Fix format conversion output.

Former-commit-id: 8ae3e66a843e57054180b1433b0fca3e9f5e1205
Former-commit-id: 6613571207f92916dd31e60bfbfd29820c194663
Former-commit-id: 865d3eda06966a5a3a1c08744aad6b25cc73e62e

src/ImageProcessor/Colors/Color.cs

@@ -238,7 +238,7 @@ namespace ImageProcessor
         /// </returns>
         public static implicit operator Color(Bgra32 color)
         {
-            return Color.FromNonPremultiplied(new Color(color.R / 255f, color.G / 255f, color.B / 255f, color.A / 255f));
+            return new Color(color.R / 255f, color.G / 255f, color.B / 255f, color.A / 255f);
         }
 
         /// <summary>
@@ -473,7 +473,7 @@ namespace ImageProcessor
         public static Color Lerp(Color from, Color to, float amount)
         {
             amount = amount.Clamp(0f, 1f);
-            
+
             // Premultiplied.
             return (from * (1 - amount)) + to;
         }

src/ImageProcessor/Colors/Formats/Bgra32.cs

@@ -94,7 +94,7 @@ namespace ImageProcessor
         /// </returns>
         public static implicit operator Bgra32(Color color)
         {
-            color = Color.ToNonPremultiplied(color.Limited);
+            color = color.Limited;
             return new Bgra32((255f * color.B).ToByte(), (255f * color.G).ToByte(), (255f * color.R).ToByte(), (255f * color.A).ToByte());
         }
 

src/ImageProcessor/Formats/Bmp/BmpEncoder.cs

@@ -130,8 +130,7 @@ namespace ImageProcessor.Formats
                     float b = data[offset + 2];
                     float a = data[offset + 3];
 
-                    // Implicit cast to Bgra32 handles premultiplication conversion.
-                    Bgra32 color = new Color(r, g, b, a);
+                    Bgra32 color = Color.ToNonPremultiplied(new Color(r, g, b, a));
 
                     if (color.A < this.Threshold)
                     {

src/ImageProcessor/Formats/Gif/GifEncoder.cs

@@ -30,7 +30,7 @@ namespace ImageProcessor.Formats
 
         /// <inheritdoc/>
         public string MimeType => "image/gif";
-        
+
         /// <summary>
         /// Gets or sets the transparency threshold.
         /// </summary>
@@ -137,7 +137,7 @@ namespace ImageProcessor.Formats
         private QuantizedImage WriteColorTable(ImageBase image, Stream stream, int quality, int bitDepth)
         {
             // Quantize the image returning a pallete.
-            IQuantizer quantizer = new OctreeQuantizer(quality.Clamp(1, 255), bitDepth) {Threshold = this.threshold};
+            IQuantizer quantizer = new OctreeQuantizer(quality.Clamp(1, 255), bitDepth) { Threshold = this.threshold };
             QuantizedImage quantizedImage = quantizer.Quantize(image);
 
             // Grab the pallete and write it to the stream.
@@ -151,10 +151,11 @@ namespace ImageProcessor.Formats
             for (int i = 0; i < pixelCount; i++)
             {
                 int offset = i * 3;
-                Bgra32 color = pallete[i];
-                colorTable[offset + 2] = color.B;
+                Bgra32 color = Color.ToNonPremultiplied(pallete[i]);
+
+                colorTable[offset] = color.R;
                 colorTable[offset + 1] = color.G;
-                colorTable[offset + 0] = color.R;
+                colorTable[offset + 2] = color.B;
             }
 
             stream.Write(colorTable, 0, colorTableLength);

src/ImageProcessor/Formats/Gif/Quantizer/QuantizedImage.cs

@@ -75,10 +75,10 @@ namespace ImageProcessor.Formats
             for (int i = 0; i < pixelCount; i++)
             {
                 int offset = i * 4;
-                Bgra32 color = this.Palette[Math.Min(palletCount, this.Pixels[i])];
-                bgraPixels[offset + 0] = color.B;
+                Color color = this.Palette[Math.Min(palletCount, this.Pixels[i])];
+                bgraPixels[offset] = color.R;
                 bgraPixels[offset + 1] = color.G;
-                bgraPixels[offset + 2] = color.R;
+                bgraPixels[offset + 2] = color.B;
                 bgraPixels[offset + 3] = color.A;
             }
 

