From 5ba19c973a92f55dc9685decf8aeb821f0cd064b Mon Sep 17 00:00:00 2001
From: Mark Renouf <mrenouf@google.com>
Date: Mon, 12 Apr 2021 17:09:21 -0400
Subject: [PATCH] Do not inset scrollBounds by padding unless
 clipToPadding==true

The intent is to avoid attempting to capture areas of a scrollable
view which will never display content. This is only the case when
clipToPadding = true (which is the default).

Bug: 185153400
Test: atest ScrollCaptureViewSupportTest
Change-Id: I2d97ba480320c3e83c056c0f51d7b4ca51715bd6
---
 .../view/ScrollCaptureViewHelper.java         | 17 +++-
 .../view/ScrollCaptureViewSupportTest.java    | 83 +++++++++++++++++++
 2 files changed, 96 insertions(+), 4 deletions(-)
 create mode 100644 core/tests/coretests/src/com/android/internal/view/ScrollCaptureViewSupportTest.java

diff --git a/core/java/com/android/internal/view/ScrollCaptureViewHelper.java b/core/java/com/android/internal/view/ScrollCaptureViewHelper.java
index 9829d0b7ae8d6..356cd6b5c9fce 100644
--- a/core/java/com/android/internal/view/ScrollCaptureViewHelper.java
+++ b/core/java/com/android/internal/view/ScrollCaptureViewHelper.java
@@ -19,8 +19,14 @@ package com.android.internal.view;
 import android.annotation.NonNull;
 import android.graphics.Rect;
 import android.view.View;
+import android.view.ViewGroup;
 
-interface ScrollCaptureViewHelper<V extends View> {
+/**
+ * Provides view-specific handling to ScrollCaptureViewSupport.
+ *
+ * @param <V> the View subclass
+ */
+public interface ScrollCaptureViewHelper<V extends View> {
     int UP = -1;
     int DOWN = 1;
 
@@ -73,9 +79,12 @@ interface ScrollCaptureViewHelper<V extends View> {
      * @param view the view being captured
      */
     @NonNull default Rect onComputeScrollBounds(@NonNull V view) {
-        return new Rect(view.getPaddingLeft(), view.getPaddingTop(),
-                view.getWidth() - view.getPaddingRight(),
-                view.getHeight() - view.getPaddingBottom());
+        Rect bounds = new Rect(0, 0, view.getWidth(), view.getHeight());
+        if (view instanceof ViewGroup && ((ViewGroup) view).getClipToPadding()) {
+            bounds.inset(view.getPaddingLeft(), view.getPaddingTop(),
+                    view.getPaddingRight(), view.getPaddingBottom());
+        }
+        return bounds;
     }
 
     /**
diff --git a/core/tests/coretests/src/com/android/internal/view/ScrollCaptureViewSupportTest.java b/core/tests/coretests/src/com/android/internal/view/ScrollCaptureViewSupportTest.java
new file mode 100644
index 0000000000000..cb72b2d0f0122
--- /dev/null
+++ b/core/tests/coretests/src/com/android/internal/view/ScrollCaptureViewSupportTest.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2021 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.internal.view;
+
+import static org.junit.Assert.assertEquals;
+
+import android.content.Context;
+import android.graphics.Rect;
+import android.view.View;
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.test.platform.app.InstrumentationRegistry;
+
+import org.junit.Test;
+
+public class ScrollCaptureViewSupportTest {
+
+    ScrollCaptureViewHelper<View> mViewHelper = new ScrollCaptureViewHelper<View>() {
+        @Override
+        public void onPrepareForStart(@NonNull View view, @NonNull Rect scrollBounds) {
+        }
+
+        @NonNull
+        @Override
+        public ScrollResult onScrollRequested(@NonNull View view, @NonNull Rect scrollBounds,
+                @NonNull Rect requestRect) {
+            return new ScrollResult();
+        }
+
+        @Override
+        public void onPrepareForEnd(@NonNull View view) {
+        }
+    };
+
+
+    /**
+     * Test scroll bounds are computed correctly. onComputeScrollBounds is currently a
+     * default interface method of ScrollCaptureViewHelper.
+     */
+    @Test
+    public void testComputeScrollBounds() {
+        Context context = InstrumentationRegistry.getInstrumentation().getContext();
+
+        ViewGroup target = new ViewGroup(context) {
+            @Override
+            protected void onLayout(boolean changed, int l, int t, int r, int b) {
+                // n/a
+            }
+        };
+
+        target.setPadding(25, 50, 25, 50);
+        target.setLeftTopRightBottom(0, 0, 200, 200);
+
+
+        // clipToPadding == false: No effect
+        target.setClipToPadding(false);
+        Rect scrollBounds = mViewHelper.onComputeScrollBounds(target);
+        assertEquals("Computed scroll bounds are incorrect with clipToPadding=false",
+                new Rect(0, 0, 200, 200), scrollBounds);
+
+        // clipToPadding == true: Inset by padding
+        target.setClipToPadding(true);
+        scrollBounds = mViewHelper.onComputeScrollBounds(target);
+        assertEquals("Computed scroll bounds are incorrect with clipToPadding=true",
+                new Rect(25, 50, 175, 150), scrollBounds);
+    }
+
+}