Ok, here's an implementation that seems to be working pretty well so
far.
`org-latex-img-process` is the new customization. Most of the execute
function is unaltered, but I've added the condition:
```
((and (not imagemagick)
(assoc extension org-latex-img-process))
```
Here's the change in full.
```
(setq org-latex-pdf-process
'("latexmk -f -interaction=nonstopmode -output-directory=%o %f"))
(setq org-latex-img-process
'(("svg" . ("dvisvgm %f -P -n -b min -o %O"))))
(defun org-babel-execute:latex (body params)
"Execute a block of Latex code with Babel.
This function is called by `org-babel-execute-src-block'."
(setq body (org-babel-expand-body:latex body params))
(if (cdr (assq :file params))
(let* ((out-file (cdr (assq :file params)))
(extension (file-name-extension out-file))
(tex-file (org-babel-temp-file "latex-" ".tex"))
(border (cdr (assq :border params)))
(imagemagick (cdr (assq :imagemagick params)))
(im-in-options (cdr (assq :iminoptions params)))
(im-out-options (cdr (assq :imoutoptions params)))
(fit (or (cdr (assq :fit params)) border))
(height (and fit (cdr (assq :pdfheight params))))
(width (and fit (cdr (assq :pdfwidth params))))
(headers (cdr (assq :headers params)))
(in-buffer (not (string= "no" (cdr (assq :buffer params)))))
(org-latex-packages-alist
(append (cdr (assq :packages params))
org-latex-packages-alist)))
(cond
((and (string-suffix-p ".png" out-file) (not imagemagick))
(org-create-formula-image
body out-file org-format-latex-options in-buffer))
((string-suffix-p ".tikz" out-file)
(when (file-exists-p out-file) (delete-file out-file))
(with-temp-file out-file
(insert body)))
((and (not imagemagick)
(assoc extension org-latex-img-process))
(with-temp-file tex-file
(insert (concat
(org-latex-make-preamble
(org-export-get-environment (org-export-get-backend
'latex))
org-format-latex-header
'snippet)
(if headers
(concat "\n"
(if (listp headers)
(mapconcat #'identity headers "\n")
headers) "\n")
"")
"\\begin{document}"
body
"\\end{document}")))
(let ((tmp-pdf (org-babel-latex-tex-to-pdf tex-file)))
(when (file-exists-p out-file) (delete-file out-file))
(let* ((log-buf (get-buffer-create "*Org Babel LaTeX Output*"))
(err-msg "fix")
(img-out (org-compile-file
tmp-pdf
(cdr (assoc "svg" org-latex-img-process))
extension err-msg log-buf)))
(shell-command (format "mv %s %s" img-out out-file)))))
((and (or (string= "svg" extension)
(string= "html" extension))
(executable-find org-babel-latex-htlatex))
;; TODO: this is a very different way of generating the
;; frame latex document than in the pdf case. Ideally, both
;; would be unified. This would prevent bugs creeping in
;; such as the one fixed on Aug 16 2014 whereby :headers was
;; not included in the SVG/HTML case.
(with-temp-file tex-file
(insert (concat
"\\documentclass[preview]{standalone}
\\def\\pgfsysdriver{pgfsys-tex4ht.def}
"
(mapconcat (lambda (pkg)
(concat "\\usepackage" pkg))
org-babel-latex-htlatex-packages
"\n")
(if headers
(concat "\n"
(if (listp headers)
(mapconcat #'identity headers "\n")
headers) "\n")
"")
"\\begin{document}"
body
"\\end{document}")))
(when (file-exists-p out-file) (delete-file out-file))
(let ((default-directory (file-name-directory tex-file)))
(shell-command (format "%s %s" org-babel-latex-htlatex
tex-file)))
(cond
((file-exists-p (concat (file-name-sans-extension tex-file)
"-1.svg"))
(if (string-suffix-p ".svg" out-file)
(progn
(shell-command "pwd")
(shell-command (format "mv %s %s"
(concat (file-name-sans-extension
tex-file) "-1.svg")
out-file)))
(error "SVG file produced but HTML file requested")))
((file-exists-p (concat (file-name-sans-extension tex-file)
".html"))
(if (string-suffix-p ".html" out-file)
(shell-command "mv %s %s"
(concat (file-name-sans-extension tex-file)
".html")
out-file)
(error "HTML file produced but SVG file requested")))))
((or (string= "pdf" extension) imagemagick)
(with-temp-file tex-file
(require 'ox-latex)
(insert
(org-latex-guess-inputenc
(org-splice-latex-header
org-format-latex-header
(delq
nil
(mapcar
(lambda (el)
(unless (and (listp el) (string= "hyperref" (cadr el)))
el))
org-latex-default-packages-alist))
org-latex-packages-alist
nil))
(if fit "\n\\usepackage[active, tightpage]{preview}\n" "")
(if border (format "\\setlength{\\PreviewBorder}{%s}" border)
"")
(if height (concat "\n" (format "\\pdfpageheight %s" height))
"")
(if width (concat "\n" (format "\\pdfpagewidth %s" width))
"")
(if headers
(concat "\n"
(if (listp headers)
(mapconcat #'identity headers "\n")
headers) "\n")
"")
(if fit
(concat "\n\\begin{document}\n\\begin{preview}\n" body
"\n\\end{preview}\n\\end{document}\n")
(concat "\n\\begin{document}\n" body
"\n\\end{document}\n"))))
(when (file-exists-p out-file) (delete-file out-file))
(let ((transient-pdf-file (org-babel-latex-tex-to-pdf tex-file)))
(cond
((string= "pdf" extension)
(rename-file transient-pdf-file out-file))
(imagemagick
(org-babel-latex-convert-pdf
transient-pdf-file out-file im-in-options im-out-options)
(when (file-exists-p transient-pdf-file)
(delete-file transient-pdf-file)))
(t
(error "Can not create %s files, please specify a .png or
.pdf file or try the :imagemagick header argument"
extension))))))
nil) ;; signal that output has already been written to file
body))
```
What do people think? This gives you much more control over how the
latex is compiled and reuses existing functionality for previews.
