Move split classes back into Shell

- These classes were previously used in WM and SysUI, but now only
  referenced by Shell code

Bug: 283146235
Test: Builds
Change-Id: I3915d6695272e5c531729dd663513444d2f77439

5 files changed, 618 insertions, 6 deletions

diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/DividerSnapAlgorithm.java b/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/DividerSnapAlgorithm.java
new file mode 100644
index 000000000000..1901e0bbe700
--- /dev/null
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/DividerSnapAlgorithm.java
@@ -0,0 +1,476 @@
+/*
+ * Copyright (C) 2023 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.wm.shell.common.split;
+
+import static android.view.WindowManager.DOCKED_INVALID;
+import static android.view.WindowManager.DOCKED_LEFT;
+import static android.view.WindowManager.DOCKED_RIGHT;
+
+import android.content.Context;
+import android.content.res.Configuration;
+import android.content.res.Resources;
+import android.graphics.Rect;
+import android.hardware.display.DisplayManager;
+import android.view.Display;
+import android.view.DisplayInfo;
+
+import java.util.ArrayList;
+
+/**
+ * Calculates the snap targets and the snap position given a position and a velocity. All positions
+ * here are to be interpreted as the left/top edge of the divider rectangle.
+ *
+ * @hide
+ */
+public class DividerSnapAlgorithm {
+
+    private static final int MIN_FLING_VELOCITY_DP_PER_SECOND = 400;
+    private static final int MIN_DISMISS_VELOCITY_DP_PER_SECOND = 600;
+
+    /**
+     * 3 snap targets: left/top has 16:9 ratio (for videos), 1:1, and right/bottom has 16:9 ratio
+     */
+    private static final int SNAP_MODE_16_9 = 0;
+
+    /**
+     * 3 snap targets: fixed ratio, 1:1, (1 - fixed ratio)
+     */
+    private static final int SNAP_FIXED_RATIO = 1;
+
+    /**
+     * 1 snap target: 1:1
+     */
+    private static final int SNAP_ONLY_1_1 = 2;
+
+    /**
+     * 1 snap target: minimized height, (1 - minimized height)
+     */
+    private static final int SNAP_MODE_MINIMIZED = 3;
+
+    private final float mMinFlingVelocityPxPerSecond;
+    private final float mMinDismissVelocityPxPerSecond;
+    private final int mDisplayWidth;
+    private final int mDisplayHeight;
+    private final int mDividerSize;
+    private final ArrayList<SnapTarget> mTargets = new ArrayList<>();
+    private final Rect mInsets = new Rect();
+    private final int mSnapMode;
+    private final boolean mFreeSnapMode;
+    private final int mMinimalSizeResizableTask;
+    private final int mTaskHeightInMinimizedMode;
+    private final float mFixedRatio;
+    private boolean mIsHorizontalDivision;
+
+    /** The first target which is still splitting the screen */
+    private final SnapTarget mFirstSplitTarget;
+
+    /** The last target which is still splitting the screen */
+    private final SnapTarget mLastSplitTarget;
+
+    private final SnapTarget mDismissStartTarget;
+    private final SnapTarget mDismissEndTarget;
+    private final SnapTarget mMiddleTarget;
+
+    public static DividerSnapAlgorithm create(Context ctx, Rect insets) {
+        DisplayInfo displayInfo = new DisplayInfo();
+        ctx.getSystemService(DisplayManager.class).getDisplay(
+                Display.DEFAULT_DISPLAY).getDisplayInfo(displayInfo);
