/*
 * Copyright (C) 2011 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.server.wm;

import android.annotation.Nullable;
import android.content.Context;
import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.graphics.Rect;
import android.os.Debug;
import android.os.Handler;
import android.os.IBinder;
import android.os.IRemoteCallback;
import android.util.Slog;
import android.view.WindowManager;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.view.animation.AnimationSet;
import android.view.animation.AnimationUtils;
import android.view.animation.ClipRectAnimation;
import android.view.animation.ClipRectLRAnimation;
import android.view.animation.ClipRectTBAnimation;
import android.view.animation.Interpolator;
import android.view.animation.PathInterpolator;
import android.view.animation.ScaleAnimation;
import android.view.animation.TranslateAnimation;
import android.view.animation.TranslateYAnimation;

import com.android.internal.util.DumpUtils.Dump;
import com.android.server.AttributeCache;
import com.android.server.wm.WindowManagerService.H;

import java.io.PrintWriter;
import java.util.ArrayList;

import static android.view.WindowManagerInternal.AppTransitionListener;
import static com.android.internal.R.styleable.WindowAnimation_activityCloseEnterAnimation;
import static com.android.internal.R.styleable.WindowAnimation_activityCloseExitAnimation;
import static com.android.internal.R.styleable.WindowAnimation_activityOpenEnterAnimation;
import static com.android.internal.R.styleable.WindowAnimation_activityOpenExitAnimation;
import static com.android.internal.R.styleable.WindowAnimation_launchTaskBehindSourceAnimation;
import static com.android.internal.R.styleable.WindowAnimation_launchTaskBehindTargetAnimation;
import static com.android.internal.R.styleable.WindowAnimation_taskCloseEnterAnimation;
import static com.android.internal.R.styleable.WindowAnimation_taskCloseExitAnimation;
import static com.android.internal.R.styleable.WindowAnimation_taskOpenEnterAnimation;
import static com.android.internal.R.styleable.WindowAnimation_taskOpenExitAnimation;
import static com.android.internal.R.styleable.WindowAnimation_taskToBackEnterAnimation;
import static com.android.internal.R.styleable.WindowAnimation_taskToBackExitAnimation;
import static com.android.internal.R.styleable.WindowAnimation_taskToFrontEnterAnimation;
import static com.android.internal.R.styleable.WindowAnimation_taskToFrontExitAnimation;
import static com.android.internal.R.styleable.WindowAnimation_wallpaperCloseEnterAnimation;
import static com.android.internal.R.styleable.WindowAnimation_wallpaperCloseExitAnimation;
import static com.android.internal.R.styleable.WindowAnimation_wallpaperIntraCloseEnterAnimation;
import static com.android.internal.R.styleable.WindowAnimation_wallpaperIntraCloseExitAnimation;
import static com.android.internal.R.styleable.WindowAnimation_wallpaperIntraOpenEnterAnimation;
import static com.android.internal.R.styleable.WindowAnimation_wallpaperIntraOpenExitAnimation;
import static com.android.internal.R.styleable.WindowAnimation_wallpaperOpenEnterAnimation;
import static com.android.internal.R.styleable.WindowAnimation_wallpaperOpenExitAnimation;

// State management of app transitions.  When we are preparing for a
// transition, mNextAppTransition will be the kind of transition to
// perform or TRANSIT_NONE if we are not waiting.  If we are waiting,
// mOpeningApps and mClosingApps are the lists of tokens that will be
// made visible or hidden at the next transition.
public class AppTransition implements Dump {
    private static final String TAG = "AppTransition";
    private static final boolean DEBUG_APP_TRANSITIONS =
            WindowManagerService.DEBUG_APP_TRANSITIONS;
    private static final boolean DEBUG_ANIM = WindowManagerService.DEBUG_ANIM;
    private static final int CLIP_REVEAL_TRANSLATION_Y_DP = 8;

    /** Not set up for a transition. */
    public static final int TRANSIT_UNSET = -1;
    /** No animation for transition. */
    public static final int TRANSIT_NONE = 0;
    /** A window in a new activity is being opened on top of an existing one in the same task. */
    public static final int TRANSIT_ACTIVITY_OPEN = 6;
    /** The window in the top-most activity is being closed to reveal the
     * previous activity in the same task. */
    public static final int TRANSIT_ACTIVITY_CLOSE = 7;
    /** A window in a new task is being opened on top of an existing one
     * in another activity's task. */
    public static final int TRANSIT_TASK_OPEN = 8;
    /** A window in the top-most activity is being closed to reveal the
     * previous activity in a different task. */
    public static final int TRANSIT_TASK_CLOSE = 9;
    /** A window in an existing task is being displayed on top of an existing one
     * in another activity's task. */
    public static final int TRANSIT_TASK_TO_FRONT = 10;
    /** A window in an existing task is being put below all other tasks. */
    public static final int TRANSIT_TASK_TO_BACK = 11;
    /** A window in a new activity that doesn't have a wallpaper is being opened on top of one that
     * does, effectively closing the wallpaper. */
    public static final int TRANSIT_WALLPAPER_CLOSE = 12;
    /** A window in a new activity that does have a wallpaper is being opened on one that didn't,
     * effectively opening the wallpaper. */
    public static final int TRANSIT_WALLPAPER_OPEN = 13;
    /** A window in a new activity is being opened on top of an existing one, and both are on top
     * of the wallpaper. */
    public static final int TRANSIT_WALLPAPER_INTRA_OPEN = 14;
    /** The window in the top-most activity is being closed to reveal the previous activity, and
     * both are on top of the wallpaper. */
    public static final int TRANSIT_WALLPAPER_INTRA_CLOSE = 15;
    /** A window in a new task is being opened behind an existing one in another activity's task.
     * The new window will show briefly and then be gone. */
    public static final int TRANSIT_TASK_OPEN_BEHIND = 16;
    /** A window in a task is being animated in-place. */
    public static final int TRANSIT_TASK_IN_PLACE = 17;

    /** Fraction of animation at which the recents thumbnail stays completely transparent */
    private static final float RECENTS_THUMBNAIL_FADEIN_FRACTION = 0.5f;
    /** Fraction of animation at which the recents thumbnail becomes completely transparent */
    private static final float RECENTS_THUMBNAIL_FADEOUT_FRACTION = 0.5f;

    private static final int DEFAULT_APP_TRANSITION_DURATION = 336;
    private static final int THUMBNAIL_APP_TRANSITION_DURATION = 336;
    private static final int THUMBNAIL_APP_TRANSITION_ALPHA_DURATION = 336;

    private final Context mContext;
    private final Handler mH;

    private int mNextAppTransition = TRANSIT_UNSET;

    private static final int NEXT_TRANSIT_TYPE_NONE = 0;
    private static final int NEXT_TRANSIT_TYPE_CUSTOM = 1;
    private static final int NEXT_TRANSIT_TYPE_SCALE_UP = 2;
    private static final int NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_UP = 3;
    private static final int NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_DOWN = 4;
    private static final int NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_UP = 5;
    private static final int NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_DOWN = 6;
    private static final int NEXT_TRANSIT_TYPE_CUSTOM_IN_PLACE = 7;
    private static final int NEXT_TRANSIT_TYPE_CLIP_REVEAL = 8;
    private int mNextAppTransitionType = NEXT_TRANSIT_TYPE_NONE;

