rockbox/manual/advanced_topics/viewports/grayscale-conditional.tex

\begin{example}
    %?C<%Vd(a)|%Vd(b)>
    %Vl(a,10,10,50,50,-)
    %Cl(0,0,50,50,c,c)
    %Cd
    %Vl(a,0,70,70,14,1)
    %s%acThere you have it: Album art.
    %Vl(b,20,14,50,14,1)
    %t(1)%acWarning:;%t(.1) 
    %Vl(b,20,30,50,50,1)
    %sNo album art found
    %scheck your filenames.
\end{example}
This example checks for album art. Album art will be displayed in viewport `a', if
it is found. Otherwise a flashing warning will be displayed in viewport `b'.