How to Soften Edges with Feathering in C# like photoshop

Question

Dear all,

 

Please help me

I want to create a feathering feature on images like photoshop in C#.

 

can anyone help me on this

 

example is given in following link:

 

http://www.dummies.com/software/adobe/photoshop/how-to-soften-edges-with-feathering-in-adobe-photoshop-cs6/