math/render.ml

   1 (* vim: set sw=8 ts=8 et: *)
   2
   3 let cmd_dvips tmpprefix = "dvips -q -R -E " ^ tmpprefix ^ ".dvi -f >" ^ tmpprefix ^ ".ps"
   4 let cmd_latex tmpprefix = "latex " ^ tmpprefix ^ ".tex >/dev/null"
   5
   6 (* Putting -transparent white in converts arguments will sort-of give you transperancy *)
   7 let cmd_convert tmpprefix finalpath = "convert -quality 100 -density 120 " ^ tmpprefix ^ ".ps " ^ finalpath ^ " >/dev/null 2>/dev/null"
   8
   9 (* Putting -bg Transparent in dvipng's arguments will give full-alpha transparency *)
  10 (* Note that IE have problems with such PNGs and need an additional javascript snippet *)
  11 (* Putting -bg transparent in dvipng's arguments will give binary transparency *)
  12 let cmd_dvipng tmpprefix finalpath backcolor = "dvipng -bg \'" ^ backcolor ^ "\' -gamma 1.5 -D 120 -T tight --strict " ^ tmpprefix ^ ".dvi -o " ^ finalpath ^ " >/dev/null 2>/dev/null"
  13
  14 exception ExternalCommandFailure of string
  15
  16 let render tmppath finalpath outtex md5 backcolor =
  17     let tmpprefix0 = (string_of_int (Unix.getpid ()))^"_"^md5 in
  18     let tmpprefix = (tmppath^"/"^tmpprefix0) in
  19     let unlink_all () =
  20       begin
  21         (* Commenting this block out will aid in debugging *)
  22         Sys.remove (tmpprefix ^ ".dvi");
  23         Sys.remove (tmpprefix ^ ".aux");
  24         Sys.remove (tmpprefix ^ ".log");
  25         Sys.remove (tmpprefix ^ ".tex");
  26         if Sys.file_exists (tmpprefix ^ ".ps")
  27         then Sys.remove (tmpprefix ^ ".ps");
  28       end in
  29
  30     let f = (Util.open_out_unless_exists (tmpprefix ^ ".tex")) in
  31       begin
  32         (* Assemble final output in file 'f' *)
  33         output_string f (Texutil.get_preface ());
  34         output_string f outtex;
  35         output_string f (Texutil.get_footer ());
  36         close_out f;
  37
  38         (* TODO: document *)
  39         if Util.run_in_other_directory tmppath (cmd_latex tmpprefix0) != 0
  40           then (
  41             unlink_all (); raise (ExternalCommandFailure "latex")
  42         ) else if (Sys.command (cmd_dvipng tmpprefix (finalpath^"/"^md5^".png") backcolor) != 0)
  43           then (
  44             if (Sys.command (cmd_dvips tmpprefix) != 0)
  45               then (
  46                 unlink_all ();
  47                 raise (ExternalCommandFailure "dvips")
  48             ) else if (Sys.command (cmd_convert tmpprefix (finalpath^"/"^md5^".png")) != 0)
  49               then (
  50                 unlink_all ();
  51                 raise (ExternalCommandFailure "convert")
  52             ) else (
  53                 unlink_all ()
  54             )
  55         ) else (
  56             unlink_all ()
  57         )
  58       end