Fix CA2225 violations

X10D/src/Drawing/Circle.cs

@@ -162,6 +162,27 @@ public readonly struct Circle : IEquatable<Circle>, IComparable<Circle>, ICompar
         return left.CompareTo(right) >= 0;
     }
 
+    /// <summary>
+    ///     Explicitly converts a <see cref="Circle" /> to a <see cref="CircleF" />.
+    /// </summary>
+    /// <param name="circle">The circle to convert.</param>
+    /// <returns>The converted circle.</returns>
+    public static explicit operator Circle(CircleF circle)
+    {
+        return Circle.FromCircleF(circle);
+    }
+
+    /// <summary>
+    ///     Converts a <see cref="Circle" /> to a <see cref="CircleF" />.
+    /// </summary>
+    /// <param name="circle">The circle to convert.</param>
+    /// <returns>The converted circle.</returns>
+    public static Circle FromCircleF(CircleF circle)
+    {
+        PointF center = circle.Center;
+        return new Circle(new Point((int)center.X, (int)center.Y), (int)circle.Radius);
+    }
+
     /// <summary>
     ///     Compares this instance to another <see cref="Circle" />.
     /// </summary>

X10D/src/Drawing/CircleF.cs

@@ -174,17 +174,6 @@ public readonly struct CircleF : IEquatable<CircleF>, IComparable<CircleF>, ICom
         return left.CompareTo(right) >= 0;
     }
 
-    /// <summary>
-    ///     Explicitly converts a <see cref="Circle" /> to a <see cref="CircleF" />.
-    /// </summary>
-    /// <param name="circle">The circle to convert.</param>
-    /// <returns>The converted circle.</returns>
-    public static explicit operator Circle(CircleF circle)
-    {
-        PointF center = circle.Center;
-        return new Circle(new Point((int)center.X, (int)center.Y), (int)circle.Radius);
-    }
-
     /// <summary>
     ///     Implicitly converts a <see cref="Circle" /> to a <see cref="CircleF" />.
     /// </summary>
@@ -192,7 +181,17 @@ public readonly struct CircleF : IEquatable<CircleF>, IComparable<CircleF>, ICom
     /// <returns>The converted circle.</returns>
     public static implicit operator CircleF(Circle circle)
     {
-        return new CircleF(circle.Center, circle.Radius);
+        return FromCircle(circle);
+    }
+
+    /// <summary>
+    ///     Converts a <see cref="Circle" /> to a <see cref="CircleF" />.
+    /// </summary>
+    /// <param name="circle">The circle to convert.</param>
+    /// <returns>The converted circle.</returns>
+    public static CircleF FromCircle(Circle circle)
+    {
+        return new Circle(circle.Center, circle.Radius);
     }
 
     /// <summary>

X10D/src/Drawing/Ellipse.cs

@@ -132,10 +132,41 @@ public readonly struct Ellipse : IEquatable<Ellipse>
     /// <param name="circle">The circle to convert.</param>
     /// <returns>The converted ellipse.</returns>
     public static implicit operator Ellipse(in Circle circle)
+    {
+        return FromCircle(circle);
+    }
+
+    /// <summary>
+    ///     Explicitly converts an <see cref="EllipseF" /> to an <see cref="Ellipse" />.
+    /// </summary>
+    /// <param name="ellipse">The ellipse to convert.</param>
+    /// <returns>The converted ellipse.</returns>
+    public static explicit operator Ellipse(in EllipseF ellipse)
+    {
+        return FromEllipseF(ellipse);
+    }
+
+    /// <summary>
+    ///     Converts a <see cref="Circle" /> to an <see cref="Ellipse" />.
+    /// </summary>
+    /// <param name="circle">The circle to convert.</param>
+    /// <returns>The converted ellipse.</returns>
+    public static Ellipse FromCircle(in Circle circle)
     {
         return new Ellipse(circle.Center, new Size(circle.Radius, circle.Radius));
     }
 
+    /// <summary>
+    ///     Converts an <see cref="EllipseF" /> to an <see cref="Ellipse" />.
+    /// </summary>
+    /// <param name="ellipse">The ellipse to convert.</param>
+    /// <returns>The converted ellipse.</returns>
+    public static Ellipse FromEllipseF(in EllipseF ellipse)
+    {
+        PointF center = ellipse.Center;
+        return new Ellipse((int)center.X, (int)center.Y, (int)ellipse.HorizontalRadius, (int)ellipse.VerticalRadius);
+    }
+
     /// <inheritdoc />
     public override bool Equals(object? obj)
     {