src/ImageProcessor/Formats/Gif/Quantizer/Quantizer.cs

@@ -79,7 +79,6 @@ namespace ImageProcessor.Formats
                 for (int x = 0; x < width; x++)
                 {
                     // Now I have the pixel, call the FirstPassQuantize function...
-                    // Implicit cast to Bgra32 handles premultiplication conversion.
                     this.InitialQuantizePixel(source[x, y]);
                 }
             }
@@ -107,7 +106,6 @@ namespace ImageProcessor.Formats
             {
                 for (int x = 0; x < width; x++)
                 {
-                    // Implicit cast to Bgra32 handles premultiplication conversion.
                     Bgra32 sourcePixel = source[x, y];
 
                     // Check if this is the same as the last pixel. If so use that value

src/ImageProcessor/Formats/Jpg/JpegEncoder.cs

@@ -125,8 +125,7 @@ namespace ImageProcessor.Formats
                             float b = sourcePixels[source + 2];
                             float a = sourcePixels[source + 3];
 
-                            // Implicit cast to Bgra32 handles premultiplication conversion.
-                            Bgra32 color = new Color(r, g, b, a);
+                            Bgra32 color = Color.ToNonPremultiplied(new Color(r, g, b, a));
 
                             if (color.A < this.Threshold)
                             {

src/ImageProcessor/Formats/Png/PngEncoder.cs

@@ -340,8 +340,7 @@ namespace ImageProcessor.Formats
                     float b = pixels[pixelOffset + 2];
                     float a = pixels[pixelOffset + 3];
 
-                    // Implicit cast to Bgra32 handles premultiplication conversion.
-                    Bgra32 color = new Color(r, g, b, a);
+                    Bgra32 color = Color.ToNonPremultiplied(new Color(r, g, b, a));
 
                     if (color.A < this.Threshold)
                     {
@@ -362,7 +361,7 @@ namespace ImageProcessor.Formats
                         b = pixels[lastOffset + 2];
                         a = pixels[lastOffset + 3];
 
-                        color = new Color(r, g, b, a);
+                        color = Color.ToNonPremultiplied(new Color(r, g, b, a));
 
                         data[dataOffset] -= color.R;
                         data[dataOffset + 1] -= color.G;

tests/ImageProcessor.Tests/Processors/Formats/EncoderDecoderTests.cs

@@ -64,5 +64,42 @@
                 }
             }
         }
+
+        [Fact]
+        public void ImageCanConvertFormat()
+        {
+            if (!Directory.Exists("TestOutput/Format"))
+            {
+                Directory.CreateDirectory("TestOutput/Format");
+            }
+
+            foreach (string file in Files)
+            {
+                using (FileStream stream = File.OpenRead(file))
+                {
+                    Image image = new Image(stream);
+
+                    using (FileStream output = File.OpenWrite($"TestOutput/Format/{Path.GetFileNameWithoutExtension(file)}.gif"))
+                    {
+                        image.SaveAsGif(output);
+                    }
+
+                    using (FileStream output = File.OpenWrite($"TestOutput/Format/{Path.GetFileNameWithoutExtension(file)}.bmp"))
+                    {
+                        image.SaveAsBmp(output);
+                    }
+
+                    using (FileStream output = File.OpenWrite($"TestOutput/Format/{Path.GetFileNameWithoutExtension(file)}.jpg"))
+                    {
+                        image.SaveAsJpeg(output);
+                    }
+
+                    using (FileStream output = File.OpenWrite($"TestOutput/Format/{Path.GetFileNameWithoutExtension(file)}.png"))
+                    {
+                        image.SaveAsPng(output);
+                    }
+                }
+            }
+        }
     }
 }