[Doxygen-develop] [PATCH] IMG ALT text for each formula, like in latex2html

[Vassilii K. <vas...@co...>]

(Please use vas...@ta... as my contact, rather
then the work email I'm submitting this from).
This is tested locally on a RH7.3 Linux system, with IE and Mozilla
as the WWW UAs.

Index: src/htmldocvisitor.cpp
===================================================================
RCS file: /u/kp3softd/cvsroot/src/htmldocvisitor.cpp,v
retrieving revision 1.16
diff -u -r1.16 htmldocvisitor.cpp
--- src/htmldocvisitor.cpp	2003/04/12 09:32:03	1.16
+++ src/htmldocvisitor.cpp	2003/04/16 14:44:57
@@ -272,6 +272,11 @@
   m_t << "\"middle\"";  // assume Windows users use IE or HtmlHelp which on
   // displays formulas nicely with align == "middle" 
 #endif
+  m_t << " alt=\"";
+  filterQuotedCdataAttr(f->text());
+  m_t << "\"";
+  /// @todo cache image dimensions on formula generation and give height/width
+  /// for faster preloading and better rendering of the page
   m_t << " src=\"" << f->name() << ".png\">";
   if (f->text().at(0)=='\\') 
     m_t << endl << "</center><p>" << endl;
@@ -916,6 +921,43 @@
       case '<':  m_t << "&lt;"; break;
       case '>':  m_t << "&gt;"; break;
       case '&':  m_t << "&amp;"; break;
+      default:   m_t << c;
+    }
+  }
+}
+
+/// Escape basic entities to produce a valid CDATA attribute value,
+/// assume that the outer quoting will be using the double quote &quot;
+void HtmlDocVisitor::filterQuotedCdataAttr(const char* str)
+{
+  if (str==0) return;
+  const char *p=str;
+  char c;
+  while (*p)
+  {
+    c=*p++;
+    switch(c)
+    {
+      case '&':  m_t << "&amp;"; break;
+      case '"':  m_t << "&quot;"; break;
+	// For SGML compliance, and given the SGML declaration for HTML syntax,
+	// it's enough to replace these two, provided that the declaration
+	// for the HTML version we generate (and as supported by the browser)
+	// specifies that all the other symbols used in rawVal are
+	// within the right charachter class (i.e., they're not
+	// some multinational weird charachters not in the BASESET).
+	// We assume that 1) the browser will support whatever is remaining
+	// in the formula and 2) the TeX formulae are generally governed
+	// by even stricter charachter restrictions so it should be enough.
+	//
+	// On some incompliant browsers, additional translation of
+	// '>' and '<' into "&gt;" and "&lt;", respectively, might be needed;
+	// but I'm unaware of particular modern (last 4 years) versions 
+	// with such problems, so let's not do it for performance.
+	// Also, some brousers will (wrongly) not process the entity references
+	// inside the attribute value and show the &...; form instead,
+	// so we won't create entites unless necessary to minimize clutter there.
+	// --vassilii
       default:   m_t << c;
     }
   }
Index: src/htmldocvisitor.h
===================================================================
RCS file: /u/kp3softd/cvsroot/src/htmldocvisitor.h,v
retrieving revision 1.8
diff -u -r1.8 htmldocvisitor.h
--- src/htmldocvisitor.h	2003/01/19 21:02:00	1.8
+++ src/htmldocvisitor.h	2003/04/16 14:44:57
@@ -133,6 +133,7 @@
     //--------------------------------------
     
     void filter(const char *str);
+    void filterQuotedCdataAttr(const char* str);
     void startLink(const QString &ref,const QString &file,
                    const QString &anchor);
     void endLink();