Various fixes

- Fix alpha clamping on Resize to prevent bleed.
- Finish Color premultiplication updates


Former-commit-id: e0cc8e3c08b0626fe1a1a7ce4c2f1246c1b912ca
Former-commit-id: 503f9fa8137a2ff561d697bb2a4cdd2071f1728d
Former-commit-id: 51ee649dbfec8fc8cc4db412ac6b743ba2ce991c

README.md

@@ -4,14 +4,40 @@
 
 This is a complete rewrite from the ground up to allow the processing of images without the use of `System.Drawing` using a cross-platform class library. It's still in early stages but progress has been pretty quick.
 
+[![Build status](https://ci.appveyor.com/api/projects/status/8ypr7527dnao04yr/branch/V3?svg=true)](https://ci.appveyor.com/project/JamesSouth/imageprocessor/branch/V3)
+[![Gitter](https://badges.gitter.im/Join Chat.svg)](https://gitter.im/JimBobSquarePants/ImageProcessor?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+
 ###Why am I writing this?
 
-With NETCore there is currently no version of `System.Drawing` to allow continued progress of the existing ImageProcessor library. Progress developing a crossplatform update are restricted to the [CoreFXLab repo](https://github.com/dotnet/corefxlab/tree/master/src/System.Drawing.Graphics) where progress seems to be very slow.
+With NETCore there is currently no version of `System.Drawing` to allow continued progress of the existing ImageProcessor library. Progress developing a cross-platform update are restricted to the [CoreFXLab repo](https://github.com/dotnet/corefxlab/tree/master/src/System.Drawing.Graphics) where progress seems to be very slow.
 
 ###Is this wise?
 
 Honestly... I don't know. I could be writing code that may be suddenly obsolete. There has been little [feedback](https://github.com/dotnet/corefxlab/issues/86#issuecomment-139930600) on questions I've asked but it's a nice learning process if anything and I will definitely be releasing the code for consumption.
 
+### Installation
+At present the code is pre-release but when ready it will be available on [Nuget](http://www.nuget.org). 
+
+**Pre-release downloads**
+
+We already have a [MyGet package repository](https://www.myget.org/F/imageprocessor/api/v3/index.json) - for bleeding-edge / development NuGet releases.
+
+### Manual build
+
+If you prefer, you can compile ImageProcessor yourself (please do and help!), you'll need:
+
+- Visual Studio 2015 (or above)
+- The [Windows 10 development tools](https://dev.windows.com/en-us/downloads) - Click `Get Visual Studio Community`.
+- Dnvm and Dnx installed
+
+To install the last two please see the instructions at the [DotNet documentation](http://dotnet.readthedocs.org/en/latest/getting-started/installing-core-windows.html)
+
+To clone it locally click the "Clone in Windows" button above or run the following git commands.
+
+```bash
+git clone https://github.com/JimBobSquarePants/ImageProcessor
+```
+
 ###What works so far/ What is planned?
 
 - Encoding/decoding of image formats (plugable)
@@ -19,8 +45,8 @@ Honestly... I don't know. I could be writing code that may be suddenly obsolete.
  - [x] bmp (More bmp format saving support required, 24bit just now)
  - [x] png (Need updating for saving indexed support)
  - [x] gif
-- Basic color structs with implicit operators. Vector backed. Need help investigating premultiplication.
- - [x] Color - Float based, No limit to r, g, b, a values allowing for a fuller color range.
+- Basic color structs with implicit operators. Vector backed.
+ - [x] Color - Float based, premultiplied alpha, No limit to r, g, b, a values allowing for a fuller color range.
  - [x] BGRA32
  - [ ] CIE Lab
  - [ ] CIE XYZ
@@ -81,6 +107,7 @@ Honestly... I don't know. I could be writing code that may be suddenly obsolete.
  - [x] Alpha
  - [x] Contrast
  - [x] Invert
+ - [x] BackgroundColor
  - [x] Brightness
  - [x] Saturation
  - [ ] Hue