X10D/src/Drawing/EllipseF.cs

@@ -161,7 +161,7 @@ public readonly struct EllipseF : IEquatable<EllipseF>
     /// <returns>The converted ellipse.</returns>
     public static implicit operator EllipseF(in Circle circle)
     {
-        return new EllipseF(circle.Center, new SizeF(circle.Radius, circle.Radius));
+        return FromCircle(circle);
     }
 
     /// <summary>
@@ -171,7 +171,7 @@ public readonly struct EllipseF : IEquatable<EllipseF>
     /// <returns>The converted ellipse.</returns>
     public static implicit operator EllipseF(in CircleF circle)
     {
-        return new EllipseF(circle.Center, new SizeF(circle.Radius, circle.Radius));
+        return FromCircleF(circle);
     }
 
     /// <summary>
@@ -181,18 +181,37 @@ public readonly struct EllipseF : IEquatable<EllipseF>
     /// <returns>The converted ellipse.</returns>
     public static implicit operator EllipseF(in Ellipse ellipse)
     {
-        return new EllipseF(ellipse.Center, ellipse.Radius);
+        return FromEllipse(ellipse);
     }
 
     /// <summary>
-    ///     Explicitly converts an <see cref="EllipseF" /> to an <see cref="Ellipse" />.
+    ///     Converts a <see cref="Circle" /> to an <see cref="EllipseF" />.
+    /// </summary>
+    /// <param name="circle">The circle to convert.</param>
+    /// <returns>The converted ellipse.</returns>
+    public static EllipseF FromCircle(in Circle circle)
+    {
+        return new EllipseF(circle.Center, new SizeF(circle.Radius, circle.Radius));
+    }
+
+    /// <summary>
+    ///     Converts a <see cref="CircleF" /> to an <see cref="EllipseF" />.
+    /// </summary>
+    /// <param name="circle">The circle to convert.</param>
+    /// <returns>The converted ellipse.</returns>
+    public static EllipseF FromCircleF(in CircleF circle)
+    {
+        return new EllipseF(circle.Center, new SizeF(circle.Radius, circle.Radius));
+    }
+
+    /// <summary>
+    ///     Converts an <see cref="Ellipse" /> to an <see cref="EllipseF" />.
     /// </summary>
     /// <param name="ellipse">The ellipse to convert.</param>
     /// <returns>The converted ellipse.</returns>
-    public static explicit operator Ellipse(in EllipseF ellipse)
+    public static EllipseF FromEllipse(in Ellipse ellipse)
     {
-        PointF center = ellipse.Center;
+        return new EllipseF(ellipse.Center, ellipse.Radius);
-        return new Ellipse((int)center.X, (int)center.Y, (int)ellipse.HorizontalRadius, (int)ellipse.VerticalRadius);
     }
 
     /// <inheritdoc />

X10D/src/Drawing/Line.cs

@@ -1,4 +1,5 @@
 using System.Drawing;
+using System.Numerics;
 
 namespace X10D.Drawing;
 
@@ -152,6 +153,50 @@ public readonly struct Line : IEquatable<Line>, IComparable<Line>, IComparable
         return left.CompareTo(right) >= 0;
     }
 
+    /// <summary>
+    ///     Explicitly converts a <see cref="Line" /> to a <see cref="LineF" />.
+    /// </summary>
+    /// <param name="line">The line to convert.</param>
+    /// <returns>The converted line.</returns>
+    public static explicit operator Line(in LineF line)
+    {
+        return FromLineF(line);
+    }
+
+    /// <summary>
+    ///     Explicitly converts a <see cref="Line3D" /> to a <see cref="Line" />.
+    /// </summary>
+    /// <param name="line">The line to convert.</param>
+    /// <returns>The converted line.</returns>
+    public static explicit operator Line(in Line3D line)
+    {
+        return FromLine3D(line);
+    }
+
+    /// <summary>
+    ///     Converts a <see cref="Line3D" /> to a <see cref="Line" />.
+    /// </summary>
+    /// <param name="line">The line to convert.</param>
+    /// <returns>The converted line.</returns>
+    public static Line FromLine3D(in Line3D line)
+    {
+        Vector3 start = line.Start;
+        Vector3 end = line.End;
+        return new Line(new Point((int)start.X, (int)start.Y), new Point((int)end.X, (int)end.Y));
+    }
+
+    /// <summary>
+    ///     Converts a <see cref="Line" /> to a <see cref="LineF" />.
+    /// </summary>
+    /// <param name="line">The line to convert.</param>
+    /// <returns>The converted line.</returns>
+    public static Line FromLineF(in LineF line)
+    {
+        PointF start = line.Start;
+        PointF end = line.End;
+        return new Line(new Point((int)start.X, (int)start.Y), new Point((int)end.X, (int)end.Y));
+    }
+
     /// <summary>
     ///     Compares this instance to another object.
     /// </summary>

