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- // Copyright (c) 2012 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #ifndef ASH_WM_WORKSPACE_MAGNETISM_MATCHER_H_
- #define ASH_WM_WORKSPACE_MAGNETISM_MATCHER_H_
- #include <stdint.h>
- #include <memory>
- #include <utility>
- #include <vector>
- #include "ash/ash_export.h"
- #include "base/compiler_specific.h"
- #include "base/notreached.h"
- #include "ui/gfx/geometry/rect.h"
- namespace ash {
- enum MagnetismEdge {
- MAGNETISM_EDGE_TOP = 1 << 0,
- MAGNETISM_EDGE_LEFT = 1 << 1,
- MAGNETISM_EDGE_BOTTOM = 1 << 2,
- MAGNETISM_EDGE_RIGHT = 1 << 3,
- };
- const uint32_t kAllMagnetismEdges = MAGNETISM_EDGE_TOP | MAGNETISM_EDGE_LEFT |
- MAGNETISM_EDGE_BOTTOM |
- MAGNETISM_EDGE_RIGHT;
- // MagnetismEdgeMatcher is used for matching a particular edge of a window. You
- // shouldn't need to use this directly, instead use MagnetismMatcher which takes
- // care of all edges.
- // MagnetismEdgeMatcher maintains a range of the visible portions of the
- // edge. As ShouldAttach() is invoked the visible range is updated.
- class MagnetismEdgeMatcher {
- public:
- MagnetismEdgeMatcher(const gfx::Rect& bounds, MagnetismEdge edge);
- MagnetismEdgeMatcher(const MagnetismEdgeMatcher&) = delete;
- MagnetismEdgeMatcher& operator=(const MagnetismEdgeMatcher&) = delete;
- ~MagnetismEdgeMatcher();
- MagnetismEdge edge() const { return edge_; }
- const gfx::Rect& bounds() const { return bounds_; }
- // Returns true if the edge is completely obscured. If true ShouldAttach()
- // will return false.
- bool is_edge_obscured() const { return ranges_.empty(); }
- // Returns true if should attach to the specified bounds.
- bool ShouldAttach(const gfx::Rect& bounds);
- private:
- typedef std::pair<int, int> Range;
- typedef std::vector<Range> Ranges;
- // Removes |range| from |ranges_|.
- void UpdateRanges(const Range& range);
- static int GetPrimaryCoordinate(const gfx::Rect& bounds, MagnetismEdge edge) {
- switch (edge) {
- case MAGNETISM_EDGE_TOP:
- return bounds.y();
- case MAGNETISM_EDGE_LEFT:
- return bounds.x();
- case MAGNETISM_EDGE_BOTTOM:
- return bounds.bottom();
- case MAGNETISM_EDGE_RIGHT:
- return bounds.right();
- }
- NOTREACHED();
- return 0;
- }
- static MagnetismEdge FlipEdge(MagnetismEdge edge) {
- switch (edge) {
- case MAGNETISM_EDGE_TOP:
- return MAGNETISM_EDGE_BOTTOM;
- case MAGNETISM_EDGE_BOTTOM:
- return MAGNETISM_EDGE_TOP;
- case MAGNETISM_EDGE_LEFT:
- return MAGNETISM_EDGE_RIGHT;
- case MAGNETISM_EDGE_RIGHT:
- return MAGNETISM_EDGE_LEFT;
- }
- NOTREACHED();
- return MAGNETISM_EDGE_LEFT;
- }
- Range GetPrimaryRange(const gfx::Rect& bounds) const {
- switch (edge_) {
- case MAGNETISM_EDGE_TOP:
- case MAGNETISM_EDGE_BOTTOM:
- return Range(bounds.y(), bounds.bottom());
- case MAGNETISM_EDGE_LEFT:
- case MAGNETISM_EDGE_RIGHT:
- return Range(bounds.x(), bounds.right());
- }
- NOTREACHED();
- return Range();
- }
- Range GetSecondaryRange(const gfx::Rect& bounds) const {
- switch (edge_) {
- case MAGNETISM_EDGE_TOP:
- case MAGNETISM_EDGE_BOTTOM:
- return Range(bounds.x(), bounds.right());
- case MAGNETISM_EDGE_LEFT:
- case MAGNETISM_EDGE_RIGHT:
- return Range(bounds.y(), bounds.bottom());
- }
- NOTREACHED();
- return Range();
- }
- static bool RangesIntersect(const Range& r1, const Range& r2) {
- return r2.first < r1.second && r2.second > r1.first;
- }
- // The bounds of window.
- const gfx::Rect bounds_;
- // The edge this matcher checks.
- const MagnetismEdge edge_;
- // Visible ranges of the edge. Initialized with GetSecondaryRange() and
- // updated as ShouldAttach() is invoked. When empty the edge is completely
- // obscured by other bounds.
- Ranges ranges_;
- };
- enum SecondaryMagnetismEdge {
- SECONDARY_MAGNETISM_EDGE_LEADING,
- SECONDARY_MAGNETISM_EDGE_TRAILING,
- SECONDARY_MAGNETISM_EDGE_NONE,
- };
- // Used to identify a matched edge. |primary_edge| is relative to the source and
- // indicates the edge the two are to share. For example, if |primary_edge| is
- // MAGNETISM_EDGE_RIGHT then the right edge of the source should snap to to the
- // left edge of the target. |secondary_edge| indicates one of the edges along
- // the opposite axis should should also be aligned. For example, if
- // |primary_edge| is MAGNETISM_EDGE_RIGHT and |secondary_edge| is
- // SECONDARY_MAGNETISM_EDGE_LEADING then the source should snap to the left top
- // corner of the target.
- struct MatchedEdge {
- MagnetismEdge primary_edge;
- SecondaryMagnetismEdge secondary_edge;
- };
- // MagnetismMatcher is used to test if a window should snap to another window.
- // To use MagnetismMatcher do the following:
- // . Create it with the bounds of the window being dragged.
- // . Iterate over the child windows checking if the window being dragged should
- // attach to it using ShouldAttach().
- // . Use AreEdgesObscured() to test if no other windows can match (because all
- // edges are completely obscured).
- class ASH_EXPORT MagnetismMatcher {
- public:
- static const int kMagneticDistance;
- // |edges| is a bitmask of MagnetismEdges to match against.
- MagnetismMatcher(const gfx::Rect& bounds, uint32_t edges);
- MagnetismMatcher(const MagnetismMatcher&) = delete;
- MagnetismMatcher& operator=(const MagnetismMatcher&) = delete;
- ~MagnetismMatcher();
- // Returns true if |bounds| is close enough to the initial bounds that the two
- // should be attached. If true is returned |edge| is set to indicates how the
- // two should snap together. See description of MatchedEdge for details.
- bool ShouldAttach(const gfx::Rect& bounds, MatchedEdge* edge);
- // Returns true if no other matches are possible.
- bool AreEdgesObscured() const;
- private:
- // Sets |secondary_edge| based on whether the secondary edges should snap.
- void AttachToSecondaryEdge(const gfx::Rect& bounds,
- MagnetismEdge edge,
- SecondaryMagnetismEdge* secondary_edge) const;
- // The edges to match against.
- const int32_t edges_;
- std::vector<std::unique_ptr<MagnetismEdgeMatcher>> matchers_;
- };
- } // namespace ash
- #endif // ASH_WM_WORKSPACE_MAGNETISM_MATCHER_H_
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