Don't adaptively encode indexed pngs

Former-commit-id: fbb4508b15ccb81f78bae6cb0e969e6ee7a34350

src/ImageProcessorCore/Formats/Jpg/JpegDecoderCore.cs.REMOVED.git-id

@@ -1 +0,0 @@
-cee4b682b4cfc0f0cef3cafb5b089c780d1cb4d1

src/ImageProcessorCore/Formats/Png/PngEncoderCore.cs

@@ -346,7 +346,7 @@ namespace ImageProcessorCore.Formats
 
             List<byte> result = new List<byte>();
 
-            foreach (var encodedScanline in filteredScanlines)
+            foreach (byte[] encodedScanline in filteredScanlines)
             {
                 result.AddRange(encodedScanline);
             }
@@ -366,17 +366,25 @@ namespace ImageProcessorCore.Formats
         {
             List<Tuple<byte[], int>> candidates = new List<Tuple<byte[], int>>();
 
-            byte[] sub = SubFilter.Encode(rawScanline, byteCount);
-            candidates.Add(new Tuple<byte[], int>(sub, this.CalculateTotalVariation(sub)));
+            if (this.PngColorType == PngColorType.Palette)
+            {
+                byte[] none = NoneFilter.Encode(rawScanline);
+                candidates.Add(new Tuple<byte[], int>(none, this.CalculateTotalVariation(none)));
+            }
+            else
+            {
+                byte[] sub = SubFilter.Encode(rawScanline, byteCount);
+                candidates.Add(new Tuple<byte[], int>(sub, this.CalculateTotalVariation(sub)));
 
-            byte[] up = UpFilter.Encode(rawScanline, previousScanline);
-            candidates.Add(new Tuple<byte[], int>(up, this.CalculateTotalVariation(up)));
+                byte[] up = UpFilter.Encode(rawScanline, previousScanline);
+                candidates.Add(new Tuple<byte[], int>(up, this.CalculateTotalVariation(up)));
 
-            byte[] average = AverageFilter.Encode(rawScanline, previousScanline, byteCount);
-            candidates.Add(new Tuple<byte[], int>(average, this.CalculateTotalVariation(average)));
+                byte[] average = AverageFilter.Encode(rawScanline, previousScanline, byteCount);
+                candidates.Add(new Tuple<byte[], int>(average, this.CalculateTotalVariation(average)));
 
-            byte[] paeth = PaethFilter.Encode(rawScanline, previousScanline, byteCount);
-            candidates.Add(new Tuple<byte[], int>(paeth, this.CalculateTotalVariation(paeth)));
+                byte[] paeth = PaethFilter.Encode(rawScanline, previousScanline, byteCount);
+                candidates.Add(new Tuple<byte[], int>(paeth, this.CalculateTotalVariation(paeth)));
+            }
 
             int lowestTotalVariation = int.MaxValue;
             int lowestTotalVariationIndex = 0;
@@ -603,7 +611,7 @@ namespace ImageProcessorCore.Formats
         /// <param name="stream">The stream.</param>
         private void WriteDataChunks(Stream stream)
         {
-            byte[] data = this.EncodePixelData();
+            byte[] data =  this.EncodePixelData();
 
             byte[] buffer;
             int bufferLength;

tests/ImageProcessorCore.Tests/TestImages/Formats/Bmp/Car.bmp.REMOVED.git-id

@@ -1 +0,0 @@
-edd8ac1feb2c4649e6f5aa80af8d4cf33642a546

tests/ImageProcessorCore.Tests/TestImages/Formats/Bmp/neg_height.bmp.REMOVED.git-id

@@ -1 +0,0 @@
-8f864b82464c595d7a81087d018db9994506e221

tests/ImageProcessorCore.Tests/TestImages/Formats/Jpg/Calliphora.jpg.REMOVED.git-id

@@ -1 +0,0 @@
-5d446f64d0636f6ad7e9f82625eeff89ef394fe2

tests/ImageProcessorCore.Tests/TestImages/Formats/Jpg/Floorplan.jpeg.REMOVED.git-id

@@ -1 +0,0 @@
-5a1eaf806b7f3793d3db41c85bac6366584bce83

tests/ImageProcessorCore.Tests/TestImages/Formats/Jpg/cmyk.jpg.REMOVED.git-id

@@ -1 +0,0 @@
-30e88773ededd890ad97f0a5cfac372e1af07aa5

tests/ImageProcessorCore.Tests/TestImages/Formats/Jpg/gamma_dalai_lama_gray.jpg.REMOVED.git-id

@@ -1 +0,0 @@
-56cbc3371def2882d1ead5d4d2456550f2b8d72c

tests/ImageProcessorCore.Tests/TestImages/Formats/Png/blur.png.REMOVED.git-id

@@ -1 +0,0 @@
-f3c65955eae84d00c5a0343c7e2aa3610a7d9df7

tests/ImageProcessorCore.Tests/TestImages/Formats/Png/splash.png.REMOVED.git-id

@@ -1 +0,0 @@
-0964ae9744027325bd6a2a19b2247c39f8349ca1