Implement PointDataSet for Chart

@@ -96,11 +96,11 @@ Future<Uint8List> generateReport(
         width: 15,
         offset: -10,
         borderColor: baseColor,
-        data: List<pw.LineChartValue>.generate(
+        data: List<pw.PointChartValue>.generate(
           dataTable.length,
           (i) {
             final v = dataTable[i][2] as num;
-            return pw.LineChartValue(i.toDouble(), v.toDouble());
+            return pw.PointChartValue(i.toDouble(), v.toDouble());
           },
         ),
       ),
@@ -110,11 +110,11 @@ Future<Uint8List> generateReport(
         width: 15,
         offset: 10,
         borderColor: PdfColors.amber,
-        data: List<pw.LineChartValue>.generate(
+        data: List<pw.PointChartValue>.generate(
           dataTable.length,
           (i) {
             final v = dataTable[i][1] as num;
-            return pw.LineChartValue(i.toDouble(), v.toDouble());
+            return pw.PointChartValue(i.toDouble(), v.toDouble());
           },
         ),
       ),
@@ -138,11 +138,11 @@ Future<Uint8List> generateReport(
         isCurved: true,
         drawPoints: false,
         color: baseColor,
-        data: List<pw.LineChartValue>.generate(
+        data: List<pw.PointChartValue>.generate(
           dataTable.length,
           (i) {
             final v = dataTable[i][2] as num;
-            return pw.LineChartValue(i.toDouble(), v.toDouble());
+            return pw.PointChartValue(i.toDouble(), v.toDouble());
           },
         ),
       ),

 # Changelog
 
-## 3.7.5
+## 3.8.0
 
 - Update xml dependency range
+- Implement PointDataSet for Chart
 
 ## 3.7.4
 

@@ -642,6 +642,11 @@ class SizedBox extends StatelessWidget {
       : width = size?.x,
         height = size?.y;
 
+  /// Creates a box whose width and height are equal.
+  SizedBox.square({this.child, double? dimension})
+      : width = dimension,
+        height = dimension;
+
   /// If non-null, requires the child to have exactly this width.
   final double? width;
 

@@ -17,14 +17,15 @@
 import '../../../pdf.dart';
 import '../flex.dart';
 import '../geometry.dart';
+import '../page.dart';
 import '../widget.dart';
 import 'chart.dart';
 import 'grid_cartesian.dart';
-import 'line_chart.dart';
+import 'point_chart.dart';
 
-class BarDataSet extends Dataset {
+class BarDataSet<T extends PointChartValue> extends PointDataSet<T> {
   BarDataSet({
-    required this.data,
+    required List<T> data,
     String? legend,
     this.borderColor,
     this.borderWidth = 1.5,
@@ -35,16 +36,26 @@ class BarDataSet extends Dataset {
     this.width = 10,
     this.offset = 0,
     this.axis = Axis.horizontal,
+    PdfColor? pointColor,
+    double pointSize = 3,
+    bool drawPoints = false,
+    BuildCallback? shape,
+    Widget Function(Context context, T value)? buildValue,
+    ValuePosition valuePosition = ValuePosition.auto,
   })  : drawBorder = drawBorder ?? borderColor != null && color != borderColor,
         assert((drawBorder ?? borderColor != null && color != borderColor) ||
             drawSurface),
         super(
           legend: legend,
-          color: color,
+          color: pointColor ?? color,
+          data: data,
+          buildValue: buildValue,
+          drawPoints: drawPoints,
+          pointSize: pointSize,
+          shape: shape,
+          valuePosition: valuePosition,
         );
 
-  final List<LineChartValue> data;
-
   final bool drawBorder;
   final PdfColor? borderColor;
   final double borderWidth;
@@ -58,7 +69,7 @@ class BarDataSet extends Dataset {
 
   final Axis axis;
 
-  void _drawSurface(Context context, ChartGrid grid, LineChartValue value) {
+  void _drawSurface(Context context, ChartGrid grid, T value) {
     switch (axis) {
       case Axis.horizontal:
         final y = (grid is CartesianGrid) ? grid.xAxisOffset : 0.0;
@@ -128,4 +139,19 @@ class BarDataSet extends Dataset {
         ..strokePath();
     }
   }
+
+  @override
+  ValuePosition automaticValuePosition(
+    PdfPoint point,
+    PdfPoint size,
+    PdfPoint? previous,
+    PdfPoint? next,
+  ) {
+    final pos = super.automaticValuePosition(point, size, previous, next);
+    if (pos == ValuePosition.right || pos == ValuePosition.left) {
+      return ValuePosition.top;
+    }
+
+    return pos;
+  }
 }

