Programatically resizing individual Groups of a PSD, then rendering them to PNG in C++

Question

I want to know if it is possible to read PSD files from C++, resize 1 specific Group programmatically, then render the result to a PNG. So far I found some code that reads and renders PSD files "as is", here: http://www.codeproject.com/Articles/10398/Import-Adobe-Photoshop-psd-images

The problem I foresee is that just rendering a PSD as is is pretty easy, but resizing Groups programmatically would require much more effort.

Answer 1

So far, there seems to be no library to do what I want to do. Reading out the composite preview from PSD files is easy, as demonstrated in the codeproject link I posted in my question, but manipulating individual groups or layers, then rendering the composite preview again seems impossible for now.