    // These are the possible states for the enter/exit activities during a thumbnail transition
    private static final int THUMBNAIL_TRANSITION_ENTER_SCALE_UP = 0;
    private static final int THUMBNAIL_TRANSITION_EXIT_SCALE_UP = 1;
    private static final int THUMBNAIL_TRANSITION_ENTER_SCALE_DOWN = 2;
    private static final int THUMBNAIL_TRANSITION_EXIT_SCALE_DOWN = 3;

    private String mNextAppTransitionPackage;
    private Bitmap mNextAppTransitionThumbnail;
    // Used for thumbnail transitions. True if we're scaling up, false if scaling down
    private boolean mNextAppTransitionScaleUp;
    private IRemoteCallback mNextAppTransitionCallback;
    private int mNextAppTransitionEnter;
    private int mNextAppTransitionExit;
    private int mNextAppTransitionInPlace;
    private int mNextAppTransitionStartX;
    private int mNextAppTransitionStartY;
    private int mNextAppTransitionStartWidth;
    private int mNextAppTransitionStartHeight;
    private Rect mNextAppTransitionInsets = new Rect();

    private Rect mTmpFromClipRect = new Rect();
    private Rect mTmpToClipRect = new Rect();

    private final static int APP_STATE_IDLE = 0;
    private final static int APP_STATE_READY = 1;
    private final static int APP_STATE_RUNNING = 2;
    private final static int APP_STATE_TIMEOUT = 3;
    private int mAppTransitionState = APP_STATE_IDLE;

    private final int mConfigShortAnimTime;
    private final Interpolator mDecelerateInterpolator;
    private final Interpolator mThumbnailFadeInInterpolator;
    private final Interpolator mThumbnailFadeOutInterpolator;
    private final Interpolator mLinearOutSlowInInterpolator;
    private final Interpolator mFastOutLinearInInterpolator;
    private final Interpolator mClipHorizontalInterpolator = new PathInterpolator(0, 0, 0.4f, 1f);

    /** Interpolator to be used for animations that respond directly to a touch */
    private final Interpolator mTouchResponseInterpolator =
            new PathInterpolator(0.3f, 0f, 0.1f, 1f);

    private final int mClipRevealTranslationY;

    private int mCurrentUserId = 0;

    private final ArrayList<AppTransitionListener> mListeners = new ArrayList<>();

    AppTransition(Context context, Handler h) {
        mContext = context;
        mH = h;
        mLinearOutSlowInInterpolator = AnimationUtils.loadInterpolator(context,
                com.android.internal.R.interpolator.linear_out_slow_in);
        mFastOutLinearInInterpolator = AnimationUtils.loadInterpolator(context,
                com.android.internal.R.interpolator.fast_out_linear_in);
        mConfigShortAnimTime = context.getResources().getInteger(
                com.android.internal.R.integer.config_shortAnimTime);
        mDecelerateInterpolator = AnimationUtils.loadInterpolator(context,
                com.android.internal.R.interpolator.decelerate_cubic);
        mThumbnailFadeInInterpolator = new Interpolator() {
            @Override
            public float getInterpolation(float input) {
                // Linear response for first fraction, then complete after that.
                if (input < RECENTS_THUMBNAIL_FADEIN_FRACTION) {
                    return 0f;
                }
                float t = (input - RECENTS_THUMBNAIL_FADEIN_FRACTION) /
                        (1f - RECENTS_THUMBNAIL_FADEIN_FRACTION);
                return mFastOutLinearInInterpolator.getInterpolation(t);
            }
        };
        mThumbnailFadeOutInterpolator = new Interpolator() {
            @Override
            public float getInterpolation(float input) {
                // Linear response for first fraction, then complete after that.
                if (input < RECENTS_THUMBNAIL_FADEOUT_FRACTION) {
                    float t = input / RECENTS_THUMBNAIL_FADEOUT_FRACTION;
                    return mLinearOutSlowInInterpolator.getInterpolation(t);
                }
                return 1f;
            }
        };
        mClipRevealTranslationY = (int) (CLIP_REVEAL_TRANSLATION_Y_DP
                * mContext.getResources().getDisplayMetrics().density);
    }

    boolean isTransitionSet() {
        return mNextAppTransition != TRANSIT_UNSET;
    }

    boolean isTransitionNone() {
        return mNextAppTransition == TRANSIT_NONE;
    }

    boolean isTransitionEqual(int transit) {
        return mNextAppTransition == transit;
    }

    int getAppTransition() {
        return mNextAppTransition;
     }

    void setAppTransition(int transit) {
        mNextAppTransition = transit;
    }

    boolean isReady() {
        return mAppTransitionState == APP_STATE_READY
                || mAppTransitionState == APP_STATE_TIMEOUT;
    }

    void setReady() {
        mAppTransitionState = APP_STATE_READY;
    }

    boolean isRunning() {
        return mAppTransitionState == APP_STATE_RUNNING;
    }

    void setIdle() {
        mAppTransitionState = APP_STATE_IDLE;
    }

    boolean isTimeout() {
        return mAppTransitionState == APP_STATE_TIMEOUT;
    }

    void setTimeout() {
        mAppTransitionState = APP_STATE_TIMEOUT;
    }

    Bitmap getNextAppTransitionThumbnail() {
        return mNextAppTransitionThumbnail;
    }

    /** Returns whether the next thumbnail transition is aspect scaled up. */
    boolean isNextThumbnailTransitionAspectScaled() {
        return mNextAppTransitionType == NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_UP ||
                mNextAppTransitionType == NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_DOWN;
    }

    /** Returns whether the next thumbnail transition is scaling up. */
    boolean isNextThumbnailTransitionScaleUp() {
        return mNextAppTransitionScaleUp;
    }

    int getStartingX() {
        return mNextAppTransitionStartX;
    }

    int getStartingY() {
        return mNextAppTransitionStartY;
    }

    boolean prepare() {
        if (!isRunning()) {
            mAppTransitionState = APP_STATE_IDLE;
            notifyAppTransitionPendingLocked();
            return true;
        }
        return false;
    }

    void goodToGo(AppWindowAnimator openingAppAnimator, AppWindowAnimator closingAppAnimator) {
        mNextAppTransition = TRANSIT_UNSET;
        mAppTransitionState = APP_STATE_RUNNING;
        notifyAppTransitionStartingLocked(
                openingAppAnimator != null ? openingAppAnimator.mAppToken.token : null,
                closingAppAnimator != null ? closingAppAnimator.mAppToken.token : null,
                openingAppAnimator != null ? openingAppAnimator.animation : null,
                closingAppAnimator != null ? closingAppAnimator.animation : null);
    }

    void clear() {
        mNextAppTransitionType = NEXT_TRANSIT_TYPE_NONE;
        mNextAppTransitionPackage = null;
        mNextAppTransitionThumbnail = null;
    }

    void freeze() {
        setAppTransition(AppTransition.TRANSIT_UNSET);
        clear();
        setReady();
        notifyAppTransitionCancelledLocked();
    }

    void registerListenerLocked(AppTransitionListener listener) {
        mListeners.add(listener);
    }

    public void notifyAppTransitionFinishedLocked(IBinder token) {
        for (int i = 0; i < mListeners.size(); i++) {
            mListeners.get(i).onAppTransitionFinishedLocked(token);
        }
    }

    private void notifyAppTransitionPendingLocked() {
        for (int i = 0; i < mListeners.size(); i++) {
            mListeners.get(i).onAppTransitionPendingLocked();
        }
    }

    private void notifyAppTransitionCancelledLocked() {
        for (int i = 0; i < mListeners.size(); i++) {
            mListeners.get(i).onAppTransitionCancelledLocked();
        }
    }

    private void notifyAppTransitionStartingLocked(IBinder openToken,
            IBinder closeToken, Animation openAnimation, Animation closeAnimation) {
        for (int i = 0; i < mListeners.size(); i++) {
            mListeners.get(i).onAppTransitionStartingLocked(openToken, closeToken, openAnimation,
                    closeAnimation);
        }
    }

