DirectX 11 Drawing Circles - directx

Question

I am trying to draw points with various thickness. I was using triangle method but resulting circles had jagged edges.I had to quit this method due to performance issues and visual quality goals of my app. I saw Pixel Shader method in this video. My problem with this method is my point thickness values are not in pixels.They are in meters. Do I have to convert back to World coordinates in pixel shader to measure distance from center? Or, is there another approach to overcome coordinate conversion process?
My attempt:
Topology
dxmanager->Context->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_POINTLIST);
Vertex Shader
struct VOut
{
float4 position : SV_POSITION;
float4 color : COLOR;
float size : RSIZE;
};
VOut main(float3 position : POSITION, float4 color : COLOR, float size: RSIZE)
{
VOut output;
output.position = float4(position, 1);
output.color = color;
output.size = size;
return output;
}
Pixel Shader
float4 main(float4 position : SV_POSITION, float4 color : COLOR, float4 centre : POSITION,float max:RSIZE) : SV_TARGET
{
if (distance(position,centre)<max) // Always False
return color;
return float4(0, 0, 0, 0);
}
Geometry Shader
[maxvertexcount(6)]
void main(point VOut input[1], inout TriangleStream<GOut> OutputStream)
{
GOut P1;
P1.pos = float4(input[0].position.x-input[0].size/2, input[0].position.y - input[0].size/2, input[0].position.z,1);
P1.color = float4(0.6f, 0.4f, 0.8f, 0.5f);
P1.pos = mul(world, P1.pos);
P1.centre = mul(world, input[0].position);
P1.max = input[0].size * scale;
OutputStream.Append(P1);
GOut P2;
P2.pos = float4(input[0].position.x - input[0].size / 2, input[0].position.y + input[0].size / 2, input[0].position.z, 1);
P2.color = float4(0.6f, 0.4f, 0.8f, 0.5f);
P2.pos = mul(world, P2.pos);
P2.centre = mul(world, input[0].position);
P2.max = input[0].size*scale;
OutputStream.Append(P2);
GOut P3;
P3.pos = float4(input[0].position.x + input[0].size / 2, input[0].position.y - input[0].size / 2, input[0].position.z, 1);
P3.color = float4(0.6f, 0.4f, 0.8f, 0.5f);
P3.pos = mul(world, P3.pos);
P3.centre = mul(world, input[0].position);
P3.max = input[0].size * scale;
OutputStream.Append(P3);
GOut P4;
P4.pos = float4(input[0].position.x + input[0].size / 2, input[0].position.y + input[0].size / 2, input[0].position.z, 1);
P4.color = float4(0.6f, 0.4f, 0.8f, 0.5f);
P4.pos = mul(world, P4.pos);
P4.centre = mul(world, input[0].position);
P4.max = input[0].size * scale;
OutputStream.Append(P4);
GOut P5;
P5.pos = float4(input[0].position.x + input[0].size / 2, input[0].position.y - input[0].size / 2, input[0].position.z, 1);
P5.color = float4(0.6f, 0.4f, 0.8f, 0.5f);
P5.pos = mul(world, P5.pos);
P5.centre = mul(world, input[0].position);
P5.max = input[0].size * scale;
OutputStream.Append(P5);
GOut P6;
P6.pos = float4(input[0].position.x - input[0].size / 2, input[0].position.y - input[0].size / 2, input[0].position.z, 1);
P6.color = float4(0.6f, 0.4f, 0.8f, 0.5f);
P6.pos = mul(world, P6.pos);
P6.centre = mul(world, input[0].position);
P6.max = input[0].size * scale;
OutputStream.Append(P6);
}