| /* |
| * Copyright (C) 2017 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.android.launcher3.anim; |
| |
| import static com.android.launcher3.util.DefaultDisplay.getSingleFrameMs; |
| |
| import android.content.Context; |
| import android.graphics.Path; |
| import android.view.animation.AccelerateDecelerateInterpolator; |
| import android.view.animation.AccelerateInterpolator; |
| import android.view.animation.DecelerateInterpolator; |
| import android.view.animation.Interpolator; |
| import android.view.animation.LinearInterpolator; |
| import android.view.animation.OvershootInterpolator; |
| import android.view.animation.PathInterpolator; |
| |
| import com.android.launcher3.Utilities; |
| |
| |
| /** |
| * Common interpolators used in Launcher |
| */ |
| public class Interpolators { |
| |
| public static final Interpolator LINEAR = new LinearInterpolator(); |
| |
| public static final Interpolator ACCEL = new AccelerateInterpolator(); |
| public static final Interpolator ACCEL_0_75 = new AccelerateInterpolator(0.75f); |
| public static final Interpolator ACCEL_1_5 = new AccelerateInterpolator(1.5f); |
| public static final Interpolator ACCEL_2 = new AccelerateInterpolator(2); |
| |
| public static final Interpolator DEACCEL = new DecelerateInterpolator(); |
| public static final Interpolator DEACCEL_1_5 = new DecelerateInterpolator(1.5f); |
| public static final Interpolator DEACCEL_1_7 = new DecelerateInterpolator(1.7f); |
| public static final Interpolator DEACCEL_2 = new DecelerateInterpolator(2); |
| public static final Interpolator DEACCEL_2_5 = new DecelerateInterpolator(2.5f); |
| public static final Interpolator DEACCEL_3 = new DecelerateInterpolator(3f); |
| public static final Interpolator DEACCEL_5 = new DecelerateInterpolator(5f); |
| |
| public static final Interpolator ACCEL_DEACCEL = new AccelerateDecelerateInterpolator(); |
| |
| public static final Interpolator FAST_OUT_SLOW_IN = new PathInterpolator(0.4f, 0f, 0.2f, 1f); |
| |
| public static final Interpolator AGGRESSIVE_EASE = new PathInterpolator(0.2f, 0f, 0f, 1f); |
| public static final Interpolator AGGRESSIVE_EASE_IN_OUT = new PathInterpolator(0.6f,0, 0.4f, 1); |
| |
| public static final Interpolator EXAGGERATED_EASE; |
| |
| public static final Interpolator INSTANT = t -> 1; |
| /** |
| * All values of t map to 0 until t == 1. This is primarily useful for setting view visibility, |
| * which should only happen at the very end of the animation (when it's already hidden). |
| */ |
| public static final Interpolator FINAL_FRAME = t -> t < 1 ? 0 : 1; |
| |
| private static final int MIN_SETTLE_DURATION = 200; |
| private static final float OVERSHOOT_FACTOR = 0.9f; |
| |
| static { |
| Path exaggeratedEase = new Path(); |
| exaggeratedEase.moveTo(0, 0); |
| exaggeratedEase.cubicTo(0.05f, 0f, 0.133333f, 0.08f, 0.166666f, 0.4f); |
| exaggeratedEase.cubicTo(0.225f, 0.94f, 0.5f, 1f, 1f, 1f); |
| EXAGGERATED_EASE = new PathInterpolator(exaggeratedEase); |
| } |
| |
| public static final Interpolator OVERSHOOT_1_2 = new OvershootInterpolator(1.2f); |
| public static final Interpolator OVERSHOOT_1_7 = new OvershootInterpolator(1.7f); |
| |
| public static final Interpolator TOUCH_RESPONSE_INTERPOLATOR = |
| new PathInterpolator(0.3f, 0f, 0.1f, 1f); |
| |
| /** |
| * Inversion of ZOOM_OUT, compounded with an ease-out. |
| */ |
| public static final Interpolator ZOOM_IN = new Interpolator() { |
| @Override |
| public float getInterpolation(float v) { |
| return DEACCEL_3.getInterpolation(1 - ZOOM_OUT.getInterpolation(1 - v)); |
| } |
| }; |
| |
| public static final Interpolator ZOOM_OUT = new Interpolator() { |
| |
| private static final float FOCAL_LENGTH = 0.35f; |
| |
| @Override |
| public float getInterpolation(float v) { |
| return zInterpolate(v); |
| } |
| |
| /** |
| * This interpolator emulates the rate at which the perceived scale of an object changes |
| * as its distance from a camera increases. When this interpolator is applied to a scale |
| * animation on a view, it evokes the sense that the object is shrinking due to moving away |
| * from the camera. |
| */ |
| private float zInterpolate(float input) { |
| return (1.0f - FOCAL_LENGTH / (FOCAL_LENGTH + input)) / |
| (1.0f - FOCAL_LENGTH / (FOCAL_LENGTH + 1.0f)); |
| } |
| }; |
| |
| public static final Interpolator SCROLL = new Interpolator() { |
| @Override |
| public float getInterpolation(float t) { |
| t -= 1.0f; |
| return t*t*t*t*t + 1; |
| } |
| }; |
| |
| public static final Interpolator SCROLL_CUBIC = new Interpolator() { |
| @Override |
| public float getInterpolation(float t) { |
| t -= 1.0f; |
| return t*t*t + 1; |
| } |
| }; |
| |
| private static final float FAST_FLING_PX_MS = 10; |
| |
| public static Interpolator scrollInterpolatorForVelocity(float velocity) { |
| return Math.abs(velocity) > FAST_FLING_PX_MS ? SCROLL : SCROLL_CUBIC; |
| } |
| |
| /** |
| * Create an OvershootInterpolator with tension directly related to the velocity (in px/ms). |
| * @param velocity The start velocity of the animation we want to overshoot. |
| */ |
| public static Interpolator overshootInterpolatorForVelocity(float velocity) { |
| return new OvershootInterpolator(Math.min(Math.abs(velocity), 3f)); |
