Is there a way to “shrink to fit” when using PhantomJS?

I looked at this: PhantomJS screen cropping up to the content size , but this is not quite what I want.

I have an element of 600x348 pixels in size on the screen and would like to write it in 5cmx9cm format, but it seems to me that I need to do the scaling to get what I want. Even then it is not very accurate. Is there a way to get a shrink effect on the printer?