Question

I have an Image object in my application which the user can drag around. The object displays an image which is partly transparent, so the window background (which is itself a bitmap) can be seen through it.

I want to add a graphics effect to this object. Assume that I already have an algorithm for this effect — that’s not the issue. The issue is how to get this algorithm into WPF.

So I tried to look at how DropShadowEffect works, but the implementation displayed in Reflector is empty. I also tried to look at what methods from the abstract classes Effect and ShaderEffect I should override and there doesn’t seem to be anything related to actually rendering an effect.

So how do I create my own effect?

Answer 1

The best and fastest way is to use pixel shaders (supported starting with WPF 3.5 SP1 I think) . It will require some shader language (HLSL) knowledge, though 🙂

Here is a tutorial: How Do I: Create Custom Pixel Shader Effects for WPF

a library on codeplex: Windows Presentation Foundation Pixel Shader Effects Library

an article with .NET 4 information (including Sliverlight support which has it too): SilverShader – Introduction to Silverlight and WPF Pixel Shaders