From 7a19cccafea96137b2cc4cb0d877efed5a96bbcf Mon Sep 17 00:00:00 2001
From: Tony Wickham <twickham@google.com>
Date: Mon, 21 Nov 2022 20:14:56 +0000
Subject: [PATCH] Override displacement for transient taskbar instead of
 mCurrentShift

mCurrentShift is based on displacement, but is used and set in different
places. To keep consistency throughout, we should override the
displacement at the source instead.

Test: manually swiped up between home/overview threshold and catch up
threshold; let go to go to overview and ensure no jump occurs.
Flag: teamfood (ENABLE_TRANSIENT_TASKBAR)
Fixes: 259981285

Change-Id: Id9f5b2bcdc2e56e15ddb6d93c4ee5d5ececc094d
---
 .../android/quickstep/AbsSwipeUpHandler.java  | 27 ++++++++++---------
 .../quickstep/SwipeUpAnimationLogic.java      | 13 ++++++++-
 2 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java b/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
index 4b35859625..1bc00be593 100644
--- a/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
+++ b/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
@@ -831,7 +831,7 @@ public abstract class AbsSwipeUpHandler<T extends StatefulActivity<S>,
             return;
         }
         mLauncherTransitionController.setProgress(
-                Math.max(getTaskbarProgress(), getScaleProgressDueToScroll()), mDragLengthFactor);
+                Math.max(mCurrentShift.value, getScaleProgressDueToScroll()), mDragLengthFactor);
     }
 
     /**
@@ -2212,7 +2212,7 @@ public abstract class AbsSwipeUpHandler<T extends StatefulActivity<S>,
             AnimatorControllerWithResistance playbackController =
                     remoteHandle.getPlaybackController();
             if (playbackController != null) {
-                playbackController.setProgress(Math.max(getTaskbarProgress(),
+                playbackController.setProgress(Math.max(mCurrentShift.value,
                         getScaleProgressDueToScroll()), mDragLengthFactor);
             }
 
@@ -2264,31 +2264,32 @@ public abstract class AbsSwipeUpHandler<T extends StatefulActivity<S>,
     }
 
     /**
-     * Overrides the current shift progress to keep the app window at the bottom of the screen
-     * while the transient taskbar is being swiped in.
+     * Overrides the gesture displacement to keep the app window at the bottom of the screen while
+     * the transient taskbar is being swiped in.
      *
      * There is also a catch up period so that the window can start moving 1:1 with the swipe.
      */
-    private float getTaskbarProgress() {
+    @Override
+    protected float overrideDisplacementForTransientTaskbar(float displacement) {
         if (!mIsTransientTaskbar) {
-            return mCurrentShift.value;
+            return displacement;
         }
 
         if (mTaskbarAlreadyOpen) {
-            return mCurrentShift.value;
+            return displacement;
         }
 
-        if (mCurrentDisplacement < mTaskbarAppWindowThreshold) {
+        if (displacement < mTaskbarAppWindowThreshold) {
             return 0;
         }
 
-        // "Catch up" with `mCurrentShift.value`.
-        if (mCurrentDisplacement < mTaskbarCatchUpThreshold) {
-            return Utilities.mapToRange(mCurrentDisplacement, mTaskbarAppWindowThreshold,
-                    mTaskbarCatchUpThreshold, 0, mCurrentShift.value, ACCEL_DEACCEL);
+        // "Catch up" with the displacement at mTaskbarCatchUpThreshold.
+        if (displacement < mTaskbarCatchUpThreshold) {
+            return Utilities.mapToRange(displacement, mTaskbarAppWindowThreshold,
+                    mTaskbarCatchUpThreshold, 0, mTaskbarCatchUpThreshold, ACCEL_DEACCEL);
         }
 
-        return mCurrentShift.value;
+        return displacement;
     }
 
     private void setDividerShown(boolean shown, boolean immediate) {
diff --git a/quickstep/src/com/android/quickstep/SwipeUpAnimationLogic.java b/quickstep/src/com/android/quickstep/SwipeUpAnimationLogic.java
index ddb06ce858..fdde45a900 100644
--- a/quickstep/src/com/android/quickstep/SwipeUpAnimationLogic.java
+++ b/quickstep/src/com/android/quickstep/SwipeUpAnimationLogic.java
@@ -116,7 +116,7 @@ public abstract class SwipeUpAnimationLogic implements
     @UiThread
     public void updateDisplacement(float displacement) {
         // We are moving in the negative x/y direction
-        displacement = -displacement;
+        displacement = overrideDisplacementForTransientTaskbar(-displacement);
         mCurrentDisplacement = displacement;
 
         float shift;
@@ -130,6 +130,17 @@ public abstract class SwipeUpAnimationLogic implements
         mCurrentShift.updateValue(shift);
     }
 
+    /**
+     * When Transient Taskbar is enabled, subclasses can override the displacement to keep the app
+     * window at the bottom of the screen while taskbar is being swiped in.
+     * @param displacement The distance the user has swiped up from the bottom of the screen. This
+     *                     value will be positive unless the user swipe downwards.
+     * @return the overridden displacement.
+     */
+    protected float overrideDisplacementForTransientTaskbar(float displacement) {
+        return displacement;
+    }
+
     /**
      * Called when the value of {@link #mCurrentShift} changes
      */