\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{beamerntnu2017common}%[2017-01-06 Common code for NTNU beamer templates]

\RequirePackage{xparse}
\RequirePackage{pdftexcmds}

% Define a string equality test
\long\def\isequal#1#2{\pdf@strcmp{#1}{#2}}

% Get the aspect ratio, 
% http://tex.stackexchange.com/questions/123106/detect-aspect-ratio-in-beamer
\ExplSyntaxOn

\NewDocumentCommand{\ifaspectratio}{mmm}
{
  % Recover the option from those passed to the class
  \keys_set:nf { zunbeltz/beameroptions } { \use:c { opt@beamer.cls } }
  \str_if_eq:nVTF { #1 } \l_zunbeltz_aspectratio_tl { #2 } { #3 }
}

\NewDocumentCommand{\xifaspectratio}{mO{}}
{
  % Recover the option from those passed to the class
  \keys_set:nf { zunbeltz/beameroptions } { \use:c { opt@beamer.cls } }
  \str_case:Vnn \l_zunbeltz_aspectratio_tl { #1 } { #2 }
}

% We need to define only one key, the other are treated as `unknown'
\keys_define:nn { zunbeltz/beameroptions }
{
  aspectratio .tl_set:N = \l_zunbeltz_aspectratio_tl,
  aspectratio .initial:n = 43,
  unknown .code:n = {},
}

% Generate the variants we need
\cs_generate_variant:Nn \keys_set:nn {nf}
\cs_generate_variant:Nn \str_if_eq:nnTF {nV}
\cs_generate_variant:Nn \str_case:nnF {V}

\ExplSyntaxOff
% Aspect ration detection finished

\ifaspectratio{169}{\def\aspect{169}}{\def\aspect{43}}