Initial commit

lib/src/circular_chart.dart

@@ -0,0 +1,65 @@
+import 'package:flutter/animation.dart';
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_circular_chart/src/animated_circular_chart.dart';
+import 'package:flutter_circular_chart/src/entry.dart';
+import 'package:flutter_circular_chart/src/stack.dart';
+import 'package:flutter_circular_chart/src/tween.dart';
+
+class CircularChart {
+  static const double _kStackWidthFraction = 0.75;
+
+  CircularChart(this.stacks, this.chartType);
+
+  factory CircularChart.empty({@required CircularChartType chartType}) {
+    return new CircularChart(<CircularChartStack>[], chartType);
+  }
+
+  final List<CircularChartStack> stacks;
+  final CircularChartType chartType;
+
+  factory CircularChart.fromData({
+    @required Size size,
+    @required List<CircularStackEntry> data,
+    @required CircularChartType chartType,
+    @required bool percentageValues,
+    @required double startAngle,
+    Map<String, int> stackRanks,
+    Map<String, int> entryRanks,
+    double holeRadius,
+  }) {
+    final double _holeRadius = holeRadius ?? size.width / (2 + data.length);
+    final double stackDistance =
+        (size.width / 2 - _holeRadius) / (2 + data.length);
+    final double stackWidth = stackDistance * _kStackWidthFraction;
+    final double startRadius = stackDistance + _holeRadius;
+
+    List<CircularChartStack> stacks = new List<CircularChartStack>.generate(
+      data.length,
+      (i) => new CircularChartStack.fromData(
+            stackRanks[data[i].rankKey] ?? i,
+            data[i].entries,
+            entryRanks,
+            percentageValues,
+            startRadius + i * stackDistance,
+            stackWidth,
+            startAngle,
+          ),
+    );
+
+    return new CircularChart(stacks, chartType);
+  }
+}
+
+class CircularChartTween extends Tween<CircularChart> {
+  CircularChartTween(CircularChart begin, CircularChart end)
+      : _stacksTween =
+            new MergeTween<CircularChartStack>(begin.stacks, end.stacks),
+        super(begin: begin, end: end);
+
+  final MergeTween<CircularChartStack> _stacksTween;
+
+  @override
+  CircularChart lerp(double t) =>
+      new CircularChart(_stacksTween.lerp(t), begin.chartType);
+}