--- trunk/webwork2/lib/WeBWorK/PG.pm	2004/01/05 01:02:41	1703
+++ trunk/webwork2/lib/WeBWorK/PG.pm	2004/05/24 02:01:25	2200
@@ -1,7 +1,7 @@
 ################################################################################
 # WeBWorK Online Homework Delivery System
 # Copyright © 2000-2003 The WeBWorK Project, http://openwebwork.sf.net/
-# $CVSHeader: webwork-modperl/lib/WeBWorK/PG.pm,v 1.46 2003/12/09 01:12:30 sh002i Exp $
+# $CVSHeader: webwork-modperl/lib/WeBWorK/PG.pm,v 1.50 2004/05/24 01:03:04 sh002i Exp $
 # 
 # This program is free software; you can redistribute it and/or modify it under
 # the terms of either: (a) the GNU General Public License as published by the
@@ -28,6 +28,30 @@
 use WeBWorK::PG::ImageGenerator;
 use WeBWorK::Utils qw(runtime_use formatDateTime makeTempDirectory);
 
+use constant DISPLAY_MODES => {
+	# display name   # mode name
+	tex           => "TeX",
+	plainText     => "HTML",
+	formattedText => "HTML_tth",
+	images        => "HTML_dpng",
+	jsMath	      => "HTML_jsMath",
+	asciimath     => "HTML_asciimath",
+};
+
+use constant DISPLAY_MODE_FAILOVER => {
+	TeX            => [],
+	HTML           => [],
+	HTML_tth       => [ "HTML", ],
+	HTML_dpng      => [ "HTML_tth", "HTML", ],
+	HTML_jsMath    => [ "HTML_dpng", "HTML_tth", "HTML", ],
+	HTML_asciimath => [ "HTML_dpng", "HTML_tth", "HTML", ],
+	# legacy modes -- these are not supported, but some problems might try to
+	# set the display mode to one of these values manually and some macros may
+	# provide rendered versions for these modes but not the one we want.
+	Latex2HTML  => [ "TeX", "HTML", ],
+	HTML_img    => [ "HTML_dpng", "HTML_tth", "HTML", ],
+};
+
 sub new {
 	shift; # throw away invocant -- we don't need it
 	my ($ce, $user, $key, $set, $problem, $psvn, $formFields,
@@ -62,22 +86,23 @@
 	# any changes are noted by "ADDED:" or "REMOVED:"
 	
 	# Vital state information
-	# ADDED: displayHintsQ, displaySolutionsQ, refreshMath2img,
-	#        texDisposition
+	# ADDED: displayModeFailover, displayHintsQ, displaySolutionsQ,
+	#        refreshMath2img, texDisposition
 	
-	$envir{psvn}              = $set->psvn;
-	$envir{psvnNumber}        = $envir{psvn};
-	$envir{probNum}           = $problem->problem_id;
-	$envir{questionNumber}    = $envir{probNum};
-	$envir{fileName}          = $problem->source_file;	 
-	$envir{probFileName}      = $envir{fileName};		 
-	$envir{problemSeed}       = $problem->problem_seed;
-	$envir{displayMode}       = translateDisplayModeNames($options->{displayMode});
-	$envir{languageMode}      = $envir{displayMode};	 
-	$envir{outputMode}        = $envir{displayMode};	 
-	$envir{displayHintsQ}     = $options->{showHints};	 
-	$envir{displaySolutionsQ} = $options->{showSolutions};
-	$envir{texDisposition}    = "pdf"; # in webwork2, we use pdflatex
+	$envir{psvn}                = $set->psvn;
+	$envir{psvnNumber}          = $envir{psvn};
+	$envir{probNum}             = $problem->problem_id;
+	$envir{questionNumber}      = $envir{probNum};
+	$envir{fileName}            = $problem->source_file;	 
+	$envir{probFileName}        = $envir{fileName};		 
+	$envir{problemSeed}         = $problem->problem_seed;
+	$envir{displayMode}         = translateDisplayModeNames($options->{displayMode});
+	$envir{languageMode}        = $envir{displayMode};	 
+	$envir{outputMode}          = $envir{displayMode};	 
+	$envir{displayModeFailover} = DISPLAY_MODE_FAILOVER();
+	$envir{displayHintsQ}       = $options->{showHints};	 
+	$envir{displaySolutionsQ}   = $options->{showSolutions};
+	$envir{texDisposition}      = "pdf"; # in webwork2, we use pdflatex
 	
 	# Problem Information
 	# ADDED: courseName, formatedDueDate
@@ -125,6 +150,8 @@
 	# Directories and URLs
 	# REMOVED: courseName
 	# ADDED: dvipngTempDir
+	# ADDED: jsMathURL
+	# ADDED: asciimathURL
 	
 	$envir{cgiDirectory}           = undef;
 	$envir{cgiURL}                 = undef;
@@ -138,6 +165,9 @@
 	$envir{tempURL}                = $ce->{courseURLs}->{html_temp}."/";
 	$envir{scriptDirectory}        = undef;
 	$envir{webworkDocsURL}         = $ce->{webworkURLs}->{docs}."/";
+	$envir{localHelpURL}           = $ce->{webworkURLs}->{local_help}."/";
+	$envir{jsMathURL}	       = $ce->{webworkURLs}->{jsMath};
+	$envir{asciimathURL}	       = $ce->{webworkURLs}->{asciimath};
 	
 	# Information for sending mail
 	
@@ -182,12 +212,7 @@
 
 sub translateDisplayModeNames($) {
 	my $name = shift;
-	return {
-		tex           => "TeX",
-		plainText     => "HTML",
-		formattedText => "HTML_tth",
-		images        => "HTML_dpng", # "HTML_img",
-	}->{$name};
+	return DISPLAY_MODES()->{$name};
 }
 
 sub oldSafetyFilter {