Efficiently moving things around in zig-zag Graphics buffer visualized w/ 24/32 bpp displays / neopixel strings

@Gordon, I know that Graphics class is natively implemented and exposes through a wrapper the buffer directly as value and with and height through methods. I plan to write as prototypic extension as module that can copy, cut, paste - implemented in it's core in C. For that I need t know how the Graphics object was setup (w, h, bpp and options)... and to get to that, I would need to know how I get to with just the pointer (pointing to the meta or header of the object).

Therefore:

How Graphics instance's 'top layer' is structured? - Where would I look for that information?