diff --git a/Basic Shapes/SvgGraphicsElement.cs b/Basic Shapes/SvgGraphicsElement.cs
index 7f09b076d57731a6b2f28bdd298160247b6cfc8e..a9316cf20b2693a92333ea9478500d36d14606a7 100644
--- a/Basic Shapes/SvgGraphicsElement.cs	
+++ b/Basic Shapes/SvgGraphicsElement.cs	
@@ -13,10 +13,11 @@ namespace Svg
     /// <summary>
     /// The class that all SVG elements should derive from when they are to be rendered.
     /// </summary>
-    public abstract partial class SvgGraphicsElement : SvgElement, ISvgStylable
+    public abstract partial class SvgGraphicsElement : SvgElement, ISvgStylable, ISvgClipable
     {
         private bool _dirty;
         private bool _requiresSmoothRendering;
+        private Region _previousClip;
 
         /// <summary>
         /// Gets the <see cref="GraphicsPath"/> for this element.
@@ -40,6 +41,16 @@ namespace Svg
             set { this._dirty = value; }
         }
 
+        /// <summary>
+        /// Gets the associated <see cref="SvgClipPath"/> if one has been specified.
+        /// </summary>
+        [SvgAttribute("clip-path")]
+        public virtual Uri ClipPath
+        {
+            get { return this.Attributes.GetAttribute<Uri>("clip-path"); }
+            set { this.Attributes["clip-path"] = value; }
+        }
+
         /// <summary>
         /// Gets or sets a value to determine if anti-aliasing should occur when the element is being rendered.
         /// </summary>
@@ -66,6 +77,7 @@ namespace Svg
             if (this.Path != null && this.Visible)
             {
                 this.PushTransforms(renderer);
+                this.SetClip(renderer);
 
                 // If this element needs smoothing enabled turn anti aliasing on
                 if (this.RequiresSmoothRendering)
@@ -104,8 +116,38 @@ namespace Svg
                     renderer.SmoothingMode = SmoothingMode.Default;
                 }
 
+                this.ResetClip(renderer);
                 this.PopTransforms(renderer);
             }
         }
+
+        protected internal virtual void SetClip(SvgRenderer renderer)
+        {
+            if (this.ClipPath != null)
+            {
+                SvgClipPath clipPath = this.OwnerDocument.GetElementById<SvgClipPath>(this.ClipPath.ToString());
+                this._previousClip = renderer.Clip;
+                renderer.SetClip(clipPath.GetClipRegion());
+            }
+        }
+
+        protected internal virtual void ResetClip(SvgRenderer renderer)
+        {
+            if (this.ClipPath != null)
+            {
+                renderer.SetClip(this._previousClip);
+                this._previousClip = null;
+            }
+        }
+
+        void ISvgClipable.SetClip(SvgRenderer renderer)
+        {
+            this.SetClip(renderer);
+        }
+
+        void ISvgClipable.ResetClip(SvgRenderer renderer)
+        {
+            this.ResetClip(renderer);
+        }
     }
 }
\ No newline at end of file
diff --git a/Clipping and Masking/ISvgClipable.cs b/Clipping and Masking/ISvgClipable.cs
index 2536579554ac62205f81f3e5e26682f2add2be2a..ff3b7dd43ab449e09206ca8186d98a87f537e8db 100644
--- a/Clipping and Masking/ISvgClipable.cs	
+++ b/Clipping and Masking/ISvgClipable.cs	
@@ -8,8 +8,11 @@ namespace Svg
 {
     public interface ISvgClipable
     {
-        SvgClipPath ClipPath { get; set; }
-        void SetClip(Graphics graphics);
-        void ResetClip(Graphics graphics);
+        /// <summary>
+        /// Gets or sets the ID of the associated <see cref="SvgClipPath"/> if one has been specified.
+        /// </summary>
+        Uri ClipPath { get; set; }
+        void SetClip(SvgRenderer renderer);
+        void ResetClip(SvgRenderer renderer);
     }
 }
\ No newline at end of file
diff --git a/Clipping and Masking/SvgClipPath.cs b/Clipping and Masking/SvgClipPath.cs
index 09779298f5e99e7ee2b3900b0b3a0e0f69393170..3d856feb18052c56aae0dd5e59f41956438651e4 100644
--- a/Clipping and Masking/SvgClipPath.cs	
+++ b/Clipping and Masking/SvgClipPath.cs	
@@ -6,12 +6,18 @@ using System.Drawing.Drawing2D;
 
