Allow to use imagemagick for previewing LaTeX fragements.

* org.el (org-latex-create-formula-image-program): New option
to use either dvipng or imagemagick to convert and preview
LaTeX fragments.
(org-preview-latex-fragment, org-format-latex): Handle the new
option.
(org-create-formula-image-with-dvipng): Rename from
`org-create-formula-image'.
(org-create-formula-image-with-imagemagick): New defun to
handle LaTeX preview with imagemagick.
(org-latex-color, org-latex-color-format): New defuns to
handle color conversions.

* org-latex.el (org-latex-to-pdf-process, org-export-as-pdf):
Allow to use imagemagick to convert LaTeX fragments.

* org-html.el (org-export-html-preprocess): Ditto.

* org-exp.el (org-export-with-LaTeX-fragments): Ditto.

* org.texi (@LaTeX{} fragments): Document imagemagick as an
alternative to dvipng.

doc/org.texi

@@ -9421,10 +9421,11 @@ this regularly or on pages with significant page views, you should install
 server in order to limit the load of our server.}.  Finally, it can also
 process the mathematical expressions into images@footnote{For this to work
 you need to be on a system with a working @LaTeX{} installation.  You also
-need the @file{dvipng} program, available at
-@url{http://sourceforge.net/projects/dvipng/}.  The @LaTeX{} header that will
-be used when processing a fragment can be configured with the variable
-@code{org-format-latex-header}.}  that can be displayed in a browser or in
+need the @file{dvipng} program or the @file{convert}, respectively available
+at @url{http://sourceforge.net/projects/dvipng/} and from the
+@file{imagemagick} suite.  The @LaTeX{} header that will be used when
+processing a fragment can be configured with the variable
+@code{org-format-latex-header}.} that can be displayed in a browser or in
 DocBook documents.
 
 @LaTeX{} fragments don't need any special marking at all.  The following

lisp/org-exp.el

@@ -540,12 +540,14 @@ This option can also be set with the +OPTIONS line, e.g. \"LaTeX:mathjax\".
 
 Allowed values are:
 
-nil        Don't do anything.
-verbatim   Keep everything in verbatim
-dvipng     Process the LaTeX fragments to images.
-           This will also include processing of non-math environments.
-t          Do MathJax preprocessing if there is at least on math snippet,
-           and arrange for MathJax.js to be loaded.
+nil             Don't do anything.
+verbatim        Keep everything in verbatim
+dvipng          Process the LaTeX fragments to images.
+                This will also include processing of non-math environments.
+imagemagick     Convert the LaTeX fragments to pdf files and use imagemagick
+                to convert pdf files to png files.
+t               Do MathJax preprocessing if there is at least on math snippet,
+                and arrange for MathJax.js to be loaded.
 
 The default is nil, because this option needs the `dvipng' program which
 is not available on all systems."
@@ -555,6 +557,7 @@ is not available on all systems."
 	  (const :tag "Do not process math in any way" nil)
 	  (const :tag "Obsolete, use dvipng setting" t)
 	  (const :tag "Use dvipng to make images" dvipng)
+	  (const :tag "Use imagemagick to make images" imagemagick)
 	  (const :tag "Use MathJax to display math" mathjax)
 	  (const :tag "Leave math verbatim" verbatim)))
 

lisp/org-html.el

@@ -697,6 +697,7 @@ The default is an extended format of the ISO 8601 specification."
       ((eq (plist-get parameters :LaTeX-fragments) 'verbatim) 'verbatim)
       ((eq (plist-get parameters :LaTeX-fragments) 'mathjax ) 'mathjax)
       ((eq (plist-get parameters :LaTeX-fragments) t        ) 'mathjax)
+      ((eq (plist-get parameters :LaTeX-fragments) 'imagemagick) 'imagemagick)
       ((eq (plist-get parameters :LaTeX-fragments) 'dvipng  ) 'dvipng)
       (t nil))))
   (goto-char (point-min))