    private AttributeCache.Entry getCachedAnimations(WindowManager.LayoutParams lp) {
        if (DEBUG_ANIM) Slog.v(TAG, "Loading animations: layout params pkg="
                + (lp != null ? lp.packageName : null)
                + " resId=0x" + (lp != null ? Integer.toHexString(lp.windowAnimations) : null));
        if (lp != null && lp.windowAnimations != 0) {
            // If this is a system resource, don't try to load it from the
            // application resources.  It is nice to avoid loading application
            // resources if we can.
            String packageName = lp.packageName != null ? lp.packageName : "android";
            int resId = lp.windowAnimations;
            if ((resId&0xFF000000) == 0x01000000) {
                packageName = "android";
            }
            if (DEBUG_ANIM) Slog.v(TAG, "Loading animations: picked package="
                    + packageName);
            return AttributeCache.instance().get(packageName, resId,
                    com.android.internal.R.styleable.WindowAnimation, mCurrentUserId);
        }
        return null;
    }

    private AttributeCache.Entry getCachedAnimations(String packageName, int resId) {
        if (DEBUG_ANIM) Slog.v(TAG, "Loading animations: package="
                + packageName + " resId=0x" + Integer.toHexString(resId));
        if (packageName != null) {
            if ((resId&0xFF000000) == 0x01000000) {
                packageName = "android";
            }
            if (DEBUG_ANIM) Slog.v(TAG, "Loading animations: picked package="
                    + packageName);
            return AttributeCache.instance().get(packageName, resId,
                    com.android.internal.R.styleable.WindowAnimation, mCurrentUserId);
        }
        return null;
    }

    Animation loadAnimationAttr(WindowManager.LayoutParams lp, int animAttr) {
        int anim = 0;
        Context context = mContext;
        if (animAttr >= 0) {
            AttributeCache.Entry ent = getCachedAnimations(lp);
            if (ent != null) {
                context = ent.context;
                anim = ent.array.getResourceId(animAttr, 0);
            }
        }
        if (anim != 0) {
            return AnimationUtils.loadAnimation(context, anim);
        }
        return null;
    }

    Animation loadAnimationRes(WindowManager.LayoutParams lp, int resId) {
        Context context = mContext;
        if (resId >= 0) {
            AttributeCache.Entry ent = getCachedAnimations(lp);
            if (ent != null) {
                context = ent.context;
            }
            return AnimationUtils.loadAnimation(context, resId);
        }
        return null;
    }

    private Animation loadAnimationRes(String packageName, int resId) {
        int anim = 0;
        Context context = mContext;
        if (resId >= 0) {
            AttributeCache.Entry ent = getCachedAnimations(packageName, resId);
            if (ent != null) {
                context = ent.context;
                anim = resId;
            }
        }
        if (anim != 0) {
            return AnimationUtils.loadAnimation(context, anim);
        }
        return null;
    }

    /**
     * Compute the pivot point for an animation that is scaling from a small
     * rect on screen to a larger rect.  The pivot point varies depending on
     * the distance between the inner and outer edges on both sides.  This
     * function computes the pivot point for one dimension.
     * @param startPos  Offset from left/top edge of outer rectangle to
     * left/top edge of inner rectangle.
     * @param finalScale The scaling factor between the size of the outer
     * and inner rectangles.
     */
    private static float computePivot(int startPos, float finalScale) {
        final float denom = finalScale-1;
        if (Math.abs(denom) < .0001f) {
            return startPos;
        }
        return -startPos / denom;
    }

    private Animation createScaleUpAnimationLocked(int transit, boolean enter,
                                                   int appWidth, int appHeight) {
        Animation a = null;
        if (enter) {
            // Entering app zooms out from the center of the initial rect.
            float scaleW = mNextAppTransitionStartWidth / (float) appWidth;
            float scaleH = mNextAppTransitionStartHeight / (float) appHeight;
            Animation scale = new ScaleAnimation(scaleW, 1, scaleH, 1,
                    computePivot(mNextAppTransitionStartX, scaleW),
                    computePivot(mNextAppTransitionStartY, scaleH));
            scale.setInterpolator(mDecelerateInterpolator);

            Animation alpha = new AlphaAnimation(0, 1);
            alpha.setInterpolator(mThumbnailFadeOutInterpolator);

            AnimationSet set = new AnimationSet(false);
            set.addAnimation(scale);
            set.addAnimation(alpha);
            set.setDetachWallpaper(true);
            a = set;
        } else  if (transit == TRANSIT_WALLPAPER_INTRA_OPEN ||
                    transit == TRANSIT_WALLPAPER_INTRA_CLOSE) {
            // If we are on top of the wallpaper, we need an animation that
            // correctly handles the wallpaper staying static behind all of
            // the animated elements.  To do this, will just have the existing
            // element fade out.
            a = new AlphaAnimation(1, 0);
            a.setDetachWallpaper(true);
        } else {
            // For normal animations, the exiting element just holds in place.
            a = new AlphaAnimation(1, 1);
        }

        // Pick the desired duration.  If this is an inter-activity transition,
        // it  is the standard duration for that.  Otherwise we use the longer
        // task transition duration.
        final long duration;
        switch (transit) {
            case TRANSIT_ACTIVITY_OPEN:
            case TRANSIT_ACTIVITY_CLOSE:
                duration = mConfigShortAnimTime;
                break;
            default:
                duration = DEFAULT_APP_TRANSITION_DURATION;
                break;
        }
        a.setDuration(duration);
        a.setFillAfter(true);
        a.setInterpolator(mDecelerateInterpolator);
        a.initialize(appWidth, appHeight, appWidth, appHeight);
        return a;
    }

    private Animation createClipRevealAnimationLocked(int transit, boolean enter, Rect appFrame) {
        final Animation anim;
        if (enter) {
            // Reveal will expand and move faster in horizontal direction

            final int appWidth = appFrame.width();
            final int appHeight = appFrame.height();

            float t = 0f;
            if (appHeight > 0) {
                t = (float) mNextAppTransitionStartY / appHeight;
            }
            int translationY = mClipRevealTranslationY
                    + (int)(appHeight / 7f * t);

            int centerX = mNextAppTransitionStartX + mNextAppTransitionStartWidth / 2;
            int centerY = mNextAppTransitionStartY + mNextAppTransitionStartHeight / 2;

            // Clip third of the from size of launch icon, expand to full width/height
            Animation clipAnimLR = new ClipRectLRAnimation(
                    centerX - mNextAppTransitionStartWidth / 2,
                    centerX + mNextAppTransitionStartWidth / 2,
                    0, appWidth);
            clipAnimLR.setInterpolator(mClipHorizontalInterpolator);
            clipAnimLR.setDuration((long) (DEFAULT_APP_TRANSITION_DURATION / 2.5f));
            Animation clipAnimTB = new ClipRectTBAnimation(
                    centerY - mNextAppTransitionStartHeight / 2 - translationY,
                    centerY + mNextAppTransitionStartHeight / 2 - translationY,
                    0, appHeight);
            clipAnimTB.setInterpolator(mTouchResponseInterpolator);
            clipAnimTB.setDuration(DEFAULT_APP_TRANSITION_DURATION);

            TranslateYAnimation translateY = new TranslateYAnimation(
                    Animation.ABSOLUTE, translationY, Animation.ABSOLUTE, 0);
            translateY.setInterpolator(mLinearOutSlowInInterpolator);
            translateY.setDuration(DEFAULT_APP_TRANSITION_DURATION);

            // Quick fade-in from icon to app window
            final int alphaDuration = DEFAULT_APP_TRANSITION_DURATION / 4;
            AlphaAnimation alpha = new AlphaAnimation(0.5f, 1);
            alpha.setDuration(alphaDuration);
            alpha.setInterpolator(mLinearOutSlowInInterpolator);

