display axis values

example/lib/main.dart

@@ -37,7 +37,6 @@ class _MyHomePageState extends State<MyHomePage> {
     final stream = getDataStream().asBroadcastStream();
 
     return Scaffold(
-      backgroundColor: Colors.black,
       appBar: AppBar(
         title: Text(widget.title),
       ),

lib/src/live_chart.dart

@@ -8,27 +8,33 @@ import 'point.dart';
 
 class RealTimeGraph extends StatefulWidget {
   const RealTimeGraph({
-    Key? key,
     this.updateDelay = const Duration(milliseconds: 50),
-    this.speed = 1,
-    this.graphStroke = 0.5,
-    this.graphColor = Colors.red,
-    this.axisColor = Colors.green,
-    this.axisWidth = 1.0,
-    required this.stream,
-    this.pointsSpacing = 3.0,
     this.displayMode = ChartDisplay.line,
+    this.displayYAxisValues = true,
+    this.axisColor = Colors.black87,
+    this.graphColor = Colors.black45,
+    this.pointsSpacing = 3.0,
+    this.graphStroke = 1,
+    this.axisStroke = 1.0,
+    this.axisTextBuilder,
+    required this.stream,
+    this.minValue = 0,
+    this.speed = 1,
+    Key? key,
   }) : super(key: key);
 
-  final Stream<double> stream;
+  final Widget Function(double)? axisTextBuilder;
-  final Color graphColor;
-  final double axisWidth;
-  final Color axisColor;
-  final Duration updateDelay;
-  final int speed;
-  final double graphStroke;
-  final double pointsSpacing;
   final ChartDisplay displayMode;
+  final bool displayYAxisValues;
+  final Stream<double> stream;
+  final Duration updateDelay;
+  final double pointsSpacing;
+  final double axisStroke;
+  final double graphStroke;
+  final Color graphColor;
+  final Color axisColor;
+  final double minValue;
+  final int speed;
 
   @override
   RealTimeGraphState createState() => RealTimeGraphState();
@@ -67,35 +73,57 @@ class RealTimeGraphState extends State<RealTimeGraph>
     });
   }
 
+  double get maxValue {
+    return _data.isEmpty ? 0 : _data.map((point) => point.y).reduce(max);
+  }
+
+  double get minValue => widget.minValue;
+
+  double get medianValue => (maxValue + minValue) / 2;
+
   @override
   Widget build(BuildContext context) {
-    return LayoutBuilder(
+    return Row(
+      mainAxisSize: MainAxisSize.max,
+      children: [
+        if (widget.displayYAxisValues)
+          Column(
+            mainAxisAlignment: MainAxisAlignment.spaceBetween,
+            children: [
+              widget.axisTextBuilder?.call(maxValue) ?? textBuilder(maxValue),
+              widget.axisTextBuilder?.call(medianValue) ??
+                  textBuilder(medianValue),
+              widget.axisTextBuilder?.call(minValue) ?? textBuilder(minValue),
+            ],
+          ),
+        Container(
+          color: widget.axisColor,
+          width: widget.axisStroke,
+          height: double.maxFinite,
+        ),
+        Expanded(
+          child: Column(
+            mainAxisSize: MainAxisSize.max,
+            children: [
+              Expanded(
+                child: LayoutBuilder(
                   builder: (context, constraints) {
-        if (!constraints.maxWidth.isFinite || !constraints.maxHeight.isFinite) {
+                    if (!constraints.maxWidth.isFinite ||
+                        !constraints.maxHeight.isFinite) {
                       return const SizedBox.shrink();
                     }
 
                     return SizedBox(
-          key: Key('${constraints.maxWidth}${constraints.maxHeight}'),
+                      key: Key(
+                          '${constraints.maxWidth}${constraints.maxHeight}'),
                       height: constraints.maxHeight,
                       width: constraints.maxWidth,
-          child: Row(
+                      child: ClipRRect(
-            mainAxisSize: MainAxisSize.max,
-            children: [
-              Container(
-                color: widget.axisColor,
-                width: widget.axisWidth,
-                height: constraints.maxHeight,
-              ),
-              Column(
-                mainAxisSize: MainAxisSize.max,
-                children: [
-                  ClipRRect(
                         child: RepaintBoundary(
                           child: CustomPaint(
                             size: Size(
-                          constraints.maxWidth - widget.axisWidth,
+                              constraints.maxWidth,
-                          constraints.maxHeight - widget.axisWidth,
+                              constraints.maxHeight,
                             ),
                             painter: widget.displayMode == ChartDisplay.points
                                 ? _PointGraphPainter(
@@ -112,17 +140,26 @@ class RealTimeGraphState extends State<RealTimeGraph>
                           ),
                         ),
                       ),
+                    );
+                  },
+                ),
+              ),
               Container(
                 color: widget.axisColor,
-                    height: widget.axisWidth,
+                height: widget.axisStroke,
-                    width: constraints.maxWidth - widget.axisWidth,
+                width: double.maxFinite,
               )
             ],
           ),
-            ],
         ),
+      ],
     );
-      },
+  }
+
+  Widget textBuilder(double value) {
+    return Text(
+      value.toString(),
+      style: const TextStyle(color: Colors.black),
     );
   }