@@ -160,7 +160,9 @@ abstract class Dataset extends Widget {
 
   void paintBackground(Context context) {}
 
-  Widget legendShape() {
+  void paintForeground(Context context) {}
+
+  Widget legendShape(Context context) {
     return Container(
       decoration: BoxDecoration(
         color: color,

@@ -116,5 +116,9 @@ class CartesianGrid extends ChartGrid {
     context.canvas.restoreContext();
     _xAxis.paint(context);
     _yAxis.paint(context);
+
+    for (final dataSet in datasets) {
+      dataSet.paintForeground(context);
+    }
   }
 }

@@ -56,7 +56,7 @@ class ChartLegend extends StatelessWidget {
           width: style.fontSize,
           height: style.fontSize,
           margin: const EdgeInsets.only(right: 5),
-          child: dataset.legendShape(),
+          child: dataset.legendShape(context),
         ),
         Text(
           dataset.legend!,

@@ -16,28 +16,31 @@
 
 import '../../../pdf.dart';
 import '../geometry.dart';
+import '../page.dart';
 import '../widget.dart';
 import 'chart.dart';
 import 'grid_cartesian.dart';
+import 'point_chart.dart';
 
-class LineChartValue extends ChartValue {
-  const LineChartValue(this.x, this.y);
-  final double x;
-  final double y;
-
-  PdfPoint get point => PdfPoint(x, y);
+@Deprecated('Use PointChartValue')
+class LineChartValue extends PointChartValue {
+  const LineChartValue(double x, double y) : super(x, y);
 }
 
-class LineDataSet extends Dataset {
+class LineDataSet<T extends PointChartValue> extends PointDataSet<T> {
   LineDataSet({
-    required this.data,
+    required List<T> data,
     String? legend,
-    this.pointColor,
-    this.pointSize = 3,
+    PdfColor? pointColor,
+    double pointSize = 3,
     PdfColor color = PdfColors.blue,
     this.lineWidth = 2,
     this.drawLine = true,
-    this.drawPoints = true,
+    this.lineColor,
+    bool drawPoints = true,
+    BuildCallback? shape,
+    Widget Function(Context context, T value)? buildValue,
+    ValuePosition valuePosition = ValuePosition.auto,
     this.drawSurface = false,
     this.surfaceOpacity = .2,
     this.surfaceColor,
@@ -46,19 +49,19 @@ class LineDataSet extends Dataset {
   })  : assert(drawLine || drawPoints || drawSurface),
         super(
           legend: legend,
-          color: color,
+          color: pointColor ?? color,
+          data: data,
+          drawPoints: drawPoints,
+          pointSize: pointSize,
+          buildValue: buildValue,
+          shape: shape,
+          valuePosition: valuePosition,
         );
 
-  final List<LineChartValue> data;
-
   final bool drawLine;
-
+  final PdfColor? lineColor;
   final double lineWidth;
 
-  final bool drawPoints;
-  final PdfColor? pointColor;
-  final double pointSize;
-
   final bool drawSurface;
   final PdfColor? surfaceColor;
   final double surfaceOpacity;
@@ -122,13 +125,6 @@ class LineDataSet extends Dataset {
     context.canvas.lineTo(pf.x, y);
   }
 
-  void _drawPoints(Context context, ChartGrid grid) {
-    for (final value in data) {
-      final p = grid.toChart(value.point);
-      context.canvas.drawEllipse(p.x, p.y, pointSize, pointSize);
-    }
-  }
-
   @override
   void paintBackground(Context context) {
     if (data.isEmpty) {
@@ -172,19 +168,46 @@ class LineDataSet extends Dataset {
       _drawLine(context, grid, true);
 
       context.canvas
-        ..setStrokeColor(color)
+        ..setStrokeColor(lineColor ?? color)
         ..setLineWidth(lineWidth)
         ..setLineCap(PdfLineCap.round)
         ..setLineJoin(PdfLineJoin.round)
         ..strokePath();
     }
+  }
 
-    if (drawPoints) {
-      _drawPoints(context, grid);
+  @override
+  ValuePosition automaticValuePosition(
+    PdfPoint point,
+    PdfPoint size,
+    PdfPoint? previous,
+    PdfPoint? next,
+  ) {
+    if (point.y - size.y - delta < box!.bottom) {
+      return ValuePosition.top;
+    }
 
-      context.canvas
-        ..setColor(pointColor ?? color)
-        ..fillPath();
+    if (previous != null &&
+        previous.y > point.y &&
+        next != null &&
+        next.y > point.y) {
+      return ValuePosition.bottom;
+    }
+
+    if (previous != null &&
+        previous.y < point.y &&
+        next != null &&
+        next.y > point.y) {
+      return ValuePosition.left;
+    }
+
+    if (previous != null &&
+        previous.y > point.y &&
+        next != null &&
+        next.y < point.y) {
+      return ValuePosition.right;
     }
+
+    return super.automaticValuePosition(point, size, previous, next);
   }
 }

