C# / Silverlight / WPF / Fast rendering lots of circles

Question

I want to render a lot of circles or small graphics within either silverlight or wpf (around 1000-10000) as fast and as frequently as possible. If I have to go to DX or OGL, that's fine, but I'm wondering about doing this within either of those two frameworks first (read: it's OK if an answer is WPF-only or Silverlight-only). Also, if there is a way to access DX through WPF and render on a surface that way, I would be interested in that as well.

So, what's the fastest way to draw a load of circles? They can be as plain as necessary, but they do need to have a radius. Currently I'm using DrawingVisual and a DrawingContext.DrawEllipse() command for each circle, then rendering the visual to a RenderTargetBItmap, but it becomes very slow as the number of circles rises.

By the way, these circles move every frame, so caching isn't really an option unless you're going to suggest caching the individual circles . . . But their sizes are dynamic, so I'm not sure that's a great approach.

Answer 1

In Silverlight 3.0+, most likely, you will use WriteableBitmap for this. In WPF it also may be a good choice.

I wrote two demo applications in Silverlight. They may be little buggy, but they demonstrate the point.

1. Hello world application. Definitely can be optimized. Performance isn't that good, but that's because I made something stupid. I believe it has ~2 500 ellipses:

alt text http://img42.imageshack.us/img42/5629/helloworld.jpg

2. Slide show application. I can't recall number of objects here, but it's way more than 10 000.

alt text http://img11.imageshack.us/img11/5264/slideshowa.jpg