src/ImageProcessor/Colors/Color.cs

@@ -81,10 +81,13 @@ namespace ImageProcessor
 
             if (hex.Length == 8)
             {
-                this.R = Convert.ToByte(hex.Substring(2, 2), 16) / 255f;
-                this.G = Convert.ToByte(hex.Substring(4, 2), 16) / 255f;
-                this.B = Convert.ToByte(hex.Substring(6, 2), 16) / 255f;
-                this.A = Convert.ToByte(hex.Substring(0, 2), 16) / 255f;
+                float r = Convert.ToByte(hex.Substring(2, 2), 16) / 255f;
+                float g = Convert.ToByte(hex.Substring(4, 2), 16) / 255f;
+                float b = Convert.ToByte(hex.Substring(6, 2), 16) / 255f;
+                float a = Convert.ToByte(hex.Substring(0, 2), 16) / 255f;
+
+                this.backingVector = Color.FromNonPremultiplied(new Color(r, g, b, a)).ToVector4();
+
             }
             else if (hex.Length == 6)
             {
@@ -95,13 +98,13 @@ namespace ImageProcessor
             }
             else
             {
-                string r = char.ToString(hex[0]);
-                string g = char.ToString(hex[1]);
-                string b = char.ToString(hex[2]);
+                string rh = char.ToString(hex[0]);
+                string gh = char.ToString(hex[1]);
+                string bh = char.ToString(hex[2]);
 
-                this.B = Convert.ToByte(b + b, 16) / 255f;
-                this.G = Convert.ToByte(g + g, 16) / 255f;
-                this.R = Convert.ToByte(r + r, 16) / 255f;
+                this.B = Convert.ToByte(bh + bh, 16) / 255f;
+                this.G = Convert.ToByte(gh + gh, 16) / 255f;
+                this.R = Convert.ToByte(rh + rh, 16) / 255f;
                 this.A = 1;
             }
         }
@@ -235,7 +238,7 @@ namespace ImageProcessor
         /// </returns>
         public static implicit operator Color(Bgra32 color)
         {
-            return new Color(color.R / 255f, color.G / 255f, color.B / 255f, color.A / 255f);
+            return Color.FromNonPremultiplied(new Color(color.R / 255f, color.G / 255f, color.B / 255f, color.A / 255f));
         }
 
         /// <summary>
@@ -471,8 +474,12 @@ namespace ImageProcessor
         {
             amount = amount.Clamp(0f, 1f);
 
-            //return (from * (1 - amount)) + (to * amount);
-            return (from * (1 - amount)) + to ;
+            if (to.A < 1)
+            {
+                return (from * (1 - amount)) + to; 
+            }
+
+            return (from * (1 - amount)) + (to * amount);
         }
 
         /// <summary>

src/ImageProcessor/Colors/Formats/Bgra32.cs

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

src/ImageProcessor/Colors/Formats/Hsv.cs

@@ -76,7 +76,7 @@ namespace ImageProcessor
         /// </returns>
         public static implicit operator Hsv(Color color)
         {
-            color = color.Limited;
+            color = Color.ToNonPremultiplied(color.Limited);
             float r = color.R;
             float g = color.G;
             float b = color.B;

src/ImageProcessor/Colors/Formats/YCbCr.cs

@@ -76,7 +76,7 @@ namespace ImageProcessor
         /// </returns>
         public static implicit operator YCbCr(Color color)
         {
-            color = color.Limited;
+            color = Color.ToNonPremultiplied(color.Limited);
             float r = color.R * 255f;
             float g = color.G * 255f;
             float b = color.B * 255f;

src/ImageProcessor/Filters/Alpha.cs

@@ -49,8 +49,9 @@ namespace ImageProcessor.Filters
                         {
                             for (int x = startX; x < endX; x++)
                             {
-                                Color color = source[x, y];
+                                Color color = Color.ToNonPremultiplied(source[x, y]);
                                 color.A = color.A * alpha;
+                                color = Color.FromNonPremultiplied(color);
                                 target[x, y] = color;
                             }
                         }

src/ImageProcessor/Filters/BackgroundColor.cs

@@ -46,8 +46,7 @@ namespace ImageProcessor.Filters
                         {
                             Color color = source[x, y];
 
