| // Copyright 2014 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 UI_EVENTS_GESTURES_FLING_CURVE_H_ |
| #define UI_EVENTS_GESTURES_FLING_CURVE_H_ |
| |
| #include "base/time/time.h" |
| #include "ui/events/events_base_export.h" |
| #include "ui/gfx/geometry/point_f.h" |
| #include "ui/gfx/geometry/vector2d_f.h" |
| |
| namespace ui { |
| |
| // FlingCurve can be used to scroll a UI element suitable for touch screen-based |
| // flings. |
| class EVENTS_BASE_EXPORT FlingCurve { |
| public: |
| FlingCurve(const gfx::Vector2dF& velocity, base::TimeTicks start_timestamp); |
| ~FlingCurve(); |
| |
| gfx::Vector2dF GetScrollAmountAtTime(base::TimeTicks current_timestamp); |
| base::TimeTicks start_timestamp() const { return start_timestamp_; } |
| |
| private: |
| const float curve_duration_; |
| const base::TimeTicks start_timestamp_; |
| |
| gfx::Vector2dF displacement_ratio_; |
| gfx::Vector2dF cumulative_scroll_; |
| base::TimeTicks last_timestamp_; |
| float time_offset_; |
| float position_offset_; |
| |
| DISALLOW_COPY_AND_ASSIGN(FlingCurve); |
| }; |
| |
| } // namespace ui |
| |
| #endif // UI_EVENTS_GESTURES_FLING_CURVE_H_ |