/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.smartandroid.sa.view;
import android.view.animation.Interpolator;
/**
* A pre-baked bezier-curved interpolator for indeterminate progress animations.
*/
final class BSRQXInterpolator implements Interpolator {
private static final BSRQXInterpolator INSTANCE = new BSRQXInterpolator();
public final static BSRQXInterpolator getInstance() {
return INSTANCE;
}
/**
* Use getInstance instead of instantiating.
*/
private BSRQXInterpolator() {
super();
}
/**
* Lookup table values. Generated using a Bezier curve from (0,0) to (1,1)
* with control points: P0 (0,0) P1 (0.4, 0) P2 (0.2, 1.0) P3 (1.0, 1.0)
*
* Values sampled with x at regular intervals between 0 and 1.
*/
private static final float[] VALUES = new float[] { 0.0f, 0.0002f, 0.0009f,
0.0019f, 0.0036f, 0.0059f, 0.0086f, 0.0119f, 0.0157f, 0.0209f,
0.0257f, 0.0321f, 0.0392f, 0.0469f, 0.0566f, 0.0656f, 0.0768f,
0.0887f, 0.1033f, 0.1186f, 0.1349f, 0.1519f, 0.1696f, 0.1928f,
0.2121f, 0.237f, 0.2627f, 0.2892f, 0.3109f, 0.3386f, 0.3667f,
0.3952f, 0.4241f, 0.4474f, 0.4766f, 0.5f, 0.5234f, 0.5468f,
0.5701f, 0.5933f, 0.6134f, 0.6333f, 0.6531f, 0.6698f, 0.6891f,
0.7054f, 0.7214f, 0.7346f, 0.7502f, 0.763f, 0.7756f, 0.7879f, 0.8f,
0.8107f, 0.8212f, 0.8326f, 0.8415f, 0.8503f, 0.8588f, 0.8672f,
0.8754f, 0.8833f, 0.8911f, 0.8977f, 0.9041f, 0.9113f, 0.9165f,
0.9232f, 0.9281f, 0.9328f, 0.9382f, 0.9434f, 0.9476f, 0.9518f,
0.9557f, 0.9596f, 0.9632f, 0.9662f, 0.9695f, 0.9722f, 0.9753f,
0.9777f, 0.9805f, 0.9826f, 0.9847f, 0.9866f, 0.9884f, 0.9901f,
0.9917f, 0.9931f, 0.9944f, 0.9955f, 0.9964f, 0.9973f, 0.9981f,
0.9986f, 0.9992f, 0.9995f, 0.9998f, 1.0f, 1.0f };
private static final float STEP_SIZE = 1.0f / (VALUES.length - 1);
@Override
public float getInterpolation(float input) {
if (input >= 1.0f) {
return 1.0f;
}
if (input <= 0f) {
return 0f;
}
int position = Math.min((int) (input * (VALUES.length - 1)),
VALUES.length - 2);
float quantized = position * STEP_SIZE;
float difference = input - quantized;
float weight = difference / STEP_SIZE;
return VALUES[position] + weight
* (VALUES[position + 1] - VALUES[position]);
}
}