[AUCTeX] preview XeLaTeX, change foreground possible?

[XeCycle]

Hello I'm using preview-latex, and using XeLaTeX.  Configuration
is like this:

(setq TeX-engine-alist
      '((xelatex "XeLaTeX" "xetex" "xelatex" "xelatex")))
(add-hook 'LaTeX-mode-hook
          '(lambda ()
             (setq TeX-engine 'xelatex)))

Preview does work, but I'm using a dark gray background in Emacs,
it's tough to recognize the preview images.  I searched the web,
and found someone said `with pdflatex, foreground appears fixed
to black'.  Is it still the case with XeLaTeX?  I tried
TeX-PDF-mode, didn't help.

Thank you.

-- 
Carl Lei (XeCycle)
Department of Physics, Shanghai Jiao Tong University
OpenPGP public key: 7795E591
Fingerprint: 1FB6 7F1F D45D F681 C845 27F7 8D71 8EC4 7795 E591

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