>>>>> David Kastrup <dak@gnu.org> writes:
> The current code is already a sledgehammer that looks like a "not again"
> approach of evading yet another changed API.  Looking at the history of
> the recommended replacements, I see that the Ghostscript developers
> state that some of those were removed in some Ghostscript versions but
> reinstated.

> So it's conceivable that reverting the last change to these code lines
> is all that it would take to work with current Ghostscript (at the price
> of breaking _some_ older version).

> Might be worth a try.

Thanks for your advice, the attached patch works well.  The foreground
color of the generated image matches with the default face of emacs
without `preview-pdf-color-string', at least for gs 9.27 on my machine.

> (at the price of breaking _some_ older version).

I don't know which version of gs needs `preview-pdf-color-string'.
Maybe we should not delete it and instead introduce a user option as a
flag whether to disable the function or not.  What do others think?

Regards,
Ikumi Keita