--- loncom/interface/lonpreferences.pm	2005/02/17 08:29:43	1.53
+++ loncom/interface/lonpreferences.pm	2005/02/25 05:54:01	1.54
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Preferences
 #
-# $Id: lonpreferences.pm,v 1.53 2005/02/17 08:29:43 albertel Exp $
+# $Id: lonpreferences.pm,v 1.54 2005/02/25 05:54:01 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -178,6 +178,88 @@ ENDVCSCREEN
 }
 
 ################################################################
+#         Tex Engine Change Subroutines                        #
+################################################################
+sub texenginechanger {
+    my $r = shift;
+    my $user       = $ENV{'user.name'};
+    my $domain     = $ENV{'user.domain'};
+    my %userenv = &Apache::lonnet::get('environment',['texengine']);
+    my $texengine=$userenv{'texengine'};
+
+    my $pref=&mt('Preferred method to display Math');
+    my %mathchoices=('' => 'No Preference',
+		     'tth' => 'TeX to HTML',
+		     #'ttm' => 'TeX to MathML',
+		     'jsMath' => 'jsMath',
+		     #'mimetex' => 'Convert to Images'
+                     );
+    my $selectionbox=&Apache::loncommon::select_form($texengine,'texengine',
+						     %mathchoices);
+    my $mathexample='$$\int\left(\frac{a+b}{c^6*d}\right)$$';
+    my $jsMath_example=&Apache::lontexconvert::jsMath_converted(\$mathexample);
+    $mathexample='$$\int\left(\frac{a+b}{c^6*d}\right)$$';
+    my $tth_example=&Apache::lontexconvert::tth_converted(\$mathexample);
+    my $change=&mt('Change');
+    $r->print(<<ENDLSCREEN);
+<form name="server" action="/adm/preferences" method="post">
+<input type="hidden" name="action" value="verify_and_change_texengine" />
+<p>$pref: $selectionbox</p>
+<p><input type="submit" value="$change" /></p>
+</form>
+Examples:
+<p> TeX to HTML <br /> $tth_example</p>
+<script type"text/javascript">function NoFontMessage () { }</script>
+<script src="/adm/jsMath/jsMath.js"></script>
+<p>jsMath <br /> 
+
+<script type"text/javascript">
+if (jsMath.nofonts == 1) {
+    document.writeln
+        ('<center><div style="padding: 10; border-style: solid; border-width:3;'
+	 +' border-color: #DD0000; background-color: #FFF8F8; width: 75%; text-align: left">'
+	 +'<small><font color="#AA0000"><b>Warning:</b> '
+	 +'It looks like you don\\\'t have the TeX math fonts installed. '
+	 +'The jsMath example on this page may not look right without them. '
+	 +'The <a href="http://www.math.union.edu/locate/jsMath/" target="_blank"> '
+	 +'jsMath Home Page</a> has information on how to download the '
+	 +'needed fonts.  In the meantime, jsMath will do the best it can '
+	 +'with the fonts you have, but it may not be pretty and some equations '
+	 +'may not be rendered correctly. '
+	 +'</font></small></div></center>');
+}
+</script>
+
+$jsMath_example</p>
+<script type="text/javascript">jsMath.Process()</script>
+ENDLSCREEN
+}
+
+
+sub verify_and_change_texengine {
+    my $r = shift;
+    my $user       = $ENV{'user.name'};
+    my $domain     = $ENV{'user.domain'};
+# Screenname
+    my $newtexengine  = $ENV{'form.texengine'};
+    $newtexengine=~s/[^\-\w]//g;
+    my $message='';
+    if ($newtexengine) {
+        &Apache::lonnet::put('environment',{'texengine' => $newtexengine});
+        &Apache::lonnet::appenv('environment.texengine' => $newtexengine);
+        $message='Set new preferred math display to '.$newtexengine;
+    } else {
+        &Apache::lonnet::del('environment',['texengine']);
+        &Apache::lonnet::delenv('environment\.texengine');
+        $message='Reset preferred math display.';
+    }
+    $r->print(<<ENDVCSCREEN);
+</p>
+$message
+ENDVCSCREEN
+}
+
+################################################################
 #         Roles Page Preference Change Subroutines         #
 ################################################################
 sub rolesprefchanger {
@@ -1048,6 +1130,22 @@ sub handler {
                       printmenu => 'yes',
                       }));
 
+    push (@Options,({ action   => 'changetexenginepref',
+                      linktext => 'Change How Math Equations Are Displayed',
+                      href     => '/adm/preferences',
+                      subroutine => \&texenginechanger,
+                      breadcrumb =>
+                          { href => '/adm/preferences?action=changetexenginepref',
+                            text => 'Change Math Pref'},
+                      },
+                    { action   => 'verify_and_change_texengine',
+                      subroutine => \&verify_and_change_texengine,
+                      breadcrumb =>
+                          { href => '/adm/preferences?action=changetexenginepref',
+                            text => 'Change Math Preferences'},
+                      printmenu => 'yes',
+                      }));
+
 
     if ($ENV{'user.name'} =~ /^(albertel|fox|foxr|koretemey|korte|hallmat3|turtle)$/) {
         push (@Options,({ action => 'debugtoggle',
@@ -1126,10 +1224,7 @@ ENDHEADER
 	$r->print('<br /><a href="'.$ENV{'form.returnurl'}.'"><font size="+1">'.
 		  &mt('Return').'</font></a>');
     }
-    $r->print(<<ENDFOOTER);
-</body>
-</html>
-ENDFOOTER
+    $r->print(&Apache::loncommon::endbodytag().'</html>');
     return OK;
 }