expose TextAlignment for text drawing

src/ImageSharp.Drawing/ImageSharp.Drawing.csproj

@@ -39,8 +39,8 @@
     <PackageReference Include="StyleCop.Analyzers" Version="1.1.0-beta001">
       <PrivateAssets>All</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="SixLabors.Fonts" Version="0.1.0-alpha0008" />
-    <PackageReference Include="SixLabors.Shapes" Version="0.1.0-alpha0011" />
+    <PackageReference Include="SixLabors.Fonts" Version="0.1.0-alpha0010" />
+    <PackageReference Include="SixLabors.Shapes" Version="0.1.0-alpha0012" />
   </ItemGroup>
   <PropertyGroup>
     <CodeAnalysisRuleSet>..\..\ImageSharp.ruleset</CodeAnalysisRuleSet>

src/ImageSharp.Drawing/Text/DrawText.cs

@@ -181,7 +181,8 @@ namespace ImageSharp
             {
                 ApplyKerning = options.ApplyKerning,
                 TabWidth = options.TabWidth,
-                WrappingWidth = options.WrapTextWidth
+                WrappingWidth = options.WrapTextWidth,
+                Alignment = options.TextAlignment
             };
 
             renderer.RenderText(text, style);

src/ImageSharp.Drawing/Text/TextGraphicsOptions.cs

@@ -2,9 +2,11 @@
 // Copyright (c) James Jackson-South and contributors.
 // Licensed under the Apache License, Version 2.0.
 // </copyright>
-
 namespace ImageSharp.Drawing
 {
+    using ImageSharp.PixelFormats;
+    using SixLabors.Fonts;
+
     /// <summary>
     /// Options for influencing the drawing functions.
     /// </summary>
@@ -15,50 +17,94 @@ namespace ImageSharp.Drawing
         /// </summary>
         public static readonly TextGraphicsOptions Default = new TextGraphicsOptions(true);
 
+        private float? blendPercentage;
+
+        private int? antialiasSubpixelDepth;
+
+        private bool? antialias;
+
+        private bool? applyKerning;
+
+        private float? tabWidth;
+
+        private PixelBlenderMode blenderMode;
+
+        private bool? useImageResolution;
+
+        private float wrapTextWidth;
+
+        private SixLabors.Fonts.TextAlignment? textAlignment;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="TextGraphicsOptions" /> struct.
+        /// </summary>
+        /// <param name="enableAntialiasing">If set to <c>true</c> [enable antialiasing].</param>
+        public TextGraphicsOptions(bool enableAntialiasing)
+        {
+            this.applyKerning = true;
+            this.tabWidth = 4;
+            this.useImageResolution = false;
+            this.wrapTextWidth = 0;
+            this.textAlignment = SixLabors.Fonts.TextAlignment.Left;
+
+            this.antialiasSubpixelDepth = 16;
+            this.blenderMode = PixelBlenderMode.Normal;
+            this.blendPercentage = 1;
+            this.antialias = enableAntialiasing;
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether antialiasing should be applied.
+        /// </summary>
+        public bool Antialias { get => this.antialias ?? true; set => this.antialias = value; }
+
+        /// <summary>
+        /// Gets or sets a value indicating the number of subpixels to use while rendering with antialiasing enabled.
+        /// </summary>
+        public int AntialiasSubpixelDepth { get => this.antialiasSubpixelDepth ?? 16; set => this.antialiasSubpixelDepth = value; }
+
         /// <summary>
-        /// Whether antialiasing should be applied.
+        /// Gets or sets a value indicating the blending percentage to apply to the drawing operation
         /// </summary>
-        public bool Antialias;
+        public float BlendPercentage { get => (this.blendPercentage ?? 1).Clamp(0, 1); set => this.blendPercentage = value; }
+
+        // In the future we could expose a PixelBlender<TPixel> directly on here
+        // or some forms of PixelBlender factory for each pixel type. Will need
+        // some API thought post V1.
 
         /// <summary>
-        /// The number of subpixels to use while rendering with antialiasing enabled.
+        /// Gets or sets a value indicating the blending percentage to apply to the drawing operation
         /// </summary>
-        public int AntialiasSubpixelDepth;
+        public PixelBlenderMode BlenderMode { get => this.blenderMode; set => this.blenderMode = value; }
 
         /// <summary>
-        /// Whether the text should be drawing with kerning enabled.
+        /// Gets or sets a value indicating whether the text should be drawing with kerning enabled.
         /// </summary>
-        public bool ApplyKerning;
+        public bool ApplyKerning { get => this.applyKerning ?? true; set => this.applyKerning = value; }
 
         /// <summary>
-        /// The number of space widths a tab should lock to.
+        /// Gets or sets a value indicating the number of space widths a tab should lock to.
         /// </summary>
-        public float TabWidth;
+        public float TabWidth { get => this.tabWidth ?? 4; set => this.tabWidth = value; }
 
         /// <summary>
-        /// Flag weather to use the current image resultion to for point size scaling.
+        /// Gets or sets a value indicating whether to use the current image resultion to for point size scaling.
         /// If this is [false] the text renders at 72dpi otherwise it renders at Image resolution
         /// </summary>
-        public bool UseImageResolution;
+        public bool UseImageResolution { get => this.useImageResolution ?? false; set => this.useImageResolution = value; }
 
         /// <summary>
-        /// If greater than zero determine the width at which text should wrap.
+        /// Gets or sets a value indicating if greater than zero determine the width at which text should wrap.
         /// </summary>
-        public float WrapTextWidth;
+        public float WrapTextWidth { get => this.wrapTextWidth; set => this.wrapTextWidth = value; }
 
         /// <summary>
-        /// Initializes a new instance of the <see cref="TextGraphicsOptions" /> struct.
+        /// Gets or sets a value indicating how to align the text relative to the rendering space.
+        /// If <see cref="WrapTextWidth"/> is greater than zero it will align relative to the space
+        /// defined by the location and width, if <see cref="WrapTextWidth"/> equals zero, and thus
+        /// wrapping disabled, then the alignment is relative to the drawing location.
         /// </summary>
-        /// <param name="enableAntialiasing">If set to <c>true</c> [enable antialiasing].</param>
-        public TextGraphicsOptions(bool enableAntialiasing)
-        {
-            this.Antialias = enableAntialiasing;
-            this.ApplyKerning = true;
-            this.TabWidth = 4;
-            this.AntialiasSubpixelDepth = 16;
-            this.UseImageResolution = false;
-            this.WrapTextWidth = 0;
-        }
+        public TextAlignment TextAlignment { get => this.textAlignment ?? TextAlignment.Left; set => this.textAlignment = value; }
 
         /// <summary>
         /// Performs an implicit conversion from <see cref="GraphicsOptions"/> to <see cref="TextGraphicsOptions"/>.
@@ -71,7 +117,9 @@ namespace ImageSharp.Drawing
         {
             return new TextGraphicsOptions(options.Antialias)
             {
-                AntialiasSubpixelDepth = options.AntialiasSubpixelDepth
+                AntialiasSubpixelDepth = options.AntialiasSubpixelDepth,
+                blendPercentage = options.BlendPercentage,
+                blenderMode = options.BlenderMode
             };
         }
 
@@ -86,7 +134,9 @@ namespace ImageSharp.Drawing
         {
             return new GraphicsOptions(options.Antialias)
             {
-                AntialiasSubpixelDepth = options.AntialiasSubpixelDepth
+                AntialiasSubpixelDepth = options.AntialiasSubpixelDepth,
+                BlenderMode = options.BlenderMode,
+                BlendPercentage = options.BlendPercentage
             };
         }
     }