Comment and standardize Sector with Arc

src/Avalonia.Controls/Shapes/Arc.cs

@@ -1,8 +1,12 @@
 using System;
 using Avalonia.Media;
+using Avalonia.Utilities;
 
 namespace Avalonia.Controls.Shapes
 {
+    /// <summary>
+    /// Represents a circular or elliptical arc (a segment of a curve).
+    /// </summary>
     public class Arc : Shape
     {
         /// <summary>
@@ -19,8 +23,12 @@ namespace Avalonia.Controls.Shapes
 
         static Arc()
         {
-            StrokeThicknessProperty.OverrideDefaultValue<Arc>(1);
-            AffectsGeometry<Arc>(BoundsProperty, StrokeThicknessProperty, StartAngleProperty, SweepAngleProperty);
+            StrokeThicknessProperty.OverrideDefaultValue<Arc>(1.0d);
+            AffectsGeometry<Arc>(
+                BoundsProperty,
+                StrokeThicknessProperty,
+                StartAngleProperty,
+                SweepAngleProperty);
         }
 
         /// <summary>
@@ -42,10 +50,11 @@ namespace Avalonia.Controls.Shapes
             set => SetValue(SweepAngleProperty, value);
         }
 
+        /// <inheritdoc/>
         protected override Geometry CreateDefiningGeometry()
         {
-            var angle1 = DegreesToRad(StartAngle);
-            var angle2 = angle1 + DegreesToRad(SweepAngle);
+            var angle1 = MathUtilities.Deg2Rad(StartAngle);
+            var angle2 = angle1 + MathUtilities.Deg2Rad(SweepAngle);
 
             var startAngle = Math.Min(angle1, angle2);
             var sweepAngle = Math.Max(angle1, angle2);
@@ -80,24 +89,25 @@ namespace Avalonia.Controls.Shapes
 
                 var arcGeometry = new StreamGeometry();
 
-                using (var ctx = arcGeometry.Open())
+                using (StreamGeometryContext context = arcGeometry.Open())
                 {
-                    ctx.BeginFigure(startPoint, false);
-                    ctx.ArcTo(endPoint, new Size(radiusX, radiusY), angleGap, angleGap >= Math.PI,
+                    context.BeginFigure(startPoint, false);
+                    context.ArcTo(
+                        endPoint,
+                        new Size(radiusX, radiusY),
+                        rotationAngle: angleGap,
+                        isLargeArc: angleGap >= Math.PI,
                         SweepDirection.Clockwise);
-                    ctx.EndFigure(false);
+                    context.EndFigure(false);
                 }
 
                 return arcGeometry;
             }
         }
 
-        static double DegreesToRad(double inAngle) =>
-            inAngle * Math.PI / 180;
+        private static double RadToNormRad(double inAngle) => ((inAngle % (Math.PI * 2)) + (Math.PI * 2)) % (Math.PI * 2);
 
-        static double RadToNormRad(double inAngle) => ((inAngle % (Math.PI * 2)) + (Math.PI * 2)) % (Math.PI * 2);
-
-        static Point GetRingPoint(double radiusX, double radiusY, double centerX, double centerY, double angle) =>
+        private static Point GetRingPoint(double radiusX, double radiusY, double centerX, double centerY, double angle) =>
             new Point((radiusX * Math.Cos(angle)) + centerX, (radiusY * Math.Sin(angle)) + centerY);
     }
 }

src/Avalonia.Controls/Shapes/Sector.cs

@@ -4,45 +4,71 @@ using Avalonia.Utilities;
 
 namespace Avalonia.Controls.Shapes
 {
+    /// <summary>
+    /// Represents a circular or elliptical sector (a pie-shaped closed region of a circle or ellipse).
+    /// </summary>
     public class Sector : Shape
     {
-        public static readonly StyledProperty<double> StartAngleProperty = AvaloniaProperty.Register<Sector, double>(nameof(StartAngle), 0.0d);
-        public static readonly StyledProperty<double> AngleProperty = AvaloniaProperty.Register<Sector, double>(nameof(Angle), 0.0d);
+        /// <summary>
+        /// Defines the <see cref="StartAngle"/> property.
+        /// </summary>
+        public static readonly StyledProperty<double> StartAngleProperty =
+            AvaloniaProperty.Register<Sector, double>(nameof(StartAngle), 0.0d);
 
