Adding support for building a "spring like animation" with precomputed values (3600fb77) · Commits · e / os / android_packages_apps_Trebuchet

quickstep/recents_ui_overrides/src/com/android/launcher3/LauncherAppTransitionManagerImpl.java

+9 −12

Original line number	Diff line number	Diff line
		@@ -18,16 +18,11 @@ package com.android.launcher3;

		import static com.android.launcher3.LauncherAnimUtils.VIEW_TRANSLATE_X;
		import static com.android.launcher3.LauncherState.NORMAL;
		import static com.android.launcher3.allapps.AllAppsTransitionController.ALL_APPS_PROGRESS;
		import static com.android.launcher3.anim.Interpolators.AGGRESSIVE_EASE;
		import static com.android.launcher3.anim.Interpolators.LINEAR;
		import static com.android.quickstep.TaskViewUtils.findTaskViewToLaunch;
		import static com.android.quickstep.TaskViewUtils.getRecentsWindowAnimator;

		import static androidx.dynamicanimation.animation.DynamicAnimation.MIN_VISIBLE_CHANGE_PIXELS;
		import static androidx.dynamicanimation.animation.SpringForce.DAMPING_RATIO_MEDIUM_BOUNCY;
		import static androidx.dynamicanimation.animation.SpringForce.STIFFNESS_MEDIUM;

		import android.animation.Animator;
		import android.animation.AnimatorListenerAdapter;
		import android.animation.AnimatorSet;
		@@ -35,18 +30,17 @@ import android.animation.ObjectAnimator;
		import android.content.Context;
		import android.view.View;

		import androidx.annotation.NonNull;
		import androidx.annotation.Nullable;

		import com.android.launcher3.allapps.AllAppsTransitionController;
		import com.android.launcher3.anim.AnimatorPlaybackController;
		import com.android.launcher3.anim.Interpolators;
		import com.android.launcher3.anim.SpringObjectAnimator;
		import com.android.launcher3.anim.SpringAnimationBuilder;
		import com.android.quickstep.util.ClipAnimationHelper;
		import com.android.quickstep.views.RecentsView;
		import com.android.quickstep.views.TaskView;
		import com.android.systemui.shared.system.RemoteAnimationTargetCompat;

		import androidx.annotation.NonNull;
		import androidx.annotation.Nullable;

		/**
		* A {@link QuickstepAppTransitionManagerImpl} that also implements recents transitions from
		* {@link RecentsView}.
		@@ -156,8 +150,11 @@ public final class LauncherAppTransitionManagerImpl extends QuickstepAppTransiti
		return ObjectAnimator.ofFloat(mLauncher.getOverviewPanel(),
		RecentsView.CONTENT_ALPHA, values);
		case INDEX_RECENTS_TRANSLATE_X_ANIM:
		return new SpringObjectAnimator<>(mLauncher.getOverviewPanel(),
		VIEW_TRANSLATE_X, MIN_VISIBLE_CHANGE_PIXELS, 0.8f, 250, values);
		return new SpringAnimationBuilder<>(mLauncher.getOverviewPanel(), VIEW_TRANSLATE_X)
		.setDampingRatio(0.8f)
		.setStiffness(250)
		.setValues(values)
		.build(mLauncher);
		default:
		return super.createStateElementAnimation(index, values);
		}

src/com/android/launcher3/anim/SpringAnimationBuilder.java

0 → 100644

+229 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2019 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 android.animation.Animator;
		import android.animation.ObjectAnimator;
		import android.content.Context;
		import android.util.FloatProperty;

		import com.android.launcher3.util.DefaultDisplay;

		import androidx.annotation.FloatRange;
		import androidx.dynamicanimation.animation.SpringForce;

		/**
		* Utility class to build an object animator which follows the same path as a spring animation for
		* an underdamped spring.
		*/
		public class SpringAnimationBuilder<T> extends FloatProperty<T> {

		private final T mTarget;
		private final FloatProperty<T> mProperty;

		private float mStartValue;
		private float mEndValue;
		private float mVelocity = 0;

		private float mStiffness = SpringForce.STIFFNESS_MEDIUM;
		private float mDampingRatio = SpringForce.DAMPING_RATIO_MEDIUM_BOUNCY;
		private float mMinVisibleChange = 1;

		// Multiplier to the min visible change value for value threshold
		private static final float THRESHOLD_MULTIPLIER = 0.65f;

		/**
		* The spring equation is given as
		* x = e^(-betat/2) (a cos(gamma * t) + b sin(gamma * t)
		* v = e^(-betat/2) ((2 * a * gamma + beta * b) * sin(gamma * t)
		* + (a * beta - 2 * b * gamma) * cos(gamma * t)) / 2
		*
		* a = x(0)
		* b = beta * x(0) / (2 * gamma) + v(0) / gamma
		*/
		private double beta;
		private double gamma;

		private double a, b;
		private double va, vb;

