add ColorTests.cs; improve CompareImages warning

potatoes1286 · potatoes1286 · commit 8ff7d651923c · 2024-10-13T19:40:32.000-04:00
diff --git a/Pinta.Core/Effects/ColorBgra.cs b/Pinta.Core/Effects/ColorBgra.cs
@@ -485,7 +485,7 @@ public static ColorBgra Blend (ReadOnlySpan<ColorBgra> colors)
 	/// <returns>A ColorBgra value in premultiplied alpha form</returns>
 	public readonly ColorBgra ToPremultipliedAlpha () => FromBgra ((byte) (B * A / 255), (byte) (G * A / 255), (byte) (R * A / 255), A);
 
-	public static bool ColorsWithinTolerance (ColorBgra a, ColorBgra b, int tolerance)
+	public static int ColorDifference (ColorBgra a, ColorBgra b)
 	{
 		int diffR = a.R - b.R;
 		int diffG = a.G - b.G;
@@ -498,10 +498,11 @@ public static bool ColorsWithinTolerance (ColorBgra a, ColorBgra b, int toleranc
 		int summandA = diffA * diffA;
 
 		int sum = summandR + summandG + summandB + summandA;
-
-		return sum <= tolerance * tolerance * 4;
+		return sum;
 	}
 
+	public static bool ColorsWithinTolerance (ColorBgra a, ColorBgra b, int tolerance) => ColorDifference (a, b) <= tolerance * tolerance * 4;
+
 	/// <summary>
 	/// Brings the color channels from premultiplied alpha in straight alpha form.
 	/// This is required for direct memory manipulation when reading from Cairo surfaces
diff --git a/tests/Pinta.Core.Tests/ColorTests.cs b/tests/Pinta.Core.Tests/ColorTests.cs
@@ -0,0 +1,46 @@
+using System;
+using Gtk;
+using NUnit.Framework;
+using Pango;
+using Color = Cairo.Color;
+
+namespace Pinta.Core.Tests;
+
+[TestFixture]
+internal sealed class ColorTests
+{
+	[TestCase (1, 0, 0, 0, 1, 1)]
+	[TestCase (0, 1, 0, 120, 1, 1)]
+	[TestCase (0, 0, 1, 240, 1, 1)]
+	[TestCase (0, 0.5, 1, 210, 1, 1)]
+	[TestCase (0.2, 0.5, 0.25, 130, 0.6, 0.5)]
+	public void ColorToHsv (double r, double g, double b, double h, double s, double v)
+	{
+		Color c = new (r, g, b);
+		HsvColor hsv = c.ToHsv ();
+		Assert.That (hsv, Is.EqualTo (new HsvColor (h, s, v)));
+		Color c2 = hsv.ToColor ();
+		// assert reversibility; color > hsv > color retains same info
+		// floating point rounding
+		c2 = new (Math.Round (c2.R, 4), Math.Round (c2.G, 4), Math.Round (c2.B, 4));
+		Assert.That (c2, Is.EqualTo (c));
+	}
+
+	[TestCase ("FFFFFF", 1, 1, 1, 1)]
+	[TestCase ("FFFF", 1, 1, 1, 1)]
+	[TestCase ("FFF", 1, 1, 1, 1)]
+	[TestCase ("#FFFFFF", 1, 1, 1, 1)]
+	[TestCase ("FFFF", 1, 1, 1, 1)]
+	[TestCase ("#FFF", 1, 1, 1, 1)]
+	[TestCase ("CC33AA99", 0.8, 0.2, 0.6667, 0.6)]
+	[TestCase ("#CC33AA99", 0.8, 0.2, 0.6667, 0.6)]
+	[TestCase ("C3A9", 0.8, 0.2, 0.6667, 0.6)]
+	[TestCase ("C3A", 0.8, 0.2, 0.6667, 1)]
+	public void Hex (string hex, double r, double g, double b, double a)
+	{
+		var hc = Color.FromHex (hex)!.Value;
+		hc = new (Math.Round (hc.R, 4), Math.Round (hc.G, 4), Math.Round (hc.B, 4));
+		var c = new Color (r, g, b);
+		Assert.That (hc, Is.EqualTo (c));
+	}
+}
diff --git a/tests/Pinta.Effects.Tests/Utilities.cs b/tests/Pinta.Effects.Tests/Utilities.cs
@@ -55,8 +55,9 @@ public static void CompareImages (ImageSurface result, ImageSurface expected, in
 				++diffs;
 
 				// Display info about the first few failures.
+
 				if (diffs <= 10)
-					Assert.Warn ($"Difference at pixel {i}, got {result_pixels[i]} vs {expected_pixels[i]}");
+					Assert.Warn ($"Difference at pixel {i}, got {result_pixels[i]} vs {expected_pixels[i]}, diff. of {ColorBgra.ColorDifference (result_pixels[i], expected_pixels[i])}");
 			}
 		}
 

Original file line number	Diff line number	Diff line change
`@@ -55,8 +55,9 @@ public static void CompareImages (ImageSurface result, ImageSurface expected, in`
`55`	`55`	`++diffs;`
`56`	`56`
`57`	`57`	`// Display info about the first few failures.`
	`58`	`+`
`58`	`59`	`if (diffs <= 10)`
`59`		`- Assert.Warn ($"Difference at pixel {i}, got {result_pixels[i]} vs {expected_pixels[i]}");`
	`60`	`+ Assert.Warn ($"Difference at pixel {i}, got {result_pixels[i]} vs {expected_pixels[i]}, diff. of {ColorBgra.ColorDifference (result_pixels[i], expected_pixels[i])}");`
`60`	`61`	`}`
`61`	`62`	`}`
`62`	`63`