1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16package android.support.car.ui;
17
18import android.animation.TimeInterpolator;
19
20/**
21 * Interpolator that can animate any of the quantum curves.
22 * You can also specify
23 * @hide
24 */
25public class QuantumInterpolator implements TimeInterpolator {
26
27    /**
28     * Lookup table values.
29     * Generated using a Bezier curve from (0,0) to (1,1) with control points:
30     * P0 (0,0)
31     * P1 (0.4, 0)
32     * P2 (0.2, 1.0)
33     * P3 (1.0, 1.0)
34     *
35     * Values sampled with x at regular intervals between 0 and 1.
36     *
37     * These values were generated using:
38     *   ./scripts/bezier_interpolator_values_gen.py 0.4 0.2
39     */
40    public static final float[] FAST_OUT_SLOW_IN = new float[] {
41            0.0f, 0.0002f, 0.0009f, 0.0019f, 0.0036f, 0.0059f, 0.0086f, 0.0119f, 0.0157f, 0.0209f,
42            0.0257f, 0.0321f, 0.0392f, 0.0469f, 0.0566f, 0.0656f, 0.0768f, 0.0887f, 0.1033f, 0.1186f,
43            0.1349f, 0.1519f, 0.1696f, 0.1928f, 0.2121f, 0.237f, 0.2627f, 0.2892f, 0.3109f, 0.3386f,
44            0.3667f, 0.3952f, 0.4241f, 0.4474f, 0.4766f, 0.5f, 0.5234f, 0.5468f, 0.5701f, 0.5933f,
45            0.6134f, 0.6333f, 0.6531f, 0.6698f, 0.6891f, 0.7054f, 0.7214f, 0.7346f, 0.7502f, 0.763f,
46            0.7756f, 0.7879f, 0.8f, 0.8107f, 0.8212f, 0.8326f, 0.8415f, 0.8503f, 0.8588f, 0.8672f,
47            0.8754f, 0.8833f, 0.8911f, 0.8977f, 0.9041f, 0.9113f, 0.9165f, 0.9232f, 0.9281f, 0.9328f,
48            0.9382f, 0.9434f, 0.9476f, 0.9518f, 0.9557f, 0.9596f, 0.9632f, 0.9662f, 0.9695f, 0.9722f,
49            0.9753f, 0.9777f, 0.9805f, 0.9826f, 0.9847f, 0.9866f, 0.9884f, 0.9901f, 0.9917f, 0.9931f,
50            0.9944f, 0.9955f, 0.9964f, 0.9973f, 0.9981f, 0.9986f, 0.9992f, 0.9995f, 0.9998f, 1.0f, 1.0f
51    };
52
53    /**
54     * These values were generated using:
55     *   ./scripts/bezier_interpolator_values_gen.py 0.0 0.2
56     */
57    public static final float[] LINEAR_OUT_SLOW_IN = new float[] {
58            0.0029f, 0.043f, 0.0785f, 0.1147f, 0.1476f, 0.1742f, 0.2024f, 0.2319f, 0.2575f, 0.2786f,
59            0.3055f, 0.3274f, 0.3498f, 0.3695f, 0.3895f, 0.4096f, 0.4299f, 0.4474f, 0.4649f,
60            0.4824f, 0.5f, 0.5176f, 0.5322f, 0.5468f, 0.5643f, 0.5788f, 0.5918f, 0.6048f, 0.6191f,
61            0.6333f, 0.6446f, 0.6573f, 0.6698f, 0.6808f, 0.6918f, 0.704f, 0.7148f, 0.7254f, 0.7346f,
62            0.7451f, 0.7554f, 0.7655f, 0.7731f, 0.783f, 0.7916f, 0.8f, 0.8084f, 0.8166f, 0.8235f,
63            0.8315f, 0.8393f, 0.8459f, 0.8535f, 0.8599f, 0.8672f, 0.8733f, 0.8794f, 0.8853f,
64            0.8911f, 0.8967f, 0.9023f, 0.9077f, 0.9121f, 0.9173f, 0.9224f, 0.9265f, 0.9313f,
65            0.9352f, 0.9397f, 0.9434f, 0.9476f, 0.9511f, 0.9544f, 0.9577f, 0.9614f, 0.9644f,
66            0.9673f, 0.9701f, 0.9727f, 0.9753f, 0.9777f, 0.98f, 0.9818f, 0.9839f, 0.9859f, 0.9877f,
