Corrected the ToString method of MagickColor for CMYK.

Author: dlemstra

src/Magick.NET/Colors/MagickColor.cs

@@ -478,7 +478,14 @@ public string ToShortString()
         public override string ToString()
         {
             if (IsCmyk)
-                return string.Format(CultureInfo.InvariantCulture, "cmyka({0},{1},{2},{3},{4:0.0###})", R, G, B, K, (double)A / Quantum.Max);
+            {
+                var r = Quantum.ScaleToByte(R);
+                var g = Quantum.ScaleToByte(G);
+                var b = Quantum.ScaleToByte(B);
+                var k = Quantum.ScaleToByte(K);
+
+                return string.Format(CultureInfo.InvariantCulture, "cmyka({0},{1},{2},{3},{4:0.0###})", r, g, b, k, (double)A / Quantum.Max);
+            }
 #if Q8
             return string.Format(CultureInfo.InvariantCulture, "#{0:X2}{1:X2}{2:X2}{3:X2}", R, G, B, A);
 #elif Q16 || Q16HDRI

tests/Magick.NET.Tests/Colors/MagickColorTests/TheToStringMethod.cs

@@ -4,6 +4,16 @@
 using ImageMagick;
 using Xunit;
 
+#if Q8
+using QuantumType = System.Byte;
+#elif Q16
+using QuantumType = System.UInt16;
+#elif Q16HDRI
+using QuantumType = System.Single;
+#else
+#error Not implemented!
+#endif
+
 namespace Magick.NET.Tests
 {
     public partial class MagickColorTests
@@ -24,17 +34,11 @@ public void ShouldReturnTheCorrectString()
             [Fact]
             public void ShouldReturnTheCorrectStringForCmykColor()
             {
-#if Q8
-                var color = new MagickColor(0, Quantum.Max, 0, 0, (System.Byte)(Quantum.Max / 3));
-#elif Q16
-                var color = new MagickColor(0, Quantum.Max, 0, 0, (System.UInt16)(Quantum.Max / 3));
-#else
-                var color = new MagickColor(0, Quantum.Max, 0, 0, (System.Single)(Quantum.Max / 3));
-#endif
-                Assert.Equal("cmyka(0," + Quantum.Max + ",0,0,0.3333)", color.ToString());
+                var color = new MagickColor(0, Quantum.Max, 0, 0, (QuantumType)(Quantum.Max / 3));
+                Assert.Equal("cmyka(0,255,0,0,0.3333)", color.ToString());
 
                 color = new MagickColor(0, Quantum.Max, 0, 0, Quantum.Max);
-                Assert.Equal("cmyka(0," + Quantum.Max + ",0,0,1.0)", color.ToString());
+                Assert.Equal("cmyka(0,255,0,0,1.0)", color.ToString());
             }
         }
     }