Merge pull request #38 from planetclegg/master

Minimal image tag support for raster images

Source/Basic Shapes/SvgImage.cs

-using System;
+using System;
+using System.Diagnostics;
 using System.Drawing;
-using System.Drawing.Drawing2D;
-using Svg.Transforms;
+using System.Drawing.Drawing2D;
+using System.IO;
+using System.Net;
+using Svg.Transforms;
 
 namespace Svg
 {
@@ -91,14 +94,80 @@ namespace Svg
 
         /// <summary>
         /// Renders the <see cref="SvgElement"/> and contents to the specified <see cref="Graphics"/> object.
-        /// </summary>
-        protected override void Render(SvgRenderer renderer)
-        {
-            if (Width.Value > 0.0f && Height.Value > 0.0f)
-            {
-				//TODO:
-                //base.Render(renderer);
-            }
+        /// </summary>
+        protected override void Render(SvgRenderer renderer)
+        {
+            if (Width.Value > 0.0f && Height.Value > 0.0f && this.Href != null)
+            {
+                using (Image b = GetImage(this.Href))
+                {
+                    if (b != null)
+                    {
+                        this.PushTransforms(renderer);
+                        this.SetClip(renderer);
+
+                        RectangleF srcRect = new RectangleF(0, 0, b.Width, b.Height);
+                        var destRect = new RectangleF(this.Location.ToDeviceValue(),
+                                        new SizeF(Width.ToDeviceValue(), Height.ToDeviceValue()));
+
+                        renderer.DrawImage(b, destRect, srcRect, GraphicsUnit.Pixel);
+
+                        this.ResetClip(renderer);
+                        this.PopTransforms(renderer);
+                    }
+                }
+                // TODO: cache images... will need a shared context for this
+                // TODO: support preserveAspectRatio, etc
+            }
+        }
+
+        protected Image GetImage(Uri uri)
+        {
+            try
+            {
+                // handle data/uri embedded images (http://en.wikipedia.org/wiki/Data_URI_scheme)
+                if (uri.Scheme == "data")
+                {
+                    string uriString = uri.OriginalString;
+                    int dataIdx = uriString.IndexOf(",") + 1;
+                    if (dataIdx <= 0 || dataIdx + 1 > uriString.Length)
+                        throw new Exception("Invalid data URI");
+
+                    // we're assuming base64, as ascii encoding would be *highly* unsusual for images
+                    // also assuming it's png or jpeg mimetype
+                    byte[] imageBytes = Convert.FromBase64String(uriString.Substring(dataIdx));
+                    Image image = Image.FromStream(new MemoryStream(imageBytes));
+                    return image;
+                }
+
+                // should work with http: and file: protocol urls
+                var httpRequest = WebRequest.Create(uri);
+
+                using (WebResponse webResponse = httpRequest.GetResponse())
+                {
+                    MemoryStream ms = BufferToMemoryStream(webResponse.GetResponseStream());
+                    Image image = Bitmap.FromStream(ms);
+                    return image;
+                }
+            }
+            catch (Exception ex)
+            {
+                Trace.TraceError("Error loading image: '{0}', error: {1} ", uri, ex.Message);
+                return null;
+            }
+        }
+
+        protected static MemoryStream BufferToMemoryStream(Stream input)
+        {
+            byte[] buffer = new byte[4 * 1024];
+            int len;
+            MemoryStream ms = new MemoryStream();
+            while ((len = input.Read(buffer, 0, buffer.Length)) > 0)
+            {
+                ms.Write(buffer, 0, len);
+            }
+            ms.Seek(0, SeekOrigin.Begin);
+            return ms;
         }
 
 

Source/SvgRenderer.cs

@@ -52,6 +52,11 @@ namespace Svg
             this._innerGraphics.DrawImageUnscaled(image, location);
         }
 
+        public void DrawImage(Image image, RectangleF destRect, RectangleF srcRect, GraphicsUnit graphicsUnit)
+        {
+            _innerGraphics.DrawImage(image, destRect, srcRect, graphicsUnit);
+        }
+
         public void SetClip(Region region)
         {
             this._innerGraphics.SetClip(region, CombineMode.Complement);