-                            // TODO: Fix this nonesense.
-                            if (color.A < .9)
+                            if (color.A < 1)
                             {
                                 color = Color.Lerp(color, backgroundColor, .5f);
                             }

src/ImageProcessor/Formats/Bmp/BmpEncoder.cs

@@ -110,9 +110,18 @@ namespace ImageProcessor.Formats
 
                     // Limit the output range and multiply out from our floating point.
                     // Convert back to b-> g-> r-> a order.
-                    writer.Write((byte)(data[offset + 2].Clamp(0, 1) * 255));
-                    writer.Write((byte)(data[offset + 1].Clamp(0, 1) * 255));
-                    writer.Write((byte)(data[offset].Clamp(0, 1) * 255));
+                    // Convert to non-premultiplied color.
+                    float r = data[offset];
+                    float g = data[offset + 1];
+                    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);
+
+                    writer.Write(color.B);
+                    writer.Write(color.G);
+                    writer.Write(color.R);
                 }
 
                 for (int i = 0; i < amount; i++)

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

@@ -79,7 +79,8 @@ namespace ImageProcessor.Formats
                 for (int x = 0; x < width; x++)
                 {
                     // Now I have the pixel, call the FirstPassQuantize function...
-                    this.InitialQuantizePixel(Color.ToNonPremultiplied(source[x, y]));
+                    // Implicit cast to Bgra32 handles premultiplication conversion.
+                    this.InitialQuantizePixel(source[x, y]);
                 }
             }
         }
@@ -106,8 +107,8 @@ namespace ImageProcessor.Formats
             {
                 for (int x = 0; x < width; x++)
                 {
-                    // Implicit cast here from Color.
-                    Bgra32 sourcePixel = Color.ToNonPremultiplied(source[x, y]);
+                    // 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
                     // rather than calculating it again. This is an inexpensive optimization.

src/ImageProcessor/Formats/Jpg/JpegEncoder.cs

@@ -111,7 +111,8 @@ namespace ImageProcessor.Formats
                             float b = sourcePixels[source + 2];
                             float a = sourcePixels[source + 3];
 
-                            Bgra32 color = Color.ToNonPremultiplied(new Color(r, g, b, a));
+                            // Implicit cast to Bgra32 handles premultiplication conversion.
+                            Bgra32 color = new Color(r, g, b, a);
 
                             samples[start] = color.R;
                             samples[start + 1] = color.G;

src/ImageProcessor/Formats/Png/PngEncoder.cs

@@ -326,7 +326,8 @@ namespace ImageProcessor.Formats
                     float b = pixels[pixelOffset + 2];
                     float a = pixels[pixelOffset + 3];
 
-                    Bgra32 color = Color.ToNonPremultiplied(new Color(r, g, b, a));
+                    // Implicit cast to Bgra32 handles premultiplication conversion.
+                    Bgra32 color = new Color(r, g, b, a);
 
                     data[dataOffset] = color.R;
                     data[dataOffset + 1] = color.G;
@@ -342,7 +343,7 @@ namespace ImageProcessor.Formats
                         b = pixels[lastOffset + 2];
                         a = pixels[lastOffset + 3];
 
-                        color = Color.ToNonPremultiplied(new Color(r, g, b, a));
+                        color = new Color(r, g, b, a);
 
                         data[dataOffset] -= color.R;
                         data[dataOffset + 1] -= color.G;

src/ImageProcessor/Samplers/Resize.cs

@@ -17,7 +17,7 @@ namespace ImageProcessor.Samplers
         /// <summary>
         /// The epsilon for comparing floating point numbers.
         /// </summary>
-        private const float Epsilon = 0.00001f;
+        private const float Epsilon = 0.01f;
 
         /// <summary>
         /// The horizontal weights.
@@ -112,6 +112,8 @@ namespace ImageProcessor.Samplers
                                 }
                             }
 