| } |
| |
| /** |
| * Runs the given interpolator such that the entire progress is set between the given bounds. |
| * That is, we set the interpolation to 0 until lowerBound and reach 1 by upperBound. |
| */ |
| public static Interpolator clampToProgress(Interpolator interpolator, float lowerBound, |
| float upperBound) { |
| if (upperBound <= lowerBound) { |
| throw new IllegalArgumentException(String.format( |
| "lowerBound (%f) must be less than upperBound (%f)", lowerBound, upperBound)); |
| } |
| return t -> { |
| if (t < lowerBound) { |
| return 0; |
| } |
| if (t > upperBound) { |
| return 1; |
| } |
| return interpolator.getInterpolation((t - lowerBound) / (upperBound - lowerBound)); |
| }; |
| } |
| |
| /** |
| * Runs the given interpolator such that the interpolated value is mapped to the given range. |
| * This is useful, for example, if we only use this interpolator for part of the animation, |
| * such as to take over a user-controlled animation when they let go. |
| */ |
| public static Interpolator mapToProgress(Interpolator interpolator, float lowerBound, |
| float upperBound) { |
| return t -> Utilities.mapRange(interpolator.getInterpolation(t), lowerBound, upperBound); |
| } |
| |
| /** |
| * Computes parameters necessary for an overshoot effect. |
| */ |
| public static class OvershootParams { |
| public Interpolator interpolator; |
| public float start; |
| public float end; |
| public long duration; |
| |
| /** |
| * Given the input params, sets OvershootParams variables to be used by the caller. |
| * @param startProgress The progress from 0 to 1 that the overshoot starts from. |
| * @param overshootPastProgress The progress from 0 to 1 where we overshoot past (should |
| * either be equal to startProgress or endProgress, depending on if we want to |
| * overshoot immediately or only once we reach the end). |
| * @param endProgress The final progress from 0 to 1 that we will settle to. |
| * @param velocityPxPerMs The initial velocity that causes this overshoot. |
| * @param totalDistancePx The distance against which progress is calculated. |
| */ |
| public OvershootParams(float startProgress, float overshootPastProgress, |
| float endProgress, float velocityPxPerMs, int totalDistancePx, Context context) { |
| velocityPxPerMs = Math.abs(velocityPxPerMs); |
| overshootPastProgress = Math.max(overshootPastProgress, startProgress); |
| start = startProgress; |
| int startPx = (int) (start * totalDistancePx); |
| // Overshoot by about half a frame. |
| float overshootBy = OVERSHOOT_FACTOR * velocityPxPerMs * |
| getSingleFrameMs(context) / totalDistancePx / 2; |
| overshootBy = Utilities.boundToRange(overshootBy, 0.02f, 0.15f); |
| end = overshootPastProgress + overshootBy; |
| int endPx = (int) (end * totalDistancePx); |
| int overshootDistance = endPx - startPx; |
| // Calculate deceleration necessary to reach overshoot distance. |
| // Formula: velocityFinal^2 = velocityInitial^2 + 2 * acceleration * distance |
| // 0 = v^2 + 2ad (velocityFinal == 0) |
| // a = v^2 / -2d |
| float decelerationPxPerMs = velocityPxPerMs * velocityPxPerMs / (2 * overshootDistance); |
| // Calculate time necessary to reach peak of overshoot. |
| // Formula: acceleration = velocity / time |
| // time = velocity / acceleration |
| duration = (long) (velocityPxPerMs / decelerationPxPerMs); |
| |
| // Now that we're at the top of the overshoot, need to settle back to endProgress. |
| float settleDistance = end - endProgress; |
| int settleDistancePx = (int) (settleDistance * totalDistancePx); |
| // Calculate time necessary for the settle. |
| // Formula: distance = velocityInitial * time + 1/2 * acceleration * time^2 |
| // d = 1/2at^2 (velocityInitial = 0, since we just stopped at the top) |
| // t = sqrt(2d/a) |
| // Above formula assumes constant acceleration. Since we use ACCEL_DEACCEL, we actually |
| // have acceleration to halfway then deceleration the rest. So the formula becomes: |
| // t = sqrt(d/a) * 2 (half the distance for accel, half for deaccel) |
| long settleDuration = (long) Math.sqrt(settleDistancePx / decelerationPxPerMs) * 4; |
| |
| settleDuration = Math.max(MIN_SETTLE_DURATION, settleDuration); |
| // How much of the animation to devote to playing the overshoot (the rest is for settle). |
| float overshootFraction = (float) duration / (duration + settleDuration); |
| duration += settleDuration; |
| // Finally, create the interpolator, composed of two interpolators: an overshoot, which |
| // reaches end > 1, and then a settle to endProgress. |
| Interpolator overshoot = Interpolators.clampToProgress(DEACCEL, 0, overshootFraction); |
| // The settle starts at 1, where 1 is the top of the overshoot, and maps to a fraction |
| // such that final progress is endProgress. For example, if we overshot to 1.1 but want |
| // to end at 1, we need to map to 1/1.1. |
| Interpolator settle = Interpolators.clampToProgress(Interpolators.mapToProgress( |
| ACCEL_DEACCEL, 1, (endProgress - start) / (end - start)), overshootFraction, 1); |
| interpolator = t -> t <= overshootFraction |
| ? overshoot.getInterpolation(t) |
| : settle.getInterpolation(t); |
| } |
| } |
| } |