+        /// <summary>
+        /// Defines the <see cref="SweepAngle"/> property.
+        /// </summary>
+        public static readonly StyledProperty<double> SweepAngleProperty =
+            AvaloniaProperty.Register<Sector, double>(nameof(SweepAngle), 0.0d);
+
+        /// <summary>
+        /// Gets or sets the angle at which the sector's arc starts, in degrees.
+        /// </summary>
         public double StartAngle
         {
             get => GetValue(StartAngleProperty);
             set => SetValue(StartAngleProperty, value);
         }
 
-        public double Angle
+        /// <summary>
+        /// Gets or sets the angle, in degrees, added to the <see cref="StartAngle"/> defining where the sector's arc ends.
+        /// A positive value is clockwise, negative is counter-clockwise.
+        /// </summary>
+        public double SweepAngle
         {
-            get => GetValue(AngleProperty);
-            set => SetValue(AngleProperty, value);
+            get => GetValue(SweepAngleProperty);
+            set => SetValue(SweepAngleProperty, value);
         }
 
         static Sector()
         {
             StrokeThicknessProperty.OverrideDefaultValue<Sector>(1.0d);
-            AffectsGeometry<Sector>(BoundsProperty, StrokeThicknessProperty, StartAngleProperty, AngleProperty);
+            AffectsGeometry<Sector>(
+                BoundsProperty,
+                StrokeThicknessProperty,
+                StartAngleProperty,
+                SweepAngleProperty);
         }
 
+        /// <inheritdoc/>
         protected override Geometry? CreateDefiningGeometry()
         {
             Rect rect = new Rect(Bounds.Size);
             Rect deflatedRect = rect.Deflate(StrokeThickness * 0.5d);
 
-            if (Angle >= 360.0d || Angle <= -360.0d)
+            if (SweepAngle >= 360.0d || SweepAngle <= -360.0d)
             {
                 return new EllipseGeometry(deflatedRect);
             }
 
-            if (Angle == 0.0d)
+            if (SweepAngle == 0.0d)
             {
                 return new StreamGeometry();
             }
 
-            (double startAngle, double endAngle) = MathUtilities.GetMinMaxFromDelta(MathUtilities.Deg2Rad(StartAngle), MathUtilities.Deg2Rad(Angle));
+            (double startAngle, double endAngle) = MathUtilities.GetMinMaxFromDelta(
+                MathUtilities.Deg2Rad(StartAngle),
+                MathUtilities.Deg2Rad(SweepAngle));
 
             Point centre = new Point(rect.Width * 0.5d, rect.Height * 0.5d);
             double radiusX = deflatedRect.Width * 0.5d;
@@ -51,13 +77,19 @@ namespace Avalonia.Controls.Shapes
             Point endCurvePoint = MathUtilities.GetEllipsePoint(centre, radiusX, radiusY, endAngle);
             Size size = new Size(radiusX, radiusY);
 
-            StreamGeometry streamGeometry = new StreamGeometry();
-            using StreamGeometryContext streamGeometryContext = streamGeometry.Open();
-
-            streamGeometryContext.BeginFigure(startCurvePoint, false);
-            streamGeometryContext.ArcTo(endCurvePoint, size, 0.0d, Math.Abs(Angle) > 180.0d, SweepDirection.Clockwise);
-            streamGeometryContext.LineTo(centre);
-            streamGeometryContext.EndFigure(true);
+            var streamGeometry = new StreamGeometry();
+            using (StreamGeometryContext context = streamGeometry.Open())
+            {
+                context.BeginFigure(startCurvePoint, false);
+                context.ArcTo(
+                    endCurvePoint,
+                    size,
+                    rotationAngle: 0.0d,
+                    isLargeArc: Math.Abs(SweepAngle) > 180.0d,
+                    SweepDirection.Clockwise);
+                context.LineTo(centre);
+                context.EndFigure(true);
+            }
 
             return streamGeometry;
         }