Document data entry classes

lib/src/entry.dart

@@ -1,10 +1,28 @@
 import 'dart:ui';
 
+/// Data object defining a segment in a circular chart.
+///
+/// In radial charts a [CircularSegmentEntry] corresponds to an arc segment of
+/// the current ring, for pie charts it is an individual slice.
+///
+/// The portion of the stack this segment will occupy is calculated from the given
+/// [value], what proportion of a stack this corresponds to depends on the [percentageValues]
+/// property of the chart.
 class CircularSegmentEntry {
   const CircularSegmentEntry(this.value, this.color, {this.rankKey});
 
+  /// The value of this data point, defines the sweep angle of the arc
+  /// that is drawn. If the chart being drawn has [percentageValues] set to false
+  /// then this segment is drawn in proportion to the total value of all segments
+  /// in the stack. Otherwise the value is considered the exact percentage of the
+  /// stack that this segment occupies.
   final double value;
+
+  /// The color drawn in the stack for this segment.
   final Color color;
+
+  /// An optional String key, used when animating charts to preserve semantics when
+  /// transitioning between data points.
   final String rankKey;
 
   String toString() {
@@ -12,9 +30,20 @@ class CircularSegmentEntry {
   }
 }
 
+/// Data object defining a stack in a circular chart.
+///
+/// Each [CircularStackEntry] corresponds to a complete circle in the chart.
+/// For radial charts that is one of the rings, for pie charts it is the whole pie.
+///
+/// A stack is composed of [entries], a List containing 1 or more [CircularSegmentEntries]
+/// and an optional [rankKey] String.
 class CircularStackEntry {
   const CircularStackEntry(this.entries, {this.rankKey});
 
+  /// List of [CircularSegmentEntry]s that make up this stack.
   final List<CircularSegmentEntry> entries;
+
+  /// An optional String key, used when animating charts to preserve semantics when
+  /// transitioning between data points.
   final String rankKey;
 }