added detectScale to FlTouchData flag and scale gesture detection option

lib/src/chart/bar_chart/bar_chart_data.dart

@@ -587,6 +587,9 @@ class BackgroundBarChartRodData with EquatableMixin {
 class BarTouchData extends FlTouchData<BarTouchResponse> with EquatableMixin {
   /// You can disable or enable the touch system using [enabled] flag,
   ///
+  /// You can disable or enable the scale detection using [detectScale] flag,
+  /// detecting scale gesture will disable pan gesture detection
+  ///
   /// [touchCallback] notifies you about the happened touch/pointer events.
   /// It gives you a [FlTouchEvent] which is the happened event such as [FlPointerHoverEvent], [FlTapUpEvent], ...
   /// It also gives you a [BarTouchResponse] which contains information
@@ -603,6 +606,7 @@ class BarTouchData extends FlTouchData<BarTouchResponse> with EquatableMixin {
   /// on [BarChartRodData.backDrawRodData] too (by default it only works on the main rods).
   BarTouchData({
     bool? enabled,
+    bool? detectScale,
     BaseTouchCallback<BarTouchResponse>? touchCallback,
     MouseCursorResolver<BarTouchResponse>? mouseCursorResolver,
     Duration? longPressDuration,
@@ -619,6 +623,7 @@ class BarTouchData extends FlTouchData<BarTouchResponse> with EquatableMixin {
           touchCallback,
           mouseCursorResolver,
           longPressDuration,
+          detectScale ?? false,
         );
 
   /// Configs of how touch tooltip popup.

lib/src/chart/base/base_chart/base_chart_data.dart

@@ -90,11 +90,16 @@ abstract class FlTouchData<R extends BaseTouchResponse> with EquatableMixin {
     this.touchCallback,
     this.mouseCursorResolver,
     this.longPressDuration,
+    this.detectScale,
   );
 
   /// You can disable or enable the touch system using [enabled] flag,
   final bool enabled;
 
+  /// You can disable or enable the scale detection using [detectScale] flag,
+  /// detecting scale gesture will disable pan gesture detection
+  final bool detectScale;
+
   /// [touchCallback] notifies you about the happened touch/pointer events.
   /// It gives you a [FlTouchEvent] which is the happened event such as [FlPointerHoverEvent], [FlTapUpEvent], ...
   /// It also gives you a [BaseTouchResponse] which is the chart specific type and contains information

lib/src/chart/base/base_chart/fl_touch_event.dart

@@ -38,6 +38,33 @@ abstract class FlTouchEvent {
   }
 }
 
+class FlScaleStartEvent extends FlTouchEvent {
+  const FlScaleStartEvent(this.details);
+
+  final ScaleStartDetails details;
+
+  @override
+  Offset get localPosition => details.focalPoint;
+}
+
+class FlScaleUpdateEvent extends FlTouchEvent {
+  const FlScaleUpdateEvent(this.details);
+
+  final ScaleUpdateDetails details;
+
+  @override
+  Offset get localPosition => details.focalPoint;
+}
+
+class FlScaleEndEvent extends FlTouchEvent {
+  const FlScaleEndEvent(this.details);
+
+  final ScaleEndDetails details;
+
+  @override
+  Offset get localPosition => Offset.zero;
+}
+
 /// When a pointer has contacted the screen and might begin to move
 ///
 /// The [details] object provides the position of the touch.

lib/src/chart/base/base_chart/render_base_chart.dart

@@ -29,18 +29,24 @@ abstract class RenderBaseChart<R extends BaseTouchResponse> extends RenderBox
     _touchCallback = value?.touchCallback;
     _mouseCursorResolver = value?.mouseCursorResolver;
     _longPressDuration = value?.longPressDuration;
+    _detectScale = value?.detectScale ?? false;
   }
 
   BaseTouchCallback<R>? _touchCallback;
   MouseCursorResolver<R>? _mouseCursorResolver;
   Duration? _longPressDuration;
+  bool _detectScale = false;
 
   MouseCursor _latestMouseCursor = MouseCursor.defer;
 
   late bool _validForMouseTracker;
 
-  /// Recognizes pan gestures, such as onDown, onStart, onUpdate, onCancel, ...
-  late PanGestureRecognizer _panGestureRecognizer;
+  // late ScaleGestureRecognizer _scaleGestureRecognizer;
+
+  // if [detectScale] is true, we use ScaleGestureRecognizer, otherwise we use PanGestureRecognizer
+  // Recognizes pan gestures, such as onDown, onStart, onUpdate, onCancel, ...
+  // or alternatively detects scale gestures, such as onStart, onUpdate, onEnd, ...
+  late OneSequenceGestureRecognizer _panOrScaleGestureRecognizer;
 