            AnimationSet set = new AnimationSet(false);
            set.addAnimation(clipAnimLR);
            set.addAnimation(clipAnimTB);
            set.addAnimation(translateY);
            set.addAnimation(alpha);
            set.setZAdjustment(Animation.ZORDER_TOP);
            set.initialize(appWidth, appHeight, appWidth, appHeight);
            anim = set;
        } else {
            final long duration;
            switch (transit) {
                case TRANSIT_ACTIVITY_OPEN:
                case TRANSIT_ACTIVITY_CLOSE:
                    duration = mConfigShortAnimTime;
                    break;
                default:
                    duration = DEFAULT_APP_TRANSITION_DURATION;
                    break;
            }
            if (transit == TRANSIT_WALLPAPER_INTRA_OPEN ||
                    transit == TRANSIT_WALLPAPER_INTRA_CLOSE) {
                // If we are on top of the wallpaper, we need an animation that
                // correctly handles the wallpaper staying static behind all of
                // the animated elements.  To do this, will just have the existing
                // element fade out.
                anim = new AlphaAnimation(1, 0);
                anim.setDetachWallpaper(true);
            } else {
                // For normal animations, the exiting element just holds in place.
                anim = new AlphaAnimation(1, 1);
            }
            anim.setInterpolator(mDecelerateInterpolator);
            anim.setDuration(duration);
            anim.setFillAfter(true);
        }
        return anim;
    }

    /**
     * Prepares the specified animation with a standard duration, interpolator, etc.
     */
    Animation prepareThumbnailAnimationWithDuration(Animation a, int appWidth, int appHeight,
            int duration, Interpolator interpolator) {
        if (duration > 0) {
            a.setDuration(duration);
        }
        a.setFillAfter(true);
        a.setInterpolator(interpolator);
        a.initialize(appWidth, appHeight, appWidth, appHeight);
        return a;
    }

    /**
     * Prepares the specified animation with a standard duration, interpolator, etc.
     */
    Animation prepareThumbnailAnimation(Animation a, int appWidth, int appHeight, int transit) {
        // Pick the desired duration.  If this is an inter-activity transition,
        // it  is the standard duration for that.  Otherwise we use the longer
        // task transition duration.
        final int duration;
        switch (transit) {
            case TRANSIT_ACTIVITY_OPEN:
            case TRANSIT_ACTIVITY_CLOSE:
                duration = mConfigShortAnimTime;
                break;
            default:
                duration = DEFAULT_APP_TRANSITION_DURATION;
                break;
        }
        return prepareThumbnailAnimationWithDuration(a, appWidth, appHeight, duration,
                mDecelerateInterpolator);
    }

    /**
     * Return the current thumbnail transition state.
     */
    int getThumbnailTransitionState(boolean enter) {
        if (enter) {
            if (mNextAppTransitionScaleUp) {
                return THUMBNAIL_TRANSITION_ENTER_SCALE_UP;
            } else {
                return THUMBNAIL_TRANSITION_ENTER_SCALE_DOWN;
            }
        } else {
            if (mNextAppTransitionScaleUp) {
                return THUMBNAIL_TRANSITION_EXIT_SCALE_UP;
            } else {
                return THUMBNAIL_TRANSITION_EXIT_SCALE_DOWN;
            }
        }
    }

    /**
     * This animation runs for the thumbnail that gets cross faded with the enter/exit activity
     * when a thumbnail is specified with the activity options.
     */
    Animation createThumbnailAspectScaleAnimationLocked(Rect appRect) {
        Animation a;
        final int thumbWidthI = mNextAppTransitionThumbnail.getWidth();
        final float thumbWidth = thumbWidthI > 0 ? thumbWidthI : 1;
        final int thumbHeightI = mNextAppTransitionThumbnail.getHeight();
        final float thumbHeight = thumbHeightI > 0 ? thumbHeightI : 1;
        final int appWidth = appRect.width();

        float scaleW = appWidth / thumbWidth;
        float unscaledHeight = thumbHeight * scaleW;
        float unscaledStartY = mNextAppTransitionStartY - (unscaledHeight - thumbHeight) / 2f;
        if (mNextAppTransitionScaleUp) {
            // Animation up from the thumbnail to the full screen
            Animation scale = new ScaleAnimation(1f, scaleW, 1f, scaleW,
                    mNextAppTransitionStartX + (thumbWidth / 2f),
                    mNextAppTransitionStartY + (thumbHeight / 2f));
            scale.setInterpolator(mTouchResponseInterpolator);
            scale.setDuration(THUMBNAIL_APP_TRANSITION_DURATION);
            Animation alpha = new AlphaAnimation(1, 0);
            alpha.setInterpolator(mThumbnailFadeOutInterpolator);
            alpha.setDuration(THUMBNAIL_APP_TRANSITION_ALPHA_DURATION);
            final float toX = appRect.left + appRect.width() / 2 -
                    (mNextAppTransitionStartX + thumbWidth / 2);
            final float toY = appRect.top + mNextAppTransitionInsets.top + -unscaledStartY;
            Animation translate = new TranslateAnimation(0, toX, 0, toY);
            translate.setInterpolator(mTouchResponseInterpolator);
            translate.setDuration(THUMBNAIL_APP_TRANSITION_DURATION);

            // This AnimationSet uses the Interpolators assigned above.
            AnimationSet set = new AnimationSet(false);
            set.addAnimation(scale);
            set.addAnimation(alpha);
            set.addAnimation(translate);
            a = set;
        } else {
            // Animation down from the full screen to the thumbnail
            Animation scale = new ScaleAnimation(scaleW, 1f, scaleW, 1f,
                    mNextAppTransitionStartX + (thumbWidth / 2f),
                    mNextAppTransitionStartY + (thumbHeight / 2f));
            scale.setInterpolator(mTouchResponseInterpolator);
            scale.setDuration(THUMBNAIL_APP_TRANSITION_DURATION);
            Animation alpha = new AlphaAnimation(0f, 1f);
            alpha.setInterpolator(mThumbnailFadeInInterpolator);
            alpha.setDuration(THUMBNAIL_APP_TRANSITION_ALPHA_DURATION);
            Animation translate = new TranslateAnimation(0, 0, -unscaledStartY +
                    mNextAppTransitionInsets.top, 0);
            translate.setInterpolator(mTouchResponseInterpolator);
            translate.setDuration(THUMBNAIL_APP_TRANSITION_DURATION);

            // This AnimationSet uses the Interpolators assigned above.
            AnimationSet set = new AnimationSet(false);
            set.addAnimation(scale);
            set.addAnimation(alpha);
            set.addAnimation(translate);
            a = set;

        }
        return prepareThumbnailAnimationWithDuration(a, appWidth, appRect.height(), 0,
                mTouchResponseInterpolator);
    }

    /**
     * This alternate animation is created when we are doing a thumbnail transition, for the
     * activity that is leaving, and the activity that is entering.
     */
    Animation createAspectScaledThumbnailEnterExitAnimationLocked(int thumbTransitState,
            int appWidth, int appHeight, int orientation, int transit, Rect containingFrame,
            Rect contentInsets, @Nullable Rect surfaceInsets, boolean resizedWindow) {
        Animation a;
        final int thumbWidthI = mNextAppTransitionStartWidth;
        final float thumbWidth = thumbWidthI > 0 ? thumbWidthI : 1;
        final int thumbHeightI = mNextAppTransitionStartHeight;
        final float thumbHeight = thumbHeightI > 0 ? thumbHeightI : 1;

