--- loncom/xml/lontexconvert.pm	2011/02/10 19:28:29	1.105
+++ loncom/xml/lontexconvert.pm	2013/09/22 02:04:31	1.112.2.3
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # TeX Conversion Module
 #
-# $Id: lontexconvert.pm,v 1.105 2011/02/10 19:28:29 raeburn Exp $
+# $Id: lontexconvert.pm,v 1.112.2.3 2013/09/22 02:04:31 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);
 }
 
@@ -165,13 +232,45 @@ sub clean_out_math_mode {
 
 sub displaystyle {
     my ($texstring)=@_;
-    #has a $$ or \[ or \displaystyle in it, guessinng it's display mode
+    #has a $$ or \[ or \displaystyle or eqnarray in it, guessinng it's display mode
     if ($$texstring=~/[^\\]\$\$/ ||
-	$$texstring=~/\\\[/ ||
-	$$texstring=~/\\displaystyle/) { return 1; }
+        $$texstring=~/\\\[/ ||
+        $$texstring=~/\\displaystyle/ ||
+        $$texstring=~/eqnarray/
+       ) { return 1; }
     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 jsMath_converted {
     my $texstring=shift;
     my $tag='span';
@@ -239,20 +338,23 @@ sub init_math_support {
 	($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;
 }
 
 sub mimetex_valign {
     my ($esc_texstring)=@_;
     my $valign = 0;
-    my $lonhost = $Apache::lonnet::perlvar{'lonHostID'};
-    my $hostname = &Apache::lonnet::hostname($lonhost);
     my $path = '/cgi-bin/mimetex.cgi?'.$esc_texstring;
     my $socket;
     &Apache::lonxml::start_alarm();
-    my $socket = IO::Socket::INET->new(PeerAddr => $hostname,
-                                        PeerPort => 'http(80)',
-                                        Proto    => 'tcp');
+    $socket = IO::Socket::INET->new(PeerAddr => 'localhost',
+                                    PeerPort => 'http(80)',
+                                    Proto    => 'tcp');
     if ($socket) {
         my $headreq = "HEAD $path HTTP/1.0\r\n\r\n";
         print $socket $headreq;
@@ -289,7 +391,7 @@ sub mimetex_converted {
     my $valign = &mimetex_valign($esc_texstring);
     my $result='<img src="/cgi-bin/mimetex.cgi?'.$esc_texstring.'" style="vertical-align:'.$valign.'px" alt="'.$alt_string.'" />';
     if ($displaystyle) {
-	$result='<center>'.$result.'</center>';
+	$result='<div style="text-align:center">'.$result.'</div>';
     }
     return $result;
 }
@@ -301,6 +403,8 @@ sub converted {
 	return &tth_converted($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) {
@@ -380,7 +484,7 @@ sub msgtexconverted {
     foreach my $fragment (split(/(?:\&lt\;|\<)\/*algebra\s*(?:\&gt\;|\>)/i,
 				$message)) {
 	if ($tex) {
-        my $algebra = &algebra($fragment, 'web', undef, undef, undef, undef, 'tth');
+        my $algebra = &algebra($fragment, 'web', undef, undef, undef, 'tth');
 	    if ($email) {
 		$outmessage.='</pre><tt>'.$algebra.'</tt><pre>';
 		$tex=0;
@@ -509,6 +613,8 @@ Header
 
 =item jsMath_converted()
 
+=item MathJax_converted()
+        - Mimics the jsMath functionality
 
 =item tex_engine()