   /// Recognizes tap gestures, such as onTapDown, onTapCancel and onTapUp
   late TapGestureRecognizer _tapGestureRecognizer;
@@ -50,23 +56,37 @@ abstract class RenderBaseChart<R extends BaseTouchResponse> extends RenderBox
 
   /// Initializes our recognizers and implement their callbacks.
   void initGestureRecognizers() {
-    _panGestureRecognizer = PanGestureRecognizer();
-    _panGestureRecognizer
-      ..onDown = (dragDownDetails) {
-        _notifyTouchEvent(FlPanDownEvent(dragDownDetails));
-      }
-      ..onStart = (dragStartDetails) {
-        _notifyTouchEvent(FlPanStartEvent(dragStartDetails));
-      }
-      ..onUpdate = (dragUpdateDetails) {
-        _notifyTouchEvent(FlPanUpdateEvent(dragUpdateDetails));
-      }
-      ..onCancel = () {
-        _notifyTouchEvent(const FlPanCancelEvent());
-      }
-      ..onEnd = (dragEndDetails) {
-        _notifyTouchEvent(FlPanEndEvent(dragEndDetails));
-      };
+    if (_detectScale) {
+      final scaleGestureRecognizer = ScaleGestureRecognizer()
+        ..onStart = (details) {
+          _notifyTouchEvent(FlScaleStartEvent(details));
+        }
+        ..onUpdate = (details) {
+          _notifyTouchEvent(FlScaleUpdateEvent(details));
+        }
+        ..onEnd = (details) {
+          _notifyTouchEvent(FlScaleEndEvent(details));
+        };
+      _panOrScaleGestureRecognizer = scaleGestureRecognizer;
+    } else {
+      final panGestureRecognizer = PanGestureRecognizer()
+        ..onDown = (dragDownDetails) {
+          _notifyTouchEvent(FlPanDownEvent(dragDownDetails));
+        }
+        ..onStart = (dragStartDetails) {
+          _notifyTouchEvent(FlPanStartEvent(dragStartDetails));
+        }
+        ..onUpdate = (dragUpdateDetails) {
+          _notifyTouchEvent(FlPanUpdateEvent(dragUpdateDetails));
+        }
+        ..onCancel = () {
+          _notifyTouchEvent(const FlPanCancelEvent());
+        }
+        ..onEnd = (dragEndDetails) {
+          _notifyTouchEvent(FlPanEndEvent(dragEndDetails));
+        };
+      _panOrScaleGestureRecognizer = panGestureRecognizer;
+    }
 
     _tapGestureRecognizer = TapGestureRecognizer();
     _tapGestureRecognizer
@@ -88,7 +108,7 @@ abstract class RenderBaseChart<R extends BaseTouchResponse> extends RenderBox
       }
       ..onLongPressMoveUpdate = (longPressMoveUpdateDetails) {
         _notifyTouchEvent(
-          FlLongPressMoveUpdate(longPressMoveUpdateDetails),
+          FlLongPressMoveUpdate(longPreqssMoveUpdateDetails),
         );
       }
       ..onLongPressEnd = (longPressEndDetails) =>
@@ -124,7 +144,7 @@ abstract class RenderBaseChart<R extends BaseTouchResponse> extends RenderBox
     if (event is PointerDownEvent) {
       _longPressGestureRecognizer.addPointer(event);
       _tapGestureRecognizer.addPointer(event);
-      _panGestureRecognizer.addPointer(event);
+      _panOrScaleGestureRecognizer.addPointer(event);
     } else if (event is PointerHoverEvent) {
       _notifyTouchEvent(FlPointerHoverEvent(event));
     }

lib/src/chart/line_chart/line_chart_data.dart

@@ -856,6 +856,9 @@ abstract class FlLineLabel with EquatableMixin {
 class LineTouchData extends FlTouchData<LineTouchResponse> with EquatableMixin {
   /// You can disable or enable the touch system using [enabled] flag,
   ///
+  /// You can disable or enable the scale detection using [detectScale] flag,
+  /// detecting scale gesture will disable pan gesture detection
+  ///
   /// [touchCallback] notifies you about the happened touch/pointer events.
   /// It gives you a [FlTouchEvent] which is the happened event such as [FlPointerHoverEvent], [FlTapUpEvent], ...
   /// It also gives you a [LineTouchResponse] which contains information
@@ -873,6 +876,7 @@ class LineTouchData extends FlTouchData<LineTouchResponse> with EquatableMixin {
   /// If you need to have a distance threshold for handling touches, use [touchSpotThreshold].
   const LineTouchData({
     bool enabled = true,
+    bool detectScale = false,
     BaseTouchCallback<LineTouchResponse>? touchCallback,
     MouseCursorResolver<LineTouchResponse>? mouseCursorResolver,
     Duration? longPressDuration,
@@ -888,6 +892,7 @@ class LineTouchData extends FlTouchData<LineTouchResponse> with EquatableMixin {
           touchCallback,
           mouseCursorResolver,
           longPressDuration,
+          detectScale,
         );
 
