Merge "Fix pinch zoom with partial magnification window not very responsive" into main

3 files changed, 41 insertions, 5 deletions

diff --git a/core/java/android/view/ScaleGestureDetector.java b/core/java/android/view/ScaleGestureDetector.java
index a0a172d366cc..5a28d5f7fc01 100644
--- a/core/java/android/view/ScaleGestureDetector.java
+++ b/core/java/android/view/ScaleGestureDetector.java
@@ -199,12 +199,33 @@ public class ScaleGestureDetector {
      * @throws NullPointerException if {@code listener} is null.
      */
     public ScaleGestureDetector(@NonNull Context context, @NonNull OnScaleGestureListener listener,
-                                @Nullable Handler handler) {
+            @Nullable Handler handler) {
+        this(context, ViewConfiguration.get(context).getScaledTouchSlop() * 2,
+                ViewConfiguration.get(context).getScaledMinimumScalingSpan(), handler, listener);
+    }
+
+    /**
+     * Creates a ScaleGestureDetector with span slop and min span.
+     *
+     * @param context the application's context.
+     * @param spanSlop the threshold for interpreting a touch movement as scaling.
+     * @param minSpan the minimum threshold of scaling span. The span could be
+     *                overridden by other usages to specify a different scaling span, for instance,
+     *                if you need pinch gestures to continue closer together than the default.
+     * @param listener the listener invoked for all the callbacks, this must not be null.
+     * @param handler the handler to use for running deferred listener events.
+     *
+     * @throws NullPointerException if {@code listener} is null.
+     *
+     * @hide
+     */
+    public ScaleGestureDetector(@NonNull Context context, @NonNull int spanSlop,
+            @NonNull int minSpan, @Nullable Handler handler,
+            @NonNull OnScaleGestureListener listener) {
         mContext = context;
         mListener = listener;
-        final ViewConfiguration viewConfiguration = ViewConfiguration.get(context);
-        mSpanSlop = viewConfiguration.getScaledTouchSlop() * 2;
-        mMinSpan = viewConfiguration.getScaledMinimumScalingSpan();
+        mSpanSlop = spanSlop;
+        mMinSpan = minSpan;
         mHandler = handler;
         // Quick scale is enabled by default after JB_MR2
         final int targetSdkVersion = context.getApplicationInfo().targetSdkVersion;
diff --git a/services/accessibility/accessibility.aconfig b/services/accessibility/accessibility.aconfig
index 11189cf9e39c..6fa9c0809f75 100644
--- a/services/accessibility/accessibility.aconfig
+++ b/services/accessibility/accessibility.aconfig
@@ -34,3 +34,10 @@ flag {
     description: "Calls WMS.addWindowToken without holding A11yManagerService#mLock"
     bug: "297972548"
 }
+
+flag {
+    name: "pinch_zoom_zero_min_span"
+    namespace: "accessibility"
+    description: "Whether to set min span of ScaleGestureDetector to zero."
+    bug: "295327792"
+}
\ No newline at end of file
diff --git a/services/accessibility/java/com/android/server/accessibility/magnification/PanningScalingHandler.java b/services/accessibility/java/com/android/server/accessibility/magnification/PanningScalingHandler.java
index c5495d98226e..94556282d0d3 100644
--- a/services/accessibility/java/com/android/server/accessibility/magnification/PanningScalingHandler.java
+++ b/services/accessibility/java/com/android/server/accessibility/magnification/PanningScalingHandler.java
@@ -28,8 +28,10 @@ import android.util.TypedValue;
 import android.view.GestureDetector;
 import android.view.MotionEvent;
 import android.view.ScaleGestureDetector;
+import android.view.ViewConfiguration;
 
 import com.android.internal.R;
+import com.android.server.accessibility.Flags;
 
 /**
  * Handles the behavior while receiving scaling and panning gestures if it's enabled.
@@ -70,7 +72,13 @@ class PanningScalingHandler extends
         mMaxScale = maxScale;
         mMinScale = minScale;
         mBlockScroll = blockScroll;
-        mScaleGestureDetector = new ScaleGestureDetector(context, this, Handler.getMain());
+        if (Flags.pinchZoomZeroMinSpan()) {
+            mScaleGestureDetector = new ScaleGestureDetector(context,
+                    ViewConfiguration.get(context).getScaledTouchSlop() * 2,
+                    /* minSpan= */ 0, Handler.getMain(), this);
+        } else {
+            mScaleGestureDetector = new ScaleGestureDetector(context, this, Handler.getMain());
+        }
         mScrollGestureDetector = new GestureDetector(context, this, Handler.getMain());
         mScaleGestureDetector.setQuickScaleEnabled(false);
         mMagnificationDelegate = magnificationDelegate;