--- loncom/xml/lontexconvert.pm	2006/11/09 21:31:54	1.81
+++ loncom/xml/lontexconvert.pm	2019/02/15 21:21:03	1.112.2.9
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # TeX Conversion Module
 #
-# $Id: lontexconvert.pm,v 1.81 2006/11/09 21:31:54 albertel Exp $
+# $Id: lontexconvert.pm,v 1.112.2.9 2019/02/15 21:21:03 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -47,7 +47,80 @@ use Apache::lonlocal;
 use Apache::lonnet;
 use lib '/home/httpd/lib/perl/';
 use LONCAPA;
- 
+use URI::Escape;
+use IO::Socket::INET;
+
+
+#
+# Table of substitutions to unicode characters.
+#
+
+my %unicode_harpoons = (
+                        '\rightleftharpoons'  => 0x21cc,
+                      );
+
+my %unicode_translations = (
+
+# Brackets - unicode for browsers/OS which support it.
+
+    ''             => 0x23a1,
+    ''             => 0x23a2,
+    ''             => 0x23a3,
+    ''             => 0x23a4,
+    ''             => 0x23a5,
+    ''             => 0x23a6,
+
+#  Parens - unicode for browsers/OS which support it
+
+    ''              => 0x239b,
+    ''              => 0x239c,
+    ''              => 0x239d,
+    ''              => 0x239e,
+    ''              => 0x239f,
+    ''              => 0x23a0,
+
+);
+
+my %ascii_8bit_translations = (
+
+# Brackets - pure 8-bit ascii ugliness for browsers/OS which can't handle unicode
+
+    ''              => 0x5b,
+    ''              => 0x5b,    # '['
+    ''              => 0x5b,
+    ''              => 0x5d,    # ']'
+    ''              => 0x5d,
+    ''              => 0x5d,
+
+# Parens - pure 8-bit ascii ugliness for browsers/OS which can't handle unicode
+
+    ''              => 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
 
@@ -79,10 +152,7 @@ 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);
@@ -109,6 +179,36 @@ sub convert_real {
     $xmlstring=~s/^\s*//;
     $xmlstring=~s/\s*$//;
     &Apache::lonxml::end_alarm();
+
+    #
+    # Several strings produced by tth require
+    # transliteration -> unicode equivalents to render reliably
+    # in browsers. %unicode_translations and %unicode_harpoons are tables of
+    # string->substitution which we now apply. (%ascii_8bit_translations used
+    # instead for Windows XP and mobile devices.
+
+    my $use_ascii;
+    if ($env{'browser.os'} eq 'win') {
+        if (($env{'browser.osversion'}) && ($env{'browser.osversion'} < 6.0)) {
+            $use_ascii = 1;
+        }
+    }
+    if ($env{'browser.mobile'}) {
+        $use_ascii = 1;
+    }
+
+    foreach my $pattern (keys(%unicode_translations)) {
+	my $unicode = $unicode_translations{$pattern};
+	if ($use_ascii) {
+	    $unicode = $ascii_8bit_translations{$pattern};
+	}
+	$xmlstring = &unicode_subst($xmlstring, $pattern, $unicode);
+    }
+
+    foreach my $pattern (keys(%unicode_harpoons)) {
+        $xmlstring = &unicode_subst($xmlstring, $pattern, $unicode_harpoons{$pattern});
+    }
+
     return ($xmlstring,$errorstring);
 }
 
@@ -151,7 +251,7 @@ ENDCONV
 
 sub clean_out_math_mode {
     my ($texstring)=@_;
-    $$texstring=~s/(?!\\)\$//g;
+    $$texstring=~s/(?<!\\)\$//g;
     $$texstring=~s/\\[\)\(\]\[]//g;
     $$texstring=~s/\\ensuremath//g;
     return '';
@@ -159,87 +259,155 @@ 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 jsMath_converted {
+sub MathJax_converted {
     my $texstring=shift;
-    my $tag='span';
-    if (&displaystyle($texstring)) { $tag='div'; }
+    my ($tag,$startspan,$endspan);
+    $tag='math/tex;';
+    if (&displaystyle($texstring)) {
+        $tag='math/tex; mode=display';
+        $startspan='';
+        $endspan='';
+    } else {
+        $startspan='<span style="display:inline-block;">';
+        $endspan='</span>';
+    }
     &clean_out_math_mode($texstring);
-    return &jsMath_header().
-	'<'.$tag.' class="math">'.$$texstring.'</'.$tag.'>';
+    return &MathJax_header().$startspan.
+      '<script type="'.$tag.'">'.$$texstring.'</script>'.$endspan;
 }
 