+        int dividerWindowWidth = ctx.getResources().getDimensionPixelSize(
+                com.android.internal.R.dimen.docked_stack_divider_thickness);
+        int dividerInsets = ctx.getResources().getDimensionPixelSize(
+                com.android.internal.R.dimen.docked_stack_divider_insets);
+        return new DividerSnapAlgorithm(ctx.getResources(),
+                displayInfo.logicalWidth, displayInfo.logicalHeight,
+                dividerWindowWidth - 2 * dividerInsets,
+                ctx.getApplicationContext().getResources().getConfiguration().orientation
+                        == Configuration.ORIENTATION_PORTRAIT,
+                insets);
+    }
+
+    public DividerSnapAlgorithm(Resources res, int displayWidth, int displayHeight, int dividerSize,
+            boolean isHorizontalDivision, Rect insets) {
+        this(res, displayWidth, displayHeight, dividerSize, isHorizontalDivision, insets,
+                DOCKED_INVALID, false /* minimized */, true /* resizable */);
+    }
+
+    public DividerSnapAlgorithm(Resources res, int displayWidth, int displayHeight, int dividerSize,
+        boolean isHorizontalDivision, Rect insets, int dockSide) {
+        this(res, displayWidth, displayHeight, dividerSize, isHorizontalDivision, insets,
+            dockSide, false /* minimized */, true /* resizable */);
+    }
+
+    public DividerSnapAlgorithm(Resources res, int displayWidth, int displayHeight, int dividerSize,
+            boolean isHorizontalDivision, Rect insets, int dockSide, boolean isMinimizedMode,
+            boolean isHomeResizable) {
+        mMinFlingVelocityPxPerSecond =
+                MIN_FLING_VELOCITY_DP_PER_SECOND * res.getDisplayMetrics().density;
+        mMinDismissVelocityPxPerSecond =
+                MIN_DISMISS_VELOCITY_DP_PER_SECOND * res.getDisplayMetrics().density;
+        mDividerSize = dividerSize;
+        mDisplayWidth = displayWidth;
+        mDisplayHeight = displayHeight;
+        mIsHorizontalDivision = isHorizontalDivision;
+        mInsets.set(insets);
+        mSnapMode = isMinimizedMode ? SNAP_MODE_MINIMIZED :
+                res.getInteger(com.android.internal.R.integer.config_dockedStackDividerSnapMode);
+        mFreeSnapMode = res.getBoolean(
+                com.android.internal.R.bool.config_dockedStackDividerFreeSnapMode);
+        mFixedRatio = res.getFraction(
+                com.android.internal.R.fraction.docked_stack_divider_fixed_ratio, 1, 1);
+        mMinimalSizeResizableTask = res.getDimensionPixelSize(
+                com.android.internal.R.dimen.default_minimal_size_resizable_task);
+        mTaskHeightInMinimizedMode = isHomeResizable ? res.getDimensionPixelSize(
+                com.android.internal.R.dimen.task_height_of_minimized_mode) : 0;
+        calculateTargets(isHorizontalDivision, dockSide);
+        mFirstSplitTarget = mTargets.get(1);
+        mLastSplitTarget = mTargets.get(mTargets.size() - 2);
+        mDismissStartTarget = mTargets.get(0);
+        mDismissEndTarget = mTargets.get(mTargets.size() - 1);
+        mMiddleTarget = mTargets.get(mTargets.size() / 2);
+        mMiddleTarget.isMiddleTarget = true;
+    }
+
+    /**
+     * @return whether it's feasible to enable split screen in the current configuration, i.e. when
+     *         snapping in the middle both tasks are larger than the minimal task size.