lisp/org-latex.el

@@ -632,11 +632,24 @@ allowed.  The default we use here encompasses both."
   '("pdflatex -interaction nonstopmode -output-directory %o %f"
     "pdflatex -interaction nonstopmode -output-directory %o %f"
     "pdflatex -interaction nonstopmode -output-directory %o %f")
-  "Commands to process a LaTeX file to a PDF file.
-This is a list of strings, each of them will be given to the shell
-as a command.  %f in the command will be replaced by the full file name, %b
-by the file base name (i.e. without extension) and %o by the base directory
-of the file.
+  "Commands to process a LaTeX file to a PDF file and process latex
+fragments to pdf files.By default,this is a list of strings,and each of
+strings will be given to the shell as a command. %f in the command will
+be replaced by the full file name, %b by the file base name (i.e. without
+extension) and %o by the base directory of the file.
+
+If you set `org-create-formula-image-program'
+`org-export-with-LaTeX-fragments' to 'imagemagick, you can add a
+sublist which contains your own command(s) for LaTeX fragments
+previewing, like this:
+
+   '(\"xelatex -interaction nonstopmode -output-directory %o %f\"
+     \"xelatex -interaction nonstopmode -output-directory %o %f\"
+     ;; use below command(s) to convert latex fragments
+     (\"xelatex %f\"))
+
+With no such sublist, the default command used to convert LaTeX
+fragments will be the first string in the list.
 
 The reason why this is a list is that it usually takes several runs of
 `pdflatex', maybe mixed with a call to `bibtex'.  Org does not have a clever
@@ -1089,22 +1102,24 @@ when PUB-DIR is set, use this as the publishing directory."
 	    (funcall cmds (shell-quote-argument file))
 	  (while cmds
 	    (setq cmd (pop cmds))
-	    (while (string-match "%b" cmd)
-	      (setq cmd (replace-match
-			 (save-match-data
-			   (shell-quote-argument base))
-			 t t cmd)))
-	    (while (string-match "%f" cmd)
-	      (setq cmd (replace-match
-			 (save-match-data
-			   (shell-quote-argument file))
-			 t t cmd)))
-	    (while (string-match "%o" cmd)
-	      (setq cmd (replace-match
-			 (save-match-data
-			   (shell-quote-argument output-dir))
-			 t t cmd)))
-	    (shell-command cmd outbuf)))))
+	    (cond
+	     ((not (listp cmd))
+	      (while (string-match "%b" cmd)
+		(setq cmd (replace-match
+			   (save-match-data
+			     (shell-quote-argument base))
+			   t t cmd)))
+	      (while (string-match "%f" cmd)
+		(setq cmd (replace-match
+			   (save-match-data
+			     (shell-quote-argument file))
+			   t t cmd)))
+	      (while (string-match "%o" cmd)
+		(setq cmd (replace-match
+			   (save-match-data
+			     (shell-quote-argument output-dir))
+			   t t cmd)))
+	      (shell-command cmd outbuf)))))))
     (message (concat "Processing LaTeX file " file "...done"))
     (setq errors (org-export-latex-get-error outbuf))
     (if (not (file-exists-p pdffile))

lisp/org.el

@@ -3390,6 +3390,20 @@ When using MathToWeb as the converter, set this to
 	  (const :tag "None" nil)
 	  (string :tag "\nShell command")))
 
+(defcustom org-latex-create-formula-image-program 'dvipng
+  "Program to convert LaTeX fragments with.
+
+dvipng          Process the LaTeX fragments to dvi file, then convert
+                dvi files to png files using dvipng.
+                This will also include processing of non-math environments.
+imagemagick     Convert the LaTeX fragments to pdf files and use imagemagick
+                to convert pdf files to png files"
+  :group 'org-latex
+  :version "24.1"
+  :type '(choice
+	  (const :tag "dvipng" dvipng)
+	  (const :tag "imagemagick" imagemagick)))
+
 (defun org-format-latex-mathml-available-p ()
   "Return t if `org-latex-to-mathml-convert-command' is usable."
   (save-match-data
@@ -16902,7 +16916,8 @@ The images can be removed again with \\[org-ctrl-c-ctrl-c]."
 	 (concat "ltxpng/" (file-name-sans-extension
 			    (file-name-nondirectory
 			     buffer-file-name)))
-	 default-directory 'overlays msg at 'forbuffer 'dvipng)
+	 default-directory 'overlays msg at 'forbuffer
+	 org-latex-create-formula-image-program)
       (message msg "done.  Use `C-c C-c' to remove images.")))))
 
