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.
5 #ifndef ASH_WM_WORKSPACE_MAGNETISM_MATCHER_H_
6 #define ASH_WM_WORKSPACE_MAGNETISM_MATCHER_H_
11 #include "ash/ash_export.h"
12 #include "base/compiler_specific.h"
13 #include "base/logging.h"
14 #include "base/memory/scoped_vector.h"
15 #include "ui/gfx/rect.h"
20 MAGNETISM_EDGE_TOP
= 1 << 0,
21 MAGNETISM_EDGE_LEFT
= 1 << 1,
22 MAGNETISM_EDGE_BOTTOM
= 1 << 2,
23 MAGNETISM_EDGE_RIGHT
= 1 << 3,
26 const uint32 kAllMagnetismEdges
=
27 MAGNETISM_EDGE_TOP
| MAGNETISM_EDGE_LEFT
| MAGNETISM_EDGE_BOTTOM
|
30 // MagnetismEdgeMatcher is used for matching a particular edge of a window. You
31 // shouldn't need to use this directly, instead use MagnetismMatcher which takes
33 // MagnetismEdgeMatcher maintains a range of the visible portions of the
34 // edge. As ShouldAttach() is invoked the visible range is updated.
35 class MagnetismEdgeMatcher
{
37 MagnetismEdgeMatcher(const gfx::Rect
& bounds
, MagnetismEdge edge
);
38 ~MagnetismEdgeMatcher();
40 MagnetismEdge
edge() const { return edge_
; }
41 const gfx::Rect
& bounds() const { return bounds_
; }
43 // Returns true if the edge is completely obscured. If true ShouldAttach()
45 bool is_edge_obscured() const { return ranges_
.empty(); }
47 // Returns true if should attach to the specified bounds.
48 bool ShouldAttach(const gfx::Rect
& bounds
);
51 typedef std::pair
<int,int> Range
;
52 typedef std::vector
<Range
> Ranges
;
54 // Removes |range| from |ranges_|.
55 void UpdateRanges(const Range
& range
);
57 static int GetPrimaryCoordinate(const gfx::Rect
& bounds
, MagnetismEdge edge
) {
59 case MAGNETISM_EDGE_TOP
:
61 case MAGNETISM_EDGE_LEFT
:
63 case MAGNETISM_EDGE_BOTTOM
:
64 return bounds
.bottom();
65 case MAGNETISM_EDGE_RIGHT
:
66 return bounds
.right();
72 static MagnetismEdge
FlipEdge(MagnetismEdge edge
) {
74 case MAGNETISM_EDGE_TOP
:
75 return MAGNETISM_EDGE_BOTTOM
;
76 case MAGNETISM_EDGE_BOTTOM
:
77 return MAGNETISM_EDGE_TOP
;
78 case MAGNETISM_EDGE_LEFT
:
79 return MAGNETISM_EDGE_RIGHT
;
80 case MAGNETISM_EDGE_RIGHT
:
81 return MAGNETISM_EDGE_LEFT
;
84 return MAGNETISM_EDGE_LEFT
;
87 Range
GetPrimaryRange(const gfx::Rect
& bounds
) const {
89 case MAGNETISM_EDGE_TOP
:
90 case MAGNETISM_EDGE_BOTTOM
:
91 return Range(bounds
.y(), bounds
.bottom());
92 case MAGNETISM_EDGE_LEFT
:
93 case MAGNETISM_EDGE_RIGHT
:
94 return Range(bounds
.x(), bounds
.right());
100 Range
GetSecondaryRange(const gfx::Rect
& bounds
) const {
102 case MAGNETISM_EDGE_TOP
:
103 case MAGNETISM_EDGE_BOTTOM
:
104 return Range(bounds
.x(), bounds
.right());
105 case MAGNETISM_EDGE_LEFT
:
106 case MAGNETISM_EDGE_RIGHT
:
107 return Range(bounds
.y(), bounds
.bottom());
113 static bool RangesIntersect(const Range
& r1
, const Range
& r2
) {
114 return r2
.first
< r1
.second
&& r2
.second
> r1
.first
;
117 // The bounds of window.
118 const gfx::Rect bounds_
;
120 // The edge this matcher checks.
121 const MagnetismEdge edge_
;
123 // Visible ranges of the edge. Initialized with GetSecondaryRange() and
124 // updated as ShouldAttach() is invoked. When empty the edge is completely
125 // obscured by other bounds.
128 DISALLOW_COPY_AND_ASSIGN(MagnetismEdgeMatcher
);
131 enum SecondaryMagnetismEdge
{
132 SECONDARY_MAGNETISM_EDGE_LEADING
,
133 SECONDARY_MAGNETISM_EDGE_TRAILING
,
134 SECONDARY_MAGNETISM_EDGE_NONE
,
137 // Used to identify a matched edge. |primary_edge| is relative to the source and
138 // indicates the edge the two are to share. For example, if |primary_edge| is
139 // MAGNETISM_EDGE_RIGHT then the right edge of the source should snap to to the
140 // left edge of the target. |secondary_edge| indicates one of the edges along
141 // the opposite axis should should also be aligned. For example, if
142 // |primary_edge| is MAGNETISM_EDGE_RIGHT and |secondary_edge| is
143 // SECONDARY_MAGNETISM_EDGE_LEADING then the source should snap to the left top
144 // corner of the target.
146 MagnetismEdge primary_edge
;
147 SecondaryMagnetismEdge secondary_edge
;
150 // MagnetismMatcher is used to test if a window should snap to another window.
151 // To use MagnetismMatcher do the following:
152 // . Create it with the bounds of the window being dragged.
153 // . Iterate over the child windows checking if the window being dragged should
154 // attach to it using ShouldAttach().
155 // . Use AreEdgesObscured() to test if no other windows can match (because all
156 // edges are completely obscured).
157 class ASH_EXPORT MagnetismMatcher
{
159 static const int kMagneticDistance
;
161 // |edges| is a bitmask of MagnetismEdges to match against.
162 MagnetismMatcher(const gfx::Rect
& bounds
, uint32 edges
);
165 // Returns true if |bounds| is close enough to the initial bounds that the two
166 // should be attached. If true is returned |edge| is set to indicates how the
167 // two should snap together. See description of MatchedEdge for details.
168 bool ShouldAttach(const gfx::Rect
& bounds
, MatchedEdge
* edge
);
170 // Returns true if no other matches are possible.
171 bool AreEdgesObscured() const;
174 // Sets |secondary_edge| based on whether the secondary edges should snap.
175 void AttachToSecondaryEdge(const gfx::Rect
& bounds
,
177 SecondaryMagnetismEdge
* secondary_edge
) const;
179 // The edges to match against.
182 ScopedVector
<MagnetismEdgeMatcher
> matchers_
;
184 DISALLOW_COPY_AND_ASSIGN(MagnetismMatcher
);
189 #endif // ASH_WM_WORKSPACE_MAGNETISM_MATCHER_H_