From 8b807d7b5048ce9f94c923e54f92ffe18c9044af Mon Sep 17 00:00:00 2001
From: fufesou <shuanglongchen@yeah.net>
Date: Tue, 3 Oct 2023 21:16:12 +0800
Subject: [PATCH] fix, cursor (hotx,hoty) mismatch sometimes

Signed-off-by: fufesou <shuanglongchen@yeah.net>
---
 flutter/lib/desktop/pages/remote_page.dart |  2 +-
 flutter/lib/models/model.dart              | 73 +++++++++++++---------
 2 files changed, 46 insertions(+), 29 deletions(-)

diff --git a/flutter/lib/desktop/pages/remote_page.dart b/flutter/lib/desktop/pages/remote_page.dart
index 13271378d..fee5bd8f4 100644
--- a/flutter/lib/desktop/pages/remote_page.dart
+++ b/flutter/lib/desktop/pages/remote_page.dart
@@ -614,7 +614,7 @@ class _ImagePaintState extends State<ImagePaint> {
     } else {
       final key = cache.updateGetKey(scale);
       if (!cursor.cachedKeys.contains(key)) {
-        debugPrint("Register custom cursor with key $key");
+        debugPrint("Register custom cursor with key $key (${cache.hotx},${cache.hoty})");
         // [Safety]
         // It's ok to call async registerCursor in current synchronous context,
         // because activating the cursor is also an async call and will always
diff --git a/flutter/lib/models/model.dart b/flutter/lib/models/model.dart
index a7082eb4b..d8ef19e08 100644
--- a/flutter/lib/models/model.dart
+++ b/flutter/lib/models/model.dart
@@ -1279,6 +1279,7 @@ class CursorModel with ChangeNotifier {
   final _cacheKeys = <String>{};
   double _x = -10000;
   double _y = -10000;
+  int _id = -1;
   double _hotx = 0;
   double _hoty = 0;
   double _displayOriginX = 0;
@@ -1287,7 +1288,7 @@ class CursorModel with ChangeNotifier {
   bool gotMouseControl = true;
   DateTime _lastPeerMouse = DateTime.now()
       .subtract(Duration(milliseconds: 3000 * kMouseControlTimeoutMSec));
-  String id = '';
+  String peerId = '';
   WeakReference<FFI> parent;
 
   ui.Image? get image => _image;
@@ -1439,32 +1440,35 @@ class CursorModel with ChangeNotifier {
   }
 
   updateCursorData(Map<String, dynamic> evt) async {
-    var id = int.parse(evt['id']);
-    _hotx = double.parse(evt['hotx']);
-    _hoty = double.parse(evt['hoty']);
-    var width = int.parse(evt['width']);
-    var height = int.parse(evt['height']);
+    final id = int.parse(evt['id']);
+    // Update last cursor id.
+    _id = id;
+    final hotx = double.parse(evt['hotx']);
+    final hoty = double.parse(evt['hoty']);
+    final width = int.parse(evt['width']);
+    final height = int.parse(evt['height']);
     List<dynamic> colors = json.decode(evt['colors']);
     final rgba = Uint8List.fromList(colors.map((s) => s as int).toList());
     final image = await img.decodeImageFromPixels(
         rgba, width, height, ui.PixelFormat.rgba8888);
-    _image = image;
-    if (await _updateCache(rgba, image, id, width, height)) {
-      _images[id] = Tuple3(image, _hotx, _hoty);
-    } else {
-      _hotx = 0;
-      _hoty = 0;
-    }
-    try {
-      // my throw exception, because the listener maybe already dispose
-      notifyListeners();
-    } catch (e) {
-      debugPrint('WARNING: updateCursorId $id, without notifyListeners(). $e');
+    if (await _updateCache(rgba, image, id, hotx, hoty, width, height)) {
+      _images[id] = Tuple3(image, hotx, hoty);
     }
+
+    // Update last cursor data.
+    // Do not use the previous `image` and `id`, because `_id` may be changed.
+    _updateCursorIdData(_id);
   }
 
   Future<bool> _updateCache(
-      Uint8List rgba, ui.Image image, int id, int w, int h) async {
+    Uint8List rgba,
+    ui.Image image,
+    int id,
+    double hotx,
+    double hoty,
+    int w,
+    int h,
+  ) async {
     Uint8List? data;
     img2.Image imgOrigin = img2.Image.fromBytes(
         width: w, height: h, bytes: rgba.buffer, order: img2.ChannelOrder.rgba);
@@ -1478,31 +1482,44 @@ class CursorModel with ChangeNotifier {
       }
       data = imgBytes.buffer.asUint8List();
     }
-    _cache = CursorData(
-      peerId: this.id,
+    final cache = CursorData(
+      peerId: peerId,
       id: id,
       image: imgOrigin,
       scale: 1.0,
       data: data,
-      hotxOrigin: _hotx,
-      hotyOrigin: _hoty,
+      hotxOrigin: hotx,
+      hotyOrigin: hoty,
       width: w,
       height: h,
     );
-    _cacheMap[id] = _cache!;
+    _cacheMap[id] = cache;
     return true;
   }
 
-  updateCursorId(Map<String, dynamic> evt) async {
-    final id = int.parse(evt['id']);
+  bool _updateCursorIdData(int id) {
     _cache = _cacheMap[id];
     final tmp = _images[id];
     if (tmp != null) {
       _image = tmp.item1;
       _hotx = tmp.item2;
       _hoty = tmp.item3;
-      notifyListeners();
+      try {
+        // may throw exception, because the listener maybe already dispose
+        notifyListeners();
+      } catch (e) {
+        debugPrint(
+            'WARNING: updateCursorId $id, without notifyListeners(). $e');
+      }
+      return true;
     } else {
+      return false;
+    }
+  }
+
+  updateCursorId(Map<String, dynamic> evt) async {
+    final id = int.parse(evt['id']);
+    if (!_updateCursorIdData(id)) {
       debugPrint(
           'WARNING: updateCursorId $id, cache is ${_cache == null ? "null" : "not null"}. without notifyListeners()');
     }
@@ -1748,7 +1765,7 @@ class FFI {
       connType = ConnType.defaultConn;
       canvasModel.id = id;
       imageModel.id = id;
-      cursorModel.id = id;
+      cursorModel.peerId = id;
     }
     // If tabWindowId != null, this session is a "tab -> window" one.
     // Else this session is a new one.