--- loncom/xml/lontexconvert.pm	2012/02/28 10:38:14	1.110
+++ loncom/xml/lontexconvert.pm	2016/01/22 22:31:51	1.117
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # TeX Conversion Module
 #
-# $Id: lontexconvert.pm,v 1.110 2012/02/28 10:38:14 foxr Exp $
+# $Id: lontexconvert.pm,v 1.117 2016/01/22 22:31:51 damieng Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -54,14 +54,53 @@ use IO::Socket::INET;
 #
 # Table of substitutions to unicode characters.
 #
+
+my %unicode_harpoons = (
+                        '\rightleftharpoons'  => 0x21cc,
+                      );
+
 my %unicode_translations = (
-    '\rightleftharpoons'  => 0x21cc,
+
+# Brackets - unicode for browsers/OS which support it.
+
     ''             => 0x23a1,
     ''             => 0x23a2,
     ''             => 0x23a3,
     ''             => 0x23a4,
     ''             => 0x23a5,
-    ''             => 0x23a6   
+    ''             => 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,
+
 );
 
 ##
@@ -126,14 +165,12 @@ sub convert_real {
     };
     &Apache::lonxml::start_alarm();
     if ($env{'browser.mathml'}) {
-	&Apache::lonnet::logthis("mathml");
 	$xmlstring=&tth::ttm($$texstring);
 	$xmlstring=~s/\<math\>/\<math xmlns=\"\&mathns\;\"\>/g;
 	$xmlstring=~s/\<br\>/\<br\/\>/g;
 	$xmlstring=~s/\<p\>/\<p\>\<\/p\>/g;
 	$errorstring.=&tth::ttmerror();
     } else {
-	&Apache::lonnet::logthis("tth");
 	$xmlstring=&tth::tth($$texstring);
 	$errorstring.=&tth::ttherror();
 	$xmlstring=~s-</font(\s*)>-</font>-g;
@@ -141,19 +178,37 @@ sub convert_real {
     $xmlstring=~s/^\s*\<br clear\=\"all\"/\<br/s;
     $xmlstring=~s/^\s*//;
     $xmlstring=~s/\s*$//;
+    $xmlstring=~s/^<br \/><table/<table/;
     &Apache::lonxml::end_alarm();
 
     #
-    #  Several strings produced by tth require
+    # 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:
+    # 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);
 }
@@ -468,7 +523,7 @@ 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;
@@ -553,6 +608,8 @@ sub postprocess_algebra {
     $string =~s/\\lim\\left\((.+?),(.+?),(.+?)\\right\)/\\lim_{$2\\to $3}$1/gs;
     return $string;
 }
+
+
 1;
 __END__