Switch default quantizer for the bitmap encoder to Wu-quantizer

brianpopow · brianpopow · commit 33192d396bf3 · 2021-05-05T19:07:07.000+02:00
diff --git a/src/ImageSharp/Formats/Bmp/BmpEncoder.cs b/src/ImageSharp/Formats/Bmp/BmpEncoder.cs
@@ -30,7 +30,7 @@ public sealed class BmpEncoder : IImageEncoder, IBmpEncoderOptions
 
         /// <summary>
         /// Gets or sets the quantizer for reducing the color count for 8-Bit images.
-        /// Defaults to OctreeQuantizer.
+        /// Defaults to Wu Quantizer.
         /// </summary>
         public IQuantizer Quantizer { get; set; }
 
diff --git a/src/ImageSharp/Formats/Bmp/BmpEncoderCore.cs b/src/ImageSharp/Formats/Bmp/BmpEncoderCore.cs
@@ -98,7 +98,7 @@ public BmpEncoderCore(IBmpEncoderOptions options, MemoryAllocator memoryAllocato
             this.memoryAllocator = memoryAllocator;
             this.bitsPerPixel = options.BitsPerPixel;
             this.writeV4Header = options.SupportTransparency;
-            this.quantizer = options.Quantizer ?? KnownQuantizers.Octree;
+            this.quantizer = options.Quantizer ?? KnownQuantizers.Wu;
         }
 
         /// <summary>
diff --git a/src/ImageSharp/Formats/Bmp/IBmpEncoderOptions.cs b/src/ImageSharp/Formats/Bmp/IBmpEncoderOptions.cs
@@ -25,7 +25,6 @@ internal interface IBmpEncoderOptions
 
         /// <summary>
         /// Gets the quantizer for reducing the color count for 8-Bit, 4-Bit, and 1-Bit images.
-        /// Defaults to the Octree Quantizer.
         /// </summary>
         IQuantizer Quantizer { get; }
     }
diff --git a/tests/ImageSharp.Tests/Formats/Bmp/BmpEncoderTests.cs b/tests/ImageSharp.Tests/Formats/Bmp/BmpEncoderTests.cs
@@ -212,11 +212,7 @@ public void Encode_1Bit_WithV3Header_Works<TPixel>(
             // The Magick Reference Decoder can not decode 1-Bit bitmaps, so only execute this on windows.
             if (TestEnvironment.IsWindows)
             {
-                TestBmpEncoderCore(
-                    provider,
-                    bitsPerPixel,
-                    supportTransparency: false,
-                    quantizer: KnownQuantizers.Wu);  // using the wu quantizer, because the octree seems to have problems with just two colors.
+                TestBmpEncoderCore(provider, bitsPerPixel, supportTransparency: false);
             }
         }
 
@@ -230,11 +226,7 @@ public void Encode_1Bit_WithV4Header_Works<TPixel>(
             // The Magick Reference Decoder can not decode 1-Bit bitmaps, so only execute this on windows.
             if (TestEnvironment.IsWindows)
             {
-                TestBmpEncoderCore(
-                    provider,
-                    bitsPerPixel,
-                    supportTransparency: true,
-                    quantizer: KnownQuantizers.Wu); // using the wu quantizer, because the octree seems to have problems with just two colors.
+                TestBmpEncoderCore(provider, bitsPerPixel, supportTransparency: true);
             }
         }
 
@@ -351,7 +343,7 @@ private static void TestBmpEncoderCore<TPixel>(
                 {
                     BitsPerPixel = bitsPerPixel,
                     SupportTransparency = supportTransparency,
-                    Quantizer = quantizer ?? KnownQuantizers.Octree
+                    Quantizer = quantizer ?? KnownQuantizers.Wu
                 };
 
                 // Does DebugSave & load reference CompareToReferenceInput():

Original file line number	Diff line number	Diff line change
`@@ -98,7 +98,7 @@ public BmpEncoderCore(IBmpEncoderOptions options, MemoryAllocator memoryAllocato`
`98`	`98`	`this.memoryAllocator = memoryAllocator;`
`99`	`99`	`this.bitsPerPixel = options.BitsPerPixel;`
`100`	`100`	`this.writeV4Header = options.SupportTransparency;`
`101`		`- this.quantizer = options.Quantizer ?? KnownQuantizers.Octree;`
	`101`	`+ this.quantizer = options.Quantizer ?? KnownQuantizers.Wu;`
`102`	`102`	`}`
`103`	`103`
`104`	`104`	`/// <summary>`
Original file line number	Diff line number	Diff line change
`@@ -25,7 +25,6 @@ internal interface IBmpEncoderOptions`
`25`	`25`
`26`	`26`	`/// <summary>`
`27`	`27`	`/// Gets the quantizer for reducing the color count for 8-Bit, 4-Bit, and 1-Bit images.`
`28`		`- /// Defaults to the Octree Quantizer.`
`29`	`28`	`/// </summary>`
`30`	`29`	`IQuantizer Quantizer { get; }`
`31`	`30`	`}`
Original file line number	Diff line number	Diff line change
`@@ -212,11 +212,7 @@ public void Encode_1Bit_WithV3Header_Works<TPixel>(`
`212`	`212`	`// The Magick Reference Decoder can not decode 1-Bit bitmaps, so only execute this on windows.`
`213`	`213`	`if (TestEnvironment.IsWindows)`
`214`	`214`	`{`
`215`		`- TestBmpEncoderCore(`
`216`		`- provider,`
`217`		`- bitsPerPixel,`
`218`		`- supportTransparency: false,`
`219`		`- quantizer: KnownQuantizers.Wu); // using the wu quantizer, because the octree seems to have problems with just two colors.`
	`215`	`+ TestBmpEncoderCore(provider, bitsPerPixel, supportTransparency: false);`
`220`	`216`	`}`
`221`	`217`	`}`
`222`	`218`
`@@ -230,11 +226,7 @@ public void Encode_1Bit_WithV4Header_Works<TPixel>(`
`230`	`226`	`// The Magick Reference Decoder can not decode 1-Bit bitmaps, so only execute this on windows.`
`231`	`227`	`if (TestEnvironment.IsWindows)`
`232`	`228`	`{`
`233`		`- TestBmpEncoderCore(`
`234`		`- provider,`
`235`		`- bitsPerPixel,`
`236`		`- supportTransparency: true,`
`237`		`- quantizer: KnownQuantizers.Wu); // using the wu quantizer, because the octree seems to have problems with just two colors.`
	`229`	`+ TestBmpEncoderCore(provider, bitsPerPixel, supportTransparency: true);`
`238`	`230`	`}`
`239`	`231`	`}`
`240`	`232`
`@@ -351,7 +343,7 @@ private static void TestBmpEncoderCore<TPixel>(`
`351`	`343`	`{`
`352`	`344`	`BitsPerPixel = bitsPerPixel,`
`353`	`345`	`SupportTransparency = supportTransparency,`
`354`		`- Quantizer = quantizer ?? KnownQuantizers.Octree`
	`346`	`+ Quantizer = quantizer ?? KnownQuantizers.Wu`
`355`	`347`	`};`
`356`	`348`
`357`	`349`	`// Does DebugSave & load reference CompareToReferenceInput():`