Add <span> tag and limited support for CSS styles to wxHTML.

Parse "style" attributes of the HTML tags and honour those of them that can be
mapped to the HTML 3 attributes.

Also add a handler for <span> tag.

Closes #10631.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64443 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/html/styleparams.h

@@ -0,0 +1,53 @@
+/////////////////////////////////////////////////////////////////////////////
+// Name:        wx/html/styleparams.h
+// Purpose:     wxHtml helper code for extracting style parameters
+// Author:      Nigel Paton
+// RCS-ID:      $Id$
+// Copyright:   wxWidgets team
+// Licence:     wxWindows licence
+/////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_HTML_STYLEPARAMS_H_
+#define _WX_HTML_STYLEPARAMS_H_
+
+#include "wx/defs.h"
+
+#if wxUSE_HTML
+
+#include "wx/arrstr.h"
+
+class WXDLLIMPEXP_FWD_HTML wxHtmlTag;
+
+// This is a private class used by wxHTML to parse "style" attributes of HTML
+// elements. Currently both parsing and support for the parsed values is pretty
+// trivial.
+class WXDLLIMPEXP_HTML wxHtmlStyleParams
+{
+public:
+    // Construct a style parameters object corresponding to the style attribute
+    // of the given HTML tag.
+    wxHtmlStyleParams(const wxHtmlTag& tag);
+
+    // Check whether the named parameter is present or not.
+    bool HasParam(const wxString& par) const
+    {
+        return m_names.Index(par, false /* ignore case */) != wxNOT_FOUND;
+    }
+
+    // Get the value of the named parameter, return empty string if none.
+    wxString GetParam(const wxString& par) const
+    {
+        int index = m_names.Index(par, false);
+        return index == wxNOT_FOUND ? wxString() : m_values[index];
+    }
+
+private:
+    // Arrays if names and values of the parameters
+    wxArrayString
+        m_names,
+        m_values;
+};
+
+#endif // wxUSE_HTML
+
+#endif // _WX_HTML_STYLEPARAMS_H_