1// Copyright (c) 2012 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 "ui/gfx/animation/slide_animation.h"
6
7#include <math.h>
8
9namespace gfx {
10
11// How many frames per second to target.
12static const int kDefaultFrameRateHz = 60;
13
14// How long animations should take by default.
15static const int kDefaultDurationMs = 120;
16
17SlideAnimation::SlideAnimation(AnimationDelegate* target)
18    : LinearAnimation(kDefaultFrameRateHz, target),
19      target_(target),
20      tween_type_(Tween::EASE_OUT),
21      showing_(false),
22      value_start_(0),
23      value_end_(0),
24      value_current_(0),
25      slide_duration_(kDefaultDurationMs) {
26}
27
28SlideAnimation::~SlideAnimation() {
29}
30
31void SlideAnimation::Reset() {
32  Reset(0);
33}
34
35void SlideAnimation::Reset(double value) {
36  Stop();
37  showing_ = static_cast<bool>(value == 1);
38  value_current_ = value;
39}
40
41void SlideAnimation::Show() {
42  // If we're already showing (or fully shown), we have nothing to do.
43  if (showing_)
44    return;
45
46  showing_ = true;
47  value_start_ = value_current_;
48  value_end_ = 1.0;
49
50  // Make sure we actually have something to do.
51  if (slide_duration_ == 0) {
52    AnimateToState(1.0);  // Skip to the end of the animation.
53    return;
54  } else if (value_current_ == value_end_)  {
55    return;
56  }
57
58  // This will also reset the currently-occurring animation.
59  SetDuration(static_cast<int>(slide_duration_ * (1 - value_current_)));
60  Start();
61}
62
63void SlideAnimation::Hide() {
64  // If we're already hiding (or hidden), we have nothing to do.
65  if (!showing_)
66    return;
67
68  showing_ = false;
69  value_start_ = value_current_;
70  value_end_ = 0.0;
71
72  // Make sure we actually have something to do.
73  if (slide_duration_ == 0) {
74    AnimateToState(0.0);  // Skip to the end of the animation.
75    return;
76  } else if (value_current_ == value_end_) {
77    return;
78  }
79
80  // This will also reset the currently-occurring animation.
81  SetDuration(static_cast<int>(slide_duration_ * value_current_));
82  Start();
83}
84
85void SlideAnimation::SetSlideDuration(int duration) {
86  slide_duration_ = duration;
87}
88
89double SlideAnimation::GetCurrentValue() const {
90  return value_current_;
91}
92
93void SlideAnimation::AnimateToState(double state) {
94  if (state > 1.0)
95    state = 1.0;
96
97  state = Tween::CalculateValue(tween_type_, state);
98
99  value_current_ = value_start_ + (value_end_ - value_start_) * state;
100
101  // Implement snapping.
102  if (tween_type_ == Tween::EASE_OUT_SNAP &&
103      fabs(value_current_ - value_end_) <= 0.06)
104    value_current_ = value_end_;
105
106  // Correct for any overshoot (while state may be capped at 1.0, let's not
107  // take any rounding error chances.
108  if ((value_end_ >= value_start_ && value_current_ > value_end_) ||
109      (value_end_ < value_start_ && value_current_ < value_end_)) {
110    value_current_ = value_end_;
111  }
112}
113
114}  // namespace gfx
115