+/*
+ * Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import '../../../pdf.dart';
+import '../basic.dart';
+import '../geometry.dart';
+import '../page.dart';
+import '../widget.dart';
+import 'chart.dart';
+
+enum ValuePosition { left, top, right, bottom, auto }
+
+class PointChartValue extends ChartValue {
+  const PointChartValue(this.x, this.y);
+  final double x;
+  final double y;
+
+  PdfPoint get point => PdfPoint(x, y);
+}
+
+class PointDataSet<T extends PointChartValue> extends Dataset {
+  PointDataSet({
+    required this.data,
+    String? legend,
+    this.pointSize = 3,
+    PdfColor color = PdfColors.blue,
+    this.drawPoints = true,
+    this.shape,
+    this.buildValue,
+    this.valuePosition = ValuePosition.auto,
+  }) : super(
+          legend: legend,
+          color: color,
+        );
+
+  final List<T> data;
+
+  final bool drawPoints;
+
+  final double pointSize;
+
+  final BuildCallback? shape;
+
+  final Widget Function(Context context, T value)? buildValue;
+
+  final ValuePosition valuePosition;
+
+  double get delta => pointSize * .5;
+
+  @override
+  void layout(Context context, BoxConstraints constraints,
+      {bool parentUsesSize = false}) {
+    box = PdfRect.fromPoints(PdfPoint.zero, constraints.biggest);
+  }
+
+  ValuePosition automaticValuePosition(
+    PdfPoint point,
+    PdfPoint size,
+    PdfPoint? previous,
+    PdfPoint? next,
+  ) {
+    // Usually on top, except on the edges
+
+    if (point.x - size.x / 2 < box!.left) {
+      return ValuePosition.right;
+    }
+
+    if (point.x + size.x / 2 > box!.right) {
+      return ValuePosition.left;
+    }
+
+    if (point.y + size.y + delta > box!.top) {
+      return ValuePosition.bottom;
+    }
+
+    return ValuePosition.top;
+  }
+
+  @override
+  void paintForeground(Context context) {
+    super.paintForeground(context);
+
+    if (data.isEmpty) {
+      return;
+    }
+
+    final grid = Chart.of(context).grid;
+
+    if (drawPoints) {
+      if (shape == null) {
+        for (final value in data) {
+          final p = grid.toChart(value.point);
+          context.canvas.drawEllipse(p.x, p.y, pointSize, pointSize);
+        }
+
+        context.canvas
+          ..setColor(color)
+          ..fillPath();
+      } else {
+        for (final value in data) {
+          final p = grid.toChart(value.point);
+
+          Widget.draw(
+            SizedBox.square(
+              dimension: pointSize * 2,
+              child: shape!(context),
+            ),
+            offset: p,
+            alignment: Alignment.center,
+            context: context,
+          );
+        }
+      }
+    }
+
+    if (buildValue != null) {
+      PdfPoint? previous;
+      var index = 1;
+
+      for (final value in data) {
+        final p = grid.toChart(value.point);
+
+        final size = Widget.measure(
+          buildValue!(context, value),
+          context: context,
+        );
+
+        final PdfPoint offset;
+        var pos = valuePosition;
+        if (pos == ValuePosition.auto) {
+          final next =
+              index < data.length ? grid.toChart(data[index++].point) : null;
+          pos = automaticValuePosition(p, size, previous, next);
+        }
+
+        switch (pos) {
+          case ValuePosition.left:
+            offset = PdfPoint(p.x - size.x / 2 - pointSize - delta, p.y);
+            break;
+          case ValuePosition.top:
+            offset = PdfPoint(p.x, p.y + size.y / 2 + pointSize + delta);
+            break;
+          case ValuePosition.right:
+            offset = PdfPoint(p.x + size.x / 2 + pointSize + delta, p.y);
+            break;
+          case ValuePosition.bottom:
+            offset = PdfPoint(p.x, p.y - size.y / 2 - pointSize - delta);
+            break;
+          case ValuePosition.auto:
+            assert(false, 'We have an issue here');
+            offset = p;
+            break;
+        }
+
+        Widget.draw(
+          buildValue!(context, value),
+          offset: offset,
+          alignment: Alignment.center,
+          context: context,
+        );
+
+        previous = p;
+      }
+    }
+  }
+
+  @override
+  Widget legendShape(Context context) {
+    return shape == null ? super.legendShape(context) : shape!(context);
+  }
+}