+                            // Ensure are alpha values only reflect possible values to prevent bleed.
+                            destination.A = (float)Math.Round(destination.A, 2);
                             target[x, y] = Color.Compand(destination);
                         }
                     }

src/ImageProcessor/project.json

@@ -2,7 +2,7 @@
   "version": "3.0.0-*",
   "description": "ImageProcessor",
   "authors": [
-    "James Jackson-South"
+    "James Jackson-South and contributors"
   ],
   "tags": [
     "Image Resize Crop Quality Gif Jpg Jpeg Bitmap Png Fluent Animated"
@@ -19,7 +19,7 @@
     "System.Runtime.Extensions": "4.0.10",
     "System.Reflection": "4.0.10",
     "System.IO": "4.0.10",
-    "StyleCop.Analyzers": "1.0.0-beta015",
+    "StyleCop.Analyzers": "1.0.0-beta016",
     "Microsoft.NETCore": "5.0.1-beta-23409",
     "Microsoft.NETCore.Platforms": "1.0.1-beta-23409"
   },

tests/ImageProcessor.Tests/Processors/Filters/FilterTests.cs

@@ -13,33 +13,34 @@ namespace ImageProcessor.Tests
     {
         public static readonly TheoryData<string, IImageProcessor> Filters = new TheoryData<string, IImageProcessor>
         {
-            { "Brightness-50", new Brightness(50) },
-            { "Brightness--50", new Brightness(-50) },
-            { "Contrast-50", new Contrast(50) },
-            { "Contrast--50", new Contrast(-50) },
-            { "Blend", new Blend(new Image(File.OpenRead("TestImages/Formats/Bmp/Car.bmp")),15)},
-            { "Saturation-50", new Saturation(50) },
-            { "Saturation--50", new Saturation(-50) },
-            { "Alpha--50", new Alpha(50) },
-            { "Invert", new Invert() },
-            { "Sepia", new Sepia() },
-            { "BlackWhite", new BlackWhite() },
-            { "Lomograph", new Lomograph() },
-            { "Polaroid", new Polaroid() },
-            { "Kodachrome", new Kodachrome() },
-            { "GreyscaleBt709", new GreyscaleBt709() },
-            { "GreyscaleBt601", new GreyscaleBt601() },
-            { "Kayyali", new Kayyali() },
-            { "Kirsch", new Kirsch() },
-            { "Laplacian3X3", new Laplacian3X3() },
-            { "Laplacian5X5", new Laplacian5X5() },
-            { "LaplacianOfGaussian", new LaplacianOfGaussian() },
-            { "Prewitt", new Prewitt() },
-            { "RobertsCross", new RobertsCross() },
-            { "Scharr", new Scharr() },
-            { "Sobel", new Sobel {Greyscale = true} },
-            { "GuassianBlur", new GuassianBlur(10) },
-            { "GuassianSharpen", new GuassianSharpen(10) }
+            //{ "Brightness-50", new Brightness(50) },
+            //{ "Brightness--50", new Brightness(-50) },
+            //{ "Contrast-50", new Contrast(50) },
+            //{ "Contrast--50", new Contrast(-50) },
+            //{ "BackgroundColor", new BackgroundColor(new Color(243 / 255f, 87 / 255f, 161 / 255f))},
+            { "Blend", new Blend(new Image(File.OpenRead("TestImages/Formats/Bmp/Car.bmp")),50)},
+            //{ "Saturation-50", new Saturation(50) },
+            //{ "Saturation--50", new Saturation(-50) },
+            //{ "Alpha--50", new Alpha(50) },
+            //{ "Invert", new Invert() },
+            //{ "Sepia", new Sepia() },
+            //{ "BlackWhite", new BlackWhite() },
+            //{ "Lomograph", new Lomograph() },
+            //{ "Polaroid", new Polaroid() },
+            //{ "Kodachrome", new Kodachrome() },
+            //{ "GreyscaleBt709", new GreyscaleBt709() },
+            //{ "GreyscaleBt601", new GreyscaleBt601() },
+            //{ "Kayyali", new Kayyali() },
+            //{ "Kirsch", new Kirsch() },
+            //{ "Laplacian3X3", new Laplacian3X3() },
+            //{ "Laplacian5X5", new Laplacian5X5() },
+            //{ "LaplacianOfGaussian", new LaplacianOfGaussian() },
+            //{ "Prewitt", new Prewitt() },
+            //{ "RobertsCross", new RobertsCross() },
+            //{ "Scharr", new Scharr() },
+            //{ "Sobel", new Sobel {Greyscale = true} },
+            //{ "GuassianBlur", new GuassianBlur(10) },
+            //{ "GuassianSharpen", new GuassianSharpen(10) }
         };
 
