Adding support for <link> css inclusion

Source/Document Structure/SvgLink.cs

@@ -0,0 +1,107 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO;
+using System.Net;
+using System.Text;
+
+namespace Svg
+{
+    [NonSvgElementAttribute("link")]
+    public class SvgLink : NonSvgElement
+    {
+        public SvgLink()
+          : base("link")
+        {
+
+        }
+        public enum RelativeValue
+        {
+            Unknown,
+            Alternate,
+            Author,
+            Help,
+            Icon,
+            License,
+            Next,
+            Pingback,
+            Preconnect,
+            Prefetch,
+            Preload,
+            Prerender,
+            Prev,
+            Search,
+            Stylesheet
+        }
+
+        public override SvgElement DeepCopy()
+        {
+            return DeepCopy<SvgLink>();
+        }
+
+
+        [SvgAttribute("href")]
+        public string Href
+        {
+            get { return GetAttribute<string>("href", false, string.Empty); }
+            set { Attributes["href"] = value; }
+        }
+
+        [SvgAttribute("rel")]
+        public RelativeValue Rel
+        {
+            get { return GetAttribute<RelativeValue>("rel", false, RelativeValue.Unknown); }
+            set { Attributes["rel"] = value; }
+        }
+
+
+
+        public string GetLinkContentAsText(RelativeValue rel)
+        {
+            var stream = GetLinkContentAsStream(rel);
+            if (stream == null)
+                return null;
+
+            string content = null;
+            using (StreamReader sr = new StreamReader(stream))
+            {
+                content = sr.ReadToEnd();
+            }
+            stream.Dispose();
+            return content;
+        }
+
+
+        public Stream GetLinkContentAsStream(RelativeValue rel = RelativeValue.Unknown)
+        {
+            if (Rel != rel && rel != RelativeValue.Unknown)
+                return null;
+            // Uri MaxLength is 65519 (https://msdn.microsoft.com/en-us/library/z6c2z492.aspx)
+            // if using data URI scheme, very long URI may happen.
+            var safeUriString = Href.Length > 65519 ? Href.Substring(0, 65519) : Href;
+
+            try
+            {
+                var uri = new Uri(safeUriString, UriKind.RelativeOrAbsolute);
+
+                if (!uri.IsAbsoluteUri)
+                    uri = new Uri(OwnerDocument.BaseUri, uri);
+
+                // should work with http: and file: protocol urls
+                var httpRequest = WebRequest.Create(uri);
+
+                var webResponse = httpRequest.GetResponse();
+                var stream = webResponse.GetResponseStream();
+                if (stream.CanSeek)
+                    stream.Position = 0;
+                return stream;
+            }
+            catch (Exception ex)
+            {
+                Trace.TraceError("Error loading Link content: '{0}', error: {1} ", Href, ex.Message);
+                return null;
+            }
+
+        }
+    }
+}

Source/NonSvgElementAttribute.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Svg
+{
+    /// <summary>
+    /// Specifies the SVG name of an <see cref="SvgElement"/>.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Class)]
+    public sealed class NonSvgElementAttribute : Attribute
+    {
+        /// <summary>
+        /// Gets the name of the SVG element.
+        /// </summary>
+        public string ElementName { get; private set; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="NonSvgElementAttribute"/> class with the specified element name;
+        /// </summary>
+        /// <param name="elementName">The name of the non SVG element.</param>
+        public NonSvgElementAttribute(string elementName)
+        {
+            this.ElementName = elementName;
+        }
+    }
+}

Source/SvgDocument.cs

@@ -48,7 +48,7 @@ private static int GetSystemDpi()
             isWindows = RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
 #else
             var platform = Environment.OSVersion.Platform;
-            isWindows = platform == PlatformID.Win32NT; 
+            isWindows = platform == PlatformID.Win32NT;
 #endif
 
             if (isWindows)
@@ -194,15 +194,15 @@ public virtual TSvgElement GetElementById<TSvgElement>(string id) where TSvgElem
         /// <returns>Boolean whether the system is capable of using GDI+</returns>
         public static bool SystemIsGdiPlusCapable()
         {
-            try 
+            try
             {
                 EnsureSystemIsGdiPlusCapable();
             }
-            catch(SvgGdiPlusCannotBeLoadedException)
+            catch (SvgGdiPlusCannotBeLoadedException)
             {
                 return false;
             }
-            catch(Exception)
+            catch (Exception)
             {
                 //If somehow another type of exception is raised by the ensure function we will let it bubble up, since that might indicate other issues/problems
                 throw;
@@ -230,7 +230,7 @@ public static void EnsureSystemIsGdiPlusCapable()
                     throw new SvgGdiPlusCannotBeLoadedException(e);
                 }
                 //If the Matrix creation is causing another type of exception we should just raise that one
-                throw;   
+                throw;
             }
         }
 
