GitHub Sync (google#9)

* Added basic pie chart rendering. Animation and slice labels are not currently supported.

PiperOrigin-RevId: 189268892

* Update gallery formatting.

PiperOrigin-RevId: 189409440

charts_common/lib/common.dart

@@ -24,7 +24,8 @@ export 'src/chart/common/behavior/zoom/pan_and_zoom_behavior.dart'
 export 'src/chart/common/behavior/zoom/pan_behavior.dart' show PanBehavior;
 export 'src/chart/common/chart_canvas.dart' show ChartCanvas, FillPatternType;
 export 'src/chart/common/base_chart.dart' show BaseChart, LifecycleListener;
-export 'src/chart/common/canvas_shapes.dart' show CanvasBarStack, CanvasRect;
+export 'src/chart/common/canvas_shapes.dart'
+    show CanvasBarStack, CanvasPie, CanvasPieSlice, CanvasRect;
 export 'src/chart/common/chart_context.dart' show ChartContext;
 export 'src/chart/common/series_renderer.dart' show SeriesRenderer;
 export 'src/chart/common/series_renderer_config.dart'
@@ -80,4 +81,7 @@ export 'src/chart/cartesian/cartesian_renderer.dart' show BaseCartesianRenderer;
 export 'src/chart/line/line_chart.dart' show LineChart;
 export 'src/chart/line/line_renderer.dart' show LineRenderer;
 export 'src/chart/line/line_renderer_config.dart' show LineRendererConfig;
+export 'src/chart/pie/arc_renderer.dart' show ArcRenderer;
+export 'src/chart/pie/arc_renderer_config.dart' show ArcRendererConfig;
+export 'src/chart/pie/pie_chart.dart' show PieChart;
 export 'src/chart/time_series/time_series_chart.dart' show TimeSeriesChart;

charts_common/lib/src/chart/common/canvas_shapes.dart

@@ -13,7 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import 'dart:math' show Rectangle, min, max;
+import 'dart:math' show Rectangle, min, max, Point;
 import 'chart_canvas.dart' show FillPatternType;
 import '../../common/color.dart' show Color;
 
@@ -89,3 +89,25 @@ class CanvasBarStack {
     this.fullStackRect,
   });
 }
+
+/// A list of [CanvasPieSlice]s to be painted by [ChartCanvas].
+class CanvasPie {
+  final List<CanvasPieSlice> slices;
+  Point center;
+  double radius;
+  double innerRadius;
+  final Color stroke;
+  double strokeWidthPx;
+
+  CanvasPie(this.slices, this.center, this.radius, this.innerRadius,
+      {this.stroke, this.strokeWidthPx = 0.0});
+}
+
+/// A circle sector to be painted by [ChartCanvas].
+class CanvasPieSlice {
+  double startAngle;
+  double endAngle;
+  Color fill;
+
+  CanvasPieSlice(this.startAngle, this.endAngle, {this.fill});
+}

charts_common/lib/src/chart/common/chart_canvas.dart

@@ -14,7 +14,7 @@
 // limitations under the License.
 
 import 'dart:math' show Point, Rectangle;
-import 'canvas_shapes.dart' show CanvasBarStack;
+import 'canvas_shapes.dart' show CanvasBarStack, CanvasPie;
 import '../../common/color.dart' show Color;
 import '../../common/text_element.dart' show TextElement;
 
@@ -23,6 +23,23 @@ abstract class ChartCanvas {
   /// or null when we believe rendering is complete.
   set drawingView(String viewName);
 
+  /// Renders a sector of a circle, with an optional hole in the center.
+  ///
+  /// [center] The x, y coordinates of the circle's center.
+  /// [radius] The radius of the circle.
+  /// [innerRadius] Optional radius of a hole in the center of the circle that
+  ///     should not be filled in as part of the sector.
+  /// [startAngle] The angle at which the arc starts, measured clockwise from
+  ///     the positive x axis and expressed in radians
+  /// [endAngle] The angle at which the arc ends, measured clockwise from the
+  ///     positive x axis and expressed in radians.
+  /// [fill] Fill color for the sector.
+  /// [stroke] Stroke color of the arc and radius lines.
+  /// [strokeWidthPx] Stroke width of the arc and radius lines.
+  void drawCircleSector(Point center, double radius, double innerRadius,
+      double startAngle, double endAngle,
+      {Color fill, Color stroke, double strokeWidthPx});
+
   /// Renders a simple line.
   ///
   /// [dashPattern] controls the pattern of dashes and gaps in a line. It is a
@@ -38,6 +55,9 @@ abstract class ChartCanvas {
       double strokeWidthPx,
       List<int> dashPattern});
 
+  /// Renders a pie, with an optional hole in the center.
+  void drawPie(CanvasPie canvasPie);
+
   /// Renders a simple point.
   void drawPoint({Point point, Color fill, double radius});