Merge pull request #125 from SixLabors/js/jpeg-quality

Allow the ability to set the quality of jpegs.

Author: JimBobSquarePants

samples/ImageSharp.Web.Sample/Startup.cs

@@ -58,7 +58,8 @@ public void ConfigureServices(IServiceCollection services)
                 .AddProvider<PhysicalFileSystemProvider>()
                 .AddProcessor<ResizeWebProcessor>()
                 .AddProcessor<FormatWebProcessor>()
-                .AddProcessor<BackgroundColorWebProcessor>();
+                .AddProcessor<BackgroundColorWebProcessor>()
+                .AddProcessor<JpegQualityWebProcessor>();
 
             // Add the default service and options.
             //
@@ -134,7 +135,8 @@ private void ConfigureCustomServicesAndCustomOptions(IServiceCollection services
                 .ClearProcessors()
                 .AddProcessor<ResizeWebProcessor>()
                 .AddProcessor<FormatWebProcessor>()
-                .AddProcessor<BackgroundColorWebProcessor>();
+                .AddProcessor<BackgroundColorWebProcessor>()
+                .AddProcessor<JpegQualityWebProcessor>();
         }
 
         /// <summary>

samples/ImageSharp.Web.Sample/wwwroot/index.html

@@ -128,6 +128,34 @@ <h2>Format</h2>
             </div>
         </section>
         <hr />
+        <section>
+            <h2>Jpeg Quality</h2>
+            <div>
+                <p>
+                    <code>imagesharp-logo.png?width=300&format=jpg&quality=100</code>
+                </p>
+                <p>
+                    <img src="imagesharp-logo.png?width=300&format=jpg&quality=100" />
+                </p>
+            </div>
+            <div>
+                <p>
+                    <code>imagesharp-logo.png?width=300&format=jpg&quality=50</code>
+                </p>
+                <p>
+                    <img src="imagesharp-logo.png?width=300&format=jpg&quality=50" />
+                </p>
+            </div>
+            <div>
+                <p>
+                    <code>imagesharp-logo.png?width=300&format=jpg&quality=1</code>
+                </p>
+                <p>
+                    <img src="imagesharp-logo.png?width=300&format=jpg&quality=1" />
+                </p>
+            </div>
+        </section>
+        <hr />
         <section>
             <h2>Background Color</h2>
             <div>

src/ImageSharp.Web/DependencyInjection/ServiceCollectionExtensions.cs

@@ -67,7 +67,8 @@ private static void AddDefaultServices(
 
             builder.AddProcessor<ResizeWebProcessor>()
                    .AddProcessor<FormatWebProcessor>()
-                   .AddProcessor<BackgroundColorWebProcessor>();
+                   .AddProcessor<BackgroundColorWebProcessor>()
+                   .AddProcessor<JpegQualityWebProcessor>();
 
             builder.AddConverter<IntegralNumberConverter<sbyte>>();
             builder.AddConverter<IntegralNumberConverter<byte>>();

src/ImageSharp.Web/FormattedImage.cs

@@ -3,6 +3,8 @@
 
 using System;
 using System.IO;
+using System.Runtime.CompilerServices;
+using SixLabors.ImageSharp.Advanced;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -11,10 +13,12 @@ namespace SixLabors.ImageSharp.Web
     /// <summary>
     /// A class encapsulating an image with a particular file encoding.
     /// </summary>
-    /// <seealso cref="IDisposable" />
+    /// <seealso cref="IDisposable"/>
     public sealed class FormattedImage : IDisposable
     {
+        private readonly ImageFormatManager imageFormatsManager;
         private IImageFormat format;
+        private IImageEncoder encoder;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="FormattedImage"/> class.
@@ -23,8 +27,9 @@ public sealed class FormattedImage : IDisposable
         /// <param name="format">The format.</param>
         internal FormattedImage(Image<Rgba32> image, IImageFormat format)
         {
-            this.format = format;
             this.Image = image;
+            this.imageFormatsManager = image.GetConfiguration().ImageFormatsManager;
+            this.Format = format;
         }
 
         /// <summary>
@@ -38,7 +43,40 @@ internal FormattedImage(Image<Rgba32> image, IImageFormat format)
         public IImageFormat Format
         {
             get => this.format;
-            set => this.format = value ?? throw new ArgumentNullException(nameof(value));
+            set
+            {
+                if (value is null)
+                {
+                    ThrowNull(nameof(value));
+                }
+
+                this.format = value;
+                this.encoder = this.imageFormatsManager.FindEncoder(value);
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets the encoder.
+        /// </summary>
+        public IImageEncoder Encoder
+        {
+            get => this.encoder;
+            set
+            {
+                if (value is null)
+                {
+                    ThrowNull(nameof(value));
+                }
+
+                // The given type should match the format encoder.
+                IImageEncoder reference = this.imageFormatsManager.FindEncoder(this.Format);
+                if (reference.GetType() != value.GetType())
+                {
+                    ThrowInvalid(nameof(value));
+                }
+
+                this.encoder = value;
+            }
         }
 
