Resize text in .pgf input

Question

I have some wide graphics as .pgf files. I include them in my .tex document as follows:

\begin{figure}[ht!]
    \centering
    \resizebox{\linewidth}{!}{\input{file.pgf}}
    \caption{the caption}
\end{figure}

Unfortunately, \resizebox{\linewidth}{!} also shrinks the text inside the graphic. How can I rescale the graphic but fix the font size?