 namespace Svg
 {
+    /// <summary>
+    /// 
+    /// </summary>
     public sealed class SvgClipPath : SvgElement
     {
         private SvgCoordinateUnits _clipPathUnits;
         private bool _pathDirty;
         private Region _region;
 
+        /// <summary>
+        /// 
+        /// </summary>
         [SvgAttribute("clipPathUnits")]
         public SvgCoordinateUnits ClipPathUnits
         {
@@ -27,7 +33,11 @@ namespace Svg
             this._clipPathUnits = SvgCoordinateUnits.ObjectBoundingBox;
         }
 
-        private Region GetClipRegion()
+        /// <summary>
+        /// Gets this <see cref="SvgClipPath"/>'s region to be clipped.
+        /// </summary>
+        /// <returns>A new <see cref="Region"/> containing the area to be clipped.</returns>
+        protected internal Region GetClipRegion()
         {
             if (_region == null || _pathDirty)
             {
@@ -44,18 +54,23 @@ namespace Svg
             return _region;
         }
 
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="region"></param>
+        /// <param name="element"></param>
         private void ComplementRegion(Region region, SvgElement element)
         {
             SvgGraphicsElement graphicsElement = element as SvgGraphicsElement;
 
-            if (graphicsElement != null)
+            if (graphicsElement != null && graphicsElement.Path != null)
             {
                 region.Complement(graphicsElement.Path);
             }
 
             foreach (SvgElement child in element.Children)
             {
-                ComplementRegion(region, element);
+                ComplementRegion(region, child);
             }
         }
 
@@ -71,6 +86,10 @@ namespace Svg
             this._pathDirty = true;
         }
 
+        /// <summary>
+        /// Renders the <see cref="SvgElement"/> and contents to the specified <see cref="SvgRenderer"/> object.
+        /// </summary>
+        /// <param name="renderer">The <see cref="SvgRenderer"/> object to render to.</param>
         protected override void Render(SvgRenderer renderer)
         {
             // Do nothing
diff --git a/DataTypes/SvgUnit.cs b/DataTypes/SvgUnit.cs
index 40befbd4b5293e15613b9affe0bd9aa6a04414b6..3346754b7b3c8a96486e699758e68d423883c134 100644
--- a/DataTypes/SvgUnit.cs
+++ b/DataTypes/SvgUnit.cs
@@ -90,6 +90,10 @@ namespace Svg
 
             switch (this.Type)
             {
+                case SvgUnitType.Em:
+                    float points = (float)(this.Value * 9);
+                    _deviceValue = (points / 72) * ppi;
+                    break;
                 case SvgUnitType.Centimeter:
                     _deviceValue = (float)((this.Value / cmInInch) * ppi);
                     break;
diff --git a/Document Structure/SvgDocument.cs b/Document Structure/SvgDocument.cs
index 8e55f346c1527dbdd6aeca336159a82e7c8c16b8..9056f929baa71ac5c6c189eb28bfd376c436a6f3 100644
--- a/Document Structure/SvgDocument.cs	
+++ b/Document Structure/SvgDocument.cs	
@@ -93,6 +93,16 @@ namespace Svg
             return IdManager.GetElementById(id);
         }
 
