[2005] Scale graphics path

Hi all

I have created a simple tool to create graphics paths and produce simple source code for some skinning tools and tutorials im doing. This little tool lets you load an image/s, click parts of an image to make a path, on click a point is added to the point array or a path which can be used for a clipping path.
What I am trying to acheive is to let the user zoom in on the image so they can place more acurate points to give a smoother, more acurate path.
The problem is that I dont know how to zoom out while making the path stick to the points it was intended to or for that matter making the existing path expand when you zoom in. I could upload source code, but its of no relevance.

Thanks in advance.