 {
-    my @jsMath_sent_header;
-    sub jsMath_reset {
-	undef(@jsMath_sent_header);
-    }
-    sub jsMath_push {
-	push(@jsMath_sent_header,0);
-    }
-    sub jsMath_header {
-	if (!@jsMath_sent_header) {
-	    &Apache::lonnet::logthis("mismatched calls of jsMath_header and jsMath_process");
-	    return '';
-	}
-	return '' if $jsMath_sent_header[-1];
-	$jsMath_sent_header[-1]=1;
-	return
-            '<script type="text/javascript">
-                     function NoFontMessage () {}
-                     jsMath = {Parser: {prototype: {environments: {\'eqnarray*\' :[\'Array\',null,null,\'rcl\',[5/18,5/18],3,\'D\']}}}};
-                   </script>'."\n".
-	    '<script type="text/javascript" src="/adm/jsMath/jsMath.js"></script>'."\n";
-    }
-    sub jsMath_process {
-	my $state = pop(@jsMath_sent_header);
-	return '' if !$state;
-	return "\n".
-	    '<script type="text/javascript">jsMath.Process()</script>'."\n";
+    #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 tex_engine {
+    if (exists($env{'form.texengine'})) {
+	if ($env{'form.texengine'} ne '') {
+            if (lc($env{'form.texengine'}) eq 'jsmath') {
+                return 'MathJax';
+            }
+            return $env{'form.texengine'};
+        }
+    }    
+    if ($env{'request.course.id'}
+	&& exists($env{'course.'.$env{'request.course.id'}.'.texengine'})) {
+        if (lc($env{'course.'.$env{'request.course.id'}.'.texengine'}) eq 'jsmath') {
+            return 'MathJax';
+        }
+	return $env{'course.'.$env{'request.course.id'}.'.texengine'};
+    }
+    if (exists($env{'environment.texengine'})) {
+        if (lc($env{'environment.texengine'}) eq 'jsmath') {
+            return 'MathJax';
+        }
+	return $env{'environment.texengine'};
+    }
+    my $dom = $env{'request.role.domain'} || $env{'user.domain'};
+    my %domdefaults = &Apache::lonnet::get_domain_defaults($dom);
+    if ($domdefaults{'texengine'} ne '') {
+        return $domdefaults{'texengine'};
+    }
+    return $Apache::lonnet::deftex;
+}
+
 sub init_math_support {
     &init_tth();
-    &Apache::lontexconvert::jsMath_push();
-    if ($env{'environment.texengine'} eq 'jsMath' ||
-	$env{'form.texengine'}        eq 'jsMath' ) {
-	return &Apache::lontexconvert::jsMath_header();
+    &Apache::lontexconvert::MathJax_push();
+    if (lc(&tex_engine()) eq 'mathjax') {
+        return &Apache::lontexconvert::MathJax_header();
     }
     return;
 }
 
+sub mimetex_valign {
+    my ($esc_texstring)=@_;
+    my $valign = 0;
+    my $path = '/cgi-bin/mimetex.cgi?'.$esc_texstring;
+    my $socket;
+    &Apache::lonxml::start_alarm();
+    $socket = IO::Socket::INET->new(PeerAddr => 'localhost',
+                                    PeerPort => 'http(80)',
+                                    Proto    => 'tcp');
+    if ($socket) {
+        my $headreq = "HEAD $path HTTP/1.0\r\n\r\n";
+        print $socket $headreq;
+        while (<$socket>) {
+            if (/Vertical\-Align\:\s*?([\-\d]+)/) {
+                $valign = $1;
+            }
+        }
+        $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>';
+	$result='<div style="text-align:center">'.$result.'</div>';
     }
     return $result;
 }
 
