Prefer lowercase enums

lib/src/animated_circular_chart.dart

@@ -17,10 +17,10 @@ enum CircularChartType {
 /// Determines how the ends of a chart's segments should be drawn.
 enum SegmentEdgeStyle {
   /// Segments begin and end with a flat edge.
-  Flat,
+  flat,
 
   /// Segments begin and end with a semi-circle.
-  Round,
+  round,
 }
 
 class AnimatedCircularChart extends StatefulWidget {
@@ -35,7 +35,7 @@ class AnimatedCircularChart extends StatefulWidget {
     this.startAngle = _kStartAngle,
     this.holeLabel,
     this.labelStyle,
-    this.edgeStyle = SegmentEdgeStyle.Flat,
+    this.edgeStyle = SegmentEdgeStyle.flat,
   })  : assert(size != null),
         super(key: key);
 
@@ -102,7 +102,7 @@ class AnimatedCircularChart extends StatefulWidget {
 
   /// The type of segment edges to be drawn.
   ///
-  /// Defaults to [SegmentEdgeStyle.Flat].
+  /// Defaults to [SegmentEdgeStyle.flat].
   final SegmentEdgeStyle edgeStyle;
 
   /// The state from the closest instance of this class that encloses the given context.

lib/src/circular_chart.dart

@@ -12,7 +12,7 @@ class CircularChart {
   CircularChart(
     this.stacks,
     this.chartType, {
-    this.edgeStyle = SegmentEdgeStyle.Flat,
+    this.edgeStyle = SegmentEdgeStyle.flat,
   });
 
   final List<CircularChartStack> stacks;

lib/src/painter.dart

@@ -57,7 +57,7 @@ void _paintChart(Canvas canvas, Size size, CircularChart chart) {
     ..style = chart.chartType == CircularChartType.Radial
         ? PaintingStyle.stroke
         : PaintingStyle.fill
-    ..strokeCap = chart.edgeStyle == SegmentEdgeStyle.Round
+    ..strokeCap = chart.edgeStyle == SegmentEdgeStyle.round
         ? StrokeCap.round
         : StrokeCap.butt;