@@ -29,6 +29,7 @@ export 'src/widgets/chart/grid_radial.dart';
 export 'src/widgets/chart/legend.dart';
 export 'src/widgets/chart/line_chart.dart';
 export 'src/widgets/chart/pie_chart.dart';
+export 'src/widgets/chart/point_chart.dart';
 export 'src/widgets/clip.dart';
 export 'src/widgets/container.dart';
 export 'src/widgets/content.dart';

@@ -3,7 +3,7 @@ description: A pdf producer for Dart. It can create pdf files for both web or fl
 homepage: https://github.com/DavBfr/dart_pdf/tree/master/pdf
 repository: https://github.com/DavBfr/dart_pdf
 issue_tracker: https://github.com/DavBfr/dart_pdf/issues
-version: 3.7.5
+version: 3.8.0
 
 environment:
   sdk: ">=2.12.0 <3.0.0"

@@ -39,10 +39,10 @@ void main() {
           ),
           datasets: <Dataset>[
             LineDataSet(
-              data: const <LineChartValue>[
-                LineChartValue(1, 1),
-                LineChartValue(2, 3),
-                LineChartValue(3, 7),
+              data: const <PointChartValue>[
+                PointChartValue(1, 1),
+                PointChartValue(2, 3),
+                PointChartValue(3, 7),
               ],
             ),
           ],
@@ -60,10 +60,10 @@ void main() {
           ),
           datasets: <Dataset>[
             LineDataSet(
-              data: const <LineChartValue>[
-                LineChartValue(1, 1),
-                LineChartValue(2, 3),
-                LineChartValue(3, 7),
+              data: const <PointChartValue>[
+                PointChartValue(1, 1),
+                PointChartValue(2, 3),
+                PointChartValue(3, 7),
               ],
               drawLine: false,
             ),
@@ -81,10 +81,10 @@ void main() {
           ),
           datasets: <Dataset>[
             LineDataSet(
-              data: const <LineChartValue>[
-                LineChartValue(1, 1),
-                LineChartValue(2, 3),
-                LineChartValue(3, 7),
+              data: const <PointChartValue>[
+                PointChartValue(1, 1),
+                PointChartValue(2, 3),
+                PointChartValue(3, 7),
               ],
               drawPoints: false,
             ),
@@ -103,10 +103,10 @@ void main() {
           ),
           datasets: <Dataset>[
             LineDataSet(
-              data: const <LineChartValue>[
-                LineChartValue(1, 1),
-                LineChartValue(2, 3),
-                LineChartValue(3, 7),
+              data: const <PointChartValue>[
+                PointChartValue(1, 1),
+                PointChartValue(2, 3),
+                PointChartValue(3, 7),
               ],
               drawLine: false,
               pointColor: PdfColors.red,
@@ -132,10 +132,10 @@ void main() {
             ),
             datasets: <Dataset>[
               LineDataSet(
-                data: const <LineChartValue>[
-                  LineChartValue(1, 1),
-                  LineChartValue(2, 3),
-                  LineChartValue(3, 7),
+                data: const <PointChartValue>[
+                  PointChartValue(1, 1),
+                  PointChartValue(2, 3),
+                  PointChartValue(3, 7),
                 ],
               ),
             ],
@@ -156,10 +156,10 @@ void main() {
             LineDataSet(
               drawPoints: false,
               isCurved: true,
-              data: const <LineChartValue>[
-                LineChartValue(1, 1),
-                LineChartValue(3, 7),
-                LineChartValue(5, 3),
+              data: const <PointChartValue>[
+                PointChartValue(1, 1),
+                PointChartValue(3, 7),
+                PointChartValue(5, 3),
               ],
             ),
           ],
@@ -179,10 +179,10 @@ void main() {
           ),
           datasets: <Dataset>[
             BarDataSet(
-              data: const <LineChartValue>[
-                LineChartValue(1, 1),
-                LineChartValue(2, 3),
-                LineChartValue(3, 7),
+              data: const <PointChartValue>[
+                PointChartValue(1, 1),
+                PointChartValue(2, 3),
+                PointChartValue(3, 7),
               ],
             ),
           ],
@@ -201,10 +201,10 @@ void main() {
           datasets: <Dataset>[
             BarDataSet(
               axis: Axis.vertical,
-              data: const <LineChartValue>[
-                LineChartValue(1, 1),
-                LineChartValue(2, 3),
-                LineChartValue(3, 7),
+              data: const <PointChartValue>[
+                PointChartValue(1, 1),
+                PointChartValue(2, 3),
+                PointChartValue(3, 7),
               ],
             ),
           ],