        // Used for the ENTER_SCALE_UP and EXIT_SCALE_DOWN transitions
        float scale = 1f;
        int scaledTopDecor = 0;

        switch (thumbTransitState) {
            case THUMBNAIL_TRANSITION_ENTER_SCALE_UP: {
                if (resizedWindow) {
                    a = createAspectScaledThumbnailEnterNonFullscreenAnimationLocked(
                            containingFrame, surfaceInsets);
                } else {
                    // App window scaling up to become full screen
                    if (orientation == Configuration.ORIENTATION_PORTRAIT) {
                        // In portrait, we scale the width and clip to the top/left square
                        scale = thumbWidth / appWidth;
                        scaledTopDecor = (int) (scale * contentInsets.top);
                        int unscaledThumbHeight = (int) (thumbHeight / scale);
                        mTmpFromClipRect.set(containingFrame);
                        mTmpFromClipRect.bottom = (mTmpFromClipRect.top + unscaledThumbHeight);
                        mTmpToClipRect.set(containingFrame);
                    } else {
                        // In landscape, we scale the height and clip to the top/left square
                        scale = thumbHeight / (appHeight - contentInsets.top);
                        scaledTopDecor = (int) (scale * contentInsets.top);
                        int unscaledThumbWidth = (int) (thumbWidth / scale);
                        mTmpFromClipRect.set(containingFrame);
                        mTmpFromClipRect.right = (mTmpFromClipRect.left + unscaledThumbWidth);
                        mTmpToClipRect.set(containingFrame);
                    }
                    // exclude top screen decor (status bar) region from the source clip.
                    mTmpFromClipRect.top = contentInsets.top;

                    mNextAppTransitionInsets.set(contentInsets);

                    Animation scaleAnim = new ScaleAnimation(scale, 1, scale, 1,
                            computePivot(mNextAppTransitionStartX, scale),
                            computePivot(mNextAppTransitionStartY, scale));
                    Animation clipAnim = new ClipRectAnimation(mTmpFromClipRect, mTmpToClipRect);
                    Animation translateAnim = new TranslateAnimation(0, 0, -scaledTopDecor, 0);

                    AnimationSet set = new AnimationSet(true);
                    set.addAnimation(clipAnim);
                    set.addAnimation(scaleAnim);
                    set.addAnimation(translateAnim);
                    a = set;
                }
                break;
            }
            case THUMBNAIL_TRANSITION_EXIT_SCALE_UP: {
                // Previous app window during the scale up
                if (transit == TRANSIT_WALLPAPER_INTRA_OPEN) {
                    // Fade out the source activity if we are animating to a wallpaper
                    // activity.
                    a = new AlphaAnimation(1, 0);
                } else {
                    a = new AlphaAnimation(1, 1);
                }
                break;
            }
            case THUMBNAIL_TRANSITION_ENTER_SCALE_DOWN: {
                // Target app window during the scale down
                if (transit == TRANSIT_WALLPAPER_INTRA_OPEN) {
                    // Fade in the destination activity if we are animating from a wallpaper
                    // activity.
                    a = new AlphaAnimation(0, 1);
                } else {
                    a = new AlphaAnimation(1, 1);
                }
                break;
            }
            case THUMBNAIL_TRANSITION_EXIT_SCALE_DOWN: {
                // App window scaling down from full screen
                if (orientation == Configuration.ORIENTATION_PORTRAIT) {
                    // In portrait, we scale the width and clip to the top/left square
                    scale = thumbWidth / appWidth;
                    scaledTopDecor = (int) (scale * contentInsets.top);
                    int unscaledThumbHeight = (int) (thumbHeight / scale);
                    mTmpFromClipRect.set(containingFrame);
                    mTmpToClipRect.set(containingFrame);
                    mTmpToClipRect.bottom = (mTmpToClipRect.top + unscaledThumbHeight);
                } else {
                    // In landscape, we scale the height and clip to the top/left square
                    scale = thumbHeight / (appHeight - contentInsets.top);
                    scaledTopDecor = (int) (scale * contentInsets.top);
                    int unscaledThumbWidth = (int) (thumbWidth / scale);
                    mTmpFromClipRect.set(containingFrame);
                    mTmpToClipRect.set(containingFrame);
                    mTmpToClipRect.right = (mTmpToClipRect.left + unscaledThumbWidth);
                }
                // exclude top screen decor (status bar) region from the destination clip.
                mTmpToClipRect.top = contentInsets.top;

                mNextAppTransitionInsets.set(contentInsets);

                Animation scaleAnim = new ScaleAnimation(1, scale, 1, scale,
                        computePivot(mNextAppTransitionStartX, scale),
                        computePivot(mNextAppTransitionStartY, scale));
                Animation clipAnim = new ClipRectAnimation(mTmpFromClipRect, mTmpToClipRect);
                Animation translateAnim = new TranslateAnimation(0, 0, 0, -scaledTopDecor);

                AnimationSet set = new AnimationSet(true);
                set.addAnimation(clipAnim);
                set.addAnimation(scaleAnim);
                set.addAnimation(translateAnim);

                a = set;
                a.setZAdjustment(Animation.ZORDER_TOP);
                break;
            }
            default:
                throw new RuntimeException("Invalid thumbnail transition state");
        }

        int duration = Math.max(THUMBNAIL_APP_TRANSITION_ALPHA_DURATION,
                THUMBNAIL_APP_TRANSITION_DURATION);
        return prepareThumbnailAnimationWithDuration(a, appWidth, appHeight, duration,
                mTouchResponseInterpolator);
    }

    private Animation createAspectScaledThumbnailEnterNonFullscreenAnimationLocked(
            Rect containingFrame, @Nullable Rect surfaceInsets) {
        float width = containingFrame.width();
        float height = containingFrame.height();
        float scaleWidth = mNextAppTransitionStartWidth / width;
        float scaleHeight = mNextAppTransitionStartHeight / height;
        AnimationSet set = new AnimationSet(true);
        int surfaceInsetsHorizontal = surfaceInsets == null
                ? 0 : surfaceInsets.left + surfaceInsets.right;
        int surfaceInsetsVertical = surfaceInsets == null
                ? 0 : surfaceInsets.top + surfaceInsets.bottom;
        // We want the scaling to happen from the center of the surface. In order to achieve that,
        // we need to account for surface insets that will be used to enlarge the surface.
        ScaleAnimation scale = new ScaleAnimation(scaleWidth, 1, scaleHeight, 1,
                (width + surfaceInsetsHorizontal) / 2, (height + surfaceInsetsVertical) / 2);
        int fromX = mNextAppTransitionStartX + mNextAppTransitionStartWidth / 2
                - (containingFrame.left + containingFrame.width() / 2);
        int fromY = mNextAppTransitionStartY + mNextAppTransitionStartHeight / 2
                - (containingFrame.top + containingFrame.height() / 2);
        TranslateAnimation translation = new TranslateAnimation(fromX, 0, fromY, 0);
        set.addAnimation(scale);
        set.addAnimation(translation);
        return set;
    }

    /**
     * This animation runs for the thumbnail that gets cross faded with the enter/exit activity
     * when a thumbnail is specified with the activity options.
     */
    Animation createThumbnailScaleAnimationLocked(int appWidth, int appHeight, int transit) {
        Animation a;
        final int thumbWidthI = mNextAppTransitionThumbnail.getWidth();
        final float thumbWidth = thumbWidthI > 0 ? thumbWidthI : 1;
        final int thumbHeightI = mNextAppTransitionThumbnail.getHeight();
        final float thumbHeight = thumbHeightI > 0 ? thumbHeightI : 1;

        if (mNextAppTransitionScaleUp) {
            // Animation for the thumbnail zooming from its initial size to the full screen
            float scaleW = appWidth / thumbWidth;
            float scaleH = appHeight / thumbHeight;
            Animation scale = new ScaleAnimation(1, scaleW, 1, scaleH,
                    computePivot(mNextAppTransitionStartX, 1 / scaleW),
                    computePivot(mNextAppTransitionStartY, 1 / scaleH));
            scale.setInterpolator(mDecelerateInterpolator);