X10D/src/Drawing/Line3D.cs

@@ -158,30 +158,6 @@ public readonly struct Line3D : IEquatable<Line3D>, IComparable<Line3D>, ICompar
         return left.CompareTo(right) >= 0;
     }
 
-    /// <summary>
-    ///     Explicitly converts a <see cref="Line3D" /> to a <see cref="Line" />.
-    /// </summary>
-    /// <param name="line">The line to convert.</param>
-    /// <returns>The converted line.</returns>
-    public static explicit operator Line(in Line3D line)
-    {
-        Vector3 start = line.Start;
-        Vector3 end = line.End;
-        return new Line(new Point((int)start.X, (int)start.Y), new Point((int)end.X, (int)end.Y));
-    }
-
-    /// <summary>
-    ///     Explicitly converts a <see cref="Line3D" /> to a <see cref="LineF" />.
-    /// </summary>
-    /// <param name="line">The line to convert.</param>
-    /// <returns>The converted line.</returns>
-    public static explicit operator LineF(in Line3D line)
-    {
-        Vector3 start = line.Start;
-        Vector3 end = line.End;
-        return new LineF(new PointF(start.X, start.Y), new PointF(end.X, end.Y));
-    }
-
     /// <summary>
     ///     Implicitly converts a <see cref="Line" /> to a <see cref="LineF" />.
     /// </summary>
@@ -189,9 +165,7 @@ public readonly struct Line3D : IEquatable<Line3D>, IComparable<Line3D>, ICompar
     /// <returns>The converted line.</returns>
     public static implicit operator Line3D(in Line line)
     {
-        Point start = line.Start;
+        return FromLine(line);
-        Point end = line.End;
-        return new Line3D(new Vector3(start.X, start.Y, 0), new Vector3(end.X, end.Y, 0));
     }
 
     /// <summary>
@@ -200,6 +174,28 @@ public readonly struct Line3D : IEquatable<Line3D>, IComparable<Line3D>, ICompar
     /// <param name="line">The line to convert.</param>
     /// <returns>The converted line.</returns>
     public static implicit operator Line3D(in LineF line)
+    {
+        return FromLineF(line);
+    }
+
+    /// <summary>
+    ///     Converts a <see cref="Line" /> to a <see cref="LineF" />.
+    /// </summary>
+    /// <param name="line">The line to convert.</param>
+    /// <returns>The converted line.</returns>
+    public static Line3D FromLine(in Line line)
+    {
+        Point start = line.Start;
+        Point end = line.End;
+        return new Line3D(new Vector3(start.X, start.Y, 0), new Vector3(end.X, end.Y, 0));
+    }
+
+    /// <summary>
+    ///     Converts a <see cref="LineF" /> to a <see cref="Line3D" />.
+    /// </summary>
+    /// <param name="line">The line to convert.</param>
+    /// <returns>The converted line.</returns>
+    public static Line3D FromLineF(in LineF line)
     {
         PointF start = line.Start;
         PointF end = line.End;

X10D/src/Drawing/LineF.cs

@@ -164,28 +164,48 @@ public readonly struct LineF : IEquatable<LineF>, IComparable<LineF>, IComparabl
         return left.CompareTo(right) >= 0;
     }
 