         [Theory]

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

@@ -44,9 +44,9 @@
         [Fact]
         public void QuantizedImageShouldPreserveMaximumColorPrecision()
         {
-            if (!Directory.Exists("Quantized"))
+            if (!Directory.Exists("TestOutput/Quantized"))
             {
-                Directory.CreateDirectory("Quantized");
+                Directory.CreateDirectory("TestOutput/Quantized");
             }
 
             foreach (string file in Files)
@@ -57,7 +57,7 @@
                     IQuantizer quantizer = new OctreeQuantizer();
                     QuantizedImage quantizedImage = quantizer.Quantize(image);
 
-                    using (FileStream output = File.OpenWrite($"Quantized/{Path.GetFileName(file)}"))
+                    using (FileStream output = File.OpenWrite($"TestOutput/Quantized/{Path.GetFileName(file)}"))
                     {
                         quantizedImage.ToImage().Save(output);
                     }

tests/ImageProcessor.Tests/Processors/ProcessorTestBase.cs

@@ -20,20 +20,20 @@ namespace ImageProcessor.Tests
         public static readonly List<string> Files = new List<string>
         {
             //"TestImages/Formats/Jpg/Backdrop.jpg",
-            //"TestImages/Formats/Jpg/Calliphora.jpg",
-            "TestImages/Formats/Jpg/china.jpg",
+            "TestImages/Formats/Jpg/Calliphora.jpg",
+            //"TestImages/Formats/Jpg/china.jpg",
             //"TestImages/Formats/Jpg/ant.jpg",
             //"TestImages/Formats/Jpg/parachute.jpg",
             //"TestImages/Formats/Jpg/lomo.jpg",
             //"TestImages/Formats/Jpg/shaftesbury.jpg",
             //"TestImages/Formats/Jpg/gamma_dalai_lama_gray.jpg",
             //"TestImages/Formats/Jpg/greyscale.jpg",
-            //"TestImages/Formats/Bmp/Car.bmp",
+            "TestImages/Formats/Bmp/Car.bmp",
             "TestImages/Formats/Png/cballs.png",
-            "TestImages/Formats/Png/blur.png",
+            //"TestImages/Formats/Png/blur.png",
             //"TestImages/Formats/Png/cmyk.png",
             //"TestImages/Formats/Png/gamma-1.0-or-2.2.png",
-            "TestImages/Formats/Png/splash.png",
+            //"TestImages/Formats/Png/splash.png",
             "TestImages/Formats/Gif/leaf.gif",
             //"TestImages/Formats/Gif/ben2.gif",
             //"TestImages/Formats/Gif/rings.gif",

tests/ImageProcessor.Tests/Processors/Samplers/SamplerTests.cs

@@ -4,7 +4,6 @@ namespace ImageProcessor.Tests
     using System.Diagnostics;
     using System.IO;
 
-    using ImageProcessor.Filters;
     using ImageProcessor.Samplers;
 
     using Xunit;
@@ -44,7 +43,7 @@ namespace ImageProcessor.Tests
                 {
                     Stopwatch watch = Stopwatch.StartNew();
                     Image image = new Image(stream);
-                    string filename = Path.GetFileNameWithoutExtension(file) + "-" + name + Path.GetExtension(file);
+                    string filename = Path.GetFileNameWithoutExtension(file) + "-" + name + ".jpg";
                     using (FileStream output = File.OpenWrite($"TestOutput/Resized/{filename}"))
                     {
                         image.Resize(image.Width / 2, image.Height / 2, sampler).Save(output);

tests/ImageProcessor.Tests/project.json

@@ -1,7 +1,7 @@
 {
   "version": "1.0.0-*",
   "description": "ImageProcessor.Tests Class Library",
-  "authors": [ "jeavon" ],
+  "authors": [ "James Jackson-South and contributors" ],
   "tags": [ "" ],
   "projectUrl": "",
   "licenseUrl": "",