Fling is not working while using the onPointerPanZoomUpdate callback #117881
Description
While using the onPointerPanZoomUpdate instead of the onPointerSignal event for trackpad zooming the fling effect is not working.
Steps to Reproduce
Run a below-shared code snippet as mentioned, while performing mouse wheel zooming in the trackpad using the onPointerSignal event it gives scrollDelta value after some time lifting the finger up on the trackpad but in onPointerPanZoomUpdate it is not working as same.
- Run a sample in windows or macOS with the latest flutter SDK version (the fling effect is not working in onPointerPanZoomUpdate)
Code sample
import 'package: flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:vector_math/vector_math_64.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(),
home: const ZoomableWidget(),
);
}
}
class ZoomableWidget extends StatefulWidget {
const ZoomableWidget({Key? key}) : super(key: key);
@override
_ZoomableWidgetState createState() => _ZoomableWidgetState();
}
class _ZoomableWidgetState extends State<ZoomableWidget> {
double _scale = 1.0;
double _oldScale = 1.0;
Matrix4? transform = Matrix4.diagonal3(
Vector3(1.0.clamp(1.0, 5.0), 1.0.clamp(1.0, 5.0), 1.0.clamp(1.0, 5.0)));
@override
Widget build(BuildContext context) {
return Listener(
onPointerSignal: (PointerSignalEvent event) {
if (event is PointerScrollEvent) {
setState(() {
_scale = _oldScale + (event.scrollDelta.dy / 180);
print(_scale);
_oldScale = _scale;
});
}
},
child: Transform(
transform: //transform!,
Matrix4.diagonal3(Vector3(_scale.clamp(1.0, 5.0),
_scale.clamp(1.0, 5.0), _scale.clamp(1.0, 5.0))),
alignment: FractionalOffset.center,
child: const Image(image: AssetImage('images/owel.jpg')),
),
);
}
}- Sample with onPointerSignal event where filing effect is working.
Code sample
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';
import 'package:vector_math/vector_math_64.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(),
home: const ZoomableWidget(),
);
}
}
class ZoomableWidget extends StatefulWidget {
const ZoomableWidget({Key? key}) : super(key: key);
@override
_ZoomableWidgetState createState() => _ZoomableWidgetState();
}
class _ZoomableWidgetState extends State<ZoomableWidget> {
double _scale = 1.0;
double _oldScale = 1.0;
Matrix4? transform = Matrix4.diagonal3(
Vector3(1.0.clamp(1.0, 5.0), 1.0.clamp(1.0, 5.0), 1.0.clamp(1.0, 5.0)));
@override
Widget build(BuildContext context) {
return Listener(
onPointerPanZoomStart: (event) {
print('start');
},
onPointerPanZoomUpdate: (PointerPanZoomUpdateEvent event) {
event.position;
setState(() {
_scale = _oldScale + (event.panDelta.dy / 180);
print(_scale);
_oldScale = _scale;
});
},
onPointerPanZoomEnd: (event) {
print('end');
},
child: Transform(
transform: //transform!,
Matrix4.diagonal3(Vector3(_scale.clamp(1.0, 5.0),
_scale.clamp(1.0, 5.0), _scale.clamp(1.0, 5.0))),
alignment: FractionalOffset.center,
child: const Image(image: AssetImage('images/owel.jpg')),
),
);
}
}
Expected results:
This is an onPointerSignal event and the expected output
Actual results:
