--- loncom/xml/lontexconvert.pm	2006/10/24 01:28:47	1.80
+++ loncom/xml/lontexconvert.pm	2009/08/12 20:31:08	1.97
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # TeX Conversion Module
 #
-# $Id: lontexconvert.pm,v 1.80 2006/10/24 01:28:47 albertel Exp $
+# $Id: lontexconvert.pm,v 1.97 2009/08/12 20:31:08 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -47,7 +47,9 @@ use Apache::lonlocal;
 use Apache::lonnet;
 use lib '/home/httpd/lib/perl/';
 use LONCAPA;
- 
+use URI::Escape;
+use IO::Socket::INET;
+use IO::Socket::SSL;
 
 # ====================================================================== Header
 
@@ -79,10 +81,7 @@ sub init_tth {
 
 $Apache::lontexconvert::messedup=0;
 
-# we need this routine because &converted can get called from inside
-# of the safespace (through &xmlparse('<m>stuff</m>') which doesn't
-# allow the opcode for alarm, so we need to compile this before we get
-# into the safe space since opcode checks only occur at compile time
+
 sub convert_real {
     my ($texstring)=@_;
     my ($xmlstring,$errorstring);
@@ -108,6 +107,14 @@ sub convert_real {
     $xmlstring=~s/^\s*\<br clear\=\"all\"/\<br/s;
     $xmlstring=~s/^\s*//;
     $xmlstring=~s/\s*$//;
+    #
+    # \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;
+
     &Apache::lonxml::end_alarm();
     return ($xmlstring,$errorstring);
 }
@@ -151,7 +158,7 @@ ENDCONV
 
 sub clean_out_math_mode {
     my ($texstring)=@_;
-    $$texstring=~s/(?!\\)\$//g;
+    $$texstring=~s/(?<!\\)\$//g;
     $$texstring=~s/\\[\)\(\]\[]//g;
     $$texstring=~s/\\ensuremath//g;
     return '';
@@ -200,30 +207,100 @@ sub jsMath_converted {
     sub jsMath_process {
 	my $state = pop(@jsMath_sent_header);
 	return '' if !$state;
-	return '<script type="text/javascript">jsMath.Process()</script>';
+	return "\n".
+	    '<script type="text/javascript">jsMath.Process()</script>'."\n";
+    }
+    sub jsMath_state {
+	my ($level) = @_;
+	return $jsMath_sent_header[$level];
+    }
+}
+
+sub tex_engine {
+    if (exists($env{'form.texengine'})) {
+	if ($env{'form.texengine'} ne '') {
+            return $env{'form.texengine'};
+        }
+    }    
+    if ($env{'request.course.id'}
+	&& exists($env{'course.'.$env{'request.course.id'}.'.texengine'})) {
+	return $env{'course.'.$env{'request.course.id'}.'.texengine'};
+    }
+    if (exists($env{'environment.texengine'})) {
+	return $env{'environment.texengine'};
     }
+    return 'tth';
 }
 
 sub init_math_support {
+    my ($inherit_jsmath) = @_;
     &init_tth();
     &Apache::lontexconvert::jsMath_push();
-    if ($env{'environment.texengine'} eq 'jsMath' ||
-	$env{'form.texengine'}        eq 'jsMath' ) {
+    if (lc(&tex_engine()) eq 'jsmath' ||
+	($inherit_jsmath && &jsMath_state(-2))) {
 	return &Apache::lontexconvert::jsMath_header();
     }
     return;
 }
 