         /// <summary>
@@ -54,18 +92,25 @@ public static FormattedImage Load(Configuration configuration, Stream source)
         }
 
         /// <summary>
-        /// Saves the specified destination.
+        /// Saves image to the specified destination stream.
         /// </summary>
-        /// <param name="destination">The destination.</param>
-        public void Save(Stream destination) => this.Image.Save(destination, this.format);
+        /// <param name="destination">The destination stream.</param>
+        public void Save(Stream destination) => this.Image.Save(destination, this.encoder);
 
         /// <summary>
-        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
+        /// Performs application-defined tasks associated with freeing, releasing, or resetting
+        /// unmanaged resources.
         /// </summary>
         public void Dispose()
         {
             this.Image?.Dispose();
             this.Image = null;
         }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static void ThrowNull(string name) => throw new ArgumentNullException(name);
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static void ThrowInvalid(string name) => throw new ArgumentException(name);
     }
 }

src/ImageSharp.Web/Middleware/ImageProcessingContext.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Six Labors.
+// Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
 using System.Collections.Generic;
@@ -18,7 +18,7 @@ public class ImageProcessingContext
         /// <param name="context">The current HTTP request context.</param>
         /// <param name="stream">The stream containing the processed image bytes.</param>
         /// <param name="commands">The parsed collection of processing commands.</param>
-        /// <param name="contentType">The content type for for the processed image..</param>
+        /// <param name="contentType">The content type for the processed image.</param>
         /// <param name="extension">The file extension for the processed image.</param>
         public ImageProcessingContext(
             HttpContext context,
@@ -59,4 +59,4 @@ public ImageProcessingContext(
         /// </summary>
         public string Extension { get; }
     }
-}
+}

src/ImageSharp.Web/Processors/FormatWebProcessor.cs

@@ -56,7 +56,8 @@ public FormattedImage Process(
 
             if (!string.IsNullOrWhiteSpace(extension))
             {
-                IImageFormat format = this.options.Configuration.ImageFormatsManager.FindFormatByFileExtension(extension);
+                IImageFormat format = this.options.Configuration
+                    .ImageFormatsManager.FindFormatByFileExtension(extension);
 
                 if (format != null)
                 {

src/ImageSharp.Web/Processors/JpegQualityWebProcessor.cs

@@ -0,0 +1,60 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.Collections.Generic;
+using System.Globalization;
+using Microsoft.Extensions.Logging;
+using SixLabors.ImageSharp.Advanced;
+using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.Web.Commands;
+
+namespace SixLabors.ImageSharp.Web.Processors
+{
+    /// <summary>
+    /// Allows the setting of quality for the jpeg image format.
+    /// </summary>
+    public class JpegQualityWebProcessor : IImageWebProcessor
+    {
+        /// <summary>
+        /// The command constant for quality.
+        /// </summary>
+        public const string Quality = "quality";
+
+        /// <summary>
+        /// The reusable collection of commands.
+        /// </summary>
+        private static readonly IEnumerable<string> QualityCommands
+            = new[] { Quality };
+
+        /// <inheritdoc/>
+        public IEnumerable<string> Commands { get; } = QualityCommands;
+
+        /// <inheritdoc/>
+        public FormattedImage Process(
+            FormattedImage image,
+            ILogger logger,
+            IDictionary<string, string> commands,
+            CommandParser parser,
+            CultureInfo culture)
+        {
+            if (commands.ContainsKey(Quality) && image.Format is JpegFormat)
+            {
+                var reference =
+                    (JpegEncoder)image.Image
+                    .GetConfiguration()
+                    .ImageFormatsManager
+                    .FindEncoder(image.Format);
+
+                // The encoder clamps any values so no validation is required.
+                int quality = parser.ParseValue<int>(commands.GetValueOrDefault(Quality), culture);
+
+                if (quality != reference.Quality)
+                {
+                    image.Encoder = new JpegEncoder() { Quality = quality, Subsample = reference.Subsample };
+                }
+            }
+
+            return image;
+        }
+    }
+}

tests/ImageSharp.Web.Tests/DependencyInjection/ServiceRegistrationExtensionsTests.cs

@@ -28,6 +28,7 @@ public void DefaultServicesAreRegistered()
             Assert.Contains(services, x => x.ServiceType == typeof(IImageWebProcessor) && x.ImplementationType == typeof(ResizeWebProcessor));
             Assert.Contains(services, x => x.ServiceType == typeof(IImageWebProcessor) && x.ImplementationType == typeof(FormatWebProcessor));
             Assert.Contains(services, x => x.ServiceType == typeof(IImageWebProcessor) && x.ImplementationType == typeof(BackgroundColorWebProcessor));
+            Assert.Contains(services, x => x.ServiceType == typeof(IImageWebProcessor) && x.ImplementationType == typeof(JpegQualityWebProcessor));
             Assert.Contains(services, x => x.ServiceType == typeof(CommandParser));
 
