Based on how non-functional it is I would say Claude churning for a weekend or less.
So probably not really clean room.
Already ArtCraft :D
This was the result of a _single_ prompt. Which actually shows the power of modern LLMs. I already have a from scratch C++ implementation of Photoshop, in my own custom UI toolkit, with my own custom GPU shaders. From scratch. Whole thing, ported over and I started last night. In preliminary benches it's roughly ~20-40% faster than their Photoshop rewrite. Will start heavy optimization passes and see how hard I can push it.
Can I ask what such a prompt looks like? Is it more along the lines of "implement all the features of Photoshop" or a detailed list of all the features that should be implemented?