67            0.9891f, 0.9907f, 0.9922f, 0.9933f, 0.9946f, 0.9957f, 0.9966f, 0.9974f, 0.9981f,
68            0.9986f, 0.9992f, 0.9995f, 0.9998f, 1.0f, 1.0f
69    };
70
71    /**
72     * These values were generated using:
73     *   ./scripts/bezier_interpolator_values_gen.py 0.0 0.2
74     */
75    public static final float[] FAST_OUT_LINEAR_IN = new float[] {
76            0.0f, 0.0002f, 0.0008f, 0.0019f, 0.0032f, 0.0049f, 0.0069f, 0.0093f, 0.0119f, 0.0149f,
77            0.0182f, 0.0218f, 0.0257f, 0.0299f, 0.0344f, 0.0392f, 0.0443f, 0.0496f, 0.0552f,
78            0.0603f, 0.0656f, 0.0719f, 0.0785f, 0.0853f, 0.0923f, 0.0986f, 0.1051f, 0.1128f,
79            0.1206f, 0.1287f, 0.1359f, 0.1433f, 0.1519f, 0.1607f, 0.1696f, 0.1776f, 0.1857f,
80            0.1952f, 0.2048f, 0.2145f, 0.2232f, 0.2319f, 0.2421f, 0.2523f, 0.2627f, 0.2733f,
81            0.2826f, 0.2919f, 0.3027f, 0.3137f, 0.3247f, 0.3358f, 0.3469f, 0.3582f, 0.3695f,
82            0.3809f, 0.3924f, 0.4039f, 0.4154f, 0.427f, 0.4386f, 0.4503f, 0.4619f, 0.4751f, 0.4883f,
83            0.5f, 0.5117f, 0.5264f, 0.5381f, 0.5497f, 0.5643f, 0.5759f, 0.5904f, 0.6033f, 0.6162f,
84            0.6305f, 0.6446f, 0.6587f, 0.6698f, 0.6836f, 0.7f, 0.7134f, 0.7267f, 0.7425f, 0.7554f,
85            0.7706f, 0.7855f, 0.8f, 0.8143f, 0.8281f, 0.8438f, 0.8588f, 0.8733f, 0.8892f, 0.9041f,
86            0.9215f, 0.9344f, 0.9518f, 0.9667f, 0.9826f, 0.9993f
87
88    };
89
90    private final float[] mValues;
91    private final float mStepSize;
92    private final float mStartTime;
93    private final float mEndTime;
94
95    public QuantumInterpolator(float[] values, float pre, float during, float post) {
96        super();
97        mValues = values;
98        mStepSize = 1.0f / (mValues.length - 1);
99        mStartTime = pre / (pre + during + post);
100        mEndTime = mStartTime + (during / (pre + during + post));
101    }
102
103    @Override
104    public float getInterpolation(float input) {
105        return getInterpolation(input, mStartTime, mEndTime);
106    }
107
108    public float getReverseInterpolation(float input) {
109        return getInterpolation(input, 1 - mEndTime, 1 - mStartTime);
110    }
111
112    public float getInterpolation(float input, float startTime, float endTime) {
113        if (input <= startTime) {
114            return 0.0f;
115        } else if (input >= endTime) {
116            return 1.0f;
117        }
118
119        input = (input - startTime) / (endTime - startTime);
120
121        int position = Math.min(
122                (int)(input * (mValues.length - 1)),
123                mValues.length - 2);
124
125        float quantized = position * mStepSize;
126        float difference = input - quantized;
127        float weight = difference / mStepSize;
128
129        return mValues[position] + weight * (mValues[position + 1] - mValues[position]);
130    }
131}
132