             Assert.Contains(services, x => x.ServiceType == typeof(ICommandConverter) && x.ImplementationType == typeof(IntegralNumberConverter<sbyte>));

tests/ImageSharp.Web.Tests/Processors/FormattedImageTests.cs

@@ -0,0 +1,72 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.Formats.Png;
+using SixLabors.ImageSharp.PixelFormats;
+using Xunit;
+
+namespace SixLabors.ImageSharp.Web.Tests.Processors
+{
+    public class FormattedImageTests
+    {
+        [Fact]
+        public void ConstructorSetsProperties()
+        {
+            using var image = new Image<Rgba32>(1, 1);
+            using var formatted = new FormattedImage(image, JpegFormat.Instance);
+
+            Assert.NotNull(formatted.Image);
+            Assert.Equal(image, formatted.Image);
+
+            Assert.NotNull(formatted.Format);
+            Assert.Equal(JpegFormat.Instance, formatted.Format);
+
+            Assert.NotNull(formatted.Encoder);
+            Assert.Equal(typeof(JpegEncoder), formatted.Encoder.GetType());
+        }
+
+        [Fact]
+        public void CanSetFormat()
+        {
+            using var image = new Image<Rgba32>(1, 1);
+            using var formatted = new FormattedImage(image, JpegFormat.Instance);
+
+            Assert.NotNull(formatted.Format);
+            Assert.Equal(JpegFormat.Instance, formatted.Format);
+
+            Assert.Throws<ArgumentNullException>(() => formatted.Format = null);
+
+            formatted.Format = PngFormat.Instance;
+            Assert.Equal(PngFormat.Instance, formatted.Format);
+            Assert.Equal(typeof(PngEncoder), formatted.Encoder.GetType());
+        }
+
+        [Fact]
+        public void CanSetEncoder()
+        {
+            using var image = new Image<Rgba32>(1, 1);
+            using var formatted = new FormattedImage(image, PngFormat.Instance);
+
+            Assert.NotNull(formatted.Format);
+            Assert.Equal(PngFormat.Instance, formatted.Format);
+
+            Assert.Throws<ArgumentNullException>(() => formatted.Encoder = null);
+            Assert.Throws<ArgumentException>(() => formatted.Encoder = new JpegEncoder());
+
+            formatted.Format = JpegFormat.Instance;
+            Assert.Equal(typeof(JpegEncoder), formatted.Encoder.GetType());
+
+            JpegSubsample current = ((JpegEncoder)formatted.Encoder).Subsample.GetValueOrDefault();
+
+            Assert.Equal(JpegSubsample.Ratio444, current);
+            formatted.Encoder = new JpegEncoder { Subsample = JpegSubsample.Ratio420 };
+
+            JpegSubsample replacement = ((JpegEncoder)formatted.Encoder).Subsample.GetValueOrDefault();
+
+            Assert.NotEqual(current, replacement);
+            Assert.Equal(JpegSubsample.Ratio420, replacement);
+        }
+    }
+}

tests/ImageSharp.Web.Tests/Processors/JpegQualityWebProcessorTests.cs

@@ -0,0 +1,40 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.Collections.Generic;
+using System.Globalization;
+using SixLabors.ImageSharp.Formats.Jpeg;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Web.Commands;
+using SixLabors.ImageSharp.Web.Commands.Converters;
+using SixLabors.ImageSharp.Web.Processors;
+using Xunit;
+
+namespace SixLabors.ImageSharp.Web.Tests.Processors
+{
+    public class JpegQualityWebProcessorTests
+    {
+        [Fact]
+        public void JpegQualityWebProcessor_UpdatesQuality()
+        {
+            var parser = new CommandParser(new[] { new IntegralNumberConverter<int>() });
+            CultureInfo culture = CultureInfo.InvariantCulture;
+
+            var commands = new Dictionary<string, string>
+            {
+                { JpegQualityWebProcessor.Quality, "42" },
+            };
+
+            using var image = new Image<Rgba32>(1, 1);
+            using var formatted = new FormattedImage(image, JpegFormat.Instance);
+            Assert.Equal(JpegFormat.Instance, formatted.Format);
+            Assert.Equal(typeof(JpegEncoder), formatted.Encoder.GetType());
+
+            new JpegQualityWebProcessor()
+                .Process(formatted, null, commands, parser, culture);
+
+            Assert.Equal(JpegFormat.Instance, formatted.Format);
+            Assert.Equal(42, ((JpegEncoder)formatted.Encoder).Quality);
+        }
+    }
+}

tests/ImageSharp.Web.Tests/TestUtilities/AzureBlobStorageCacheTestServerFixture.cs

@@ -54,6 +54,7 @@ protected override void ConfigureServices(IServiceCollection services)
                 {
                     Assert.NotNull(context);
                     Assert.NotNull(context.Format);
+                    Assert.NotNull(context.Encoder);
                     Assert.NotNull(context.Image);
 
                     return onBeforeSaveAsync.Invoke(context);