Max Katz
5 years ago
committed by
GitHub
GitHub
32 changed files with 837 additions and 284 deletions
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using System; |
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using Avalonia.Media; |
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namespace Avalonia.Controls.Shapes |
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{ |
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public class Arc : Shape |
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{ |
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/// <summary>
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/// Defines the <see cref="StartAngle"/> property.
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/// </summary>
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public static readonly StyledProperty<double> StartAngleProperty = |
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AvaloniaProperty.Register<Arc, double>(nameof(StartAngle), 0.0); |
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/// <summary>
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/// Defines the <see cref="SweepAngle"/> property.
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/// </summary>
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public static readonly StyledProperty<double> SweepAngleProperty = |
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AvaloniaProperty.Register<Arc, double>(nameof(SweepAngle), 0.0); |
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static Arc() |
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{ |
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StrokeThicknessProperty.OverrideDefaultValue<Arc>(1); |
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AffectsGeometry<Arc>(BoundsProperty, StrokeThicknessProperty, StartAngleProperty, SweepAngleProperty); |
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} |
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/// <summary>
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/// Gets or sets the angle at which the arc starts, in degrees.
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/// </summary>
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public double StartAngle |
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{ |
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get => GetValue(StartAngleProperty); |
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set => SetValue(StartAngleProperty, value); |
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} |
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/// <summary>
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/// Gets or sets the angle, in degrees, added to the <see cref="StartAngle"/> defining where the arc ends.
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/// A positive value is clockwise, negative is counter-clockwise.
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/// </summary>
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public double SweepAngle |
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{ |
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get => GetValue(SweepAngleProperty); |
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set => SetValue(SweepAngleProperty, value); |
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} |
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protected override Geometry CreateDefiningGeometry() |
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{ |
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var angle1 = DegreesToRad(StartAngle); |
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var angle2 = angle1 + DegreesToRad(SweepAngle); |
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var startAngle = Math.Min(angle1, angle2); |
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var sweepAngle = Math.Max(angle1, angle2); |
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var normStart = RadToNormRad(startAngle); |
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var normEnd = RadToNormRad(sweepAngle); |
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var rect = new Rect(Bounds.Size); |
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if ((normStart == normEnd) && (startAngle != sweepAngle)) // Complete ring.
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{ |
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return new EllipseGeometry(rect.Deflate(StrokeThickness / 2)); |
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} |
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else if (SweepAngle == 0) |
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{ |
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return new StreamGeometry(); |
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} |
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else // Partial arc.
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{ |
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var deflatedRect = rect.Deflate(StrokeThickness / 2); |
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var centerX = rect.Center.X; |
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var centerY = rect.Center.Y; |
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var radiusX = deflatedRect.Width / 2; |
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var radiusY = deflatedRect.Height / 2; |
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var angleGap = RadToNormRad(sweepAngle - startAngle); |
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var startPoint = GetRingPoint(radiusX, radiusY, centerX, centerY, startAngle); |
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var endPoint = GetRingPoint(radiusX, radiusY, centerX, centerY, sweepAngle); |
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var arcGeometry = new StreamGeometry(); |
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using (var ctx = arcGeometry.Open()) |
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{ |
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ctx.BeginFigure(startPoint, false); |
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ctx.ArcTo(endPoint, new Size(radiusX, radiusY), angleGap, angleGap >= Math.PI, |
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SweepDirection.Clockwise); |
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ctx.EndFigure(false); |
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} |
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return arcGeometry; |
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} |
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} |
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static double DegreesToRad(double inAngle) => |
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inAngle * Math.PI / 180; |
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static double RadToNormRad(double inAngle) => ((inAngle % (Math.PI * 2)) + (Math.PI * 2)) % (Math.PI * 2); |
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static Point GetRingPoint(double radiusX, double radiusY, double centerX, double centerY, double angle) => |
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new Point((radiusX * Math.Cos(angle)) + centerX, (radiusY * Math.Sin(angle)) + centerY); |
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} |
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} |
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