how to Zoom drawn ellipse using graphic path

Hello,

I am developing application in Windows form c#. I am referring https://www.codeproject.com/Articles/22549/OpenS-CAD-a-simple-D-CAD-application .

1.I have 3 options say optRed,optWhite and optBlue.

my requirement is to draw filled circle of corresponding color based on clicked options.

2. To draw filled circles of different color, I have maintained separate graphics path for each color type circle.

3.But I am unable to Zoom functionality to these drawn circles.

4.Also,I want to remove specific subpath from graphics path. How can i do that?