Render decorators

- Split pattened and solid pens
- Add pen aware apis for text decorations
- Add abbility fro pen to have no width and inherit a default value while generating outline

Author: tocsoft

src/ImageSharp.Drawing/Processing/Extensions/DrawBezierExtensions.cs

@@ -53,7 +53,7 @@ public static IImageProcessingContext DrawBeziers(
             IBrush brush,
             float thickness,
             params PointF[] points) =>
-            source.Draw(options, new Pen(brush, thickness), new Path(new CubicBezierLineSegment(points)));
+            source.Draw(options, new SolidPen(brush, thickness), new Path(new CubicBezierLineSegment(points)));
 
         /// <summary>
         /// Draws the provided points as an open Bezier path at the provided thickness with the supplied brush
@@ -68,7 +68,7 @@ public static IImageProcessingContext DrawBeziers(
             IBrush brush,
             float thickness,
             params PointF[] points) =>
-            source.Draw(new Pen(brush, thickness), new Path(new CubicBezierLineSegment(points)));
+            source.Draw(new SolidPen(brush, thickness), new Path(new CubicBezierLineSegment(points)));
 
         /// <summary>
         /// Draws the provided points as an open Bezier path at the provided thickness with the supplied brush

src/ImageSharp.Drawing/Processing/Extensions/DrawLineExtensions.cs

@@ -25,7 +25,7 @@ public static IImageProcessingContext DrawLines(
             IBrush brush,
             float thickness,
             params PointF[] points) =>
-            source.Draw(options, new Pen(brush, thickness), new Path(new LinearLineSegment(points)));
+            source.Draw(options, new SolidPen(brush, thickness), new Path(new LinearLineSegment(points)));
 
         /// <summary>
         /// Draws the provided points as an open linear path at the provided thickness with the supplied brush.
@@ -40,7 +40,7 @@ public static IImageProcessingContext DrawLines(
             IBrush brush,
             float thickness,
             params PointF[] points) =>
-            source.Draw(new Pen(brush, thickness), new Path(new LinearLineSegment(points)));
+            source.Draw(new SolidPen(brush, thickness), new Path(new LinearLineSegment(points)));
 
         /// <summary>
         /// Draws the provided points as an open linear path at the provided thickness with the supplied brush.

src/ImageSharp.Drawing/Processing/Extensions/DrawPathCollectionExtensions.cs

@@ -58,7 +58,7 @@ public static IImageProcessingContext Draw(
             IBrush brush,
             float thickness,
             IPathCollection paths) =>
-            source.Draw(options, new Pen(brush, thickness), paths);
+            source.Draw(options, new SolidPen(brush, thickness), paths);
 
         /// <summary>
         /// Draws the outline of the polygon with the provided brush at the provided thickness.
@@ -73,7 +73,7 @@ public static IImageProcessingContext Draw(
             IBrush brush,
             float thickness,
             IPathCollection paths) =>
-            source.Draw(new Pen(brush, thickness), paths);
+            source.Draw(new SolidPen(brush, thickness), paths);
 
         /// <summary>
         /// Draws the outline of the polygon with the provided brush at the provided thickness.

src/ImageSharp.Drawing/Processing/Extensions/DrawPathExtensions.cs

@@ -51,7 +51,7 @@ public static IImageProcessingContext Draw(
             IBrush brush,
             float thickness,
             IPath path) =>
-            source.Draw(options, new Pen(brush, thickness), path);
+            source.Draw(options, new SolidPen(brush, thickness), path);
 
         /// <summary>
         /// Draws the outline of the polygon with the provided brush at the provided thickness.
@@ -66,7 +66,7 @@ public static IImageProcessingContext Draw(
             IBrush brush,
             float thickness,
             IPath path) =>
-            source.Draw(new Pen(brush, thickness), path);
+            source.Draw(new SolidPen(brush, thickness), path);
 
         /// <summary>
         /// Draws the outline of the polygon with the provided brush at the provided thickness.

src/ImageSharp.Drawing/Processing/Extensions/DrawPolygonExtensions.cs

@@ -53,7 +53,7 @@ public static IImageProcessingContext DrawPolygon(
             IBrush brush,
             float thickness,
             params PointF[] points) =>
-            source.DrawPolygon(options, new Pen(brush, thickness), points);
+            source.DrawPolygon(options, new SolidPen(brush, thickness), points);
 
         /// <summary>
         /// Draws the provided points as a closed linear polygon with the provided brush at the provided thickness.
@@ -68,7 +68,7 @@ public static IImageProcessingContext DrawPolygon(
             IBrush brush,
             float thickness,
             params PointF[] points) =>
-            source.DrawPolygon(new Pen(brush, thickness), points);
+            source.DrawPolygon(new SolidPen(brush, thickness), points);
 
         /// <summary>
         /// Draws the provided points as a closed linear polygon with the provided brush at the provided thickness.

