From d4e6b2aad76a9c5e98a321341f3df36364814235 Mon Sep 17 00:00:00 2001
From: Taran Singh <tarandeep@google.com>
Date: Thu, 28 Oct 2021 21:18:03 +0000
Subject: [PATCH] Add an input feature for a stylus interceptor

A stylus interceptor is a window that receives all stylus events within
its touchable bounds, while letting all other events be dispatched to
windows behind it. This makes it possible for the framework to create a
stylus interceptor on top of another app to implement handwriting
recognition.

The feature has no effect when the window flag FLAG_NOT_TOUCHABLE is
not set.

The feature has no effect when the window is not a trusted overlay.

Test: manual
Change-Id: Ia481ee8d831643bc99445b47659a7f5e9875c388
---
 core/java/android/view/WindowManager.java | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/core/java/android/view/WindowManager.java b/core/java/android/view/WindowManager.java
index aa6cb83085575..32646113fd310 100644
--- a/core/java/android/view/WindowManager.java
+++ b/core/java/android/view/WindowManager.java
@@ -3363,6 +3363,22 @@ public interface WindowManager extends ViewManager {
          */
         public static final int INPUT_FEATURE_SPY = 0x00000020;
 
+        /**
+         * When used with the window flag {@link #FLAG_NOT_TOUCHABLE}, this window will continue
+         * to receive events from a stylus device within its touchable region. All other pointer
+         * events, such as from a mouse or touchscreen, will be dispatched to the windows behind it.
+         *
+         * This input feature has no effect when the window flag {@link #FLAG_NOT_TOUCHABLE} is
+         * not set.
+         *
+         * The window must be a trusted overlay to use this input feature.
+         *
+         * @see #FLAG_NOT_TOUCHABLE
+         *
+         * @hide
+         */
+        public static final int INPUT_FEATURE_INTERCEPTS_STYLUS = 0x00000040;
+
         /**
          * An internal annotation for flags that can be specified to {@link #inputFeatures}.
          *
@@ -3373,6 +3389,7 @@ public interface WindowManager extends ViewManager {
             INPUT_FEATURE_DISABLE_POINTER_GESTURES,
             INPUT_FEATURE_NO_INPUT_CHANNEL,
             INPUT_FEATURE_DISABLE_USER_ACTIVITY,
+            INPUT_FEATURE_INTERCEPTS_STYLUS,
         })
         public @interface InputFeatureFlags {}
 
@@ -3382,6 +3399,7 @@ public interface WindowManager extends ViewManager {
          * @see #INPUT_FEATURE_DISABLE_POINTER_GESTURES
          * @see #INPUT_FEATURE_NO_INPUT_CHANNEL
          * @see #INPUT_FEATURE_DISABLE_USER_ACTIVITY
+         * @see #INPUT_FEATURE_INTERCEPTS_STYLUS
          * @hide
          */
         @InputFeatureFlags