@@ -260,32 +260,35 @@ private static bool ExceptionCaughtIsGdiPlusRelated(Exception e)
         /// Opens the document at the specified path and loads the SVG contents.
         /// </summary>
         /// <param name="path">A <see cref="string"/> containing the path of the file to open.</param>
+        /// <param name="baseUri"> base uri for linked file</param>
         /// <returns>An <see cref="SvgDocument"/> with the contents loaded.</returns>
         /// <exception cref="FileNotFoundException">The document at the specified <paramref name="path"/> cannot be found.</exception>
-        public static SvgDocument Open(string path)
+        public static SvgDocument Open(string path, Uri baseUri = null)
         {
-            return Open<SvgDocument>(path, null);
+            return Open<SvgDocument>(path, null, baseUri == null ? new Uri(System.IO.Path.GetFullPath(path)) : baseUri);
         }
 
         /// <summary>
         /// Opens the document at the specified path and loads the SVG contents.
         /// </summary>
         /// <param name="path">A <see cref="string"/> containing the path of the file to open.</param>
+        /// <param name="baseUri"> base uri for linked file</param>
         /// <returns>An <see cref="SvgDocument"/> with the contents loaded.</returns>
         /// <exception cref="FileNotFoundException">The document at the specified <paramref name="path"/> cannot be found.</exception>
-        public static T Open<T>(string path) where T : SvgDocument, new()
+        public static T Open<T>(string path, Uri baseUri = null) where T : SvgDocument, new()
         {
-            return Open<T>(path, null);
+            return Open<T>(path, null, baseUri);
         }
 
         /// <summary>
         /// Opens the document at the specified path and loads the SVG contents.
         /// </summary>
         /// <param name="path">A <see cref="string"/> containing the path of the file to open.</param>
+        /// <param name="baseUri"> base uri for linked file</param>
         /// <param name="entities">A dictionary of custom entity definitions to be used when resolving XML entities within the document.</param>
         /// <returns>An <see cref="SvgDocument"/> with the contents loaded.</returns>
         /// <exception cref="FileNotFoundException">The document at the specified <paramref name="path"/> cannot be found.</exception>
-        public static T Open<T>(string path, Dictionary<string, string> entities) where T : SvgDocument, new()
+        public static T Open<T>(string path, Dictionary<string, string> entities, Uri baseUri = null) where T : SvgDocument, new()
         {
             if (string.IsNullOrEmpty(path))
             {
@@ -299,8 +302,11 @@ public static SvgDocument Open(string path)
 
             using (var stream = File.OpenRead(path))
             {
-                var doc = Open<T>(stream, entities);
-                doc.BaseUri = new Uri(System.IO.Path.GetFullPath(path));
+                var doc = Open<T>(stream, entities, baseUri == null ? new Uri(System.IO.Path.GetFullPath(path)) : baseUri);
+                if (baseUri == null)
+                    doc.BaseUri = new Uri(System.IO.Path.GetFullPath(path));
+                else
+                    doc.BaseUri = baseUri;
                 return doc;
             }
         }
@@ -309,9 +315,10 @@ public static SvgDocument Open(string path)
         /// Attempts to open an SVG document from the specified <see cref="Stream"/>.
         /// </summary>
         /// <param name="stream">The <see cref="Stream"/> containing the SVG document to open.</param>
-        public static T Open<T>(Stream stream) where T : SvgDocument, new()
+        /// <param name="baseUri"> base uri for linked file</param>
+        public static T Open<T>(Stream stream, Uri baseUri = null) where T : SvgDocument, new()
         {
-            return Open<T>(stream, null);
+            return Open<T>(stream, null, baseUri);
         }
 
 
@@ -342,8 +349,9 @@ public static SvgDocument Open(string path)
         /// </summary>
         /// <param name="stream">The <see cref="Stream"/> containing the SVG document to open.</param>
         /// <param name="entities">Custom entity definitions.</param>
+        /// <param name="baseUri"> base uri for linked file</param>
         /// <exception cref="ArgumentNullException">The <paramref name="stream"/> parameter cannot be <c>null</c>.</exception>
-        public static T Open<T>(Stream stream, Dictionary<string, string> entities) where T : SvgDocument, new()
+        public static T Open<T>(Stream stream, Dictionary<string, string> entities, Uri baseUri = null) where T : SvgDocument, new()
         {
             if (stream == null)
             {
@@ -356,10 +364,10 @@ public static SvgDocument Open(string path)
                 XmlResolver = new SvgDtdResolver(),
                 WhitespaceHandling = WhitespaceHandling.None
             };
-            return Open<T>(reader);
+            return Open<T>(reader, baseUri);
         }
 