 (defvar org-latex-regexps
@@ -16966,7 +16981,8 @@ Some of the options can be changed using the variable
 				'(org-protected t))))
 		(add-text-properties (match-beginning n) (match-end n)
 				     '(org-protected t))))
-	     ((eq processing-type 'dvipng)
+	     ((or (eq processing-type 'dvipng)
+		  (eq processing-type 'imagemagick))
 	      ;; Process to an image
 	      (setq txt (match-string n)
 		    beg (match-beginning n) end (match-end n)
@@ -16987,17 +17003,25 @@ Some of the options can be changed using the variable
 	      (unless checkdir ; make sure the directory exists
 		(setq checkdir t)
 		(or (file-directory-p todir) (make-directory todir t)))
-
-	      (unless executables-checked
-		(org-check-external-command
-		 "latex" "needed to convert LaTeX fragments to images")
-		(org-check-external-command
-		 "dvipng" "needed to convert LaTeX fragments to images")
-		(setq executables-checked t))
-
-	      (unless (file-exists-p movefile)
-		(org-create-formula-image
-		 txt movefile opt forbuffer))
+	      (cond
+	       ((eq processing-type 'dvipng)
+		(unless executables-checked
+		  (org-check-external-command
+		   "latex" "needed to convert LaTeX fragments to images")
+		  (org-check-external-command
+		   "dvipng" "needed to convert LaTeX fragments to images")
+		  (setq executables-checked t))
+		(unless (file-exists-p movefile)
+		  (org-create-formula-image-with-dvipng
+		   txt movefile opt forbuffer)))
+	       ((eq processing-type 'imagemagick)
+		(unless executables-checked
+		  (org-check-external-command
+		   "converte" "you need to install imagemagick")
+		  (setq executables-checked t))
+		(unless (file-exists-p movefile)
+		  (org-create-formula-image-with-imagemagick
+		   txt movefile opt forbuffer))))
 	      (if overlays
 		  (progn
 		    (mapc (lambda (o)
@@ -17133,7 +17157,7 @@ inspection."
       latex-frag)))
 
