I have an image with a set "canvas" size of 400x400. I want to zoom in and out on this image with a slider or zoom in/out buttons but keep the canvas dimensions. I've found many examples, but they resize the image (eg 500x500) or have a hover box, etc... etc... I need to keep that 400x400 and "magnify" it. Zooming in on the center is fine, just can't figure out how to pull it off.

Thanks in advance for any thoughts or examples.