> I have a problem with instant preview of equations (which
> I shut off). I find that defined math symbols don't show up.
>
> If I define
>
> \newcommand\Pc{P^c}
>
> and then have an equation
>
> \Pc = P^c
>
> the left-hand side will show up in the preview, but not the
> right. Nothing shows up, including in the .dvi or .png files,
Where do you define \newcommand? If you add it to the LyX preamble, then it
should be exported to the preview LaTeX file. If you define it as ERT in the
body of the LyX document, it won't be exported.
You can check yourself. The preview.tex file that is used to generate your
previews will be in the LyX temp directory.
> I also get messages such as shown below when the equation preview
> processes and equation (perhaps a side effect of something else)
> \special{!/preview <at> version(11.84)def}. dvipng warning: at
> (4294967070,4294967271) ignored header \special{!userdict
> begin/preview-bop-level 0 def/bop-hook{/preview-bop-level dup
> load dup 0 le{/isls false def/vsize 792 def/hsize 612 def}if 1
> add store}bind def/eop-hook{/preview-bop-level dup load dup 0
> gt{1 sub}if store}bind def end}.
The previews are generated using a python script, lyxpreview2bitmap.py, that
itself uses external tools. The script can either use dvipng to convert a .dvi
file directly to multiple .png files containing the previewed snippets, or it
can use dvips and gs. This latter approach is slower, but gs understands all
PostScript specials inserted in the .dvi. dvipng simply doesn't. So, the
warning is simply telling you that dvipng has encountered a PostScript
special. It looks like it ignored it.
You can use dvips and gs rather than dvipng by editing the
lyxpreview2bitmap.py script:
156 # This can go once dvipng becomes widespread.
157 dvipng = find_exe(["dvipng"], path)
158 if dvipng == None:
Comment out the existing line 157 and add a line
dvipng = None
Angus
