How does bounds work in combination with bearing?

[musicformellons]

I am trying to hack something related to #1740 as I would think that is possible. To do so I need to know the length of the side of the viewbox, X:

Blue shaded is the mobile viewbox. Alpha is the bearing.

As far as I remember math, X would be equal to (after some nasty equation solution work):
{(Northbound - Southbound) x cosine bearingindegrees - (Eastbound - Westbound) x sine bearingindegrees} / (1 - (sine bearingindegrees)²)

Results are not satisfying, also not after extensive fiddling. So right now my question is:

• Is my understanding as depicted in the drawing of how the bounds relate to the viewbox when there is a bearing correct?

Don't dare to ask but feel free to check my math.

[musicformellons]

I think this:
http://wiki.openstreetmap.org/wiki/Bounding_Box

tells me that the concept I use of bounding box is correct, so any idea what I am doing wrong?

[musicformellons]

Mmmh, calculation must be wrong as X must be undetermined: suddenly realized that although the bearing is a given you can still make different sized viewport rectangles within the bounding box rectangle with different lengths of X. Will close this and continue looking at:
https://www.mapbox.com/mapbox-gl-js/api/#Map.unproject

as that provides maybe a solution for me.