Test commit

example/lib/main.dart

@@ -1,3 +1,4 @@
+import 'package:fl_chart/fl_chart.dart';
 import 'package:fl_chart_app/presentation/resources/app_resources.dart';
 import 'package:flutter/material.dart';
 import 'package:google_fonts/google_fonts.dart';
@@ -13,19 +14,114 @@ class MyApp extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return MaterialApp.router(
-      title: AppTexts.appName,
-      theme: ThemeData(
-        brightness: Brightness.dark,
-        useMaterial3: true,
-        textTheme: GoogleFonts.assistantTextTheme(
-          Theme.of(context).textTheme.apply(
-                bodyColor: AppColors.mainTextColor3,
-              ),
+    return const MaterialApp(
+      home: HomePage(),
+    );
+  }
+}
+
+class HomePage extends StatefulWidget {
+  const HomePage({super.key});
+
+  @override
+  State<HomePage> createState() => _HomePageState();
+}
+
+class _HomePageState extends State<HomePage> {
+
+  List<LineChartBarData> lines = [
+    LineChartBarData(
+      spots: const [
+        FlSpot(0, 0),
+        FlSpot(1, 10),
+        FlSpot(2, 4),
+        FlSpot(3, 9),
+      ],
+      isCurved: true,
+    ),
+    LineChartBarData(
+      spots: const [
+        FlSpot(0, 5),
+        FlSpot(1, 3),
+        FlSpot(2, 9),
+        FlSpot(3, 4),
+      ],
+      isCurved: true,
+    ),
+  ];
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: Center(
+        child: AspectRatio(
+          aspectRatio: 2,
+          child: LineChart(
+            LineChartData(
+              minX: 0,
+              maxX: 3,
+              minY: 0,
+              maxY: 10,
+              lineBarsData: lines,
+              gridData: const FlGridData(show: false),
+              lineTouchData: LineTouchData(
+                handleBuiltInTouches: false,
+                touchCallback: _handleTouch,
+              )
+            ),
+          ),
         ),
-        scaffoldBackgroundColor: AppColors.pageBackground,
       ),
-      routerConfig: appRouterConfig,
     );
   }
+
+  TouchLineBarSpot? _draggingSpot;
+
+  void _handleTouch(FlTouchEvent event, LineTouchResponse? response) {
+    print('_handleTouch 1');
+    if (response == null) {
+      _draggingSpot = null;
+      print('_handleTouch 1 - null');
+      return;
+    }
+
+    print('_handleTouch 2');
+    if ((event is FlPanDownEvent ||
+        event is FlPanStartEvent ||
+        event is FlLongPressStart ||
+        event is FlTapDownEvent) &&
+        response.lineBarSpots != null &&
+        response.lineBarSpots!.isNotEmpty &&
+        _draggingSpot == null) {
+      setState(() {
+        _draggingSpot = response.lineBarSpots!.first;
+      });
+      print('_handleTouch 2 - $_draggingSpot');
+    }
+
+    print('_handleTouch 3');
+    if (event is FlPanUpdateEvent || event is FlLongPressMoveUpdate) {
+      setState(() {
+        final line = lines[_draggingSpot!.barIndex];
+        final newSpots = List.of(line.spots);
+        newSpots[_draggingSpot!.spotIndex] = FlSpot(
+          response.touchedChartPosition.dx,
+          response.touchedChartPosition.dy,
+        );
+        lines[_draggingSpot!.barIndex] =
+            lines[_draggingSpot!.barIndex].copyWith(
+          spots: newSpots,
+        );
+      });
+    }
+
+    print('_handleTouch 4');
+    if (event is FlPanEndEvent ||
+        event is FlPanCancelEvent ||
+        event is FlLongPressEnd ||
+        event is FlTapUpEvent) {
+      print('_handleTouch 4 - null');
+      _draggingSpot = null;
+    }
+  }
 }

lib/src/chart/bar_chart/bar_chart_data.dart

@@ -852,18 +852,26 @@ class BarTooltipItem with EquatableMixin {
 class BarTouchResponse extends BaseTouchResponse {
   /// If touch happens, [BarChart] processes it internally and passes out a BarTouchedSpot
   /// that contains a [spot], it gives you information about the touched spot.
-  BarTouchResponse(this.spot) : super();
+  BarTouchResponse(
+    this.spot,
+    this.touchedChartPosition,
+  ) : super();
 
   /// Gives information about the touched spot
   final BarTouchedSpot? spot;
 
+  /// Touched position in the chart's axis scale
+  final Offset touchedChartPosition;
+
   /// Copies current [BarTouchResponse] to a new [BarTouchResponse],
   /// and replaces provided values.
   BarTouchResponse copyWith({
     BarTouchedSpot? spot,
+    Offset? touchedChartPosition,
   }) {
     return BarTouchResponse(
       spot ?? this.spot,
+      touchedChartPosition ?? this.touchedChartPosition,
     );
   }
 }

lib/src/chart/bar_chart/bar_chart_renderer.dart

@@ -104,6 +104,10 @@ class RenderBarChart extends RenderBaseChart<BarTouchResponse> {
       mockTestSize ?? size,
       paintHolder,
     );
-    return BarTouchResponse(touchedSpot);
+    final touchedPosition = Offset(
+      painter.getXByPixel(localPosition.dx, size, paintHolder),
+      painter.getYByPixel(localPosition.dy, size, paintHolder),
+    );
+    return BarTouchResponse(touchedSpot, touchedPosition);
   }
 }

lib/src/chart/base/axis_chart/axis_chart_painter.dart

@@ -399,6 +399,16 @@ abstract class AxisChartPainter<D extends AxisChartData>
     return ((spotX - data.minX) / deltaX) * viewSize.width;
   }
 
