Add golden spiral variant
Currently in darktable there is only one way a golden spiral guide line is constructed. This fits well for landscape modes, but does look awkward for portrait modes. The flipping options do not allow to transform the one into the other. It would be very helpful if the other way could be chosen too. Maybe the spiral guides should and their derivativeseven be rotated upon rotating the crop aspect rather than constructing them the same way (which is essentially just stretching them, if I am not mistaken).
To illustrate what I mean, the attached sketch shows the first two path sections of the two construction ways of the golden spiral in a portrait mode 5:7 rectangle, where the black one is the one currently available in darktable and the red one is the one which I propose to be added.