+     */
+    public boolean isSplitScreenFeasible() {
+        int statusBarSize = mInsets.top;
+        int navBarSize = mIsHorizontalDivision ? mInsets.bottom : mInsets.right;
+        int size = mIsHorizontalDivision
+                ? mDisplayHeight
+                : mDisplayWidth;
+        int availableSpace = size - navBarSize - statusBarSize - mDividerSize;
+        return availableSpace / 2 >= mMinimalSizeResizableTask;
+    }
+
+    public SnapTarget calculateSnapTarget(int position, float velocity) {
+        return calculateSnapTarget(position, velocity, true /* hardDismiss */);
+    }
+
+    /**
+     * @param position the top/left position of the divider
+     * @param velocity current dragging velocity
+     * @param hardDismiss if set, make it a bit harder to get reach the dismiss targets
+     */
+    public SnapTarget calculateSnapTarget(int position, float velocity, boolean hardDismiss) {
+        if (position < mFirstSplitTarget.position && velocity < -mMinDismissVelocityPxPerSecond) {
+            return mDismissStartTarget;
+        }
+        if (position > mLastSplitTarget.position && velocity > mMinDismissVelocityPxPerSecond) {
+            return mDismissEndTarget;
+        }
+        if (Math.abs(velocity) < mMinFlingVelocityPxPerSecond) {
+            return snap(position, hardDismiss);
+        }
+        if (velocity < 0) {
+            return mFirstSplitTarget;
+        } else {
+            return mLastSplitTarget;
+        }
+    }
+
+    public SnapTarget calculateNonDismissingSnapTarget(int position) {
+        SnapTarget target = snap(position, false /* hardDismiss */);
+        if (target == mDismissStartTarget) {
+            return mFirstSplitTarget;
+        } else if (target == mDismissEndTarget) {
+            return mLastSplitTarget;
+        } else {
+            return target;
+        }
+    }
+
+    public float calculateDismissingFraction(int position) {
+        if (position < mFirstSplitTarget.position) {
+            return 1f - (float) (position - getStartInset())
+                    / (mFirstSplitTarget.position - getStartInset());
+        } else if (position > mLastSplitTarget.position) {
+            return (float) (position - mLastSplitTarget.position)
+                    / (mDismissEndTarget.position - mLastSplitTarget.position - mDividerSize);
+        }
+        return 0f;
+    }
+
+    public SnapTarget getClosestDismissTarget(int position) {
+        if (position < mFirstSplitTarget.position) {
+            return mDismissStartTarget;
+        } else if (position > mLastSplitTarget.position) {
+            return mDismissEndTarget;
+        } else if (position - mDismissStartTarget.position
+                < mDismissEndTarget.position - position) {
+            return mDismissStartTarget;
+        } else {
+            return mDismissEndTarget;
+        }
+    }
+
+    public SnapTarget getFirstSplitTarget() {
+        return mFirstSplitTarget;
+    }
+
+    public SnapTarget getLastSplitTarget() {
+        return mLastSplitTarget;
+    }
+
+    public SnapTarget getDismissStartTarget() {
+        return mDismissStartTarget;
+    }
+
+    public SnapTarget getDismissEndTarget() {
+        return mDismissEndTarget;
+    }
+
+    private int getStartInset() {
+        if (mIsHorizontalDivision) {
+            return mInsets.top;
+        } else {
+            return mInsets.left;
+        }
+    }
+
+    private int getEndInset() {
+        if (mIsHorizontalDivision) {
+            return mInsets.bottom;
+        } else {
+            return mInsets.right;
+        }
+    }
+
+    private boolean shouldApplyFreeSnapMode(int position) {
+        if (!mFreeSnapMode) {
+            return false;
+        }
+        if (!isFirstSplitTargetAvailable() || !isLastSplitTargetAvailable()) {
+            return false;
+        }
+        return mFirstSplitTarget.position < position && position < mLastSplitTarget.position;
+    }
+
+    private SnapTarget snap(int position, boolean hardDismiss) {
+        if (shouldApplyFreeSnapMode(position)) {
+            return new SnapTarget(position, position, SnapTarget.FLAG_NONE);
+        }
+        int minIndex = -1;
+        float minDistance = Float.MAX_VALUE;
+        int size = mTargets.size();
+        for (int i = 0; i < size; i++) {
+            SnapTarget target = mTargets.get(i);
+            float distance = Math.abs(position - target.position);
+            if (hardDismiss) {
+                distance /= target.distanceMultiplier;
+            }
+            if (distance < minDistance) {
+                minIndex = i;
+                minDistance = distance;
+            }
+        }
+        return mTargets.get(minIndex);
+    }
+
+    private void calculateTargets(boolean isHorizontalDivision, int dockedSide) {
+        mTargets.clear();
+        int dividerMax = isHorizontalDivision
+                ? mDisplayHeight
+                : mDisplayWidth;
+        int startPos = -mDividerSize;
+        if (dockedSide == DOCKED_RIGHT) {
+            startPos += mInsets.left;
+        }
+        mTargets.add(new SnapTarget(startPos, startPos, SnapTarget.FLAG_DISMISS_START,
+                0.35f));
+        switch (mSnapMode) {
+            case SNAP_MODE_16_9:
+                addRatio16_9Targets(isHorizontalDivision, dividerMax);
+                break;
+            case SNAP_FIXED_RATIO:
+                addFixedDivisionTargets(isHorizontalDivision, dividerMax);
+                break;
+            case SNAP_ONLY_1_1:
+                addMiddleTarget(isHorizontalDivision);
+                break;
+            case SNAP_MODE_MINIMIZED:
+                addMinimizedTarget(isHorizontalDivision, dockedSide);
+                break;
+        }
+        mTargets.add(new SnapTarget(dividerMax, dividerMax, SnapTarget.FLAG_DISMISS_END, 0.35f));
+    }
+
+    private void addNonDismissingTargets(boolean isHorizontalDivision, int topPosition,
+            int bottomPosition, int dividerMax) {
+        maybeAddTarget(topPosition, topPosition - getStartInset());
+        addMiddleTarget(isHorizontalDivision);
+        maybeAddTarget(bottomPosition,
+                dividerMax - getEndInset() - (bottomPosition + mDividerSize));
+    }
+
+    private void addFixedDivisionTargets(boolean isHorizontalDivision, int dividerMax) {
+        int start = isHorizontalDivision ? mInsets.top : mInsets.left;
+        int end = isHorizontalDivision
+                ? mDisplayHeight - mInsets.bottom
+                : mDisplayWidth - mInsets.right;
+        int size = (int) (mFixedRatio * (end - start)) - mDividerSize / 2;
+        int topPosition = start + size;
+        int bottomPosition = end - size - mDividerSize;
+        addNonDismissingTargets(isHorizontalDivision, topPosition, bottomPosition, dividerMax);
+    }
+
+    private void addRatio16_9Targets(boolean isHorizontalDivision, int dividerMax) {
+        int start = isHorizontalDivision ? mInsets.top : mInsets.left;
+        int end = isHorizontalDivision
+                ? mDisplayHeight - mInsets.bottom
+                : mDisplayWidth - mInsets.right;
+        int startOther = isHorizontalDivision ? mInsets.left : mInsets.top;
+        int endOther = isHorizontalDivision
+                ? mDisplayWidth - mInsets.right
+                : mDisplayHeight - mInsets.bottom;
+        float size = 9.0f / 16.0f * (endOther - startOther);
+        int sizeInt = (int) Math.floor(size);
+        int topPosition = start + sizeInt;
+        int bottomPosition = end - sizeInt - mDividerSize;
+        addNonDismissingTargets(isHorizontalDivision, topPosition, bottomPosition, dividerMax);
+    }
+
+    /**
+     * Adds a target at {@param position} but only if the area with size of {@param smallerSize}
+     * meets the minimal size requirement.