+  /// Returns a value in chart's x-coordinate based on the provided [pixelX]
+  double getXByPixel(double pixelX, Size viewSize, PaintHolder<D> holder) {
+    final data = holder.data;
+    final deltaX = data.maxX - data.minX;
+    if (deltaX == 0.0) {
+      return 0;
+    }
+    return (pixelX / viewSize.width) * deltaX + data.minX;
+  }
+
   /// With this function we can convert our [FlSpot] y
   /// to the view base axis y.
   double getPixelY(double spotY, Size viewSize, PaintHolder<D> holder) {
@@ -410,6 +420,16 @@ abstract class AxisChartPainter<D extends AxisChartData>
     return viewSize.height - (((spotY - data.minY) / deltaY) * viewSize.height);
   }
 
+  /// Returns a value in chart's y-coordinate based on the provided [pixelY]
+  double getYByPixel(double pixelY, Size viewSize, PaintHolder<D> holder) {
+    final data = holder.data;
+    final deltaY = data.maxY - data.minY;
+    if (deltaY == 0.0) {
+      return 0;
+    }
+    return data.maxY - (pixelY / viewSize.height) * deltaY;
+  }
+
   /// With this function we can get horizontal
   /// position for the tooltip.
   double getTooltipLeft(

lib/src/chart/line_chart/line_chart_data.dart

@@ -1470,19 +1470,27 @@ class LineTouchResponse extends BaseTouchResponse {
   /// If touch happens, [LineChart] processes it internally and
   /// passes out a list of [lineBarSpots] it gives you information about the touched spot.
   /// They are sorted based on their distance to the touch event
-  const LineTouchResponse(this.lineBarSpots);
+  const LineTouchResponse(
+    this.lineBarSpots,
+    this.touchedChartPosition,
+  );
 
   /// touch happened on these spots
   /// (if a single line provided on the chart, [lineBarSpots]'s length will be 1 always)
   final List<TouchLineBarSpot>? lineBarSpots;
 
+  /// Touched position in the chart's axis scale
+  final Offset touchedChartPosition;
+
   /// Copies current [LineTouchResponse] to a new [LineTouchResponse],
   /// and replaces provided values.
   LineTouchResponse copyWith({
     List<TouchLineBarSpot>? lineBarSpots,
+    Offset? touchedChartPosition,
   }) {
     return LineTouchResponse(
       lineBarSpots ?? this.lineBarSpots,
+      touchedChartPosition ?? this.touchedChartPosition,
     );
   }
 }

lib/src/chart/line_chart/line_chart_renderer.dart

@@ -109,6 +109,10 @@ class RenderLineChart extends RenderBaseChart<LineTouchResponse> {
       mockTestSize ?? size,
       paintHolder,
     );
-    return LineTouchResponse(touchedSpots);
+    final touchedPosition = Offset(
+      painter.getXByPixel(localPosition.dx, size, paintHolder),
+      painter.getYByPixel(localPosition.dy, size, paintHolder),
+    );
+    return LineTouchResponse(touchedSpots, touchedPosition);
   }
 }

lib/src/chart/pie_chart/pie_chart_renderer.dart

@@ -168,4 +168,7 @@ class RenderPieChart extends RenderBaseChart<PieTouchResponse>
     ///
     /// I don't know how to solve this error. That's why we disabled semantics for now.
   }
+
+  @override
+  Offset? getChartPositionByPixel(Offset pixelPosition) => null;
 }

lib/src/chart/radar_chart/radar_chart_renderer.dart

@@ -110,4 +110,7 @@ class RenderRadarChart extends RenderBaseChart<RadarTouchResponse> {
     );
     return RadarTouchResponse(touchedSpot);
   }
+
+  @override
+  Offset? getChartPositionByPixel(Offset pixelPosition) => null;
 }

lib/src/chart/scatter_chart/scatter_chart_data.dart

@@ -339,15 +339,22 @@ class ScatterTouchResponse extends BaseTouchResponse {
   ///
   /// [touchedSpot] tells you
   /// in which spot (of [ScatterChartData.scatterSpots]) touch happened.
-  ScatterTouchResponse(this.touchedSpot) : super();
+  ScatterTouchResponse(this.touchedSpot, this.touchedChartPosition) : super();
   final ScatterTouchedSpot? touchedSpot;
 
+  /// Touched position in the chart's axis scale
+  final Offset touchedChartPosition;
+
   /// Copies current [ScatterTouchResponse] to a new [ScatterTouchResponse],
   /// and replaces provided values.
   ScatterTouchResponse copyWith({
     ScatterTouchedSpot? touchedSpot,
+    Offset? touchedChartPosition,
   }) {
-    return ScatterTouchResponse(touchedSpot ?? this.touchedSpot);
+    return ScatterTouchResponse(
+      touchedSpot ?? this.touchedSpot,
+      touchedChartPosition ?? this.touchedChartPosition,
+    );
   }
 }
 

lib/src/chart/scatter_chart/scatter_chart_renderer.dart

@@ -112,6 +112,10 @@ class RenderScatterChart extends RenderBaseChart<ScatterTouchResponse> {
       mockTestSize ?? size,
       paintHolder,
     );
-    return ScatterTouchResponse(touchedSpot);
+    final touchedPosition = Offset(
+      painter.getXByPixel(localPosition.dx, size, paintHolder),
+      painter.getYByPixel(localPosition.dy, size, paintHolder),
+    );
+    return ScatterTouchResponse(touchedSpot, touchedPosition);
   }
 }