by Tom
26. January 2009 10:33
As some of you might know, I am a really big fan of community-driven technologies. I also like to contribute myself in order to exchange new ideas and meet new people with common interests.Since I am quite new to ASP.NET MVC, I was thinking I would submit my first contribution : handling all your images through a custom actionresult/controller.
This allows me to do several things :
- uniform access to images
- possibility for custom types (this example ALWAYs renders as PNG)
- generation of thumbnails.
Let's start with the code for the ActionResult (initially inspired by/copy-pasted from this , but since the new RC it is my own code):
using System.IO;
using System.Web.Mvc;
using System.Drawing;
using System.Drawing.Imaging;
namespace Be.Corebvba.MVC
{
public class ImageResult : FileStreamResult
{
public ImageResult(Image input):this(input,input.Width,input.Height) { }
public ImageResult(Image input, int width,int height) :
base(
GetMemoryStream(input,width,height,ImageFormat.Png),
"image/png")
{ }
static MemoryStream GetMemoryStream(Image input,int width,int height,ImageFormat fmt)
{
// maintain aspect ratio
if (input.Width > input.Height)
height = input.Height * width / input.Width;
else
width = input.Width * height / input.Height;
var bmp = new Bitmap(input, width, height);
var ms = new MemoryStream();
bmp.Save(ms, ImageFormat.Png);
ms.Position = 0;
return ms;
}
}
}
The code for the controller is pretty straighforward as well :
public ActionResult ThumbImage(int id,int width,int height)
{
var d = _rDocument.GetById(id);
Image i=null;
try
{
i = Image.FromFile(d.PhysicalFilename);
return new Be.Corebvba.MVC.ImageResult(i, width, height);
}
catch (Exception ex)
{
i = new Bitmap(1, 1);
return new Be.Corebvba.MVC.ImageResult(i,1,1);
}
finally
{
if (i != null) i.Dispose();
}
}
This does need some better errorhandling, but I suppose you get the idea... (The _rDocument is a pointer to a Document repository which stores physical files. If you access your images from a database, you could simply use Image.FromStream instead of an Image.FromFile .In my document i reference the image as follows, et voila, automatic thumbnails :
<% var imgurl = Url.Action("ThumbImage", "Documents", new { id = d.ID,width=100,height=100 }); %>
<img src="<%=imgurl %>" style="float:left"/>
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