            Animation alpha = new AlphaAnimation(1, 0);
            alpha.setInterpolator(mThumbnailFadeOutInterpolator);

            // This AnimationSet uses the Interpolators assigned above.
            AnimationSet set = new AnimationSet(false);
            set.addAnimation(scale);
            set.addAnimation(alpha);
            a = set;
        } else {
            // Animation for the thumbnail zooming down from the full screen to its final size
            float scaleW = appWidth / thumbWidth;
            float scaleH = appHeight / thumbHeight;
            a = new ScaleAnimation(scaleW, 1, scaleH, 1,
                    computePivot(mNextAppTransitionStartX, 1 / scaleW),
                    computePivot(mNextAppTransitionStartY, 1 / scaleH));
        }

        return prepareThumbnailAnimation(a, appWidth, appHeight, transit);
    }

    /**
     * This animation is created when we are doing a thumbnail transition, for the activity that is
     * leaving, and the activity that is entering.
     */
    Animation createThumbnailEnterExitAnimationLocked(int thumbTransitState, int appWidth,
            int appHeight, int transit) {
        Animation a;
        final int thumbWidthI = mNextAppTransitionThumbnail.getWidth();
        final float thumbWidth = thumbWidthI > 0 ? thumbWidthI : 1;
        final int thumbHeightI = mNextAppTransitionThumbnail.getHeight();
        final float thumbHeight = thumbHeightI > 0 ? thumbHeightI : 1;

        switch (thumbTransitState) {
            case THUMBNAIL_TRANSITION_ENTER_SCALE_UP: {
                // Entering app scales up with the thumbnail
                float scaleW = thumbWidth / appWidth;
                float scaleH = thumbHeight / appHeight;
                a = new ScaleAnimation(scaleW, 1, scaleH, 1,
                        computePivot(mNextAppTransitionStartX, scaleW),
                        computePivot(mNextAppTransitionStartY, scaleH));
                break;
            }
            case THUMBNAIL_TRANSITION_EXIT_SCALE_UP: {
                // Exiting app while the thumbnail is scaling up should fade or stay in place
                if (transit == TRANSIT_WALLPAPER_INTRA_OPEN) {
                    // Fade out while bringing up selected activity. This keeps the
                    // current activity from showing through a launching wallpaper
                    // activity.
                    a = new AlphaAnimation(1, 0);
                } else {
                    // noop animation
                    a = new AlphaAnimation(1, 1);
                }
                break;
            }
            case THUMBNAIL_TRANSITION_ENTER_SCALE_DOWN: {
                // Entering the other app, it should just be visible while we scale the thumbnail
                // down above it
                a = new AlphaAnimation(1, 1);
                break;
            }
            case THUMBNAIL_TRANSITION_EXIT_SCALE_DOWN: {
                // Exiting the current app, the app should scale down with the thumbnail
                float scaleW = thumbWidth / appWidth;
                float scaleH = thumbHeight / appHeight;
                Animation scale = new ScaleAnimation(1, scaleW, 1, scaleH,
                        computePivot(mNextAppTransitionStartX, scaleW),
                        computePivot(mNextAppTransitionStartY, scaleH));

                Animation alpha = new AlphaAnimation(1, 0);

                AnimationSet set = new AnimationSet(true);
                set.addAnimation(scale);
                set.addAnimation(alpha);
                set.setZAdjustment(Animation.ZORDER_TOP);
                a = set;
                break;
            }
            default:
                throw new RuntimeException("Invalid thumbnail transition state");
        }

        return prepareThumbnailAnimation(a, appWidth, appHeight, transit);
    }

    /**
     * @return true if and only if the first frame of the transition can be skipped, i.e. the first
     *         frame of the transition doesn't change the visuals on screen, so we can start
     *         directly with the second one
     */
    boolean canSkipFirstFrame() {
        return mNextAppTransitionType != NEXT_TRANSIT_TYPE_CUSTOM
                && mNextAppTransitionType != NEXT_TRANSIT_TYPE_CUSTOM_IN_PLACE
                && mNextAppTransitionType != NEXT_TRANSIT_TYPE_CLIP_REVEAL;
    }

