[NTG-context] externalfigure and width/height scaling

[Hans Hagen]

nico wrote:
> Hello,
>
> I am new to ConTeXt, so please be patient with my newbie questions.  
> Looking at the \externalfigure capabilities, I haven't found any option  
> allowing to scale only one dimension (or scale both dimensions in an  
> anamorphous way).
>
> Am I right, and if so what is the best method to perform this?
>
> I thought about using the \getfiguredimensions macro to get the natural  
> dimensions, and then use something like  
> width=0.2\imgwidth,height=0.8\imgheight, but it is a pity that the  
> externalfigure interface does not allow this directly (something like  
> wscale and hscale options).
>   
there is indeed no xscale and yscale (although 
\scale[sx=1.5,sy=2,3]{...} is available)

% put this in cont-new.tex

\unprotect

\let\@@efxscale\empty
\let\@@efyscale\empty

\def\setnaturalfiguresize
  {\doifsomething\@@efwidth
     {\global\figwid\@@efwidth}%
   \doifsomething\@@efheight
     {\global\fighei\@@efheight}%
   \doifsomething\@@efscale
     {\figxsca\@@efscale
      \figysca\@@efscale}%
   \doifsomething\@@efxscale
     {\figxsca\@@efxscale}%
   \doifsomething\@@efyscale
     {\figxsca\@@efyscale}}

\def\setscalefiguresize
  {\doifsomething{\@@efscale\@@efxscale\@@efxscale}
     {\doapplyfigurescale\figwid\@@epw\figxsca\@@efxscale
      \doapplyfigurescale\fighei\@@eph\figysca\@@efyscale
      \global\figwid\zeropoint
      \global\fighei\zeropoint
      \doifelsenothing\@@efmaxwidth
        {\doifsomething\@@efmaxheight
           {\ifdim\@@eph>\@@efmaxheight
              \global\fighei\@@efmaxheight
            \fi}}
        {\ifdim\@@epw>\@@efmaxwidth
           \global\figwid\@@efmaxwidth
         \fi}}}

  \def\doapplyfigurescale#1#2#3#4%
    {\ifcase0#4\relax % @@ef.scale kan empty zijn
       \ifcase0\@@efscale\relax % @@efscale kan empty zijn
         #3=\plusthousand
       \else
         #3=\@@efscale
       \fi
     \else
       #3=#4%
     \fi
     \relax % important !
     
\global#1\ifnum#3=\plusthousand#2\else\dimexpr#3\dimexpr#2/\plusthousand\relax\relax\fi
     \relax}

\def\setdimensionfiguresize
  {\ifdim\figwid>\zeropoint\relax
     \ifdim\fighei>\zeropoint\relax
       \dosetdimensionfiguresize
         {\docalculatefigurescale\fighei\@@eph\figysca
          \docalculatefigurescale\figwid\@@epw\figxsca}%
         {\docalculatefigurescale\fighei\@@eph\figysca
          \docalculatefigurescale\figwid\@@epw\figxsca}%
         {\docalculatefigurescale\fighei\@@eph\figysca
          \docalculatefigurescale\figwid\@@epw\figxsca}%
     \else
       \dosetdimensionfiguresize
         {\docalculatefigurescales\figwid\@@epw\fighei\@@eph}%
         {\docalculatefigurescales\figwid\@@epw\fighei\@@eph}%
         {\docalculatefigurescales\figwid\@@epw\fighei\@@eph}%
     \fi
   \else
     \ifdim\fighei>\zeropoint\relax
       \dosetdimensionfiguresize
         {\docalculatefigurescales\fighei\@@eph\figwid\@@epw}%
         {\docalculatefigurescales\fighei\@@eph\figwid\@@epw}%
         {\docalculatefigurescales\fighei\@@eph\figwid\@@epw}%
     \else
       \dosetdimensionfiguresize
         {\doapplyfigurescale\figwid\@@epw\figxsca\@@efxscale
          \doapplyfigurescale\fighei\@@eph\figysca\@@efyscale}%
         {\docalculatefigurescales\figwid\@@epw\fighei\@@eph}%
         {\docalculatefigurescales\fighei\@@eph\figwid\@@epw}%
     \fi
   \fi}

\protect

% end of patch

\starttext

\externalfigure[cow][scale=1000]
\externalfigure[cow][scale=200]
\externalfigure[cow][yscale=200]
\externalfigure[cow][xscale=800,yscale=200]

\stoptext