Digital Light & Color

I would like to add a composition guide to the crop tool: 4 lines that show the angle bisector of the 4 corners of a rectangular crop. So, lines at 45 and 135 degrees.
The format of the composition guide files (e.g. Diagonals or Thirds-diagonals) has, logically, the corners of the crop rectangle as a reference, to adapt the guides to the crop size. But in my case the angle of the lines is independent of the crop size, they don't change direction as the crop dimensions change. I don't see how to define them in the current format. Is there a solution?

You cannot implement what you are talking about with the current custom composition guide feature -- it is something I would need to build into Picture Window. As it happens, I believe the type of composition guide you are describing is already implemented under the name: Westhoff Diagonal Method.

You are right, it is the Westhoff Diagonal method and years ago I read the paper he wrote about it. When I still had a b&w analog darkroom, I used a transparent paper with 45deg lines drawn on it on top of the photo paper, to position e.g. an eye in a portrait on the diagonal. And took that away when I exposed the paper, of course.
In case you might build this composition guide into Picture Window in the future, it would be nice if it works in PWPro 7 as well.... Still using both versions.

PWP 8 already has Westhoff Diagonal method built in. I am no longer updating PWP 7.

I see, it's in the "grid" menu. Excuse me, I didn't search well enough.
As I said, I still use PWP7 next to 8, and mainly use 8 for those transformations that are not, or less convenient, in 7. Old habits slowly die. I will use 8 a bit more.
My question has been answered, and even faster than I could imagine: the feature was already there before the request. Thanks.