    Animation loadAnimation(WindowManager.LayoutParams lp, int transit, boolean enter,
            int appWidth, int appHeight, int orientation, Rect containingFrame, Rect contentInsets,
            @Nullable Rect surfaceInsets, Rect appFrame, boolean isVoiceInteraction,
            boolean resizedWindow) {
        Animation a;
        if (isVoiceInteraction && (transit == TRANSIT_ACTIVITY_OPEN
                || transit == TRANSIT_TASK_OPEN
                || transit == TRANSIT_TASK_TO_FRONT)) {
            a = loadAnimationRes(lp, enter
                    ? com.android.internal.R.anim.voice_activity_open_enter
                    : com.android.internal.R.anim.voice_activity_open_exit);
            if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) Slog.v(TAG,
                    "applyAnimation voice:"
                    + " anim=" + a + " transit=" + appTransitionToString(transit)
                    + " isEntrance=" + enter + " Callers=" + Debug.getCallers(3));
        } else if (isVoiceInteraction && (transit == TRANSIT_ACTIVITY_CLOSE
                || transit == TRANSIT_TASK_CLOSE
                || transit == TRANSIT_TASK_TO_BACK)) {
            a = loadAnimationRes(lp, enter
                    ? com.android.internal.R.anim.voice_activity_close_enter
                    : com.android.internal.R.anim.voice_activity_close_exit);
            if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) Slog.v(TAG,
                    "applyAnimation voice:"
                    + " anim=" + a + " transit=" + appTransitionToString(transit)
                    + " isEntrance=" + enter + " Callers=" + Debug.getCallers(3));
        } else if (mNextAppTransitionType == NEXT_TRANSIT_TYPE_CUSTOM) {
            a = loadAnimationRes(mNextAppTransitionPackage, enter ?
                    mNextAppTransitionEnter : mNextAppTransitionExit);
            if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) Slog.v(TAG,
                    "applyAnimation:"
                    + " anim=" + a + " nextAppTransition=ANIM_CUSTOM"
                    + " transit=" + appTransitionToString(transit) + " isEntrance=" + enter
                    + " Callers=" + Debug.getCallers(3));
        } else if (mNextAppTransitionType == NEXT_TRANSIT_TYPE_CUSTOM_IN_PLACE) {
            a = loadAnimationRes(mNextAppTransitionPackage, mNextAppTransitionInPlace);
            if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) Slog.v(TAG,
                    "applyAnimation:"
                    + " anim=" + a + " nextAppTransition=ANIM_CUSTOM_IN_PLACE"
                    + " transit=" + appTransitionToString(transit)
                    + " Callers=" + Debug.getCallers(3));
        } else if (mNextAppTransitionType == NEXT_TRANSIT_TYPE_CLIP_REVEAL) {
            a = createClipRevealAnimationLocked(transit, enter, appFrame);
            if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) Slog.v(TAG,
                    "applyAnimation:"
                            + " anim=" + a + " nextAppTransition=ANIM_CLIP_REVEAL"
                            + " Callers=" + Debug.getCallers(3));
        } else if (mNextAppTransitionType == NEXT_TRANSIT_TYPE_SCALE_UP) {
            a = createScaleUpAnimationLocked(transit, enter, appWidth, appHeight);
            if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) Slog.v(TAG,
                    "applyAnimation:"
                    + " anim=" + a + " nextAppTransition=ANIM_SCALE_UP"
                    + " transit=" + appTransitionToString(transit) + " isEntrance=" + enter
                    + " Callers=" + Debug.getCallers(3));
        } else if (mNextAppTransitionType == NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_UP ||
                mNextAppTransitionType == NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_DOWN) {
            mNextAppTransitionScaleUp =
                    (mNextAppTransitionType == NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_UP);
            a = createThumbnailEnterExitAnimationLocked(getThumbnailTransitionState(enter),
                    appWidth, appHeight, transit);
            if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) {
                String animName = mNextAppTransitionScaleUp ?
                        "ANIM_THUMBNAIL_SCALE_UP" : "ANIM_THUMBNAIL_SCALE_DOWN";
                Slog.v(TAG, "applyAnimation:"
                        + " anim=" + a + " nextAppTransition=" + animName
                        + " transit=" + appTransitionToString(transit) + " isEntrance=" + enter
                        + " Callers=" + Debug.getCallers(3));
            }
        } else if (mNextAppTransitionType == NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_UP ||
                mNextAppTransitionType == NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_DOWN) {
            mNextAppTransitionScaleUp =
                    (mNextAppTransitionType == NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_UP);
            a = createAspectScaledThumbnailEnterExitAnimationLocked(
                    getThumbnailTransitionState(enter), appWidth, appHeight, orientation, transit,
                    containingFrame, contentInsets, surfaceInsets, resizedWindow);
            if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) {
                String animName = mNextAppTransitionScaleUp ?
                        "ANIM_THUMBNAIL_ASPECT_SCALE_UP" : "ANIM_THUMBNAIL_ASPECT_SCALE_DOWN";
                Slog.v(TAG, "applyAnimation:"
                        + " anim=" + a + " nextAppTransition=" + animName
                        + " transit=" + appTransitionToString(transit) + " isEntrance=" + enter
                        + " Callers=" + Debug.getCallers(3));
            }
        } else {
            int animAttr = 0;
            switch (transit) {
                case TRANSIT_ACTIVITY_OPEN:
                    animAttr = enter
                            ? WindowAnimation_activityOpenEnterAnimation
                            : WindowAnimation_activityOpenExitAnimation;
                    break;
                case TRANSIT_ACTIVITY_CLOSE:
                    animAttr = enter
                            ? WindowAnimation_activityCloseEnterAnimation
                            : WindowAnimation_activityCloseExitAnimation;
                    break;
                case TRANSIT_TASK_OPEN:
                    animAttr = enter
                            ? WindowAnimation_taskOpenEnterAnimation
                            : WindowAnimation_taskOpenExitAnimation;
                    break;
                case TRANSIT_TASK_CLOSE:
                    animAttr = enter
                            ? WindowAnimation_taskCloseEnterAnimation
                            : WindowAnimation_taskCloseExitAnimation;
                    break;
                case TRANSIT_TASK_TO_FRONT:
                    animAttr = enter
                            ? WindowAnimation_taskToFrontEnterAnimation
                            : WindowAnimation_taskToFrontExitAnimation;
                    break;
                case TRANSIT_TASK_TO_BACK:
                    animAttr = enter
                            ? WindowAnimation_taskToBackEnterAnimation
                            : WindowAnimation_taskToBackExitAnimation;
                    break;
                case TRANSIT_WALLPAPER_OPEN:
                    animAttr = enter
                            ? WindowAnimation_wallpaperOpenEnterAnimation
                            : WindowAnimation_wallpaperOpenExitAnimation;
                    break;
                case TRANSIT_WALLPAPER_CLOSE:
                    animAttr = enter
                            ? WindowAnimation_wallpaperCloseEnterAnimation
                            : WindowAnimation_wallpaperCloseExitAnimation;
                    break;
                case TRANSIT_WALLPAPER_INTRA_OPEN:
                    animAttr = enter
                            ? WindowAnimation_wallpaperIntraOpenEnterAnimation
                            : WindowAnimation_wallpaperIntraOpenExitAnimation;
                    break;
                case TRANSIT_WALLPAPER_INTRA_CLOSE:
                    animAttr = enter
                            ? WindowAnimation_wallpaperIntraCloseEnterAnimation
                            : WindowAnimation_wallpaperIntraCloseExitAnimation;
                    break;
                case TRANSIT_TASK_OPEN_BEHIND:
                    animAttr = enter
                            ? WindowAnimation_launchTaskBehindSourceAnimation
                            : WindowAnimation_launchTaskBehindTargetAnimation;
            }
            a = animAttr != 0 ? loadAnimationAttr(lp, animAttr) : null;
            if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) Slog.v(TAG,
                    "applyAnimation:"
                    + " anim=" + a
                    + " animAttr=0x" + Integer.toHexString(animAttr)
                    + " transit=" + appTransitionToString(transit) + " isEntrance=" + enter
                    + " Callers=" + Debug.getCallers(3));
        }
        return a;
    }

    void postAnimationCallback() {
        if (mNextAppTransitionCallback != null) {
            mH.sendMessage(mH.obtainMessage(H.DO_ANIMATION_CALLBACK, mNextAppTransitionCallback));
            mNextAppTransitionCallback = null;
        }
    }

    void overridePendingAppTransition(String packageName, int enterAnim, int exitAnim,
                                             IRemoteCallback startedCallback) {
        if (isTransitionSet()) {
            mNextAppTransitionType = NEXT_TRANSIT_TYPE_CUSTOM;
            mNextAppTransitionPackage = packageName;
            mNextAppTransitionThumbnail = null;
            mNextAppTransitionEnter = enterAnim;
            mNextAppTransitionExit = exitAnim;
            postAnimationCallback();
            mNextAppTransitionCallback = startedCallback;
        } else {
            postAnimationCallback();
        }
    }

    void overridePendingAppTransitionScaleUp(int startX, int startY, int startWidth,
                                                    int startHeight) {
        if (isTransitionSet()) {
            mNextAppTransitionType = NEXT_TRANSIT_TYPE_SCALE_UP;
            mNextAppTransitionPackage = null;
            mNextAppTransitionThumbnail = null;
            mNextAppTransitionStartX = startX;
            mNextAppTransitionStartY = startY;
            mNextAppTransitionStartWidth = startWidth;
            mNextAppTransitionStartHeight = startHeight;
            postAnimationCallback();
            mNextAppTransitionCallback = null;
        }
    }

    void overridePendingAppTransitionClipReveal(int startX, int startY,
                                                int startWidth, int startHeight) {
        if (isTransitionSet()) {
            mNextAppTransitionType = NEXT_TRANSIT_TYPE_CLIP_REVEAL;
            mNextAppTransitionStartX = startX;
            mNextAppTransitionStartY = startY;
            mNextAppTransitionStartWidth = startWidth;
            mNextAppTransitionStartHeight = startHeight;
            postAnimationCallback();
            mNextAppTransitionCallback = null;
        }
    }

    void overridePendingAppTransitionThumb(Bitmap srcThumb, int startX, int startY,
                                           IRemoteCallback startedCallback, boolean scaleUp) {
        if (isTransitionSet()) {
            mNextAppTransitionType = scaleUp ? NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_UP
                    : NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_DOWN;
            mNextAppTransitionPackage = null;
            mNextAppTransitionThumbnail = srcThumb;
            mNextAppTransitionScaleUp = scaleUp;
            mNextAppTransitionStartX = startX;
            mNextAppTransitionStartY = startY;
            postAnimationCallback();
            mNextAppTransitionCallback = startedCallback;
        } else {
            postAnimationCallback();
        }
    }

    void overridePendingAppTransitionAspectScaledThumb(Bitmap srcThumb, int startX, int startY,
            int targetWidth, int targetHeight, IRemoteCallback startedCallback, boolean scaleUp) {
        if (isTransitionSet()) {
            mNextAppTransitionType = scaleUp ? NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_UP
                    : NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_DOWN;
            mNextAppTransitionPackage = null;
            mNextAppTransitionThumbnail = srcThumb;
            mNextAppTransitionScaleUp = scaleUp;
            mNextAppTransitionStartX = startX;
            mNextAppTransitionStartY = startY;
            mNextAppTransitionStartWidth = targetWidth;
            mNextAppTransitionStartHeight = targetHeight;
            postAnimationCallback();
            mNextAppTransitionCallback = startedCallback;
        } else {
            postAnimationCallback();
        }
    }

    void overrideInPlaceAppTransition(String packageName, int anim) {
        if (isTransitionSet()) {
            mNextAppTransitionType = NEXT_TRANSIT_TYPE_CUSTOM_IN_PLACE;
            mNextAppTransitionPackage = packageName;
            mNextAppTransitionInPlace = anim;
        } else {
            postAnimationCallback();
        }
    }

