1 /* 2 * Copyright (C) 2017 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 */ 16 17 package com.android.launcher3.anim; 18 19 import android.graphics.Path; 20 import android.view.animation.AccelerateInterpolator; 21 import android.view.animation.DecelerateInterpolator; 22 import android.view.animation.Interpolator; 23 import android.view.animation.LinearInterpolator; 24 import android.view.animation.OvershootInterpolator; 25 import android.view.animation.PathInterpolator; 26 27 28 /** 29 * Common interpolators used in Launcher 30 */ 31 public class Interpolators { 32 33 public static final Interpolator LINEAR = new LinearInterpolator(); 34 35 public static final Interpolator ACCEL = new AccelerateInterpolator(); 36 public static final Interpolator ACCEL_1_5 = new AccelerateInterpolator(1.5f); 37 public static final Interpolator ACCEL_2 = new AccelerateInterpolator(2); 38 39 public static final Interpolator DEACCEL = new DecelerateInterpolator(); 40 public static final Interpolator DEACCEL_1_5 = new DecelerateInterpolator(1.5f); 41 public static final Interpolator DEACCEL_1_7 = new DecelerateInterpolator(1.7f); 42 public static final Interpolator DEACCEL_2 = new DecelerateInterpolator(2); 43 public static final Interpolator DEACCEL_2_5 = new DecelerateInterpolator(2.5f); 44 public static final Interpolator DEACCEL_3 = new DecelerateInterpolator(3f); 45 46 public static final Interpolator FAST_OUT_SLOW_IN = new PathInterpolator(0.4f, 0f, 0.2f, 1f); 47 48 public static final Interpolator AGGRESSIVE_EASE = new PathInterpolator(0.2f, 0f, 0f, 1f); 49 public static final Interpolator AGGRESSIVE_EASE_IN_OUT = new PathInterpolator(0.6f,0, 0.4f, 1); 50 51 public static final Interpolator EXAGGERATED_EASE; 52 53 static { 54 Path exaggeratedEase = new Path(); 55 exaggeratedEase.moveTo(0, 0); 56 exaggeratedEase.cubicTo(0.05f, 0f, 0.133333f, 0.08f, 0.166666f, 0.4f); 57 exaggeratedEase.cubicTo(0.225f, 0.94f, 0.5f, 1f, 1f, 1f); 58 EXAGGERATED_EASE = new PathInterpolator(exaggeratedEase); 59 } 60 61 public static final Interpolator OVERSHOOT_1_2 = new OvershootInterpolator(1.2f); 62 63 public static final Interpolator TOUCH_RESPONSE_INTERPOLATOR = 64 new PathInterpolator(0.3f, 0f, 0.1f, 1f); 65 66 /** 67 * Inversion of ZOOM_OUT, compounded with an ease-out. 68 */ 69 public static final Interpolator ZOOM_IN = new Interpolator() { 70 @Override 71 public float getInterpolation(float v) { 72 return DEACCEL_3.getInterpolation(1 - ZOOM_OUT.getInterpolation(1 - v)); 73 } 74 }; 75 76 public static final Interpolator ZOOM_OUT = new Interpolator() { 77 78 private static final float FOCAL_LENGTH = 0.35f; 79 80 @Override 81 public float getInterpolation(float v) { 82 return zInterpolate(v); 83 } 84 85 /** 86 * This interpolator emulates the rate at which the perceived scale of an object changes 87 * as its distance from a camera increases. When this interpolator is applied to a scale 88 * animation on a view, it evokes the sense that the object is shrinking due to moving away 89 * from the camera. 90 */ 91 private float zInterpolate(float input) { 92 return (1.0f - FOCAL_LENGTH / (FOCAL_LENGTH + input)) / 93 (1.0f - FOCAL_LENGTH / (FOCAL_LENGTH + 1.0f)); 94 } 95 }; 96 97 public static final Interpolator SCROLL = new Interpolator() { 98 @Override 99 public float getInterpolation(float t) { 100 t -= 1.0f; 101 return t*t*t*t*t + 1; 102 } 103 }; 104 105 public static final Interpolator SCROLL_CUBIC = new Interpolator() { 106 @Override 107 public float getInterpolation(float t) { 108 t -= 1.0f; 109 return t*t*t + 1; 110 } 111 }; 112 113 private static final float FAST_FLING_PX_MS = 10; 114 scrollInterpolatorForVelocity(float velocity)115 public static Interpolator scrollInterpolatorForVelocity(float velocity) { 116 return Math.abs(velocity) > FAST_FLING_PX_MS ? SCROLL : SCROLL_CUBIC; 117 } 118 119 /** 120 * Runs the given interpolator such that the entire progress is set between the given bounds. 121 * That is, we set the interpolation to 0 until lowerBound and reach 1 by upperBound. 122 */ clampToProgress(Interpolator interpolator, float lowerBound, float upperBound)123 public static Interpolator clampToProgress(Interpolator interpolator, float lowerBound, 124 float upperBound) { 125 if (upperBound <= lowerBound) { 126 throw new IllegalArgumentException("lowerBound must be less than upperBound"); 127 } 128 return t -> { 129 if (t < lowerBound) { 130 return 0; 131 } 132 if (t > upperBound) { 133 return 1; 134 } 135 return interpolator.getInterpolation((t - lowerBound) / (upperBound - lowerBound)); 136 }; 137 } 138 }