+     */
+    private void maybeAddTarget(int position, int smallerSize) {
+        if (smallerSize >= mMinimalSizeResizableTask) {
+            mTargets.add(new SnapTarget(position, position, SnapTarget.FLAG_NONE));
+        }
+    }
+
+    private void addMiddleTarget(boolean isHorizontalDivision) {
+        int position = DockedDividerUtils.calculateMiddlePosition(isHorizontalDivision,
+                mInsets, mDisplayWidth, mDisplayHeight, mDividerSize);
+        mTargets.add(new SnapTarget(position, position, SnapTarget.FLAG_NONE));
+    }
+
+    private void addMinimizedTarget(boolean isHorizontalDivision, int dockedSide) {
+        // In portrait offset the position by the statusbar height, in landscape add the statusbar
+        // height as well to match portrait offset
+        int position = mTaskHeightInMinimizedMode + mInsets.top;
+        if (!isHorizontalDivision) {
+            if (dockedSide == DOCKED_LEFT) {
+                position += mInsets.left;
+            } else if (dockedSide == DOCKED_RIGHT) {
+                position = mDisplayWidth - position - mInsets.right - mDividerSize;
+            }
+        }
+        mTargets.add(new SnapTarget(position, position, SnapTarget.FLAG_NONE));
+    }
+
+    public SnapTarget getMiddleTarget() {
+        return mMiddleTarget;
+    }
+
+    public SnapTarget getNextTarget(SnapTarget snapTarget) {
+        int index = mTargets.indexOf(snapTarget);
+        if (index != -1 && index < mTargets.size() - 1) {
+            return mTargets.get(index + 1);
+        }
+        return snapTarget;
+    }
+
+    public SnapTarget getPreviousTarget(SnapTarget snapTarget) {
+        int index = mTargets.indexOf(snapTarget);
+        if (index != -1 && index > 0) {
+            return mTargets.get(index - 1);
+        }
+        return snapTarget;
+    }
+
+    /**
+     * @return whether or not there are more than 1 split targets that do not include the two
+     * dismiss targets, used in deciding to display the middle target for accessibility
+     */
+    public boolean showMiddleSplitTargetForAccessibility() {
+        return (mTargets.size() - 2) > 1;
+    }
+
+    public boolean isFirstSplitTargetAvailable() {
+        return mFirstSplitTarget != mMiddleTarget;
+    }
+
+    public boolean isLastSplitTargetAvailable() {
+        return mLastSplitTarget != mMiddleTarget;
+    }
+
+    /**
+     * Cycles through all non-dismiss targets with a stepping of {@param increment}. It moves left
+     * if {@param increment} is negative and moves right otherwise.
+     */
+    public SnapTarget cycleNonDismissTarget(SnapTarget snapTarget, int increment) {
+        int index = mTargets.indexOf(snapTarget);
+        if (index != -1) {
+            SnapTarget newTarget = mTargets.get((index + mTargets.size() + increment)
+                    % mTargets.size());
+            if (newTarget == mDismissStartTarget) {
+                return mLastSplitTarget;
+            } else if (newTarget == mDismissEndTarget) {
+                return mFirstSplitTarget;
+            } else {
+                return newTarget;
+            }
+        }
+        return snapTarget;
+    }
+
+    /**
+     * Represents a snap target for the divider.
+     */
+    public static class SnapTarget {
+        public static final int FLAG_NONE = 0;
+
+        /** If the divider reaches this value, the left/top task should be dismissed. */
+        public static final int FLAG_DISMISS_START = 1;
+
+        /** If the divider reaches this value, the right/bottom task should be dismissed */
+        public static final int FLAG_DISMISS_END = 2;
+
+        /** Position of this snap target. The right/bottom edge of the top/left task snaps here. */
+        public final int position;
+
+        /**
+         * Like {@link #position}, but used to calculate the task bounds which might be different
+         * from the stack bounds.
