Use file paths as well as image objects

Author: mattleibow

source/SkiaSharp.Extended/Comparer/SKPixelComparer.cs

@@ -4,6 +4,13 @@ namespace SkiaSharp.Extended
 {
 	public static class SKPixelComparer
 	{
+		public static SKPixelComparisonResult Compare(string firstFilename, string secondFilename)
+		{
+			using var first = SKImage.FromEncodedData(firstFilename);
+			using var second = SKImage.FromEncodedData(secondFilename);
+			return Compare(first, second);
+		}
+
 		public static SKPixelComparisonResult Compare(SKBitmap first, SKBitmap second)
 		{
 			using var firstPixmap = first.PeekPixels();
@@ -55,6 +62,14 @@ public static SKPixelComparisonResult Compare(SKImage first, SKImage second)
 			return new SKPixelComparisonResult(totalPixels, errorPixels, absoluteError);
 		}
 
+		public static SKPixelComparisonResult Compare(string firstFilename, string secondFilename, string maskFilename)
+		{
+			using var first = SKImage.FromEncodedData(firstFilename);
+			using var second = SKImage.FromEncodedData(secondFilename);
+			using var mask = SKImage.FromEncodedData(maskFilename);
+			return Compare(first, second, mask);
+		}
+
 		public static SKPixelComparisonResult Compare(SKBitmap first, SKBitmap second, SKBitmap mask)
 		{
 			using var firstPixmap = first.PeekPixels();
@@ -121,6 +136,13 @@ public static SKPixelComparisonResult Compare(SKImage first, SKImage second, SKI
 			return new SKPixelComparisonResult(totalPixels, errorPixels, absoluteError);
 		}
 
+		public static SKImage GenerateDifferenceMask(string firstFilename, string secondFilename)
+		{
+			using var first = SKImage.FromEncodedData(firstFilename);
+			using var second = SKImage.FromEncodedData(secondFilename);
+			return GenerateDifferenceMask(first, second);
+		}
+
 		public static SKImage GenerateDifferenceMask(SKBitmap first, SKBitmap second)
 		{
 			using var firstPixmap = first.PeekPixels();

tests/SkiaSharp.Extended.Tests/Comparer/SKPixelComparerTest.cs

@@ -85,7 +85,7 @@ public void DifferentPixmapsReportDifferenceCorrectly(uint firstColor, uint seco
 		[InlineData(pngFirst, pngFirst)]
 		[InlineData(jpgSecond, jpgSecond)]
 		[InlineData(pngSecond, pngSecond)]
-		public void SameFilesReportNoDifference(string first, string second)
+		public void SameImagesReportNoDifference(string first, string second)
 		{
 			using var firstImage = SKImage.FromEncodedData(GetImagePath(first));
 			using var secondImage = SKImage.FromEncodedData(GetImagePath(second));
@@ -101,6 +101,18 @@ public void SameFilesReportNoDifference(string first, string second)
 		[InlineData(jpgFirst, jpgSecond, 2259184, 15870, 0.05288166768853464)]
 		[InlineData(pngFirst, pngSecond, 2249290, 12570, 0.041885479700370536)]
 		public void SimilarFilesAreSimilar(string first, string second, int expAbsError, int expPixError, double expPixPercent)
+		{
+			var result = SKPixelComparer.Compare(GetImagePath(first), GetImagePath(second));
+
+			Assert.Equal(expAbsError, result.AbsoluteError);
+			Assert.Equal(expPixError, result.ErrorPixelCount);
+			Assert.Equal(expPixPercent, result.ErrorPixelPercentage);
+		}
+
+		[Theory]
+		[InlineData(jpgFirst, jpgSecond, 2259184, 15870, 0.05288166768853464)]
+		[InlineData(pngFirst, pngSecond, 2249290, 12570, 0.041885479700370536)]
+		public void SimilarImagesAreSimilar(string first, string second, int expAbsError, int expPixError, double expPixPercent)
 		{
 			using var firstImage = SKImage.FromEncodedData(GetImagePath(first));
 			using var secondImage = SKImage.FromEncodedData(GetImagePath(second));
@@ -116,6 +128,18 @@ public void SimilarFilesAreSimilar(string first, string second, int expAbsError,
 		[InlineData(jpgFirst, pngFirst, 884487, 231040, 0.7698664462986164)]
 		[InlineData(jpgSecond, pngSecond, 873399, 221697, 0.7387339055793991)]
 		public void SimilarFilesAreCompressedDifferent(string first, string second, int expAbsError, int expPixError, double expPixPercent)
+		{
+			var result = SKPixelComparer.Compare(GetImagePath(first), GetImagePath(second));
+
+			Assert.Equal(expAbsError, result.AbsoluteError);
+			Assert.Equal(expPixError, result.ErrorPixelCount);
+			Assert.Equal(expPixPercent, result.ErrorPixelPercentage);
+		}
+
+		[Theory]
+		[InlineData(jpgFirst, pngFirst, 884487, 231040, 0.7698664462986164)]
+		[InlineData(jpgSecond, pngSecond, 873399, 221697, 0.7387339055793991)]
+		public void SimilarImagesAreCompressedDifferent(string first, string second, int expAbsError, int expPixError, double expPixPercent)
 		{
 			using var firstImage = SKImage.FromEncodedData(GetImagePath(first));
 			using var secondImage = SKImage.FromEncodedData(GetImagePath(second));