+        /// <summary>
+        /// Retrieves the <see cref="SvgElement"/> with the specified ID.
+        /// </summary>
+        /// <param name="id">A <see cref="string"/> containing the ID of the element to find.</param>
+        /// <returns>An <see cref="SvgElement"/> of one exists with the specified ID; otherwise false.</returns>
+        public virtual TSvgElement GetElementById<TSvgElement>(string id) where TSvgElement : SvgElement
+        {
+            return (this.GetElementById(id) as TSvgElement);
+        }
+
         /// <summary>
         /// Opens the document at the specified path and loads the contents.
         /// </summary>
diff --git a/Document Structure/SvgUse.cs b/Document Structure/SvgUse.cs
index b9ed59b6115f376cf875e9a2f96ad6d496ad8b3d..515caf634a11705625b48d93ea3940a4d213953a 100644
--- a/Document Structure/SvgUse.cs	
+++ b/Document Structure/SvgUse.cs	
@@ -46,7 +46,11 @@ namespace Svg
 
         public override System.Drawing.Drawing2D.GraphicsPath Path
         {
-            get { return null; }
+            get
+            {
+                SvgGraphicsElement element = (SvgGraphicsElement)this.OwnerDocument.IdManager.GetElementById(this.ReferencedElement);
+                return (element != null) ? element.Path : null;
+            }
         }
 
         public override System.Drawing.RectangleF Bounds
@@ -54,6 +58,17 @@ namespace Svg
             get { return new System.Drawing.RectangleF(); }
         }
 
+        public override SvgElementCollection Children
+        {
+            get
+            {
+                SvgElement element = this.OwnerDocument.IdManager.GetElementById(this.ReferencedElement);
+                SvgElementCollection elements = new SvgElementCollection(this, true);
+                elements.Add(element);
+                return elements;
+            }
+        }
+
         protected override void Render(SvgRenderer renderer)
         {
             this.PushTransforms(renderer);
diff --git a/Svg.csproj b/Svg.csproj
index 6e5ef311aaafd4f5505df07002ebe190ae174027..b83ba77850d076f5b78ab20344f92fc4c6afb017 100644
--- a/Svg.csproj
+++ b/Svg.csproj
@@ -135,8 +135,11 @@
     <Compile Include="Text\SvgTextAnchor.cs" />
     <Compile Include="Text\SvgTextSpan.cs" />
     <Compile Include="Transforms\ISvgTransformable.cs" />
+    <Compile Include="Transforms\SvgMatrix.cs" />
     <Compile Include="Transforms\SvgRotate.cs" />
     <Compile Include="Transforms\SvgScale.cs" />
+    <Compile Include="Transforms\SvgShear.cs" />
+    <Compile Include="Transforms\SvgSkew.cs" />
     <Compile Include="Transforms\SvgTransform.cs" />
     <Compile Include="Transforms\SvgTransformCollection.cs" />
     <Compile Include="Transforms\SvgTransformConverter.cs" />
diff --git a/SvgElementCollection.cs b/SvgElementCollection.cs
index d2bb9d8fdee7a1cbbb8a6ef16e669539711cbd15..dcf61ae7de088529f4657eea23d59f3b467fa4f7 100644
--- a/SvgElementCollection.cs
+++ b/SvgElementCollection.cs
@@ -11,12 +11,19 @@ namespace Svg
     {
         private List<SvgElement> _elements;
         private SvgElement _owner;
+        private bool _mock;
 
         /// <summary>
         /// Initialises a new instance of an <see cref="SvgElementCollection"/> class.
         /// </summary>
         /// <param name="owner">The owner <see cref="SvgElement"/> of the collection.</param>
         internal SvgElementCollection(SvgElement owner)
+            : this(owner, false)
+        {
+
+        }
+
+        internal SvgElementCollection(SvgElement owner, bool mock)
         {
             if (owner == null)
             {
@@ -25,6 +32,7 @@ namespace Svg
 
             this._elements = new List<SvgElement>();
             this._owner = owner;
+            this._mock = mock;
         }
 
