| // 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_ANDROID_EDGE_EFFECT_BASE_H_ |
| #define UI_ANDROID_EDGE_EFFECT_BASE_H_ |
| |
| #include "base/time/time.h" |
| #include "ui/gfx/geometry/size_f.h" |
| #include "ui/gfx/transform.h" |
| |
| namespace cc { |
| class Layer; |
| } |
| |
| namespace ui { |
| |
| // A base class for overscroll-related Android effects. |
| class EdgeEffectBase { |
| public: |
| enum State { |
| STATE_IDLE = 0, |
| STATE_PULL, |
| STATE_ABSORB, |
| STATE_RECEDE, |
| STATE_PULL_DECAY |
| }; |
| |
| enum Edge { EDGE_TOP, EDGE_LEFT, EDGE_BOTTOM, EDGE_RIGHT, EDGE_COUNT }; |
| |
| virtual ~EdgeEffectBase() {} |
| |
| virtual void Pull(base::TimeTicks current_time, |
| float delta_distance, |
| float displacement) = 0; |
| virtual void Absorb(base::TimeTicks current_time, float velocity) = 0; |
| virtual bool Update(base::TimeTicks current_time) = 0; |
| virtual void Release(base::TimeTicks current_time) = 0; |
| |
| virtual void Finish() = 0; |
| virtual bool IsFinished() const = 0; |
| virtual float GetAlpha() const = 0; |
| |
| virtual void ApplyToLayers(Edge edge, |
| const gfx::SizeF& viewport_size, |
| float offset) = 0; |
| virtual void SetParent(cc::Layer* parent) = 0; |
| |
| protected: |
| // Computes the transform for an edge effect given the |edge|, |viewport_size| |
| // and edge |offset|. This assumes the the effect transform anchor is at the |
| // centered edge of the effect. |
| static gfx::Transform ComputeTransform(Edge edge, |
| const gfx::SizeF& viewport_size, |
| float offset); |
| |
| // Computes the maximum effect size relative to the screen |edge|. For |
| // top/bottom edges, thsi is simply |viewport_size|, while for left/right |
| // edges this is |viewport_size| with coordinates swapped. |
| static gfx::SizeF ComputeOrientedSize(Edge edge, |
| const gfx::SizeF& viewport_size); |
| }; |
| |
| } // namespace ui |
| |
| #endif // UI_ANDROID_EDGE_EFFECT_BASE_H_ |