[Orgmode] :scale option in org-format-latex-options

[Dan Davison]

When creating png images of latex fragments in org-create-formula-image,
the :scale option in org-format-latex-options is not currently honoured
(it's commented out). My dvipng documentation says

       -x num

           Set the x magnification ratio to num/1000. Overrides the
           magnification specified in the DVI file.  Must be between 10
           and 100000.  It is recommended that you use standard magstep
           values (1095, 1200, 1440, 1728, 2074, 2488, 2986, and so on)
           to help reduce the total number of PK files generated.  num
           may be a real number, not an integer, for increased
           precision.

I don't know what a magstep is, let alone a PK file, but it seems to
suggest something like the patch below. Is there any reason not to make
a change like this?

--8<---------------cut here---------------start------------->8---
diff --git a/lisp/org.el b/lisp/org.el
index aa22309..e5d046e 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -15043,6 +15043,7 @@ Some of the options can be changed using the variable
                   (font-height (get-face-font 'default))
                 (face-attribute 'default :height nil)))
         (scale (or (plist-get options (if buffer :scale :html-scale)) 1.0))
+        (dvipng-scale (number-to-string (* 1000 scale)))
         (dpi (number-to-string (* scale (floor (* 0.9 (if buffer fnh 140.))))))
         (fg (or (plist-get options (if buffer :foreground :html-foreground))
                 "Black"))
@@ -15078,7 +15079,7 @@ Some of the options can be changed using the variable
          (call-process "dvipng" nil nil nil
                        "-fg" fg "-bg" bg
                        "-D" dpi
-                       ;;"-x" scale "-y" scale
+                       "-x" dvipng-scale "-y" dvipng-scale
                        "-T" "tight"
                        "-o" pngfile
                        dvifile)
--8<---------------cut here---------------end--------------->8---


Also, this looks to me like a typo in the docstring of
org-format-latex-options, is that right?


--8<---------------cut here---------------start------------->8---
diff --git a/lisp/org.el b/lisp/org.el
index aa22309..e5d046e 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -2860,7 +2860,7 @@ This is a property list with the following properties:
              \"$\"      find math expressions surrounded by $...$
              \"$$\"     find math expressions surrounded by $$....$$
              \"\\(\"     find math expressions surrounded by \\(...\\)
-             \"\\ [\"    find math expressions surrounded by \\ [...\\]"
+             \"\\[\"    find math expressions surrounded by \\[...\\]"
   :group 'org-latex
   :type 'plist)
--8<---------------cut here---------------end--------------->8---
 

Dan