org-preview-latex rendering weirdness when a space after initial inline expression delimiter

Question

\(S\) renders fine. No problem here.

$S$ renders fine. No problem here.

$ S $ does nothing. I wouldn't expect this. Comment below referencing manual explains this case.

$S $ does nothing. I wouldn't expect this. Comment below referencing manual explains this case.

\( S \) renders with an image of TLT TLT over the expression. Using luatex. Weird. This remains unexplained.

\(S \) renders fine. Similar to previous but notice no space after initial inline expression delimiter.

I wouldn't expect spaces just after the opening inline expression delimiter to be a problem.

Question: Any ideas on what I should look at in my config to allow space after opening inline delimiter \(?

This issue happens when rendering org-mode latex fragments. I have found that it happens with the default value of org-preview-latex-process-alist of:

((dvipng :programs
         ("latex" "dvipng")
         :description "dvi > png" :message "you need to install the programs: latex and dvipng." :image-input-type "dvi" :image-output-type "png" :image-size-adjust
         (1.0 . 1.0)
         :latex-compiler
         ("latex -interaction nonstopmode -output-directory %o %f")
         :image-converter
         ("dvipng -D %D -T tight -o %O %f"))
 (dvisvgm :programs
          ("latex" "dvisvgm")
          :description "dvi > svg" :message "you need to install the programs: latex and dvisvgm." :image-input-type "dvi" :image-output-type "svg" :image-size-adjust
          (1.7 . 1.5)
          :latex-compiler
          ("latex -interaction nonstopmode -output-directory %o %f")
          :image-converter
          ("dvisvgm %f -n -b min -c %S -o %O"))
 (imagemagick :programs
              ("latex" "convert")
              :description "pdf > png" :message "you need to install the programs: latex and imagemagick." :image-input-type "pdf" :image-output-type "png" :image-size-adjust
              (1.0 . 1.0)
              :latex-compiler
              ("pdflatex -interaction nonstopmode -output-directory %o %f")
              :image-converter
              ("convert -density %D -trim -antialias %f -quality 100 %O")))

and default value for org-preview-latex-default-process of: dvipng.

Update: This happens when Org version > 9.0 uses its default config, i.e., no use of luatex. I am no longer using luatex but the problem still remains.

Answer 1

For the $-delimited cases, there is a simple explanation: you are not allowed to have a space after the opening delimiter and before the closing delimiter. The manual says:

Text within the usual LaTeX math delimiters. To avoid conflicts with currency specifications, single ‘$’ characters are only recognized as math delimiters if the enclosed text contains at most two line breaks, is directly attached to the ‘$’ characters with no whitespace in between, and if the closing ‘$’ is followed by whitespace, punctuation or a dash. For the other delimiters, there is no such restriction, so when in doubt, use \(...\) as inline math delimiters.

Using default settings for the dvipng section of org-preview-latex-process-alist and the dvipng setting for org-preview-latex-default-process, all the \(...\) constructs work, both when exporting to PDF and when previewing.

One possibility is that you have old files produced by LuaTeX, polluting your environment, in particular, the PNG files in the ltximg/ subdirectory. When you remove those, the preview mechanism will be forced to recreate them with the current settings.