[OpenLayers-Users] rotation angle and orthogonal line drawing

[Mika Lehtonen]

Hi,
I have two separate issues. If anyone can give me any advice on them, I 
will be very grateful. I have to admit that I haven't been drilling into 
these very deeply by myself yet. I am just looking for some ideas to 
start with.

First, I have square polygons and modifyFeatures control to drag and 
rotate them. What is the simplest way to get the rotation angle counted 
from the initial position after rotate? Actually the squares are 
orthogonal against the xy-axis at the start, but they can be rotated 
several times and the absolute (rotation against the very starting 
position) rotation will be passed to server after every rotation. So 
should I just observe the vertex which was aligned with the e.g. x-axis 
at the start and count its rotation angle or is there any 
functions/attributes already to use?

Second issue. I have a floor plan. I would like to draw some lines 
orthogonally on top of it. In other words, I would like to lock the 
drawing direction for example to north, west, south and to east only. 
This is familiar feature to all who has been using any CAD software. If 
there is no such feature in OL, could someone give me starting point to 
design such.
One chewing-gum-solution would be using gridlayer and snap control, 
right? With the proper grid spacing, it might work, you know like 
drawing onto grid paper.

I am not looking for ready made solutions, just creative ideas to 
achieve the solutions for my problems. I am also willing to drill into 
OL-code, if some minor development would resolve my needs. maybe someone 
else is also looking for something similar?

cheers,
- mika -