Looks like a total beginner question and i apologize for being a shader beginner...
but i thought, if i do a project from view, i would get a non distorted result, but i didn't get it.
Why is that and how can i solve that?
i just took a simple cube, deleted one side face and expanded it in edit mode in x-direction. Then i changed the view so that i can look inside and used "project from view" with this shader: