Re: preview latex fragments

[Nick Dokos <nicholas.dokos@hp.com>]

Andreas Leha <andreas.leha@med.uni-goettingen.de> wrote:

> Andreas Leha <andreas.leha@med.uni-goettingen.de> writes:
> 
> > Hi Bastien,
> >
> > Bastien <bzg@gnu.org> writes:
> >
> >> Hi Andreas,
> >>
> >> Andreas Leha <andreas.leha@med.uni-goettingen.de> writes:
> >>
> >>> I experience a problem with the preview of latex fragments:  I can not
> >>> change the foreground color (in org-format-latex-options).  On a dark
> >>> background, the black fragments are barely visible.
> >>>
> >>> The settings for background and scale (in the same variable) are
> >>> honored, though.
> >>
> >> Can you post a reproducible case with a specific Org version?
> >
> > Thanks a lot for looking into this, but:
> > No, I can not.  Now it works as it should.  No clue what happened
> > actually.  Sorry for the noise.
> >
> > - Andreas
> 
> 
> Actually, now I can again reproduce it.  The problem seems to be tikz:
> With tikz in the latex header, foreground is always black.  So probably
> more a LaTeX-issue?
> 
> Example: Change the :foreground color in org-format-latex-options to
> "Red" and do the preview (C-c C-x C-l) on this subtree:
> 
> #+begin_org
> #+LATEX_HEADER: \usepackage{tikz}
> 
> 
> * Test 
>   Hi, 
> 
>   set :foreground in org-format-latex-options to "Red" and take this
>   fragment $1 = 2$ and press C-c C-x C-l.
> #+end_org
> 
> 
> So the question becomes:
> Can I make the foreground changing work even with tikz loaded in the
> latex document?
> 

I can reproduce it too, without tikz. I have a green-on-black setup but
I think the underlying reason (at least in my case: Andreas's case might
be different) is minted. I'm appending an org file with my
investigation.

Nick

--8<---------------cut here---------------start------------->8---

* previewing a latex fragment produces a black blob 

I use a green-on-black scheme:

#+BEGIN_SRC elisp
  (setq frame-inherited-parameters '(foreground-color background-color))

  (set-foreground-color "green")
  (set-background-color "black")
  (set-cursor-color "red")
  (set-mouse-color "red")
  (set-face-foreground 'menu "light grey")
  (set-face-background 'menu "black")

#+END_SRC

Here's a simple latex fragment:

\[
2 + 2 = 4
\]

Previewing it with C-c C-x C-l, I get an invisible black blob.

The current value of org-format-latex-options is

(:foreground default
 :background default
 :scale 1.4
 :html-foreground "Black"
 :html-background "Transparent"
 :html-scale 1.0
 :matchers
	     ("begin" "$1" "$" "$$" "\\(" "\\["))

If I link to the produced png file:

[[file:./ltxpng/dark-bg_ca60306327ae6b995f92a473e1e8787c7917c488.png]]

and follow the link, I get nothing. The file has size 84 which seems
ridiculously low.  Indeed, I can ``display'' it and get info on the
image: the channel statistics show it's all black.

OTOH, if I take the following tex program, latex and dvipng it with
the same parameters, I get a reasonable result:

#+BEGIN_EXAMPLE
\documentclass{article}

\begin{document}
\[
2 + 2 = 4
\]
\end{document}

%%% Local Variables: 
%%% mode: latex
%%% TeX-master: "fragment"
%%% End: 

#+END_EXAMPLE

#+BEGIN_SRC sh
 latex fragment.tex
 dvipng -fg "rgb 0 1 0" -bg "rgb 0 0 0" -D 140 -T tight -o fragment.png fragment.dvi

#+END_SRC

So either the production of the fragment is wrong or the production of
the png from the fragment, probably the former. The latex code for the
fragment follows. If I again do the latex/dvipng run by hand (with
--shell-escape to accommodate minted) I get an all-black png. If I
comment out minted, it works.

#+BEGIN_SRC latex
\documentclass{article}
\usepackage[usenames]{color}
\usepackage{amsmath}
\usepackage[mathscr]{eucal}
\pagestyle{empty}             % do not remove
\usepackage{minted}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
% Package fixltx2e omitted
\usepackage{graphicx}
% Package longtable omitted
% Package float omitted
% Package wrapfig omitted
\usepackage{soul}
\usepackage{textcomp}
\usepackage{marvosym}
\usepackage{wasysym}
\usepackage{latexsym}
\usepackage{amssymb}
% Package hyperref omitted
\tolerance=1000
% The settings below are copied from fullpage.sty
\setlength{\textwidth}{\paperwidth}
\addtolength{\textwidth}{-3cm}
\setlength{\oddsidemargin}{1.5cm}
\addtolength{\oddsidemargin}{-2.54cm}
\setlength{\evensidemargin}{\oddsidemargin}
\setlength{\textheight}{\paperheight}
\addtolength{\textheight}{-\headheight}
\addtolength{\textheight}{-\headsep}
\addtolength{\textheight}{-\footskip}
\addtolength{\textheight}{-3cm}
\setlength{\topmargin}{1.5cm}
\addtolength{\topmargin}{-2.54cm}
\begin{document}
\[
2 + 2 = 4
\]
\end{document}

#+END_SRC
--8<---------------cut here---------------end--------------->8---