-    /// <summary>
-    ///     Explicitly converts a <see cref="Line" /> to a <see cref="LineF" />.
-    /// </summary>
-    /// <param name="line">The line to convert.</param>
-    /// <returns>The converted line.</returns>
-    public static explicit operator Line(in LineF line)
-    {
-        PointF start = line.Start;
-        PointF end = line.End;
-        return new Line(new Point((int)start.X, (int)start.Y), new Point((int)end.X, (int)end.Y));
-    }
-
     /// <summary>
     ///     Implicitly converts a <see cref="Line" /> to a <see cref="LineF" />.
     /// </summary>
     /// <param name="line">The line to convert.</param>
     /// <returns>The converted line.</returns>
     public static implicit operator LineF(in Line line)
+    {
+        return FromLine(line);
+    }
+
+    /// <summary>
+    ///     Explicitly converts a <see cref="Line3D" /> to a <see cref="LineF" />.
+    /// </summary>
+    /// <param name="line">The line to convert.</param>
+    /// <returns>The converted line.</returns>
+    public static explicit operator LineF(in Line3D line)
+    {
+        return FromLine3D(line);
+    }
+
+    /// <summary>
+    ///     Converts a <see cref="Line" /> to a <see cref="LineF" />.
+    /// </summary>
+    /// <param name="line">The line to convert.</param>
+    /// <returns>The converted line.</returns>
+    public static LineF FromLine(in Line line)
     {
         return new LineF(line.Start, line.End);
     }
 
+    /// <summary>
+    ///     Converts a <see cref="Line3D" /> to a <see cref="LineF" />.
+    /// </summary>
+    /// <param name="line">The line to convert.</param>
+    /// <returns>The converted line.</returns>
+    public static LineF FromLine3D(in Line3D line)
+    {
+        Vector3 start = line.Start;
+        Vector3 end = line.End;
+        return new LineF(new PointF(start.X, start.Y), new PointF(end.X, end.Y));
+    }
+
     /// <summary>
     ///     Compares this instance to another object.
     /// </summary>

X10D/src/Drawing/Polygon.cs

@@ -1,4 +1,4 @@
-using System.Drawing;
+using System.Drawing;
 
 namespace X10D.Drawing;
 
@@ -133,6 +133,43 @@ public class Polygon : IEquatable<Polygon>
         return !left.Equals(right);
     }
 
+    /// <summary>
+    ///     Explicitly converts a <see cref="Polygon" /> to a <see cref="PolygonF" />.
+    /// </summary>
+    /// <param name="polygon">The polygon to convert.</param>
+    /// <returns>The converted polygon.</returns>
+    public static explicit operator Polygon?(PolygonF? polygon)
+    {
+        return polygon is null ? null : FromPolygonF(polygon);
+    }
+
+    /// <summary>
+    ///     Explicitly converts a <see cref="Polygon" /> to a <see cref="PolygonF" />.
+    /// </summary>
+    /// <param name="polygon">The polygon to convert.</param>
+    /// <returns>The converted polygon.</returns>
+    /// <exception cref="ArgumentNullException"><paramref name="polygon" /> is <see langword="null" />.</exception>
+    public static Polygon FromPolygonF(PolygonF polygon)
+    {
+#if NET6_0_OR_GREATER
+        ArgumentNullException.ThrowIfNull(polygon);
+#else
+        if (polygon is null)
+        {
+            throw new ArgumentNullException(nameof(polygon));
+        }
+#endif
+
+        var vertices = new List<Point>();
+
+        foreach (PointF vertex in polygon.Vertices)
+        {
+            vertices.Add(new Point((int)vertex.X, (int)vertex.Y));
+        }
+
+        return new Polygon(vertices);
+    }
+
     /// <summary>
     ///     Adds a vertex to this polygon.
     /// </summary>

X10D/src/Drawing/PolygonF.cs

@@ -163,20 +163,13 @@ public class PolygonF
     }
 
     /// <summary>
-    ///     Explicitly converts a <see cref="Polygon" /> to a <see cref="PolygonF" />.
+    ///     Implicitly converts a <see cref="Polygon" /> to a <see cref="PolygonF" />.
     /// </summary>
     /// <param name="polygon">The polygon to convert.</param>
     /// <returns>The converted polygon.</returns>
-    public static explicit operator Polygon(PolygonF polygon)
+    public static implicit operator PolygonF?(Polygon? polygon)
     {
-        var vertices = new List<Point>();
+        return polygon is null ? null : FromPolygon(polygon);
-
-        foreach (PointF vertex in polygon.Vertices)
-        {
-            vertices.Add(new Point((int)vertex.X, (int)vertex.Y));
-        }
-
-        return new Polygon(vertices);
     }
 
