Merge pull request #915 from AvaloniaUI/size-aspect-divide

Added AspectRatio and division to Size.

src/Avalonia.Visuals/Size.cs

@@ -43,6 +43,11 @@ namespace Avalonia
             _height = height;
         }
 
+        /// <summary>
+        /// Gets the aspect ratio of the size.
+        /// </summary>
+        public double AspectRatio => _width / _height;
+
         /// <summary>
         /// Gets the width.
         /// </summary>
@@ -97,6 +102,17 @@ namespace Avalonia
             return new Size(size._width / scale.X, size._height / scale.Y);
         }
 
+        /// <summary>
+        /// Divides a size by another size to produce a scaling factor.
+        /// </summary>
+        /// <param name="left">The first size</param>
+        /// <param name="right">The second size.</param>
+        /// <returns>The scaled size.</returns>
+        public static Vector operator /(Size left, Size right)
+        {
+            return new Vector(left._width / right._width, left._height / right._height);
+        }
+
         /// <summary>
         /// Scales a size.
         /// </summary>

tests/Avalonia.Visuals.UnitTests/Avalonia.Visuals.UnitTests.csproj

@@ -80,6 +80,7 @@
     <Compile Include="Media\FormattedTextTests.cs" />
     <Compile Include="Media\PathMarkupParserTests.cs" />
     <Compile Include="RelativeRectComparer.cs" />
+    <Compile Include="SizeTests.cs" />
     <Compile Include="RectTests.cs" />
     <Compile Include="RelativeRectTests.cs" />
     <Compile Include="ThicknessTests.cs" />

tests/Avalonia.Visuals.UnitTests/SizeTests.cs

@@ -0,0 +1,26 @@
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using Xunit;
+
+namespace Avalonia.Visuals.UnitTests
+{
+    public class SizeTests
+    {
+        [Fact]
+        public void Should_Produce_Correct_Aspect_Ratio()
+        {
+            var result = new Size(3, 2).AspectRatio;
+
+            Assert.Equal(1.5, result);
+        }
+
+        [Fact]
+        public void Dividing_Should_Produce_Scaling_Factor()
+        {
+            var result = new Size(15, 10) / new Size(5, 5);
+
+            Assert.Equal(new Vector(3, 2), result);
+        }
+    }
+}