         /// <summary>
@@ -65,14 +73,19 @@ namespace Svg
 
         public void Add(SvgElement item)
         {
-            if (this._owner.OwnerDocument != null)
+            if (!this._mock)
             {
-                this._owner.OwnerDocument.IdManager.Add(item);
+                if (this._owner.OwnerDocument != null)
+                {
+                    this._owner.OwnerDocument.IdManager.Add(item);
+                }
+
+                item._parent = this._owner;
             }
 
-            this._elements.Add(item);
-            item._parent = this._owner;
             item._parent.OnElementAdded(item, this.Count - 1);
+
+            this._elements.Add(item);
         }
 
         public void Clear()
@@ -111,11 +124,15 @@ namespace Svg
             if (removed)
             {
                 this._owner.OnElementRemoved(item);
-                item._parent = null;
 
-                if (this._owner.OwnerDocument != null)
+                if (!this._mock)
                 {
-                    this._owner.OwnerDocument.IdManager.Remove(item);
+                    item._parent = null;
+
+                    if (this._owner.OwnerDocument != null)
+                    {
+                        this._owner.OwnerDocument.IdManager.Remove(item);
+                    }
                 }
             }
 
diff --git a/SvgElementIdManager.cs b/SvgElementIdManager.cs
index 2a77531ddd174cf5dfd0f3e00ab4bbe66544c35b..1956501922db0dd3df0d6d795bd8e19ee76ed627 100644
--- a/SvgElementIdManager.cs
+++ b/SvgElementIdManager.cs
@@ -20,11 +20,20 @@ namespace Svg
         /// <returns>An <see cref="SvgElement"/> of one exists with the specified ID; otherwise false.</returns>
         public virtual SvgElement GetElementById(string id)
         {
+            if (id.StartsWith("url("))
+            {
+                id = id.Substring(4);
+                id = id.TrimEnd(')');
+            }
             if (id.StartsWith("#"))
             {
                 id = id.Substring(1);
             }
-            return this._idValueMap[id];
+
+            SvgElement element = null;
+            this._idValueMap.TryGetValue(id, out element);
+
+            return element;
         }
 
         public virtual SvgElement GetElementById(Uri uri)
diff --git a/SvgRenderer.cs b/SvgRenderer.cs
index 155390110bbb436e936d188827f9367235b83719..c216e39fd0a7ec83a0266f76760436bfd6b95240 100644
--- a/SvgRenderer.cs
+++ b/SvgRenderer.cs
@@ -19,6 +19,12 @@ namespace Svg
         {
         }
 
+        public Region Clip
+        {
+            get { return this._innerGraphics.Clip; }
+            set { this._innerGraphics.Clip = value; }
+        }
+
         /// <summary>
         /// Creates a new <see cref="SvgRenderer"/> from the specified <see cref="Image"/>.
         /// </summary>
@@ -30,6 +36,11 @@ namespace Svg
             return renderer;
         }
 
+        public void SetClip(Region region)
+        {
+            this._innerGraphics.SetClip(region, CombineMode.Union);
+        }
+
         public void FillPath(Brush brush, GraphicsPath path)
         {
             this._innerGraphics.FillPath(brush, path);
diff --git a/Transforms/SvgRotate.cs b/Transforms/SvgRotate.cs
index 6d2310b5ac69bc833494decb5dfa98fa2b7139ec..4743aae822b6833b27a845bc690f8fa90708d485 100644
--- a/Transforms/SvgRotate.cs
+++ b/Transforms/SvgRotate.cs
@@ -4,7 +4,7 @@ using System.Text;
 
 namespace Svg.Transforms
 {
-    public class SvgRotate : SvgTransform
+    public sealed class SvgRotate : SvgTransform
     {
         private float angle;
 
diff --git a/Transforms/SvgScale.cs b/Transforms/SvgScale.cs
index 9be303a8b8903a103161f5c6edf0a617c6ac69c2..1961e17e79342132d6d9f3fe598acb3ec2a07a33 100644
--- a/Transforms/SvgScale.cs
+++ b/Transforms/SvgScale.cs
@@ -5,7 +5,7 @@ using System.Drawing.Drawing2D;
 
