Partial solution for threading issues

Source/Css/CssQuery.cs

@@ -9,9 +9,9 @@ namespace Svg.Css
 {
     internal static class CssQuery
     {
-        public static IEnumerable<SvgElement> QuerySelectorAll(this SvgElement elem, string selector)
+        public static IEnumerable<SvgElement> QuerySelectorAll(this SvgElement elem, string selector, SvgElementFactory elementFactory)
         {
-            var generator = new SelectorGenerator<SvgElement>(new SvgElementOps());
+            var generator = new SelectorGenerator<SvgElement>(new SvgElementOps(elementFactory));
             Fizzler.Parser.Parse(selector, generator);
             return generator.Selector(Enumerable.Repeat(elem, 1));
         }

Source/Css/SvgElementOps.cs

@@ -8,10 +8,17 @@ namespace Svg.Css
 {
     internal class SvgElementOps : IElementOps<SvgElement>
     {
+	    private readonly SvgElementFactory _elementFactory;
+
+	    public SvgElementOps(SvgElementFactory elementFactory)
+	    {
+		    _elementFactory = elementFactory;
+	    }
+
 	    public Selector<SvgElement> Type(NamespacePrefix prefix, string name)
         {
             SvgElementFactory.ElementInfo type = null;
-            if (SvgElementFactory.AvailableElements.TryGetValue(name, out type)) 
+            if (_elementFactory.AvailableElements.TryGetValue(name, out type)) 
             {
                 return nodes => nodes.Where(n => n.GetType() == type.ElementType);
             }

Source/SvgDocument.cs

@@ -243,6 +243,7 @@ namespace Svg
             SvgElement element = null;
             SvgElement parent;
             T svgDocument = null;
+			var elementFactory = new SvgElementFactory();
 
             var styles = new List<ISvgNode>();
 
@@ -259,11 +260,11 @@ namespace Svg
                             // Create element
                             if (elementStack.Count > 0)
                             {
-                                element = SvgElementFactory.CreateElement(reader, svgDocument);
+                                element = elementFactory.CreateElement(reader, svgDocument);
                             }
                             else
                             {
-                                svgDocument = SvgElementFactory.CreateDocument<T>(reader);
+                                svgDocument = elementFactory.CreateDocument<T>(reader);
                                 element = svgDocument;
                             }
 
@@ -349,7 +350,7 @@ namespace Svg
 
                     foreach (var selector in selectors)
                     {
-                        elemsToStyle = svgDocument.QuerySelectorAll(rule.Selector.ToString());
+                        elemsToStyle = svgDocument.QuerySelectorAll(rule.Selector.ToString(), elementFactory);
                         foreach (var elem in elemsToStyle)
                         {
                             foreach (var decl in rule.Declarations)

Source/SvgElementFactory.cs

@@ -14,13 +14,13 @@ namespace Svg
     /// </summary>
     internal class SvgElementFactory
     {
-        private static Dictionary<string, ElementInfo> availableElements;
-        private static Parser cssParser = new Parser();
+        private Dictionary<string, ElementInfo> availableElements;
+        private Parser cssParser = new Parser();
 
         /// <summary>
         /// Gets a list of available types that can be used when creating an <see cref="SvgElement"/>.
         /// </summary>
-        public static Dictionary<string, ElementInfo> AvailableElements
+        public Dictionary<string, ElementInfo> AvailableElements
         {
             get
             {
@@ -47,7 +47,7 @@ namespace Svg
         /// <param name="reader">The <see cref="XmlTextReader"/> containing the node to parse into an <see cref="SvgDocument"/>.</param>
         /// <exception cref="ArgumentNullException">The <paramref name="reader"/> parameter cannot be <c>null</c>.</exception>
         /// <exception cref="InvalidOperationException">The CreateDocument method can only be used to parse root &lt;svg&gt; elements.</exception>
-        public static T CreateDocument<T>(XmlReader reader) where T : SvgDocument, new()
+        public T CreateDocument<T>(XmlReader reader) where T : SvgDocument, new()
         {
             if (reader == null)
             {
@@ -68,7 +68,7 @@ namespace Svg
         /// <param name="reader">The <see cref="XmlTextReader"/> containing the node to parse into a subclass of <see cref="SvgElement"/>.</param>
         /// <param name="document">The <see cref="SvgDocument"/> that the created element belongs to.</param>
         /// <exception cref="ArgumentNullException">The <paramref name="reader"/> and <paramref name="document"/> parameters cannot be <c>null</c>.</exception>
-        public static SvgElement CreateElement(XmlReader reader, SvgDocument document)
+        public SvgElement CreateElement(XmlReader reader, SvgDocument document)
         {
             if (reader == null)
             {
@@ -78,7 +78,7 @@ namespace Svg
             return CreateElement<SvgDocument>(reader, false, document);
         }
 
-        private static SvgElement CreateElement<T>(XmlReader reader, bool fragmentIsDocument, SvgDocument document) where T : SvgDocument, new()
+        private SvgElement CreateElement<T>(XmlReader reader, bool fragmentIsDocument, SvgDocument document) where T : SvgDocument, new()
         {
             SvgElement createdElement = null;
             string elementName = reader.LocalName;
@@ -122,7 +122,7 @@ namespace Svg
             return createdElement;
         }
 
-        private static void SetAttributes(SvgElement element, XmlReader reader, SvgDocument document)
+        private void SetAttributes(SvgElement element, XmlReader reader, SvgDocument document)
         {
             //Trace.TraceInformation("Begin SetAttributes");
 

Source/Text/GdiFontDefn.cs

@@ -68,8 +68,8 @@ namespace Svg
             return new SizeF(rect.Width, Ascent(renderer));
         }
 
-        private static Graphics _graphics;
-        private static Graphics GetGraphics(object renderer)
+        private Graphics _graphics;
+        private Graphics GetGraphics(object renderer)
         {
             var provider = renderer as IGraphicsProvider;
             if (provider == null)

Tests/Svg.UnitTests/MultiThreadingTest.cs

@@ -34,17 +34,9 @@ namespace Svg.UnitTests
 		public void TestMultiThread()
 		{
 			bool valid = true;
-			Parallel.For(0, 10, (x) =>
-			{
-				try
+			Parallel.For(0, 3, (x) =>
 			{
 				LoadFile();
-				}
-				catch (Exception e)
-				{
-					Trace.WriteLine("Run error in parallel: " + e.Message);
-					valid = false;
-				}
 			});
 			Assert.IsTrue(valid, "One or more of the runs was invalid");
 			Trace.WriteLine("Done");