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| 1 // Copyright (c) 2012 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 "ash/wm/workspace/magnetism_matcher.h" | |
| 6 | |
| 7 #include <algorithm> | |
| 8 #include <cmath> | |
| 9 | |
| 10 namespace ash { | |
| 11 namespace { | |
| 12 | |
| 13 // Returns true if |a| is close enough to |b| that the two edges snap. | |
| 14 bool IsCloseEnough(int a, int b) { | |
| 15 return abs(a - b) <= MagnetismMatcher::kMagneticDistance; | |
| 16 } | |
| 17 | |
| 18 // Returns true if the specified SecondaryMagnetismEdge can be matched with a | |
| 19 // primary edge of |primary|. |edges| is a bitmask of the allowed | |
| 20 // MagnetismEdges. | |
| 21 bool CanMatchSecondaryEdge(MagnetismEdge primary, | |
| 22 SecondaryMagnetismEdge secondary, | |
| 23 uint32_t edges) { | |
| 24 // Convert |secondary| to a MagnetismEdge so we can compare it to |edges|. | |
| 25 MagnetismEdge secondary_as_magnetism_edge = MAGNETISM_EDGE_TOP; | |
| 26 switch (primary) { | |
| 27 case MAGNETISM_EDGE_TOP: | |
| 28 case MAGNETISM_EDGE_BOTTOM: | |
| 29 if (secondary == SECONDARY_MAGNETISM_EDGE_LEADING) | |
| 30 secondary_as_magnetism_edge = MAGNETISM_EDGE_LEFT; | |
| 31 else if (secondary == SECONDARY_MAGNETISM_EDGE_TRAILING) | |
| 32 secondary_as_magnetism_edge = MAGNETISM_EDGE_RIGHT; | |
| 33 else | |
| 34 NOTREACHED(); | |
| 35 break; | |
| 36 case MAGNETISM_EDGE_LEFT: | |
| 37 case MAGNETISM_EDGE_RIGHT: | |
| 38 if (secondary == SECONDARY_MAGNETISM_EDGE_LEADING) | |
| 39 secondary_as_magnetism_edge = MAGNETISM_EDGE_TOP; | |
| 40 else if (secondary == SECONDARY_MAGNETISM_EDGE_TRAILING) | |
| 41 secondary_as_magnetism_edge = MAGNETISM_EDGE_BOTTOM; | |
| 42 else | |
| 43 NOTREACHED(); | |
| 44 break; | |
| 45 } | |
| 46 return (edges & secondary_as_magnetism_edge) != 0; | |
| 47 } | |
| 48 | |
| 49 } // namespace | |
| 50 | |
| 51 // MagnetismEdgeMatcher -------------------------------------------------------- | |
| 52 | |
| 53 MagnetismEdgeMatcher::MagnetismEdgeMatcher(const gfx::Rect& bounds, | |
| 54 MagnetismEdge edge) | |
| 55 : bounds_(bounds), | |
| 56 edge_(edge) { | |
| 57 ranges_.push_back(GetSecondaryRange(bounds_)); | |
| 58 } | |
| 59 | |
| 60 MagnetismEdgeMatcher::~MagnetismEdgeMatcher() { | |
| 61 } | |
| 62 | |
| 63 bool MagnetismEdgeMatcher::ShouldAttach(const gfx::Rect& bounds) { | |
| 64 if (is_edge_obscured()) | |
| 65 return false; | |
| 66 | |
| 67 if (IsCloseEnough(GetPrimaryCoordinate(bounds_, edge_), | |
| 68 GetPrimaryCoordinate(bounds, FlipEdge(edge_)))) { | |
| 69 const Range range(GetSecondaryRange(bounds)); | |
| 70 Ranges::const_iterator i = | |
| 71 std::lower_bound(ranges_.begin(), ranges_.end(), range); | |
| 72 // Close enough, but only attach if some portion of the edge is visible. | |
| 73 if ((i != ranges_.begin() && RangesIntersect(*(i - 1), range)) || | |
| 74 (i != ranges_.end() && RangesIntersect(*i, range))) { | |
| 75 return true; | |
| 76 } | |
| 77 } | |
| 78 // NOTE: this checks against the current bounds, we may want to allow some | |
| 79 // flexibility here. | |
| 80 const Range primary_range(GetPrimaryRange(bounds)); | |
| 81 if (primary_range.first <= GetPrimaryCoordinate(bounds_, edge_) && | |
| 82 primary_range.second >= GetPrimaryCoordinate(bounds_, edge_)) { | |
| 83 UpdateRanges(GetSecondaryRange(bounds)); | |
| 84 } | |
| 85 return false; | |
| 86 } | |
| 87 | |
| 88 void MagnetismEdgeMatcher::UpdateRanges(const Range& range) { | |
| 89 Ranges::const_iterator it = | |
| 90 std::lower_bound(ranges_.begin(), ranges_.end(), range); | |
| 91 if (it != ranges_.begin() && RangesIntersect(*(it - 1), range)) | |
| 92 --it; | |
| 93 if (it == ranges_.end()) | |
| 94 return; | |
| 95 | |
| 96 for (size_t i = it - ranges_.begin(); | |
| 97 i < ranges_.size() && RangesIntersect(ranges_[i], range); ) { | |
