| James Robinson | e2ac7e8 | 2014-10-15 13:21:59 -0700 | [diff] [blame] | 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 UI_EVENTS_GESTURE_CURVE_H_ |
| 6 | #define UI_EVENTS_GESTURE_CURVE_H_ |
| 7 | |
| 8 | #include "base/time/time.h" |
| 9 | #include "ui/gfx/geometry/vector2d_f.h" |
| 10 | |
| 11 | namespace ui { |
| 12 | |
| 13 | // An abstraction of curve-based gesture motion, allowing platform-specific |
| 14 | // motion tailoring. |
| 15 | class EVENTS_BASE_EXPORT GestureCurve { |
| 16 | public: |
| 17 | virtual ~GestureCurve() {} |
| 18 | |
| 19 | // The output |offset| represents the total movement of the curve from its |
| 20 | // start until |time|. |
| 21 | // The output |velocity| represents the instantenous velocity at |time|. |
| 22 | // Returns false if |time| exceeds the fling duration, in which case |
| 23 | // the terminal offset will be reported. |
| 24 | virtual bool ComputeScrollOffset(base::TimeTicks time, |
| 25 | gfx::Vector2dF* offset, |
| 26 | gfx::Vector2dF* velocity) = 0; |
| 27 | }; |
| 28 | |
| 29 | } // namespace ui |
| 30 | |
| 31 | #endif // UI_EVENTS_GESTURE_CURVE_H_ |
