--- loncom/xml/lontexconvert.pm	2011/12/06 16:10:53	1.109
+++ loncom/xml/lontexconvert.pm	2012/05/10 19:19:30	1.112.2.1
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # TeX Conversion Module
 #
-# $Id: lontexconvert.pm,v 1.109 2011/12/06 16:10:53 dseaton Exp $
+# $Id: lontexconvert.pm,v 1.112.2.1 2012/05/10 19:19:30 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -50,6 +50,68 @@ use LONCAPA;
 use URI::Escape;
 use IO::Socket::INET;
 
+
+#
+# Table of substitutions to unicode characters.
+#
+my %unicode_translations = (
+    '\rightleftharpoons'  => 0x21cc,
+
+# Brackets - unicode is commented out with pure 8-bit ascii ugliness while we need it.
+
+#    ''             => 0x23a1,
+#    ''             => 0x23a2,
+#    ''             => 0x23a3,   # when unicode catches up with browsers
+#    ''             => 0x23a4,   # use these instead of the cheesey brackets below
+#    ''             => 0x23a5,
+#    ''             => 0x23a6   
+    ''              => 0x5b,
+    ''              => 0x5b,    # '['
+    ''              => 0x5b,
+    ''              => 0x5d,    # ']'
+    ''              => 0x5d,
+    ''              => 0x5d,
+
+#  Parens..again the unicode is commented out with the 8-bit ascii ugliness
+#  turned on until browsers catch up with the unicode world.
+
+#    ''              => 0x239b,
+#    ''              => 0x239c,
+#    ''              => 0x239d,
+#    ''              => 0x239e,
+#    ''              => 0x239f,
+#    ''              => 0x23a0
+
+    ''              => 0x28,
+    ''              => 0x28,      # '('
+    ''              => 0x28,
+
+    ''              => 0x29,
+    ''              => 0x29,      # '('
+    ''              => 0x29
+
+
+);
+
+##
+# Utility to convert elements of a string to unicode:
+#
+# @param input - Input string
+# @param pattern - Pattern to convert
+# @param unicode - Unicode to substitute for pattern.
+#
+# @return string - resulting string.
+# 
+sub unicode_subst {
+    my ($input, $pattern, $unicode) = @_;
+    
+    my $char = pack('U', $unicode);
+
+    $input =~ s/$pattern/$char/g;
+
+    return $input;
+}
+
 # ====================================================================== Header
 
 sub init_tth {
@@ -106,15 +168,20 @@ sub convert_real {
     $xmlstring=~s/^\s*\<br clear\=\"all\"/\<br/s;
     $xmlstring=~s/^\s*//;
     $xmlstring=~s/\s*$//;
+    &Apache::lonxml::end_alarm();
+
     #
-    # \rightleftharpoons is not converted by tth but maps
-    # reasonably well to &#8660;.  If we get many more of these,
-    # we're going to need to have a translation sub.
-    #
-    my $lrharpoon = pack("U", 0x21cc);
-    $xmlstring=~s/\\rightleftharpoons/$lrharpoon/g;
+    #  Several strings produced by tth require
+    # transliteration -> unicode equivalents to render reliably
+    # in browsers. %unicode_translations is a table of
+    # string->substitution which we now apply:
+
+    foreach my $pattern (keys(%unicode_translations)) {
+	my $unicode = $unicode_translations{$pattern};
+	$xmlstring = &unicode_subst($xmlstring, $pattern, $unicode);
+    }
+
 
-    &Apache::lonxml::end_alarm();
     return ($xmlstring,$errorstring);
 }
 
@@ -174,47 +241,6 @@ sub displaystyle {
     return 0;
 }
 
-sub MathJax_converted {
-    my $texstring=shift;
-    my $tag='math/tex;';
-    if (&displaystyle($texstring)) { $tag='math/tex; mode=display'; }
-    &clean_out_math_mode($texstring);
-    return &MathJax_header().
-      '<script type="'.$tag.'">'.$$texstring.'</script>';
-}
-
-{
-    #Relies heavily on the previous jsMath installation
-    my @MathJax_sent_header;
-    sub MathJax_reset {
-        undef(@MathJax_sent_header);
-    }
-    sub MathJax_push {
-        push(@MathJax_sent_header,0);
-    }
-    sub MathJax_header {
-        if (!@MathJax_sent_header) {
-            &Apache::lonnet::logthis("mismatched calls of MathJax_header and MathJax_process");
-            return '';
-        }
-        return '' if $MathJax_sent_header[-1];
-        $MathJax_sent_header[-1]=1;
-        return
-          '<script type="text/javascript" src="/adm/MathJax/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>'."\n";
-    }
-    #sub MathJax_process {
-    #    my $state = pop(@MathJax_sent_header);
-    #    return '' if !$state;
-    #    return "\n".
-    #        '<script type="text/javascript">MathJax.Process()</script>'."\n";
-    #}
-    #sub MathJax_state {
-    #    my ($level) = @_;
-    #    return $MathJax_sent_header[$level];
-    #}
-}
-
-
 sub jsMath_converted {
     my $texstring=shift;
     my $tag='span';
@@ -282,11 +308,6 @@ sub init_math_support {
 	($inherit_jsmath && &jsMath_state(-2))) {
 	return &Apache::lontexconvert::jsMath_header();
     }
-    &Apache::lontexconvert::MathJax_push();
-    if (lc(&tex_engine()) eq 'mathjax') { # ||
-        #($inherit_jsmath && &jsMath_state(-2))) {
-        return &Apache::lontexconvert::MathJax_header();
-    }
     return;
 }
 
@@ -347,8 +368,6 @@ sub converted {
 	return &tth_converted($string);
     } elsif ($mode =~ /jsmath/i) {
 	return &jsMath_converted($string);
-    } elsif ($mode =~ /mathjax/i) {
-	return &MathJax_converted($string);
     } elsif ($mode =~ /mimetex/i) {
 	return &mimetex_converted($string);
     } elsif ($mode =~ /raw/i) {
@@ -557,9 +576,6 @@ Header
 
 =item jsMath_converted()
 
-=item MathJax_converted()
-	- Mimics the jsMath functionality
-
 =item tex_engine()