 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) {
-	return &jsMath_converted($string);
+	return &MathJax_converted($string);
+    } elsif ($mode =~ /mathjax/i) {
+        return &MathJax_converted($string);
     } elsif ($mode =~ /mimetex/i) {
 	return &mimetex_converted($string);
+    } elsif ($mode =~ /raw/i) {
+        return $$string;
     }
     return &tth_converted($string);
 }
@@ -248,6 +416,7 @@ sub converted {
 
 sub to_convert {
     my ($string) = @_;
+    &init_tth();
     $string=~s/\<br\s*\/?\>/ /gs;
 #    $string=~s/\s/ /gs;
     $string=&HTML::Entities::decode($string);
@@ -256,24 +425,37 @@ sub to_convert {
 
 sub smiley {
     my $expression=shift;
-    if ($env{'browser.imagesuppress'} eq 'on') { return $expression; }
-    my %smileys=('\:\-\)' => 'smiley',
-		 '8\-\)'  => 'coolsmile',
-		 '8\-(I|\|)'   => 'coolindiff',
-		 ':\-(I|\|)'   => 'neutral',
-		 '\:\-(o|O|\(\))' => 'shocked',
-		 ':\-\('  => 'frowny',
-		 '\;\-\)' => 'wink',
-		 '\:\-P'  => 'baeh',
-		 '\:\-(\\\|\\/)' => 'hrrm',
-		 '\:\-D'  => 'bigsmile',
-		 '\:\-C'  => 'angry',
-		 '\:(\'|\`)\-\(' => 'cry',
-		 '\:\-(X|\#)' => 'lipsrsealed',
-		 '\:\-S' => 'huh');
+    my %smileys=(
+    	 '\:\-*\)' => 'face-smile.png',
+		 '8\-\)'  => 'face-cool.png',
+		 '8\-(I|\|)'   => 'face-glasses.png',
+		 '\:\-(I|\|)'   => 'face-plain.png',
+		 '\:\-(o|O|\(\))' => 'face-surprise.png',
+		 ':\-\('  => 'face-sad.png',
+		 '\;\-\)' => 'face-wink.png',
+		 '\:\-(P|p)'  => 'face-raspberry.png',
+		 '\:\-(\\\|\\/)' => 'face-uncertain.png',
+		 '\:\-D'  => 'face-smile-big.png',
+		 '\:\-(C|\@)'  => 'face-angry.png',
+		 '\:(\'|\`)\-*\(' => 'face-crying.png',
+		 '\:\-(X|x|\#)' => 'face-quiet.png',
+		 '\:\-(s|S)' => 'face-uncertain.png',
+		 '\:\-\$' => 'face-embarrassed.png',
+		 '\:\-\*' => 'face-kiss.png',
+		 '\+O\(' => 'face-sick.png',
+		 '(\&lt\;3|\(heart\))' => 'heart.png',
+		 '\(rose\)' => 'rose.png',
+		 '\(pizza\)' => 'food-pizza.png',
+		 '\(cake\)' => 'food-cake.png',
+		 '\(ninja\)' => 'face-ninja.png',
+		 '\(pirate\)' => 'face-pirate.png',
+		 '\((agree|yes)\)' => 'opinion-agree.png',
+		 '\((disagree|nay)\)' => 'opinion-disagree.png',
+		 '(o|O)\-\)' => 'face-angel.png',
+		 );
     my $iconpath=$Apache::lonnet::perlvar{'lonIconsURL'};
     foreach my $smiley (keys(%smileys)) {
-	$expression=~s/$smiley/\<img src="$iconpath\/$smileys{$smiley}.gif" \/\>/gs; 
+	$expression=~s/$smiley/\<img src="$iconpath\/$smileys{$smiley}" \/\>/gs; 
     }
     return $expression;
 }
@@ -281,7 +463,6 @@ sub smiley {
 sub msgtexconverted {
     my ($message,$email) = @_;
     $errorstring='';
-    &init_tth();
     my $outmessage='';
     my $tex=0;
     foreach my $fragment (split(/(?:\&lt\;|\<)\/*m\s*(?:\&gt\;|\>)/i,$message)) {
@@ -302,15 +483,16 @@ sub msgtexconverted {
     foreach my $fragment (split(/(?:\&lt\;|\<)\/*algebra\s*(?:\&gt\;|\>)/i,
 				$message)) {
 	if ($tex) {
+        my $algebra = &algebra($fragment, 'web', undef, undef, undef, 'tth');
 	    if ($email) {
-		$outmessage.='</pre><tt>'.&algebra($fragment,'web').'</tt><pre>';
+		$outmessage.='</pre><tt>'.$algebra.'</tt><pre>';
 		$tex=0;
 	    } else {
-		$outmessage.=&algebra($fragment,'web');
+		$outmessage.=$algebra;
 		$tex=0;
 	    }
 	} else {
-            $outmessage.=$fragment;
+        $outmessage.=$fragment;
 	    $tex=1;
 	}
     }
@@ -323,9 +505,9 @@ sub msgtexconverted {
 