     /// <summary>
@@ -184,8 +177,18 @@ public class PolygonF
     /// </summary>
     /// <param name="polygon">The polygon to convert.</param>
     /// <returns>The converted polygon.</returns>
-    public static implicit operator PolygonF(Polygon polygon)
+    /// <exception cref="ArgumentNullException"><paramref name="polygon" /> is <see langword="null" />.</exception>
+    public static PolygonF FromPolygon(Polygon polygon)
     {
+#if NET6_0_OR_GREATER
+        ArgumentNullException.ThrowIfNull(polygon);
+#else
+        if (polygon is null)
+        {
+            throw new ArgumentNullException(nameof(polygon));
+        }
+#endif
+
         var vertices = new List<PointF>();
 
         foreach (Point vertex in polygon.Vertices)

X10D/src/Drawing/Polyhedron.cs

@@ -1,4 +1,4 @@
-using System.Drawing;
+using System.Drawing;
 using System.Numerics;
 
 namespace X10D.Drawing;
@@ -135,10 +135,44 @@ public class Polyhedron : IEquatable<Polyhedron>
     ///     Implicitly converts a <see cref="Polygon" /> to a <see cref="Polyhedron" />.
     /// </summary>
     /// <param name="polygon">The polyhedron to convert.</param>
-    /// <returns>The converted polyhedron.</returns>
+    /// <returns>
-    public static implicit operator Polyhedron(Polygon polygon)
+    ///     The converted polyhedron, or <see langword="null" /> if <paramref name="polygon" /> is <see langword="null" />.
+    /// </returns>
+    public static implicit operator Polyhedron?(Polygon? polygon)
     {
-        List<Vector3> vertices = new List<Vector3>();
+        return polygon is null ? null : FromPolygon(polygon);
+    }
+
+    /// <summary>
+    ///     Implicitly converts a <see cref="PolygonF" /> to a <see cref="Polyhedron" />.
+    /// </summary>
+    /// <param name="polygon">The polyhedron to convert.</param>
+    /// <returns>
+    ///     The converted polyhedron, or <see langword="null" /> if <paramref name="polygon" /> is <see langword="null" />.
+    /// </returns>
+    public static implicit operator Polyhedron?(PolygonF? polygon)
+    {
+        return polygon is null ? null : FromPolygonF(polygon);
+    }
+
+    /// <summary>
+    ///     Converts a <see cref="Polygon" /> to a <see cref="Polyhedron" />.
+    /// </summary>
+    /// <param name="polygon">The polyhedron to convert.</param>
+    /// <returns>The converted polyhedron.</returns>
+    /// <exception cref="ArgumentNullException"><paramref name="polygon" /> is <see langword="null" />.</exception>
+    public static Polyhedron FromPolygon(Polygon polygon)
+    {
+#if NET6_0_OR_GREATER
+        ArgumentNullException.ThrowIfNull(polygon);
+#else
+        if (polygon is null)
+        {
+            throw new ArgumentNullException(nameof(polygon));
+        }
+#endif
+
+        var vertices = new List<Vector3>();
 
         foreach (Point vertex in polygon.Vertices)
         {
@@ -149,13 +183,23 @@ public class Polyhedron : IEquatable<Polyhedron>
     }
 
     /// <summary>
-    ///     Implicitly converts a <see cref="PolygonF" /> to a <see cref="Polyhedron" />.
+    ///     Converts a <see cref="PolygonF" /> to a <see cref="Polyhedron" />.
     /// </summary>
     /// <param name="polygon">The polyhedron to convert.</param>
     /// <returns>The converted polyhedron.</returns>
-    public static implicit operator Polyhedron(PolygonF polygon)
+    /// <exception cref="ArgumentNullException"><paramref name="polygon" /> is <see langword="null" />.</exception>
+    public static Polyhedron FromPolygonF(PolygonF polygon)
     {
-        List<Vector3> vertices = new List<Vector3>();
+#if NET6_0_OR_GREATER
+        ArgumentNullException.ThrowIfNull(polygon);
+#else
+        if (polygon is null)
+        {
+            throw new ArgumentNullException(nameof(polygon));
+        }
+#endif
+
+        var vertices = new List<Vector3>();
 
         foreach (PointF vertex in polygon.Vertices)
         {