		// Threshold for velocity and value to determine when it's reasonable to assume that the spring
		// is approximately at rest.
		private double mValueThreshold;
		private double mVelocityThreshold;

		private float mCurrentTime = 0;

		public SpringAnimationBuilder(T target, FloatProperty<T> property) {
		super("dynamic-spring-property");
		mTarget = target;
		mProperty = property;

		mStartValue = mProperty.get(target);
		}

		public SpringAnimationBuilder<T> setEndValue(float value) {
		mEndValue = value;
		return this;
		}

		public SpringAnimationBuilder<T> setStartValue(float value) {
		mStartValue = value;
		return this;
		}

		public SpringAnimationBuilder<T> setValues(float... values) {
		if (values.length > 1) {
		mStartValue = values[0];
		mEndValue = values[values.length - 1];
		} else {
		mEndValue = values[0];
		}
		return this;
		}

		public SpringAnimationBuilder<T> setStiffness(
		@FloatRange(from = 0.0, fromInclusive = false) float stiffness) {
		if (stiffness <= 0) {
		throw new IllegalArgumentException("Spring stiffness constant must be positive.");
		}
		mStiffness = stiffness;
		return this;
		}

		public SpringAnimationBuilder<T> setDampingRatio(
		@FloatRange(from = 0.0, to = 1.0, fromInclusive = false, toInclusive = false)
		float dampingRatio) {
		if (dampingRatio <= 0 \|\| dampingRatio >= 1) {
		throw new IllegalArgumentException("Damping ratio must be between 0 and 1");
		}
		mDampingRatio = dampingRatio;
		return this;
		}

		public SpringAnimationBuilder<T> setMinimumVisibleChange(
		@FloatRange(from = 0.0, fromInclusive = false) float minimumVisibleChange) {
		if (minimumVisibleChange <= 0) {
		throw new IllegalArgumentException("Minimum visible change must be positive.");
		}
		mMinVisibleChange = minimumVisibleChange;
		return this;
		}

		public SpringAnimationBuilder<T> setStartVelocity(float startVelocity) {
		mVelocity = startVelocity;
		return this;
		}

		@Override
		public void setValue(T object, float time) {
		mCurrentTime = time;
		mProperty.setValue(
		object, (float) (exponentialComponent(time) * cosSinX(time)) + mEndValue);
		}

		@Override
		public Float get(T t) {
		return mCurrentTime;
		}

		public ObjectAnimator build(Context context) {
		int singleFrameMs = DefaultDisplay.getSingleFrameMs(context);
		double naturalFreq = Math.sqrt(mStiffness);
		double dampedFreq = naturalFreq * Math.sqrt(1 - mDampingRatio * mDampingRatio);

		// All the calculations assume the stable position to be 0, shift the values accordingly.
		beta = 2 * mDampingRatio * naturalFreq;
		gamma = dampedFreq;
		a = mStartValue - mEndValue;
		b = beta * a / (2 * gamma) + mVelocity / gamma;

		va = a * beta / 2 - b * gamma;
		vb = a * gamma + beta * b / 2;

		mValueThreshold = mMinVisibleChange * THRESHOLD_MULTIPLIER;

		// This multiplier is used to calculate the velocity threshold given a certain value
		// threshold. The idea is that if it takes >= 1 frame to move the value threshold amount,
		// then the velocity is a reasonable threshold.
		mVelocityThreshold = mValueThreshold * 1000.0 / singleFrameMs;

		// Find the duration (in seconds) for the spring to reach equilibrium.
		// equilibrium is reached when x = 0
		double duration = Math.atan2(-a, b) / gamma;

		// Keep moving ahead until the velocity reaches equilibrium.
		double piByG = Math.PI / gamma;
		while (duration < 0 \|\| Math.abs(exponentialComponent(duration) * cosSinV(duration))
		>= mVelocityThreshold) {
		duration += piByG;
		}

		// Find the shortest time
		double edgeTime = Math.max(0, duration - piByG / 2);
		double minDiff = singleFrameMs / 2000.0; // Half frame time in seconds

		do {
		if ((duration - edgeTime) < minDiff) {
		break;
		}
		double mid = (edgeTime + duration) / 2;
		if (isAtEquilibrium(mid)) {
		duration = mid;
		} else {
		edgeTime = mid;
		}
		} while (true);


		long durationMs = (long) (1000.0 * duration);
		ObjectAnimator animator = ObjectAnimator.ofFloat(mTarget, this, 0, (float) duration);
		animator.setDuration(durationMs).setInterpolator(Interpolators.LINEAR);
		animator.addListener(new AnimationSuccessListener() {
		@Override
		public void onAnimationSuccess(Animator animator) {
		mProperty.setValue(mTarget, mEndValue);
		}
		});
		return animator;
		}

		private boolean isAtEquilibrium(double t) {
		double ec = exponentialComponent(t);

		if (Math.abs(ec * cosSinX(t)) >= mValueThreshold) {
		return false;
		}
		return Math.abs(ec * cosSinV(t)) < mVelocityThreshold;
		}

		private double exponentialComponent(double t) {
		return Math.pow(Math.E, - beta * t / 2);
		}

		private double cosSinX(double t) {
		return cosSin(t, a, b);
		}

		private double cosSinV(double t) {
		return cosSin(t, va, vb);
		}

		private double cosSin(double t, double cosFactor, double sinFactor) {
		double angle = t * gamma;
		return cosFactor * Math.cos(angle) + sinFactor * Math.sin(angle);
		}
		}