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| 1 // Copyright (c) 2006-2008 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 // Provides some utilities for iterating over a RenderObject graph in |
| 6 // stacking order. |
| 7 |
| 8 #ifndef WEBKIT_GLUE_STACKING_ORDER_ITERATOR_H__ |
| 9 #define WEBKIT_GLUE_STACKING_ORDER_ITERATOR_H__ |
| 10 |
| 11 #include <vector> |
| 12 |
| 13 namespace WebCore { |
| 14 class RenderLayer; |
| 15 class RenderObject; |
| 16 } |
| 17 |
| 18 // Iterates over a subtree of RenderLayers in stacking order, back to |
| 19 // front. Modifying the RenderObject graph invalidates this iterator. |
| 20 // |
| 21 // TODO(tulrich): this could go in webkit. |
| 22 // TODO(tulrich): needs unittests. |
| 23 class RenderLayerIterator { |
| 24 public: |
| 25 RenderLayerIterator(); |
| 26 |
| 27 // Sets the RenderLayer subtree to iterate over. |
| 28 void Reset(WebCore::RenderLayer* rl); |
| 29 |
| 30 // Returns the next RenderLayer in stacking order, back to front. |
| 31 WebCore::RenderLayer* Next(); |
| 32 private: |
| 33 class Context { |
| 34 public: |
| 35 Context(WebCore::RenderLayer* layer); |
| 36 |
| 37 bool HasMoreNeg(); |
| 38 Context NextNeg(); |
| 39 bool HasSelf(); |
| 40 WebCore::RenderLayer* NextSelf(); |
| 41 bool HasMoreOverflow(); |
| 42 Context NextOverflow(); |
| 43 bool HasMorePos(); |
| 44 Context NextPos(); |
| 45 |
| 46 private: |
| 47 WebCore::RenderLayer* layer_; |
| 48 size_t next_neg_; |
| 49 size_t next_self_; |
| 50 size_t next_overflow_; |
| 51 size_t next_pos_; |
| 52 }; |
| 53 |
| 54 std::vector<Context> context_stack_; |
| 55 }; |
| 56 |
| 57 // Iterates over a subtree of RenderObjects below a given RenderLayer. |
| 58 // |
| 59 // TODO(tulrich): this could go in webkit. |
| 60 // TODO(tulrich): needs unittests. |
| 61 class StackingOrderIterator { |
| 62 public: |
| 63 StackingOrderIterator(); |
| 64 void Reset(WebCore::RenderLayer* rl); |
| 65 WebCore::RenderObject* Next(); |
| 66 |
| 67 private: |
| 68 RenderLayerIterator layer_iterator_; |
| 69 WebCore::RenderObject* current_object_; |
| 70 WebCore::RenderObject* current_layer_root_; |
| 71 }; |
| 72 |
| 73 #endif // WEBKIT_GLUE_STACKING_ORDER_ITERATOR_H__ |
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