This question is a follow up of TikZ: how to find the intersection of two extended lines?
I have a moderately complicated TikZ graphic that shows the setup of an optical system. I need to calculate the intersection of two extended lines defined as the lines which pass respectively through (A)--(B) and (C)--(D).
I have a few
\def at the beginning which I can modify to alter some parameters of the optics. These
\def obviously also alter the relative positioning of the four points. The solution proposed in the question I linked is not perfect for me, because I can't a priorii know the length I should use in the
$(A)!length!(B)$, neither I can do
\path [name path=AB] (A) -- ($(B)!-100cm!(A)$);, which creates an enormous line, even if not drawn.
Mi ideal solution would be something like the one proposed by Count-Zero using
tkz-euclide package, which it's quite hard for me to use because I can't translate my whole drawing in
tkz-euclide style due to the lack of english documentation of the package...