1 // Copyright 2013 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 #include "cc/animation/scroll_offset_animation_curve.h" 6 7 #include <algorithm> 8 #include <cmath> 9 10 #include "base/logging.h" 11 #include "cc/animation/timing_function.h" 12 #include "ui/gfx/animation/tween.h" 13 14 const double kDurationDivisor = 60.0; 15 16 namespace cc { 17 18 scoped_ptr<ScrollOffsetAnimationCurve> ScrollOffsetAnimationCurve::Create( 19 const gfx::Vector2dF& target_value, 20 scoped_ptr<TimingFunction> timing_function) { 21 return make_scoped_ptr( 22 new ScrollOffsetAnimationCurve(target_value, timing_function.Pass())); 23 } 24 25 ScrollOffsetAnimationCurve::ScrollOffsetAnimationCurve( 26 const gfx::Vector2dF& target_value, 27 scoped_ptr<TimingFunction> timing_function) 28 : target_value_(target_value), timing_function_(timing_function.Pass()) { 29 } 30 31 ScrollOffsetAnimationCurve::~ScrollOffsetAnimationCurve() {} 32 33 void ScrollOffsetAnimationCurve::SetInitialValue( 34 const gfx::Vector2dF& initial_value) { 35 initial_value_ = initial_value; 36 37 // The duration of a scroll animation depends on the size of the scroll. 38 // The exact relationship between the size and the duration isn't specified 39 // by the CSSOM View smooth scroll spec and is instead left up to user agents 40 // to decide. The calculation performed here will very likely be further 41 // tweaked before the smooth scroll API ships. 42 float delta_x = std::abs(target_value_.x() - initial_value_.x()); 43 float delta_y = std::abs(target_value_.y() - initial_value_.y()); 44 float max_delta = std::max(delta_x, delta_y); 45 duration_ = base::TimeDelta::FromMicroseconds( 46 (std::sqrt(max_delta) / kDurationDivisor) * 47 base::Time::kMicrosecondsPerSecond); 48 } 49 50 gfx::Vector2dF ScrollOffsetAnimationCurve::GetValue(double t) const { 51 double duration = duration_.InSecondsF(); 52 53 if (t <= 0) 54 return initial_value_; 55 56 if (t >= duration) 57 return target_value_; 58 59 double progress = (timing_function_->GetValue(t / duration)); 60 return gfx::Vector2dF(gfx::Tween::FloatValueBetween( 61 progress, initial_value_.x(), target_value_.x()), 62 gfx::Tween::FloatValueBetween( 63 progress, initial_value_.y(), target_value_.y())); 64 } 65 66 double ScrollOffsetAnimationCurve::Duration() const { 67 return duration_.InSecondsF(); 68 } 69 70 AnimationCurve::CurveType ScrollOffsetAnimationCurve::Type() const { 71 return ScrollOffset; 72 } 73 74 scoped_ptr<AnimationCurve> ScrollOffsetAnimationCurve::Clone() const { 75 scoped_ptr<TimingFunction> timing_function( 76 static_cast<TimingFunction*>(timing_function_->Clone().release())); 77 scoped_ptr<ScrollOffsetAnimationCurve> curve_clone = 78 Create(target_value_, timing_function.Pass()); 79 curve_clone->initial_value_ = initial_value_; 80 curve_clone->duration_ = duration_; 81 return curve_clone.PassAs<AnimationCurve>(); 82 } 83 84 } // namespace cc 85
