Bug#7252: Patch to enable dvipng support in math rendering

(If used on Wikimedia environment, dvipng package from http://dammit.lt/tech/packages/ should be installed on FC3 boxes)

diff --git a/math/README b/math/README
index d36e09c..818ce6b 100644 (file)
--- a/math/README
+++ b/math/README
@@ -1,7 +1,7 @@
 == About texvc ==
 
 texvc takes LaTeX-compatible equations and produces formatted output in
-HTML, MathML, and (via LaTeX/dvips/ImageMagick) rasterized PNG images.
+HTML, MathML, and (via LaTeX/dvipng) rasterized PNG images.
 Input data is parsed and scrutinized for safety, and the output includes
 an estimate of whether the code is simple enough that HTML rendering will
 look acceptable.
@@ -21,8 +21,8 @@ from http://caml.inria.fr/ if your system doesn't have it available.
 
 The makefile requires GNU make.
 
-Rasterization is done via LaTeX, dvips, and ImageMagick. These need
-to be installed and in the PATH: latex, dvips, convert
+Rasterization is done via LaTeX, dvipng. These need
+to be installed and in the PATH: latex, dvipng
 
 AMS* packages for LaTeX also need to be installed. Without AMS* some
 equations will render correctly while others won't render.
@@ -115,7 +115,6 @@ which is basically:
 2. texvc does its magic, which is basically to check for invalid latex code.
 3. texvc takes the user input if valid and creates a latex file containing it, see
    get_preface in texutil.ml
-4. latex(1) gets called to create a .dvi file, then a .ps file is created from the
-   .dvi file using dvips(1), and finally convert(1) creates a .png file from
-   the .ps file. See render.ml for this process (commenting out the removal of
+4. dvipng(1) gets called to create a .png file
+   See render.ml for this process (commenting out the removal of
    the temporary file is useful for debugging).

diff --git a/math/render.ml b/math/render.ml
index f070a91..864681e 100644 (file)
--- a/math/render.ml
+++ b/math/render.ml
@@ -2,6 +2,10 @@ let cmd_dvips tmpprefix = "dvips -R -E " ^ tmpprefix ^ ".dvi -f >" ^ tmpprefix ^
 let cmd_latex tmpprefix = "latex " ^ tmpprefix ^ ".tex >/dev/null"
 (* Putting -transparent white in converts arguments will sort-of give you transperancy *)
 let cmd_convert tmpprefix finalpath = "convert -quality 100 -density 120 " ^ tmpprefix ^ ".ps " ^ finalpath ^ " >/dev/null 2>/dev/null"
+(* Putting -bg Transparent in dvipng's arguments will give full-alpha transparency *)
+(* Note that IE have problems with such PNGs and need an additional javascript snippet *)
+(* Putting -bg transparent in dvipng's arguments will give binary transparency *)
+let cmd_dvipng tmpprefix finalpath = "dvipng -gamma 1.5 -D 120 -T tight --strict " ^ tmpprefix ^ ".dvi -o " ^ finalpath ^ " >/dev/null 2>/dev/null"
 
 exception ExternalCommandFailure of string
 
@@ -25,9 +29,11 @@ let render tmppath finalpath outtex md5 =
        close_out f;
        if Util.run_in_other_directory tmppath (cmd_latex tmpprefix0) != 0
        then (unlink_all (); raise (ExternalCommandFailure "latex"))
-       else if (Sys.command (cmd_dvips tmpprefix) != 0)
+       else if (Sys.command (cmd_dvipng tmpprefix (finalpath^"/"^md5^".png")) != 0)
+       then (if (Sys.command (cmd_dvips tmpprefix) != 0)
        then (unlink_all (); raise (ExternalCommandFailure "dvips"))
        else if (Sys.command (cmd_convert tmpprefix (finalpath^"/"^md5^".png")) != 0)
        then (unlink_all (); raise (ExternalCommandFailure "convert"))
+       else unlink_all ())
        else unlink_all ()
       end