From 6dbd5ae840f02333f83d40a9c27be06968279563 Mon Sep 17 00:00:00 2001
From: Matt Huszagh <huszaghmatt@gmail.com>
Date: Fri, 28 Aug 2020 22:26:05 -0700
Subject: [PATCH] ob-latex.el: Make latex to svg compilation very customizable

* lisp/ob-latex.el (org-babel-latex-preamble): Add latex preamble
customization.
(org-babel-latex-begin-env): Add latex document environment begin
customization.
(org-babel-latex-end-env): Add latex document environment end
customization.
(org-babel-latex-pdf-svg-process): Add customization for converting a
pdf to svg.
(org-babel-execute:latex): Add specific case for svg generation from
latex block.
---
 lisp/ob-latex.el | 57 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 55 insertions(+), 2 deletions(-)

diff --git a/lisp/ob-latex.el b/lisp/ob-latex.el
index 4b343dd14..359179476 100644
--- a/lisp/ob-latex.el
+++ b/lisp/ob-latex.el
@@ -70,6 +70,45 @@
   :group 'org-babel
   :type 'string)
 
+(defcustom org-babel-latex-preamble
+  (lambda (_)
+    "\\documentclass[preview]{standalone}
+\\def\\pgfsysdriver{pgfsys-tex4ht.def}
+")
+  "Closure which evaluates at runtime to the latex preamble.  It
+takes 1 argument which is the parameters of the source block."
+  :group 'org-babel
+  :type 'function)
+
+(defcustom org-babel-latex-begin-env
+  (lambda (_)
+    "\\begin{document}")
+  "Closure which evaluates at runtime to the begin part of the
+document environment.  It takes 1 argument which is the
+parameters of the source block.  This allows adding additional
+code that will be ignored when exporting the literal latex
+source."
+  :group 'org-babel
+  :type 'function)
+
+(defcustom org-babel-latex-end-env
+  (lambda (_)
+    "\\end{document}")
+  "Closure which evaluates at runtime to the end part of the
+document environment.  It takes 1 argument which is the
+parameters of the source block.  This allows adding additional
+code that will be ignored when exporting the literal latex
+source."
+  :group 'org-babel
+  :type 'function)
+
+(defcustom org-babel-latex-pdf-svg-process
+  "inkscape --pdf-poppler %f -T -l -o %O"
+  "Command used to convert a PDF file to an SVG file when
+executing a latex source block."
+  :group 'org-babel
+  :type 'string)
+
 (defcustom org-babel-latex-htlatex-packages
   '("[usenames]{color}" "{tikz}" "{color}" "{listings}" "{amsmath}")
   "Packages to use for htlatex export."
@@ -114,12 +153,26 @@ This function is called by `org-babel-execute-src-block'."
 			 (mapconcat #'identity headers "\n"))))
 	   (org-create-formula-image
             body out-file org-format-latex-options in-buffer)))
+	 ((string= "svg" extension)
+	  (with-temp-file tex-file
+		 (insert (concat (funcall org-babel-latex-preamble params)
+			 (mapconcat #'identity headers "\n")
+			 (funcall org-babel-latex-begin-env)
+			 body
+			 (funcall org-babel-latex-end-env))))
+	  (let ((tmp-pdf (org-babel-latex-tex-to-pdf tex-file)))
+                  (let* ((log-buf (get-buffer-create "*Org Babel LaTeX Output*"))
+                         (err-msg "org babel latex failed")
+                         (img-out (org-compile-file
+	                           tmp-pdf
+                                   (list org-babel-latex-pdf-svg-process)
+                                   extension err-msg log-buf)))
+                    (shell-command (format "mv %s %s" img-out out-file)))))
          ((string-suffix-p ".tikz" out-file)
 	  (when (file-exists-p out-file) (delete-file out-file))
 	  (with-temp-file out-file
 	    (insert body)))
-	 ((and (or (string= "svg" extension)
-		   (string= "html" extension))
+	 ((and (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
-- 
2.28.0