| 98 if (range.first <= ranges_[i].first && | |
| 99 range.second >= ranges_[i].second) { | |
| 100 ranges_.erase(ranges_.begin() + i); | |
| 101 } else if (range.first < ranges_[i].first) { | |
| 102 DCHECK_GT(range.second, ranges_[i].first); | |
| 103 ranges_[i] = Range(range.second, ranges_[i].second); | |
| 104 ++i; | |
| 105 } else { | |
| 106 Range existing(ranges_[i]); | |
| 107 ranges_[i].second = range.first; | |
| 108 ++i; | |
| 109 if (existing.second > range.second) { | |
| 110 ranges_.insert(ranges_.begin() + i, | |
| 111 Range(range.second, existing.second)); | |
| 112 ++i; | |
| 113 } | |
| 114 } | |
| 115 } | |
| 116 } | |
| 117 | |
| 118 // MagnetismMatcher ------------------------------------------------------------ | |
| 119 | |
| 120 // static | |
| 121 const int MagnetismMatcher::kMagneticDistance = 8; | |
| 122 | |
| 123 MagnetismMatcher::MagnetismMatcher(const gfx::Rect& bounds, uint32_t edges) | |
| 124 : edges_(edges) { | |
| 125 if (edges & MAGNETISM_EDGE_TOP) | |
| 126 matchers_.push_back(new MagnetismEdgeMatcher(bounds, MAGNETISM_EDGE_TOP)); | |
| 127 if (edges & MAGNETISM_EDGE_LEFT) | |
| 128 matchers_.push_back(new MagnetismEdgeMatcher(bounds, MAGNETISM_EDGE_LEFT)); | |
| 129 if (edges & MAGNETISM_EDGE_BOTTOM) { | |
| 130 matchers_.push_back(new MagnetismEdgeMatcher(bounds, | |
| 131 MAGNETISM_EDGE_BOTTOM)); | |
| 132 } | |
| 133 if (edges & MAGNETISM_EDGE_RIGHT) | |
| 134 matchers_.push_back(new MagnetismEdgeMatcher(bounds, MAGNETISM_EDGE_RIGHT)); | |
| 135 } | |
| 136 | |
| 137 MagnetismMatcher::~MagnetismMatcher() { | |
| 138 } | |
| 139 | |
| 140 bool MagnetismMatcher::ShouldAttach(const gfx::Rect& bounds, | |
| 141 MatchedEdge* edge) { | |
| 142 for (size_t i = 0; i < matchers_.size(); ++i) { | |
| 143 if (matchers_[i]->ShouldAttach(bounds)) { | |
| 144 edge->primary_edge = matchers_[i]->edge(); | |
| 145 AttachToSecondaryEdge(bounds, edge->primary_edge, | |
| 146 &(edge->secondary_edge)); | |
| 147 return true; | |
| 148 } | |
| 149 } | |
| 150 return false; | |
| 151 } | |
| 152 | |
| 153 bool MagnetismMatcher::AreEdgesObscured() const { | |
| 154 for (size_t i = 0; i < matchers_.size(); ++i) { | |
| 155 if (!matchers_[i]->is_edge_obscured()) | |
| 156 return false; | |
| 157 } | |
| 158 return true; | |
| 159 } | |
| 160 | |
| 161 void MagnetismMatcher::AttachToSecondaryEdge( | |
| 162 const gfx::Rect& bounds, | |
| 163 MagnetismEdge edge, | |
| 164 SecondaryMagnetismEdge* secondary_edge) const { | |
| 165 const gfx::Rect& src_bounds(matchers_[0]->bounds()); | |
| 166 if (edge == MAGNETISM_EDGE_LEFT || edge == MAGNETISM_EDGE_RIGHT) { | |
| 167 if (CanMatchSecondaryEdge(edge, SECONDARY_MAGNETISM_EDGE_LEADING, edges_) && | |
| 168 IsCloseEnough(bounds.y(), src_bounds.y())) { | |
| 169 *secondary_edge = SECONDARY_MAGNETISM_EDGE_LEADING; | |
| 170 } else if (CanMatchSecondaryEdge(edge, SECONDARY_MAGNETISM_EDGE_TRAILING, | |
| 171 edges_) && | |
| 172 IsCloseEnough(bounds.bottom(), src_bounds.bottom())) { | |
| 173 *secondary_edge = SECONDARY_MAGNETISM_EDGE_TRAILING; | |
| 174 } else { | |
| 175 *secondary_edge = SECONDARY_MAGNETISM_EDGE_NONE; | |
| 176 } | |
| 177 } else { | |
| 178 if (CanMatchSecondaryEdge(edge, SECONDARY_MAGNETISM_EDGE_LEADING, edges_) && | |
| 179 IsCloseEnough(bounds.x(), src_bounds.x())) { | |
| 180 *secondary_edge = SECONDARY_MAGNETISM_EDGE_LEADING; | |
| 181 } else if (CanMatchSecondaryEdge(edge, SECONDARY_MAGNETISM_EDGE_TRAILING, | |
| 182 edges_) && | |
| 183 IsCloseEnough(bounds.right(), src_bounds.right())) { | |
| 184 *secondary_edge = SECONDARY_MAGNETISM_EDGE_TRAILING; | |
| 185 } else { | |
| 186 *secondary_edge = SECONDARY_MAGNETISM_EDGE_NONE; | |
| 187 } | |
| 188 } | |
| 189 } | |
| 190 | |
| 191 } // namespace ash | |
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