UVs on procedurally generated mesh

Hi all,
I am trying to calculate the uvs for a mesh i generate in code. Its a very simple circle (2d)


and I want to texture it such that a texture like this

i am trying to work out the uv like this

		uvs <em>= new Vector2((verts_.x+radius)/(2*radius) ,_</em> 


but this just ends in a very distorted image.
Can anyone see the flaw?

uvs = new Vector2(0.5f + (verts_.x)/(2radius) ,
0.5f + (verts.y)/(2radius));

figured it out_