+         */
+        public final int taskPosition;
+
+        public final int flag;
+
+        public boolean isMiddleTarget;
+
+        /**
+         * Multiplier used to calculate distance to snap position. The lower this value, the harder
+         * it's to snap on this target
+         */
+        private final float distanceMultiplier;
+
+        public SnapTarget(int position, int taskPosition, int flag) {
+            this(position, taskPosition, flag, 1f);
+        }
+
+        public SnapTarget(int position, int taskPosition, int flag, float distanceMultiplier) {
+            this.position = position;
+            this.taskPosition = taskPosition;
+            this.flag = flag;
+            this.distanceMultiplier = distanceMultiplier;
+        }
+    }
+}
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/DividerView.java b/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/DividerView.java
index 2dbc4445d606..0b0c6937553b 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/DividerView.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/DividerView.java
@@ -53,7 +53,6 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
 import com.android.internal.annotations.VisibleForTesting;
-import com.android.internal.policy.DividerSnapAlgorithm;
 import com.android.internal.protolog.common.ProtoLog;
 import com.android.wm.shell.R;
 import com.android.wm.shell.animation.Interpolators;
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/DockedDividerUtils.java b/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/DockedDividerUtils.java
new file mode 100644
index 000000000000..f25dfeafb32c
--- /dev/null
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/DockedDividerUtils.java
@@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 2023 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.wm.shell.common.split;
+
+import static android.view.WindowManager.DOCKED_BOTTOM;
+import static android.view.WindowManager.DOCKED_INVALID;
+import static android.view.WindowManager.DOCKED_LEFT;
+import static android.view.WindowManager.DOCKED_RIGHT;
+import static android.view.WindowManager.DOCKED_TOP;
+
+import android.content.res.Resources;
+import android.graphics.Rect;
+
+/**
+ * Utility functions for docked stack divider used by both window manager and System UI.
+ *
+ * @hide
+ */
+public class DockedDividerUtils {
+
+    public static void calculateBoundsForPosition(int position, int dockSide, Rect outRect,
+            int displayWidth, int displayHeight, int dividerSize) {
+        outRect.set(0, 0, displayWidth, displayHeight);
+        switch (dockSide) {
+            case DOCKED_LEFT:
+                outRect.right = position;
+                break;
+            case DOCKED_TOP:
+                outRect.bottom = position;
+                break;
+            case DOCKED_RIGHT:
+                outRect.left = position + dividerSize;
+                break;
+            case DOCKED_BOTTOM:
+                outRect.top = position + dividerSize;
+                break;
+        }
+        sanitizeStackBounds(outRect, dockSide == DOCKED_LEFT || dockSide == DOCKED_TOP);
+    }
+
+    /**
+     * Makes sure that the bounds are always valid, i. e. they are at least one pixel high and wide.
+     *
+     * @param bounds The bounds to sanitize.
+     * @param topLeft Pass true if the bounds are at the top/left of the screen, false if they are
+     *                at the bottom/right. This is used to determine in which direction to extend
+     *                the bounds.
+     */
+    public static void sanitizeStackBounds(Rect bounds, boolean topLeft) {
+
+        // If the bounds are either on the top or left of the screen, rather move it further to the
+        // left/top to make it more offscreen. If they are on the bottom or right, push them off the
+        // screen by moving it even more to the bottom/right.