src/ImageSharp.Drawing/Processing/Extensions/DrawRectangleExtensions.cs

@@ -50,7 +50,7 @@ public static IImageProcessingContext Draw(
             IBrush brush,
             float thickness,
             RectangleF shape) =>
-            source.Draw(options, new Pen(brush, thickness), shape);
+            source.Draw(options, new SolidPen(brush, thickness), shape);
 
         /// <summary>
         /// Draws the outline of the rectangle with the provided brush at the provided thickness.
@@ -65,7 +65,7 @@ public static IImageProcessingContext Draw(
             IBrush brush,
             float thickness,
             RectangleF shape) =>
-            source.Draw(new Pen(brush, thickness), shape);
+            source.Draw(new SolidPen(brush, thickness), shape);
 
         /// <summary>
         /// Draws the outline of the rectangle with the provided brush at the provided thickness.

src/ImageSharp.Drawing/Processing/GradientBrush.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
+using System.Linq;
 using System.Numerics;
 using SixLabors.ImageSharp.Drawing.Utilities;
 using SixLabors.ImageSharp.Memory;
@@ -33,6 +34,18 @@ protected GradientBrush(GradientRepetitionMode repetitionMode, params ColorStop[
         /// </summary>
         protected ColorStop[] ColorStops { get; }
 
+        /// <inheritdoc />
+        public bool Equals(IBrush other)
+        {
+            if (other is GradientBrush sb)
+            {
+                return sb.RepetitionMode == this.RepetitionMode &&
+                    Enumerable.SequenceEqual(sb.ColorStops, this.ColorStops);
+            }
+
+            return false;
+        }
+
         /// <inheritdoc />
         public abstract BrushApplicator<TPixel> CreateApplicator<TPixel>(
             Configuration configuration,

src/ImageSharp.Drawing/Processing/IBrush.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Apache License, Version 2.0.
 
+using System;
 using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Drawing.Processing
@@ -12,7 +13,7 @@ namespace SixLabors.ImageSharp.Drawing.Processing
     /// A brush is a simple class that will return an <see cref="BrushApplicator{TPixel}" /> that will perform the
     /// logic for retrieving pixel values for specific locations.
     /// </remarks>
-    public interface IBrush
+    public interface IBrush : IEquatable<IBrush>
     {
         /// <summary>
         /// Creates the applicator for this brush.

src/ImageSharp.Drawing/Processing/IPen.cs

@@ -8,31 +8,40 @@ namespace SixLabors.ImageSharp.Drawing.Processing
     /// <summary>
     /// Interface representing the pattern and size of the stroke to apply with a Pen.
     /// </summary>
-    public interface IPen
+    public interface IPen : IEquatable<IPen>
     {
         /// <summary>
         /// Gets the stroke fill.
         /// </summary>
         IBrush StrokeFill { get; }
 
-        /// <summary>
-        /// Gets the width to apply to the stroke
-        /// </summary>
-        float StrokeWidth { get; }
+        ///// <summary>
+        ///// Gets the width to apply to the stroke
+        ///// </summary>
+        //float StrokeWidth { get; }
 
-        /// <summary>
-        /// Gets the stoke pattern.
-        /// </summary>
-        ReadOnlySpan<float> StrokePattern { get; }
+        ///// <summary>
+        ///// Gets the stoke pattern.
+        ///// </summary>
+        //ReadOnlySpan<float> StrokePattern { get; }
 
-        /// <summary>
-        /// Gets or sets the stroke joint style
-        /// </summary>
-        public JointStyle JointStyle { get; set; }
+        ///// <summary>
+        ///// Gets or sets the stroke joint style
+        ///// </summary>
+        //public JointStyle JointStyle { get; set; }
+
+        ///// <summary>
+        ///// Gets or sets the stroke endcap style
+        ///// </summary>
+        //public EndCapStyle EndCapStyle { get; set; }
 
         /// <summary>
-        /// Gets or sets the stroke endcap style
+        /// Applies the styleing from the pen to a path and generate a new path with the final vector.
         /// </summary>
-        public EndCapStyle EndCapStyle { get; set; }
+        /// <param name="path">the source path</param>
+        /// <param name="defaultWidth">the default width to apply if the pen does not have one.</param>
+        /// <returns>the path withthe pen styleing applied</returns>
+        public IPath GeneratePath(IPath path, float? defaultWidth = null);
+
     }
 }

src/ImageSharp.Drawing/Processing/ImageBrush.cs

@@ -46,6 +46,17 @@ internal ImageBrush(Image image, RectangleF region)
             this.region = region;
         }
 
+        /// <inheritdoc />
+        public bool Equals(IBrush other)
+        {
+            if (other is ImageBrush sb)
+            {
+                return sb.image == this.image && sb.region == this.region;
+            }
+
+            return false;
+        }
+
         /// <inheritdoc />
         public BrushApplicator<TPixel> CreateApplicator<TPixel>(
             Configuration configuration,