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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 #ifndef CC_INPUT_SCROLL_ELASTICITY_HELPER_H_ | |
6 #define CC_INPUT_SCROLL_ELASTICITY_HELPER_H_ | |
7 | |
8 #include "base/time/time.h" | |
9 #include "cc/base/cc_export.h" | |
10 #include "ui/gfx/geometry/vector2d_f.h" | |
11 | |
12 namespace cc { | |
13 | |
14 class LayerTreeHostImpl; | |
15 | |
16 // ScrollElasticityHelper is based on | |
17 // WebKit/Source/platform/mac/ScrollElasticityController.h | |
18 /* | |
19 * Copyright (C) 2011 Apple Inc. All rights reserved. | |
20 * | |
21 * Redistribution and use in source and binary forms, with or without | |
22 * modification, are permitted provided that the following conditions | |
23 * are met: | |
24 * 1. Redistributions of source code must retain the above copyright | |
25 * notice, this list of conditions and the following disclaimer. | |
26 * 2. Redistributions in binary form must reproduce the above copyright | |
27 * notice, this list of conditions and the following disclaimer in the | |
28 * documentation and/or other materials provided with the distribution. | |
29 * | |
30 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' | |
31 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, | |
32 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
33 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS | |
34 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
35 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
36 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
37 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
38 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
39 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF | |
40 * THE POSSIBILITY OF SUCH DAMAGE. | |
41 */ | |
42 | |
43 // Interface between a LayerTreeHostImpl and the ScrollElasticityController. It | |
44 // would be possible, in principle, for LayerTreeHostImpl to implement this | |
45 // interface itself. This artificial boundary is introduced to reduce the amount | |
46 // of logic and state held directly inside LayerTreeHostImpl. | |
47 class CC_EXPORT ScrollElasticityHelper { | |
48 public: | |
49 explicit ScrollElasticityHelper(LayerTreeHostImpl* layer_tree); | |
50 ~ScrollElasticityHelper(); | |
51 | |
52 bool AllowsHorizontalStretching(); | |
53 bool AllowsVerticalStretching(); | |
54 // The amount that the view is stretched past the normal allowable bounds. | |
55 // The "overhang" amount. | |
56 gfx::Vector2dF StretchAmount(); | |
57 bool PinnedInDirection(const gfx::Vector2dF& direction); | |
58 bool CanScrollHorizontally(); | |
59 bool CanScrollVertically(); | |
60 | |
61 // Return the absolute scroll position, not relative to the scroll origin. | |
62 gfx::Vector2dF AbsoluteScrollPosition(); | |
63 | |
64 void ImmediateScrollBy(const gfx::Vector2dF& scroll); | |
65 void ImmediateScrollByWithoutContentEdgeConstraints( | |
66 const gfx::Vector2dF& scroll); | |
67 void StartSnapRubberbandTimer(); | |
68 void StopSnapRubberbandTimer(); | |
69 void SnapRubberbandTimerFired(); | |
70 | |
71 // If the current scroll position is within the overhang area, this function | |
72 // will cause | |
73 // the page to scroll to the nearest boundary point. | |
74 void AdjustScrollPositionToBoundsIfNecessary(); | |
75 | |
76 private: | |
77 LayerTreeHostImpl* layer_tree_; | |
aelias_OOO_until_Jul13
2014/11/13 02:11:03
Please rename this to layer_tree_host_impl_. Ther
ccameron
2014/11/13 02:45:57
Done.
| |
78 gfx::Vector2dF stretch_offset_; | |
79 bool timer_active_; | |
80 }; | |
81 | |
82 } // namespace cc | |
83 | |
84 #endif // CC_INPUT_SCROLL_ELASTICITY_HELPER_H_ | |
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