Hi Keita and Ken,
Le 22/06/2019 à 14:35, Ikumi Keita a écrit :
Perhaps it might be a loophole left in gs-9.27 and we possibly have to
be prepared that the future Ghostscript disables this feature as well.
Is it not possible to alter the production of the PDF file in the
first place ?
I'm not currently sure, but I'll propose other AUCTeX developers that
idea.
Thank you very much Ken, I appreciate your effort provided for us.
I have not looked up in detail (I am still with gs 9.26, and besides I
do not use that much the preview functionality -- hope that is pardonable),
but this small tex file
\documentclass{article}
\AtBeginDocument{\RequirePackage{color}\pagecolor{yellow}\color{red}}
\begin{document}
\[E = mc^2\]
\end{document}
works as expected, hence it seems it is quite feasible to alter the PDF
production as suggested by Ken.
I only tested with pdflatex. The document above is using
\AtBeginDocument so that this can be added to the pdflatex
invocation which was explained by Keita. (I have forgotten
the details of whether AUCTeX re-uses the user preamble
declarations but anyhow I tested with a an extra
\usepackage[...options...]{color}, where for options I used
monochrome or dvipsnames and it compiled).
Here is another example
\documentclass{article}
\AtBeginDocument{\RequirePackage{color}\pagecolor[rgb]{0.8,0.85,1}\color[gray]{0.75}}
\begin{document}
\[E = mc^2\]
\end{document}
which uses the "rgb" model (3 decimal numbers between zero and one, comma
separated)
and the "gray" model. There is also the "cmyk" model.
rgb Red Green Blue: A comma separated list of three numbers between 0 and 1,
giving the components of the colour.
cmyk Cyan Magenta Yellow [K]Black: A comma separated list of four numbers
between 0 and 1, giving the components of the colour according to the additive
model used in most printers.
gray Grey scale: a single number between 0 and 1.
and the "named" model which by default uses 68 names so called dvipsnames.
Package xcolor has more extensive interface (and documentation) but
quite probably color package is enough.
But perhaps I am missing a key aspect of the issue here
(which as said above I have not myself have had to deal with).
From my naive stand, the sole problem is to convert the emacs color
specs into color package specs using syntax as above.