Add Color.ToHex() (#6272)

* Updated Color to have ToHex() method. Created Unit tests to ensure method is working as expected.

* Updated ToHex() use uint values. Updated unit tests for ToHex.
fixes #6003

diff --git a/Xamarin.Forms.Core.UnitTests/ColorUnitTests.cs b/Xamarin.Forms.Core.UnitTests/ColorUnitTests.cs
index 8668e5b..e217f5a 100644 (file)
--- a/Xamarin.Forms.Core.UnitTests/ColorUnitTests.cs
+++ b/Xamarin.Forms.Core.UnitTests/ColorUnitTests.cs
@@ -225,6 +225,23 @@ namespace Xamarin.Forms.Core.UnitTests
                }
 
                [Test]
+               public void TestToHex()
+               {
+                       var colorRgb = Color.FromRgb(138, 43, 226);
+                       Assert.AreEqual(Color.FromHex(colorRgb.ToHex()), colorRgb);
+                       var colorRgba = Color.FromRgba(138, 43, 226,.2);
+                       Assert.AreEqual(Color.FromHex(colorRgba.ToHex()), colorRgba);
+                       var colorHsl = Color.FromHsla(240, 1, 1);       
+                       Assert.AreEqual(Color.FromHex(colorHsl.ToHex()),colorHsl);
+                       var colorHsla = Color.FromHsla(240, 1, 1,.1);
+                       var hexFromHsla = Color.FromHex(colorHsla.ToHex());
+                       Assert.That(hexFromHsla.A, Is.EqualTo(colorHsla.A).Within(0.002));
+                       Assert.That(hexFromHsla.R, Is.EqualTo(colorHsla.R).Within(0.001));
+                       Assert.That(hexFromHsla.G, Is.EqualTo(colorHsla.G).Within(0.001));
+                       Assert.That(hexFromHsla.B, Is.EqualTo(colorHsla.B).Within(0.001));
+               }
+
+               [Test]
                public void FromRGBDouble ()
                {
                        var color = Color.FromRgb (0.2, 0.3, 0.4);

diff --git a/Xamarin.Forms.Core/Color.cs b/Xamarin.Forms.Core/Color.cs
index 305d833..c52ae6d 100644 (file)
--- a/Xamarin.Forms.Core/Color.cs
+++ b/Xamarin.Forms.Core/Color.cs
@@ -301,6 +301,15 @@ namespace Xamarin.Forms
                        return string.Format(CultureInfo.InvariantCulture, "[Color: A={0}, R={1}, G={2}, B={3}, Hue={4}, Saturation={5}, Luminosity={6}]", A, R, G, B, Hue, Saturation, Luminosity);
                }
 
+               public string ToHex()
+               {
+                       var red = (uint)(R * 255);
+                       var green = (uint)(G * 255);
+                       var blue = (uint)(B * 255);
+                       var alpha = (uint)(A * 255);
+                       return $"#{alpha:X2}{red:X2}{green:X2}{blue:X2}";
+               }
+
                static uint ToHex (char c)
                {
                        ushort x = (ushort)c;
@@ -311,7 +320,7 @@ namespace Xamarin.Forms
                        if (x >= 'a' && x <= 'f')
                                return (uint)(x - 'a' + 10);
                        return 0;
-               }
+               } 
 
                static uint ToHexD (char c)
                {