 ;; This function borrows from Ganesh Swami's latex2png.el
-(defun org-create-formula-image (string tofile options buffer)
+(defun org-create-formula-image-with-dvipng (string tofile options buffer)
   "This calls dvipng."
   (require 'org-latex)
   (let* ((tmpdir (if (featurep 'xemacs)
@@ -17195,7 +17219,111 @@ inspection."
 	    nil)
 	;; Use the requested file name and clean up
 	(copy-file pngfile tofile 'replace)
-	(loop for e in '(".dvi" ".tex" ".aux" ".log" ".png") do
+	(loop for e in '(".dvi" ".tex" ".aux" ".log" ".png" ".out") do
+	      (delete-file (concat texfilebase e)))
+	pngfile))))
+
+(defvar org-latex-to-pdf-process) ;; Defined in org-latex.el
+(defun org-create-formula-image-with-imagemagick (string tofile options buffer)
+  "This calls convert, which is included into imagemagick."
+  (require 'org-latex)
+  (let* ((tmpdir (if (featurep 'xemacs)
+		     (temp-directory)
+		   temporary-file-directory))
+	 (texfilebase (make-temp-name
+		       (expand-file-name "orgtex" tmpdir)))
+	 (texfile (concat texfilebase ".tex"))
+	 (pdffile (concat texfilebase ".pdf"))
+	 (pngfile (concat texfilebase ".png"))
+	 (fnh (if (featurep 'xemacs)
+                  (font-height (face-font 'default))
+                (face-attribute 'default :height nil)))
+	 (scale (or (plist-get options (if buffer :scale :html-scale)) 1.0))
+	 (dpi (number-to-string (* scale (floor (* 0.9 (if buffer fnh 140.))))))
+	 (fg (or (plist-get options (if buffer :foreground :html-foreground))
+		 "black"))
+	 (bg (or (plist-get options (if buffer :background :html-background))
+		 "white")))
+    (if (eq fg 'default) (setq fg (org-latex-color :foreground))
+      (setq fg (org-latex-color-format fg)))
+    (if (eq bg 'default) (setq bg (org-latex-color :background))
+      (setq bg (org-latex-color-format
+		(if (string= bg "Transparent")(setq bg "white")))))
+    (with-temp-file texfile
+      (insert (org-splice-latex-header
+	       org-format-latex-header
+	       org-export-latex-default-packages-alist
+	       org-export-latex-packages-alist t
+	       org-format-latex-header-extra))
+      (insert "\n\\begin{document}\n"
+	      "\\definecolor{fg}{rgb}{" fg "}\n"
+	      "\\definecolor{bg}{rgb}{" bg "}\n"
+	      "\n\\pagecolor{bg}\n"
+	      "\n{\\color{fg}\n"
+	      string
+	      "\n}\n"
+	      "\n\\end{document}\n" )
+      (require 'org-latex)
+      (org-export-latex-fix-inputenc))
+    (let ((dir default-directory) cmd cmds latex-frags-cmds)
+      (condition-case nil
+	  (progn
+	    (cd tmpdir)
+	    (setq cmds org-latex-to-pdf-process)
+	    (while cmds
+	      (setq latex-frags-cmds (pop cmds))
+	      (if (listp latex-frags-cmds)
+		  (setq cmds nil)
+		(setq latex-frags-cmds (list (car org-latex-to-pdf-process)))))
+	    (while latex-frags-cmds
+	      (setq cmd (pop latex-frags-cmds))
+	      (while (string-match "%b" cmd)
+		(setq cmd (replace-match
+			   (save-match-data
+			     (shell-quote-argument texfile))
+			   t t cmd)))
+	      (while (string-match "%f" cmd)
+		(setq cmd (replace-match
+			   (save-match-data
+			     (shell-quote-argument (file-name-nondirectory texfile)))
+			   t t cmd)))
+	      (while (string-match "%o" cmd)
+		(setq cmd (replace-match
+			   (save-match-data
+			     (shell-quote-argument (file-name-directory texfile)))
+			   t t cmd)))
+	      (shell-command cmd)))
+	(error nil))
+      (cd dir))
+    (if (not (file-exists-p pdffile))
+	(progn (message "Failed to create pdf file from %s" texfile) nil)
+      (condition-case nil
+	  (if (featurep 'xemacs)
+	      (call-process "convert" nil nil nil
+			    "-density" "96"
+			    "-trim"
+			    "-antialias"
+			    pdffile
+			    "-quality" "100"
+;;			    "-sharpen" "0x1.0"
+			    pngfile)
+	    (call-process "convert" nil nil nil
+			  "-density" dpi
+			  "-trim"
+			  "-antialias"
+			  pdffile
+			  "-quality" "100"
+;			  "-sharpen" "0x1.0"
+			  pngfile))
+	(error nil))
+      (if (not (file-exists-p pngfile))
+	  (if org-format-latex-signal-error
+	      (error "Failed to create png file from %s" texfile)
+	    (message "Failed to create png file from %s" texfile)
+	    nil)
+	;; Use the requested file name and clean up
+	(copy-file pngfile tofile 'replace)
+	(loop for e in '(".pdf" ".tex" ".aux" ".log" ".png") do
 	      (delete-file (concat texfilebase e)))
 	pngfile))))
 
@@ -17259,7 +17387,7 @@ SNIPPETS-P indicates if this is run to create snippet images for HTML."
   (if newline (concat pkg "\n") pkg))
 
 (defun org-dvipng-color (attr)
-  "Return an rgb color specification for dvipng."
+  "Return a RGB color specification for dvipng."
   (apply 'format "rgb %s %s %s"
 	 (mapcar 'org-normalize-color
 		 (if (featurep 'xemacs)
@@ -17269,6 +17397,23 @@ SNIPPETS-P indicates if this is run to create snippet images for HTML."
 					   ((eq attr :background) 'background))))
 		   (color-values (face-attribute 'default attr nil))))))
 
+(defun org-latex-color (attr)
+  "Return a RGB color for the LaTeX color package."
+  (apply 'format "%s,%s,%s"
+	 (mapcar 'org-normalize-color
+		 (if (featurep 'xemacs)
+		     (color-rgb-components
+		      (face-property 'default
+				     (cond ((eq attr :foreground) 'foreground)
+					   ((eq attr :background) 'background))))
+		   (color-values (face-attribute 'default attr nil))))))
+
+(defun org-latex-color-format (color-name)
+  "Convert COLOR-NAME to a RGB color value."
+  (apply 'format "%s,%s,%s"
+	 (mapcar 'org-normalize-color
+		   (color-values color-name))))
+
 (defun org-normalize-color (value)
   "Return string to be used as color value for an RGB component."
   (format "%g" (/ value 65535.0)))