    @Override
    public String toString() {
        return "mNextAppTransition=" + appTransitionToString(mNextAppTransition);
    }

    /**
     * Returns the human readable name of a window transition.
     *
     * @param transition The window transition.
     * @return The transition symbolic name.
     */
    public static String appTransitionToString(int transition) {
        switch (transition) {
            case TRANSIT_UNSET: {
                return "TRANSIT_UNSET";
            }
            case TRANSIT_NONE: {
                return "TRANSIT_NONE";
            }
            case TRANSIT_ACTIVITY_OPEN: {
                return "TRANSIT_ACTIVITY_OPEN";
            }
            case TRANSIT_ACTIVITY_CLOSE: {
                return "TRANSIT_ACTIVITY_CLOSE";
            }
            case TRANSIT_TASK_OPEN: {
                return "TRANSIT_TASK_OPEN";
            }
            case TRANSIT_TASK_CLOSE: {
                return "TRANSIT_TASK_CLOSE";
            }
            case TRANSIT_TASK_TO_FRONT: {
                return "TRANSIT_TASK_TO_FRONT";
            }
            case TRANSIT_TASK_TO_BACK: {
                return "TRANSIT_TASK_TO_BACK";
            }
            case TRANSIT_WALLPAPER_CLOSE: {
                return "TRANSIT_WALLPAPER_CLOSE";
            }
            case TRANSIT_WALLPAPER_OPEN: {
                return "TRANSIT_WALLPAPER_OPEN";
            }
            case TRANSIT_WALLPAPER_INTRA_OPEN: {
                return "TRANSIT_WALLPAPER_INTRA_OPEN";
            }
            case TRANSIT_WALLPAPER_INTRA_CLOSE: {
                return "TRANSIT_WALLPAPER_INTRA_CLOSE";
            }
            case TRANSIT_TASK_OPEN_BEHIND: {
                return "TRANSIT_TASK_OPEN_BEHIND";
            }
            default: {
                return "<UNKNOWN>";
            }
        }
    }

    private String appStateToString() {
        switch (mAppTransitionState) {
            case APP_STATE_IDLE:
                return "APP_STATE_IDLE";
            case APP_STATE_READY:
                return "APP_STATE_READY";
            case APP_STATE_RUNNING:
                return "APP_STATE_RUNNING";
            case APP_STATE_TIMEOUT:
                return "APP_STATE_TIMEOUT";
            default:
                return "unknown state=" + mAppTransitionState;
        }
    }

    private String transitTypeToString() {
        switch (mNextAppTransitionType) {
            case NEXT_TRANSIT_TYPE_NONE:
                return "NEXT_TRANSIT_TYPE_NONE";
            case NEXT_TRANSIT_TYPE_CUSTOM:
                return "NEXT_TRANSIT_TYPE_CUSTOM";
            case NEXT_TRANSIT_TYPE_CUSTOM_IN_PLACE:
                return "NEXT_TRANSIT_TYPE_CUSTOM_IN_PLACE";
            case NEXT_TRANSIT_TYPE_SCALE_UP:
                return "NEXT_TRANSIT_TYPE_SCALE_UP";
            case NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_UP:
                return "NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_UP";
            case NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_DOWN:
                return "NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_DOWN";
            case NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_UP:
                return "NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_UP";
            case NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_DOWN:
                return "NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_DOWN";
            default:
                return "unknown type=" + mNextAppTransitionType;
        }
    }

    @Override
    public void dump(PrintWriter pw, String prefix) {
        pw.print(prefix); pw.println(this);
        pw.print(prefix); pw.print("mAppTransitionState="); pw.println(appStateToString());
        if (mNextAppTransitionType != NEXT_TRANSIT_TYPE_NONE) {
            pw.print(prefix); pw.print("mNextAppTransitionType=");
                    pw.println(transitTypeToString());
        }
        switch (mNextAppTransitionType) {
            case NEXT_TRANSIT_TYPE_CUSTOM:
                pw.print(prefix); pw.print("mNextAppTransitionPackage=");
                        pw.println(mNextAppTransitionPackage);
                pw.print(prefix); pw.print("mNextAppTransitionEnter=0x");
                        pw.print(Integer.toHexString(mNextAppTransitionEnter));
                        pw.print(" mNextAppTransitionExit=0x");
                        pw.println(Integer.toHexString(mNextAppTransitionExit));
                break;
            case NEXT_TRANSIT_TYPE_CUSTOM_IN_PLACE:
                pw.print(prefix); pw.print("mNextAppTransitionPackage=");
                        pw.println(mNextAppTransitionPackage);
                pw.print(prefix); pw.print("mNextAppTransitionInPlace=0x");
                        pw.print(Integer.toHexString(mNextAppTransitionInPlace));
                break;
            case NEXT_TRANSIT_TYPE_SCALE_UP:
                pw.print(prefix); pw.print("mNextAppTransitionStartX=");
                        pw.print(mNextAppTransitionStartX);
                        pw.print(" mNextAppTransitionStartY=");
                        pw.println(mNextAppTransitionStartY);
                pw.print(prefix); pw.print("mNextAppTransitionStartWidth=");
                        pw.print(mNextAppTransitionStartWidth);
                        pw.print(" mNextAppTransitionStartHeight=");
                        pw.println(mNextAppTransitionStartHeight);
                break;
            case NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_UP:
            case NEXT_TRANSIT_TYPE_THUMBNAIL_SCALE_DOWN:
            case NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_UP:
            case NEXT_TRANSIT_TYPE_THUMBNAIL_ASPECT_SCALE_DOWN:
                pw.print(prefix); pw.print("mNextAppTransitionThumbnail=");
                        pw.print(mNextAppTransitionThumbnail);
                        pw.print(" mNextAppTransitionStartX=");
                        pw.print(mNextAppTransitionStartX);
                        pw.print(" mNextAppTransitionStartY=");
                        pw.println(mNextAppTransitionStartY);
                pw.print(prefix); pw.print("mNextAppTransitionStartWidth=");
                        pw.print(mNextAppTransitionStartWidth);
                        pw.print(" mNextAppTransitionStartHeight=");
                        pw.println(mNextAppTransitionStartHeight);
                pw.print(prefix); pw.print("mNextAppTransitionScaleUp=");
                        pw.println(mNextAppTransitionScaleUp);
                break;
        }
        if (mNextAppTransitionCallback != null) {
            pw.print(prefix); pw.print("mNextAppTransitionCallback=");
                    pw.println(mNextAppTransitionCallback);
        }
    }

    public void setCurrentUser(int newUserId) {
        mCurrentUserId = newUserId;
    }
}