+        if (topLeft) {
+            if (bounds.left >= bounds.right) {
+                bounds.left = bounds.right - 1;
+            }
+            if (bounds.top >= bounds.bottom) {
+                bounds.top = bounds.bottom - 1;
+            }
+        } else {
+            if (bounds.right <= bounds.left) {
+                bounds.right = bounds.left + 1;
+            }
+            if (bounds.bottom <= bounds.top) {
+                bounds.bottom = bounds.top + 1;
+            }
+        }
+    }
+
+    public static int calculatePositionForBounds(Rect bounds, int dockSide, int dividerSize) {
+        switch (dockSide) {
+            case DOCKED_LEFT:
+                return bounds.right;
+            case DOCKED_TOP:
+                return bounds.bottom;
+            case DOCKED_RIGHT:
+                return bounds.left - dividerSize;
+            case DOCKED_BOTTOM:
+                return bounds.top - dividerSize;
+            default:
+                return 0;
+        }
+    }
+
+    public static int calculateMiddlePosition(boolean isHorizontalDivision, Rect insets,
+            int displayWidth, int displayHeight, int dividerSize) {
+        int start = isHorizontalDivision ? insets.top : insets.left;
+        int end = isHorizontalDivision
+                ? displayHeight - insets.bottom
+                : displayWidth - insets.right;
+        return start + (end - start) / 2 - dividerSize / 2;
+    }
+
+    public static int invertDockSide(int dockSide) {
+        switch (dockSide) {
+            case DOCKED_LEFT:
+                return DOCKED_RIGHT;
+            case DOCKED_TOP:
+                return DOCKED_BOTTOM;
+            case DOCKED_RIGHT:
+                return DOCKED_LEFT;
+            case DOCKED_BOTTOM:
+                return DOCKED_TOP;
+            default:
+                return DOCKED_INVALID;
+        }
+    }
+
+    /** Returns the inset distance from the divider window edge to the dividerview. */
+    public static int getDividerInsets(Resources res) {
+        return res.getDimensionPixelSize(com.android.internal.R.dimen.docked_stack_divider_insets);
+    }
+
+    /** Returns the size of the divider */
+    public static int getDividerSize(Resources res, int dividerInsets) {
+        final int windowWidth = res.getDimensionPixelSize(
+                com.android.internal.R.dimen.docked_stack_divider_thickness);
+        return windowWidth - 2 * dividerInsets;
+    }
+
+    /** Returns the docked-stack side */
+    public static int getDockSide(int displayWidth, int displayHeight) {
+        return displayWidth > displayHeight ? DOCKED_LEFT : DOCKED_TOP;
+    }
+}
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/SplitLayout.java b/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/SplitLayout.java
index e8fa638bea31..33b6c2bb4c9e 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/SplitLayout.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/SplitLayout.java
@@ -25,8 +25,8 @@ import static android.view.WindowManager.DOCKED_RIGHT;
 import static android.view.WindowManager.DOCKED_TOP;
 
 import static com.android.internal.jank.InteractionJankMonitor.CUJ_SPLIT_SCREEN_RESIZE;
-import static com.android.internal.policy.DividerSnapAlgorithm.SnapTarget.FLAG_DISMISS_END;
-import static com.android.internal.policy.DividerSnapAlgorithm.SnapTarget.FLAG_DISMISS_START;
+import static com.android.wm.shell.common.split.DividerSnapAlgorithm.SnapTarget.FLAG_DISMISS_END;
+import static com.android.wm.shell.common.split.DividerSnapAlgorithm.SnapTarget.FLAG_DISMISS_START;
 import static com.android.wm.shell.animation.Interpolators.DIM_INTERPOLATOR;
 import static com.android.wm.shell.animation.Interpolators.SLOWDOWN_INTERPOLATOR;
 import static com.android.wm.shell.common.split.SplitScreenConstants.SPLIT_POSITION_BOTTOM_OR_RIGHT;
@@ -58,8 +58,6 @@ import android.window.WindowContainerTransaction;
 import androidx.annotation.Nullable;
 
 import com.android.internal.annotations.VisibleForTesting;
-import com.android.internal.policy.DividerSnapAlgorithm;
-import com.android.internal.policy.DockedDividerUtils;
 import com.android.wm.shell.R;
 import com.android.wm.shell.ShellTaskOrganizer;
 import com.android.wm.shell.animation.Interpolators;
diff --git a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/common/split/SplitLayoutTests.java b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/common/split/SplitLayoutTests.java
index 443cea245a4f..fe2da5dd19fc 100644
--- a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/common/split/SplitLayoutTests.java
+++ b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/common/split/SplitLayoutTests.java
@@ -38,7 +38,6 @@ import androidx.test.annotation.UiThreadTest;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import androidx.test.filters.SmallTest;
 
-import com.android.internal.policy.DividerSnapAlgorithm;
 import com.android.wm.shell.ShellTaskOrganizer;
 import com.android.wm.shell.ShellTestCase;
 import com.android.wm.shell.TestRunningTaskInfoBuilder;