-        private static T Open<T>(XmlReader reader) where T : SvgDocument, new()
+        private static T Open<T>(XmlReader reader, Uri baseUri = null) where T : SvgDocument, new()
         {
             if (!SkipGdiPlusCapabilityCheck)
             {
@@ -392,6 +400,8 @@ public static SvgDocument Open(string path)
                             else
                             {
                                 svgDocument = elementFactory.CreateDocument<T>(reader);
+                                if (baseUri != null)
+                                    svgDocument.BaseUri = baseUri;
                                 element = svgDocument;
                             }
 
@@ -435,6 +445,16 @@ public static SvgDocument Open(string path)
                             {
                                 styles.Add(unknown);
                             }
+                            else if (element is SvgLink)
+                            {
+                                var stylecontent = ((SvgLink)element).GetLinkContentAsText(SvgLink.RelativeValue.Stylesheet);
+                                if (!string.IsNullOrEmpty(stylecontent))
+                                {
+                                    var elem = new SvgUnknownElement("style");
+                                    elem.Content = stylecontent;
+                                    styles.Add(elem);
+                                }
+                            }
                             break;
                         case XmlNodeType.CDATA:
                         case XmlNodeType.Text:
@@ -491,16 +511,17 @@ public static SvgDocument Open(string path)
         /// Opens an SVG document from the specified <see cref="XmlDocument"/>.
         /// </summary>
         /// <param name="document">The <see cref="XmlDocument"/> containing the SVG document XML.</param>
+        /// <param name="baseUri"> base uri for linked file</param>
         /// <exception cref="ArgumentNullException">The <paramref name="document"/> parameter cannot be <c>null</c>.</exception>
-        public static SvgDocument Open(XmlDocument document)
+        public static SvgDocument Open(XmlDocument document, Uri baseUri = null)
         {
             if (document == null)
             {
                 throw new ArgumentNullException("document");
             }
 
             var reader = new SvgNodeReader(document.DocumentElement, null);
-            return Open<SvgDocument>(reader);
+            return Open<SvgDocument>(reader, baseUri);
         }
 
         public static Bitmap OpenAsBitmap(string path)

Source/SvgElementFactory.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.Xml;
@@ -15,6 +15,7 @@ namespace Svg
     internal class SvgElementFactory
     {
         private List<ElementInfo> availableElements;
+        private List<ElementInfo> availableNonSvgElements;
         private Parser cssParser = new Parser();
 
         /// <summary>
@@ -38,6 +39,31 @@ where t.GetCustomAttributes(typeof(SvgElementAttribute), true).Length > 0
             }
         }
 
+
+
+        /// <summary>
+        /// Gets a list of available types that can be used when creating an <see cref="NonSvgElement"/>.
+        /// </summary>
+        public List<ElementInfo> AvailableNonSvgElements
+        {
+            get
+            {
+                if (availableNonSvgElements == null)
+                {
+                    var nonSvgTypes = from t in typeof(SvgDocument).Assembly.GetExportedTypes()
+                                      where t.GetCustomAttributes(typeof(NonSvgElementAttribute), true).Length > 0
+                                      && t.IsSubclassOf(typeof(NonSvgElement))
+                                      select new ElementInfo { ElementName = ((NonSvgElementAttribute)t.GetCustomAttributes(typeof(NonSvgElementAttribute), true)[0]).ElementName, ElementType = t };
+
+                    availableNonSvgElements = nonSvgTypes.ToList();
+                }
+
+                return availableNonSvgElements;
+            }
+        }
+
+
+
         /// <summary>
         /// Creates an <see cref="SvgDocument"/> from the current node in the specified <see cref="XmlTextReader"/>.
         /// </summary>
@@ -111,8 +137,21 @@ public SvgElement CreateElement(XmlReader reader, SvgDocument document)
             else
             {
                 // All non svg element (html, ...)
-                createdElement = new NonSvgElement(elementName);
-                SetAttributes(createdElement, reader, document);
+                ElementInfo validType;
+                if (AvailableNonSvgElements.ToDictionary(e => e.ElementName, e => e).TryGetValue(elementName, out validType))
+                {
+                    createdElement = (NonSvgElement)Activator.CreateInstance(validType.ElementType);
+                }
+                else
+                {
+                    createdElement = new NonSvgElement(elementName);
+                }
+
+                if (createdElement != null)
+                {
+                    SetAttributes(createdElement, reader, document);
+                }
+
             }
 
             //Trace.TraceInformation("End CreateElement");