From 82a76d38b5e60bace4dc9aa9e552a03e256bd892 Mon Sep 17 00:00:00 2001
From: thepurpleblob <thepurpleblob>
Date: Wed, 10 Aug 2005 12:58:38 +0000
Subject: [PATCH] Some more tweaks to LaTeX filter - see bug #3829.

---
 filter/tex/filter.php | 9 +++++----
 filter/tex/latex.php  | 7 ++++++-
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/filter/tex/filter.php b/filter/tex/filter.php
index 591b5c2d86f..c29220ee253 100644
--- a/filter/tex/filter.php
+++ b/filter/tex/filter.php
@@ -88,7 +88,7 @@ function tex_filter ($courseid, $text) {
     global $CFG;
 
     /// Do a quick check using stripos to avoid unnecessary work
-    if (!preg_match('/<tex/i',$text) and !strstr($text,'$$') and !strstr($text,'\\[')) { //added one more tag (dlnsk)
+    if (!preg_match('/<tex/i',$text) and !strstr($text,'$$') and !strstr($text,'\\[') and !preg_match('/\[tex/i',$text)) { //added one more tag (dlnsk)
         return $text;
     }
 
@@ -119,10 +119,11 @@ function tex_filter ($courseid, $text) {
 
     // <tex> TeX expression </tex>
     // or $$ TeX expression $$
-    // or \[ TeX expression \]        // original tag of MathType and TeXaide (dlnsk)
-    preg_match_all('/<tex>(.+?)<\/tex>|\$\$(.+?)\$\$|\\\\\[(.+?)\\\\\]/is', $text, $matches);
+    // or \[ TeX expression \]          // original tag of MathType and TeXaide (dlnsk)
+    // or [tex] TeX expression [/tex]   // somtime it's more comfortable than <tex> (dlnsk)
+    preg_match_all('/<tex>(.+?)<\/tex>|\$\$(.+?)\$\$|\\\\\[(.+?)\\\\\]|\\[tex\\](.+?)\\[\/tex\\]/is', $text, $matches);
     for ($i=0; $i<count($matches[0]); $i++) {
-        $texexp = $matches[1][$i] . $matches[2][$i] . $matches[3][$i];
+        $texexp = $matches[1][$i] . $matches[2][$i] . $matches[3][$i] . $matches[4][$i];
         $texexp = str_replace('<nolink>','',$texexp);
         $texexp = str_replace('</nolink>','',$texexp);
         $texexp = str_replace('<span class="nolink">','',$texexp);
diff --git a/filter/tex/latex.php b/filter/tex/latex.php
index 3cffaa90a96..e9a65179fc1 100644
--- a/filter/tex/latex.php
+++ b/filter/tex/latex.php
@@ -51,7 +51,12 @@
             $doc .=  $CFG->filter_tex_latexpreamble;
             $doc .= "\\pagestyle{empty}\n";
             $doc .= "\\begin{document}\n";
-            $doc .= "$ {$formula} $\n";
+//dlnsk            $doc .= "$ {$formula} $\n";
+            if (preg_match("/^[[:space:]]*\\\\begin\\{(gather|align|alignat|multline).?\\}/i",$formula)) {
+               $doc .= "$formula\n";
+            } else {
+               $doc .= "$ {$formula} $\n";
+            }
             $doc .= "\\end{document}\n";
             return $doc;
         }