 namespace Svg.Transforms
 {
-    public class SvgScale : SvgTransform
+    public sealed class SvgScale : SvgTransform
     {
         private float scaleFactorX;
         private float scaleFactorY;
diff --git a/Transforms/SvgTransformConverter.cs b/Transforms/SvgTransformConverter.cs
index 15ae0b42391c8528560a923ea1aca307180f418f..1bcff7f1c47c1b8bea2537b89fa3c3045baa4189 100644
--- a/Transforms/SvgTransformConverter.cs
+++ b/Transforms/SvgTransformConverter.cs
@@ -20,7 +20,7 @@ namespace Svg.Transforms
                 if (transforms[i] == ')')
                 {
                     yield return transforms.Substring(transformEnd, i - transformEnd + 1).Trim();
-                    transformEnd = i+1;
+                    transformEnd = i + 1;
                 }
             }
         }
@@ -57,7 +57,7 @@ namespace Svg.Transforms
                     switch (transformName)
                     {
                         case "translate":
-                            string[] coords = contents.Split(new char[]{',', ' '}, StringSplitOptions.RemoveEmptyEntries);
+                            string[] coords = contents.Split(new char[] { ',', ' ' }, StringSplitOptions.RemoveEmptyEntries);
 
                             if (coords.Length != 2)
                             {
@@ -92,6 +92,51 @@ namespace Svg.Transforms
                                 transformList.Add(new SvgScale(sx));
                             }
 
+                            break;
+                        case "matrix":
+                            string[] points = contents.Split(new char[] { ',', ' ' }, StringSplitOptions.RemoveEmptyEntries);
+
+                            if (points.Length != 6)
+                            {
+                                throw new FormatException("Matrix transforms must be in the format 'matrix(m11, m12, m21, m22, dx, dy)'");
+                            }
+
+                            List<float> mPoints = new List<float>();
+                            foreach (string point in points)
+                            {
+                                mPoints.Add(float.Parse(point.Trim(), NumberStyles.Float, CultureInfo.InvariantCulture));
+                            }
+
+                            transformList.Add(new SvgMatrix(mPoints));
+                            break;
+                        case "shear":
+                            string[] shears = contents.Split(new char[] { ',', ' ' }, StringSplitOptions.RemoveEmptyEntries);
+
+                            if (shears.Length == 0 || shears.Length > 2)
+                            {
+                                throw new FormatException("Shear transforms must be in the format 'shear(x [,y])'");
+                            }
+
+                            float hx = float.Parse(shears[0].Trim(), NumberStyles.Float, CultureInfo.InvariantCulture);
+
+                            if (shears.Length > 1)
+                            {
+                                float hy = float.Parse(shears[1].Trim(), NumberStyles.Float, CultureInfo.InvariantCulture);
+                                transformList.Add(new SvgShear(hx, hy));
+                            }
+                            else
+                            {
+                                transformList.Add(new SvgShear(hx));
+                            }
+
+                            break;
+                        case "skewX":
+                            float ax = float.Parse(contents, NumberStyles.Float, CultureInfo.InvariantCulture);
+                            transformList.Add(new SvgSkew(ax, 0));
+                            break;
+                        case "skewY":
+                            float ay = float.Parse(contents, NumberStyles.Float, CultureInfo.InvariantCulture);
+                            transformList.Add(new SvgSkew(0, ay));
                             break;
                     }
                 }
diff --git a/Transforms/SvgTranslate.cs b/Transforms/SvgTranslate.cs
index d3a54e6bf74cf9e69d6de7c0a88da546ed311e13..5e04a1d8893a520b98c285cf59c2a0ef2307a9f0 100644
--- a/Transforms/SvgTranslate.cs
+++ b/Transforms/SvgTranslate.cs
@@ -4,7 +4,7 @@ using System.Text;
 
 namespace Svg.Transforms
 {
-    public class SvgTranslate : SvgTransform
+    public sealed class SvgTranslate : SvgTransform
     {
         private float x;
         private float y;