+sub mimetex_valign {
+    my ($esc_texstring)=@_;
+    my $valign = 0;
+    my $lonhost = $Apache::lonnet::perlvar{'lonHostID'};
+    my $hostname = &Apache::lonnet::hostname($lonhost);
+    my $protocol = $Apache::lonnet::protocol{$lonhost};
+    my $path = '/cgi-bin/mimetex.cgi?'.$esc_texstring;
+    my $socket;
+    &Apache::lonxml::start_alarm();
+    if ($protocol eq 'https') {
+        $socket = IO::Socket::SSL->new(PeerAddr => $hostname,
+                                       PeerPort => 'https(443)',
+                                       Proto    => 'tcp');
+    } else {
+        $socket = IO::Socket::INET->new(PeerAddr => $hostname,
+                                        PeerPort => 'http(80)',
+                                        Proto    => 'tcp');
+    }
+    if ($socket) {
+        my $headreq = "HEAD $path HTTP/1.0\r\n\r\n";
+        print $socket $headreq;
+        while (<$socket>) {
+            if (/Vertical\-Align\:\s*?([\-\d]+)/) {
+                $valign = $1;
+            }
+        }
+        if ($protocol eq 'https') {
+            $socket->close(SSL_no_shutdown => 1,
+                           SSL_ctx_free => 1);
+        } else {
+            $socket->close();
+        }
+    }
+    &Apache::lonxml::end_alarm();
+    return $valign;
+}
+
 sub mimetex_converted {
     my $texstring=shift;
+
+# Alt-Argument for screen readers
+    my $alt_string=$$texstring;
+    $alt_string=~s/\"/\'\'/g;
+
+# Is this displaystyle?
+
     my $displaystyle=&displaystyle($texstring);
 
+# Remove math environment delimiters
+
     &clean_out_math_mode($texstring);
 
     if ($displaystyle) {
 	$$texstring='\\displaystyle \\Large '.$$texstring;
     }
-    my $result='<img src="/cgi-bin/mimetex.cgi?'.&escape($$texstring).'" />';
+    my $esc_texstring = &uri_escape($$texstring);
+    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>';
     }
@@ -232,7 +309,7 @@ sub mimetex_converted {
 
 sub converted {
     my ($string,$mode)=@_;
-    if ($mode eq '') { $mode=$env{'environment.texengine'}; }
+    if ($mode eq '') { $mode = &tex_engine(); }
     if ($mode =~ /tth/i) {
 	return &tth_converted($string);
     } elsif ($mode =~ /jsmath/i) {
@@ -323,7 +400,7 @@ sub msgtexconverted {
 sub algebra {
     use AlgParser;
 
-    my ($string,$target,$style)=@_;
+    my ($string,$target,$style,$parstack,$safeeval)=@_;
     my $parser = new AlgParserWithImplicitExpand;
     $string=&prepare_algebra($string);
     my $ret = $parser->parse($string);
@@ -340,7 +417,9 @@ sub algebra {
 	    $latex='\\ensuremath{'.$latex.'}';
 	}
 	if ($target eq 'web' || $target eq 'analyze') {
-	    $result = &converted(\$latex);
+            my $display=&Apache::lonxml::get_param('display',$parstack,$safeeval);
+            $result = &converted(\$latex,$display);
+#	    $result = &converted(\$latex);
 	} else {
 	    $result = $latex;
 	}
@@ -387,8 +466,78 @@ sub postprocess_algebra {
 __END__
 
 
+=pod
+
+=head1 NAME
+
+Apache::lontexconvert;
+
+=head1 SYNOPSIS
+
+Access to tth/ttm
+
+This is part of the LearningOnline Network with CAPA project
+described at http://www.lon-capa.org.
+
+
+=head1 SUBROUTINES
+
+=over
+
+=item init_tth()
+
+Header
+
+=item convert_real()
+
+ we need this routine because &converted can get called from inside
+ of the safespace (through &xmlparse('<m>stuff</m>') which doesn't
+ allow the opcode for alarm, so we need to compile this before we get
+ into the safe space since opcode checks only occur at compile time
+
+=item tth_converted()
+
+
+=item clean_out_math_mode()
+
+
+=item displaystyle()
+
+
+=item jsMath_converted()
+
+
+=item tex_engine()
+
+
+=item init_math_support()
+
+
+=item mimetex_converted()
+
+
+=item converted()
+
+
+=item to_convert()
+
+message display
+
+=item smiley()
+
+???
+
+=item msgtexconverted()
+
+=item algebra()
+
+=item prepare_algebra()
+
+=item postprocess_algebra()
 
+=back
 
+=cut