From 48139549212d6cf8b6581f2988f8369d0eeea42e Mon Sep 17 00:00:00 2001
From: Garfield Tan <xutan@google.com>
Date: Thu, 29 Jun 2023 15:21:41 -0700
Subject: [PATCH] Fix a few issues with mouse cursors and resize handles

1. We will not start a resize when the cursor is less than the corner
   radius close to one edge, and more than the corner radius close to
   the adjacent edge.
2. We will not set the cursor type on hover exits, because it should be
   the entering input window that sets it.
3. Only update to default once, so that views behind non-mouse touch
   regions of DragResizeInputHandler can set mouse cursors. However, we
   don't want to update to other cursor types only once because we will
   pilfer the gesture when we decide to resize tasks, and we shouldn't
   let views behind DragResizeInputHandler to change the mouse cursor.
   The TaskInputSink can't prevent all views behind mouse active touch
   region from getting events, because there is a small region out of
   each rounded corner that's inside the task bounds. Ultimately, we're
   limited by that the touch region isn't capable to enough to
   effectively express rounded corners.

Bug: 266866903
Test: All mentioned issues aren't reproducible anymore.
Change-Id: Ie3b4eba80749b5382932293b626122f8fabc7e48
---
 .../windowdecor/DragResizeInputListener.java  | 27 ++++++++++++++++---
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DragResizeInputListener.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DragResizeInputListener.java
index 336d95e7b62b4..7c6fb99e9c8b6 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DragResizeInputListener.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DragResizeInputListener.java
@@ -336,6 +336,7 @@ class DragResizeInputListener implements AutoCloseable {
         private final Runnable mConsumeBatchEventRunnable;
         private boolean mConsumeBatchEventScheduled;
         private boolean mShouldHandleEvents;
+        private int mLastCursorType = PointerIcon.TYPE_DEFAULT;
 
         private TaskResizeInputEventReceiver(
                 InputChannel inputChannel, Handler handler, Choreographer choreographer) {
@@ -437,7 +438,6 @@ class DragResizeInputListener implements AutoCloseable {
                     break;
                 }
                 case MotionEvent.ACTION_HOVER_EXIT:
-                    mInputManager.setPointerIconType(PointerIcon.TYPE_DEFAULT);
                     result = true;
                     break;
             }
@@ -477,7 +477,13 @@ class DragResizeInputListener implements AutoCloseable {
             if (y > mTaskHeight - mTaskCornerRadius) {
                 ctrlType |= CTRL_TYPE_BOTTOM;
             }
-            return checkDistanceFromCenter(ctrlType, x, y);
+            // Check distances from the center if it's in one of four corners.
+            if ((ctrlType & (CTRL_TYPE_LEFT | CTRL_TYPE_RIGHT)) != 0
+                    && (ctrlType & (CTRL_TYPE_TOP | CTRL_TYPE_BOTTOM)) != 0) {
+                return checkDistanceFromCenter(ctrlType, x, y);
+            }
+            // Otherwise, we should make sure we don't resize tasks inside task bounds.
+            return (x < 0 || y < 0 || x >= mTaskWidth || y >= mTaskHeight) ? ctrlType : 0;
         }
 
         // If corner input is not within appropriate distance of corner radius, do not use it.
@@ -511,7 +517,8 @@ class DragResizeInputListener implements AutoCloseable {
                     break;
                 }
                 default: {
-                    return ctrlType;
+                    throw new IllegalArgumentException("ctrlType should be complex, but it's 0x"
+                            + Integer.toHexString(ctrlType));
                 }
             }
             double distanceFromCenter = Math.hypot(x - centerX, y - centerY);
@@ -564,7 +571,19 @@ class DragResizeInputListener implements AutoCloseable {
                     cursorType = PointerIcon.TYPE_TOP_RIGHT_DIAGONAL_DOUBLE_ARROW;
                     break;
             }
-            mInputManager.setPointerIconType(cursorType);
+            // Only update the cursor type to default once so that views behind the decor container
+            // layer that aren't in the active resizing regions have chances to update the cursor
+            // type. We would like to enforce the cursor type by setting the cursor type multilple
+            // times in active regions because we shouldn't allow the views behind to change it, as
+            // we'll pilfer the gesture initiated in this area. This is necessary because 1) we
+            // should allow the views behind regions only for touches to set the cursor type; and 2)
+            // there is a small region out of each rounded corner that's inside the task bounds,
+            // where views in the task can receive input events because we can't set touch regions
+            // of input sinks to have rounded corners.
+            if (mLastCursorType != cursorType || cursorType != PointerIcon.TYPE_DEFAULT) {
+                mInputManager.setPointerIconType(cursorType);
+                mLastCursorType = cursorType;
+            }
         }
     }
 }
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