 sub algebra {
     use AlgParser;
-
-    my ($string,$target,$style)=@_;
+    my ($string,$target,$style,$parstack,$safeeval,$tth)=@_;
     my $parser = new AlgParserWithImplicitExpand;
+    if ($tth eq 'tth') {&init_tth();}
     $string=&prepare_algebra($string);
     my $ret = $parser->parse($string);
     my $result='['.&mt('Algebra unconverted due to previous errors').']';
@@ -341,7 +523,9 @@ 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;
 	}
@@ -366,7 +550,7 @@ sub postprocess_algebra {
     # $string =~s/\\fun/ /g;
 
     # sqrt(3,4) means the 4 root of 3
-    $string =~s/\\sqrt{([^,]+),([^\}]+)}/\\sqrt[$2]{$1}/gs;
+    $string =~s/\\sqrt\{([^,]+),([^\}]+)}/\\sqrt[$2]{$1}/gs;
 
     # log(3,4) means the log base 4 of 3
     $string =~s/\\log\\left\((.+?),(.+?)\\right\)/\\log_{$2}\\left($1\\right)/gs;
@@ -384,12 +568,115 @@ sub postprocess_algebra {
     $string =~s/\\lim\\left\((.+?),(.+?),(.+?)\\right\)/\\lim_{$2\\to $3}$1/gs;
     return $string;
 }
+
+
 1;
 __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 MathJax_converted()
+
+=item tex_engine()
+
+=item init_math_support()
+
+=item mimetex_valign()
+
+ Makes a HEAD call to /cgi-bin/mimetex.cgi via IO:: to retrieve the 
+ vertical alignment, before the subsequent call to mimetex_converted()
+ which generates the <img> tag and the corresponding image.
+
+ Input: 1.  $esc_texstring (escaped TeX to be rendered by mimetex).
+ Output: 1. $valign - number of pixels: positive or negative integer 
+            which will be included in <img> tag for mimetex image to
+            support vertical alignment of image within a line of text.
+
+ If a server is running SSL, and Apache rewrite rules are in place 
+ to rewrite requests for http to https, modification will most likely 
+ be needed for pass through for HEAD requests for /cgi-bin/mimetex.cgi. 
+
+ Example rewrite rules which rewrite all http traffic to https, 
+ except HEAD requests for /cgi-bin/mimetex.cgi are:
+
+ <IfModule mod_rewrite.c>
+     RewriteEngine On
+     RewriteLogLevel 0
+
+     RewriteCond %{HTTPS} off
+     RewriteCond %{HTTP:Host} (.*)
+     RewriteCond %{REQUEST_METHOD} !HEAD 
+     RewriteRule ^/(.*) https://%1/$1 [R=301,L]
+
+     RewriteCond %{HTTPS} off
+     RewriteCond %{HTTP:Host} (.*)
+     RewriteCond %{REQUEST_METHOD} HEAD
+     RewriteCond %{REQUEST_URI} !^/cgi-bin/mimetex.cgi
+     RewriteRule ^/(.*) https://%1/$1 [R=301,L]
+ </IfModule>
+
+=item mimetex_converted()
+
+
+=item converted()
+
+
+=item to_convert()
+
+message display
+
+=item smiley()
+
+???
+
+=item msgtexconverted()
+
+=item algebra()
+
+=item prepare_algebra()
+
+=item postprocess_algebra()
 
+=back
 
+=cut