drop IsEmpty logic as not required

src/SixLabors.Shapes/Size.cs

@@ -13,22 +13,10 @@ namespace SixLabors.Shapes
     /// <summary>
     /// Stores an ordered pair of integers, which specify a height and width.
     /// </summary>
-    /// <remarks>
-    /// This struct is fully mutable. This is done (against the guidelines) for the sake of performance,
-    /// as it avoids the need to create new values for modification operations.
-    /// </remarks>
     public struct Size : IEquatable<Size>
     {
-        /// <summary>
-        /// Represents a <see cref="Size"/> that has Width and Height values set to zero.
-        /// </summary>
-        [EditorBrowsable(EditorBrowsableState.Never)]
-        public static readonly Size Empty = default(Size);
-
         private readonly Vector2 backingVector;
 
-        private readonly bool isSet;
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Size"/> struct.
         /// </summary>
@@ -46,7 +34,6 @@ namespace SixLabors.Shapes
         public Size(Vector2 vector)
         {
             this.backingVector = vector;
-            this.isSet = true;
         }
 
         /// <summary>
@@ -59,12 +46,6 @@ namespace SixLabors.Shapes
         /// </summary>
         public float Height => this.backingVector.Y;
 
-        /// <summary>
-        /// Gets a value indicating whether this <see cref="Size"/> is empty.
-        /// </summary>
-        [EditorBrowsable(EditorBrowsableState.Never)]
-        public bool IsEmpty => this.Equals(Empty);
-
         /// <summary>
         /// Computes the sum of adding two Sizes.
         /// </summary>
@@ -108,12 +89,7 @@ namespace SixLabors.Shapes
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool operator ==(Size left, Size right)
         {
-            if (left.isSet && right.isSet)
-            {
-                return left.backingVector == right.backingVector;
-            }
-
-            return left.isSet == right.isSet;
+            return left.backingVector == right.backingVector;
         }
 
         /// <summary>
@@ -131,12 +107,7 @@ namespace SixLabors.Shapes
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool operator !=(Size left, Size right)
         {
-            if (left.isSet && right.isSet)
-            {
-                return left.backingVector != right.backingVector;
-            }
-
-            return left.isSet != right.isSet;
+            return left.backingVector != right.backingVector;
         }
 
         /// <summary>
@@ -157,11 +128,6 @@ namespace SixLabors.Shapes
         /// <inheritdoc/>
         public override string ToString()
         {
-            if (this.IsEmpty)
-            {
-                return "Size [ Empty ]";
-            }
-
             return $"Size [ Width={this.Width}, Height={this.Height} ]";
         }
 

tests/SixLabors.Shapes.Tests/SizeTests.cs

@@ -8,12 +8,6 @@ namespace SixLabors.Shapes.Tests
 {
     public class SizeTests
     {
-        [Fact]
-        public void EmptyIsDefault()
-        {
-            Assert.Equal(true, Size.Empty.IsEmpty);
-        }
-
         [Fact]
         public void Addition()
         {
@@ -49,20 +43,6 @@ namespace SixLabors.Shapes.Tests
             Assert.True(actual);
         }
 
-        [Fact]
-        public void Equal_Empty()
-        {
-            var actual = default(Size) == Size.Empty;
-            Assert.True(actual);
-        }
-
-        [Fact]
-        public void NotEqual_Empty()
-        {
-            var actual = default(Size) != Size.Empty;
-            Assert.False(actual);
-        }
-
         [Fact]
         public void Equal_False_SameType()
         {
@@ -100,12 +80,6 @@ namespace SixLabors.Shapes.Tests
             Assert.Equal(inst1.GetHashCode(), inst2.GetHashCode());
         }
 
-        [Fact]
-        public void ToString_Empty()
-        {
-            Assert.Equal("Size [ Empty ]", Size.Empty.ToString());
-        }
-
         [Fact]
         public void ToString_Val()
         {