| // Copyright 2014 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef UI_EVENTS_GESTURE_CURVE_H_ |
| #define UI_EVENTS_GESTURE_CURVE_H_ |
| |
| #include "base/time/time.h" |
| #include "ui/gfx/geometry/vector2d_f.h" |
| |
| namespace ui { |
| |
| // An abstraction of curve-based gesture motion, allowing platform-specific |
| // motion tailoring. |
| class EVENTS_BASE_EXPORT GestureCurve { |
| public: |
| virtual ~GestureCurve() {} |
| |
| // The output |offset| represents the total movement of the curve from its |
| // start until |time|. |
| // The output |velocity| represents the instantenous velocity at |time|. |
| // Returns false if |time| exceeds the fling duration, in which case |
| // the terminal offset will be reported. |
| virtual bool ComputeScrollOffset(base::TimeTicks time, |
| gfx::Vector2dF* offset, |
| gfx::Vector2dF* velocity) = 0; |
| }; |
| |
| } // namespace ui |
| |
| #endif // UI_EVENTS_GESTURE_CURVE_H_ |