   /// Configs of how touch tooltip popup.

lib/src/chart/pie_chart/pie_chart_data.dart

@@ -296,6 +296,9 @@ class PieChartSectionData {
 class PieTouchData extends FlTouchData<PieTouchResponse> with EquatableMixin {
   /// You can disable or enable the touch system using [enabled] flag,
   ///
+  /// You can disable or enable the scale detection using [detectScale] flag,
+  /// detecting scale gesture will disable pan gesture detection
+  ///
   /// [touchCallback] notifies you about the happened touch/pointer events.
   /// It gives you a [FlTouchEvent] which is the happened event such as [FlPointerHoverEvent], [FlTapUpEvent], ...
   /// It also gives you a [PieTouchResponse] which contains information
@@ -305,6 +308,7 @@ class PieTouchData extends FlTouchData<PieTouchResponse> with EquatableMixin {
   /// based on the provided [FlTouchEvent] and [PieTouchResponse]
   PieTouchData({
     bool? enabled,
+    bool? detectScale,
     BaseTouchCallback<PieTouchResponse>? touchCallback,
     MouseCursorResolver<PieTouchResponse>? mouseCursorResolver,
     Duration? longPressDuration,
@@ -313,6 +317,7 @@ class PieTouchData extends FlTouchData<PieTouchResponse> with EquatableMixin {
           touchCallback,
           mouseCursorResolver,
           longPressDuration,
+          detectScale ?? false,
         );
 
   /// Used for equality check, see [EquatableMixin].

lib/src/chart/radar_chart/radar_chart_data.dart

@@ -382,6 +382,12 @@ class RadarTouchData extends FlTouchData<RadarTouchResponse>
     with EquatableMixin {
   /// You can disable or enable the touch system using [enabled] flag,
   ///
+  /// You can disable or enable the scale detection using [detectScale] flag,
+  /// detecting scale gesture will disable pan gesture detection
+  ///
+  /// You can disable or enable the scale detection using [detectScale] flag,
+  /// detecting scale gesture will disable pan gesture detection
+  ///
   /// [touchCallback] notifies you about the happened touch/pointer events.
   /// It gives you a [FlTouchEvent] which is the happened event such as [FlPointerHoverEvent], [FlTapUpEvent], ...
   /// It also gives you a [RadarTouchResponse] which contains information
@@ -391,6 +397,7 @@ class RadarTouchData extends FlTouchData<RadarTouchResponse>
   /// based on the provided [FlTouchEvent] and [RadarTouchResponse]
   RadarTouchData({
     bool? enabled,
+    bool? detectScale = false,
     BaseTouchCallback<RadarTouchResponse>? touchCallback,
     MouseCursorResolver<RadarTouchResponse>? mouseCursorResolver,
     Duration? longPressDuration,
@@ -401,6 +408,7 @@ class RadarTouchData extends FlTouchData<RadarTouchResponse>
           touchCallback,
           mouseCursorResolver,
           longPressDuration,
+          detectScale ?? false,
         );
 
   /// we find the nearest spots on touched position based on this threshold

lib/src/chart/scatter_chart/scatter_chart_data.dart

@@ -263,6 +263,9 @@ class ScatterTouchData extends FlTouchData<ScatterTouchResponse>
     with EquatableMixin {
   /// You can disable or enable the touch system using [enabled] flag,
   ///
+  /// You can disable or enable the scale detection using [detectScale] flag,
+  /// detecting scale gesture will disable pan gesture detection
+  ///
   /// [touchCallback] notifies you about the happened touch/pointer events.
   /// It gives you a [FlTouchEvent] which is the happened event such as [FlPointerHoverEvent], [FlTapUpEvent], ...
   /// It also gives you a [ScatterTouchResponse] which contains information
@@ -278,6 +281,7 @@ class ScatterTouchData extends FlTouchData<ScatterTouchResponse>
   /// If you need to have a distance threshold for handling touches, use [touchSpotThreshold].
   ScatterTouchData({
     bool? enabled,
+    bool? detectScale,
     BaseTouchCallback<ScatterTouchResponse>? touchCallback,
     MouseCursorResolver<ScatterTouchResponse>? mouseCursorResolver,
     Duration? longPressDuration,
@@ -292,6 +296,7 @@ class ScatterTouchData extends FlTouchData<ScatterTouchResponse>
           touchCallback,
           mouseCursorResolver,
           longPressDuration,
+          detectScale ?? false,
         );
 
   /// show a tooltip on touched spots