0) 485 return NULL; 486 487 best_node = NULL; 488 } 489 } 490 491 // Ensure that our children are always Nodes and not Records. 492 DCHECK_GE(level_, 1); 493 return static_cast<Node*>(best_node); 494 } 495 496 RTreeBase::Node* RTreeBase::Node::LeastAreaEnlargement( 497 const Rect& node_rect, 498 const Rects& expanded_rects) { 499 DCHECK(!children_.empty()); 500 DCHECK_EQ(children_.size(), expanded_rects.size()); 501 502 NodeBase* best_node = children_.front(); 503 int least_area_enlargement = 504 expanded_rects[0].size().GetArea() - best_node->rect().size().GetArea(); 505 for (size_t i = 1; i < children_.size(); ++i) { 506 NodeBase* candidate_node = children_[i]; 507 int area_change = expanded_rects[i].size().GetArea() - 508 candidate_node->rect().size().GetArea(); 509 DCHECK_GE(area_change, 0); 510 if (area_change < least_area_enlargement) { 511 best_node = candidate_node; 512 least_area_enlargement = area_change; 513 } else if (area_change == least_area_enlargement && 514 candidate_node->rect().size().GetArea() < 515 best_node->rect().size().GetArea()) { 516 // Ties are broken by choosing the entry with the least area. 517 best_node = candidate_node; 518 } 519 } 520 521 // Ensure that our children are always Nodes and not Records. 522 DCHECK_GE(level_, 1); 523 return static_cast<Node*>(best_node); 524 } 525 526 527 // RTreeBase ------------------------------------------------------------------ 528 529 RTreeBase::RTreeBase(size_t min_children, size_t max_children) 530 : root_(new Node()), 531 min_children_(min_children), 532 max_children_(max_children) { 533 DCHECK_GE(min_children_, 2U); 534 DCHECK_LE(min_children_, max_children_ / 2U); 535 } 536 537 RTreeBase::~RTreeBase() { 538 } 539 540 void RTreeBase::InsertNode( 541 scoped_ptr<NodeBase> node, int* highest_reinsert_level) { 542 // Find the most appropriate parent to insert node into. 543 Node* parent = root_->ChooseSubtree(node.get()); 544 DCHECK(parent); 545 // Verify ChooseSubtree returned a Node at the correct level. 546 DCHECK_EQ(parent->Level(), node->Level() + 1); 547 Node* insert_parent = static_cast<Node*>(parent); 548 NodeBase* needs_bounds_recomputed = insert_parent->parent(); 549 Nodes reinserts; 550 // Attempt to insert the Node, if this overflows the Node we must handle it. 551 while (insert_parent && 552 insert_parent->AddChild(node.Pass()) > max_children_) { 553 // If we have yet to re-insert nodes at this level during this data insert, 554 // and we're not at the root, R*-Tree calls for re-insertion of some of the 555 // nodes, resulting in a better balance on the tree. 556 if (insert_parent->parent() && 557 insert_parent->Level() > *highest_reinsert_level) { 558 insert_parent->RemoveNodesForReinsert(max_children_ / 3, &reinserts); 559 // Adjust highest_reinsert_level to this level. 560 *highest_reinsert_level = insert_parent->Level(); 561 // RemoveNodesForReinsert() does not recompute bounds, so mark it. 562 needs_bounds_recomputed = insert_parent; 563 break; 564 } 565 566 // Split() will create a sibling to insert_parent both of which will have 567 // valid bounds, but this invalidates their parent's bounds. 568 node = insert_parent->Split(min_children_, max_children_); 569 insert_parent = static_cast<Node*>(insert_parent->parent()); 570 needs_bounds_recomputed = insert_parent; 571 } 572 573 // If we have a Node to insert, and we hit the root of the current tree, 574 // we create a new root which is the parent of the current root and the 575 // insert_node. Note that we must release() the |root_| since 576 // ConstructParent() will take ownership of it. 577 if (!insert_parent && node) { 578 root_ = root_.release()->ConstructParent(); 579 root_->AddChild(node.Pass()); 580 } 581 582 // Recompute bounds along insertion path. 583 if (needs_bounds_recomputed) 584 needs_bounds_recomputed->RecomputeBoundsUpToRoot(); 585 586 // Complete re-inserts, if any. The algorithm only allows for one invocation 587 // of RemoveNodesForReinsert() per level of the tree in an overall call to 588 // Insert(). 589 while (!reinserts.empty()) { 590 Nodes::iterator last_element = reinserts.end() - 1; 591 NodeBase* temp_ptr(*last_element); 592 reinserts.weak_erase(last_element); 593 InsertNode(make_scoped_ptr(temp_ptr), highest_reinsert_level); 594 } 595 } 596 597 scoped_ptr<RTreeBase::NodeBase> RTreeBase::RemoveNode(NodeBase* node) { 598 // We need to remove this node from its parent. 599 Node* parent = static_cast<Node*>(node->parent()); 600 // Record nodes are never allowed as the root, so we should always have a 601 // parent. 602 DCHECK(parent); 603 // Should always be a leaf that had the record. 604 DCHECK_EQ(0, parent->Level()); 605 606 Nodes orphans; 607 scoped_ptr<NodeBase> removed_node(parent->RemoveChild(node, &orphans)); 608 609 // It's possible that by removing |node| from |parent| we have made |parent| 610 // have less than the minimum number of children, in which case we will need 611 // to remove and delete |parent| while reinserting any other children that it 612 // had. We traverse up the tree doing this until we remove a child from a 613 // parent that still has greater than or equal to the minimum number of Nodes. 614 while (parent->count() < min_children_) { 615 NodeBase* child = parent; 616 parent = static_cast<Node*>(parent->parent()); 617 618 // If we've hit the root, stop. 619 if (!parent) 620 break; 621 622 parent->RemoveChild(child, &orphans); 623 } 624 625 // If we stopped deleting nodes up the tree before encountering the root, 626 // we'll need to fix up the bounds from the first parent we didn't delete 627 // up to the root. 628 if (parent) 629 parent->RecomputeBoundsUpToRoot(); 630 else 631 root_->RecomputeBoundsUpToRoot(); 632 633 while (!orphans.empty()) { 634 Nodes::iterator last_element = orphans.end() - 1; 635 NodeBase* temp_ptr(*last_element); 636 orphans.weak_erase(last_element); 637 int starting_level = -1; 638 InsertNode(make_scoped_ptr(temp_ptr), &starting_level); 639 } 640 641 return removed_node.Pass(); 642 } 643 644 void RTreeBase::PruneRootIfNecessary() { 645 if (root()->count() == 1 && root()->Level() > 0) { 646 // Awkward reset(cast(release)) pattern here because there's no better way 647 // to downcast the scoped_ptr from RemoveAndReturnLastChild() from NodeBase 648 // to Node. 649 root_.reset( 650 static_cast<Node*>(root_->RemoveAndReturnLastChild().release())); 651 } 652 } 653 654 void RTreeBase::ResetRoot() { 655 root_.reset(new Node()); 656 } 657 658 } // namespace gfx 659