added wxHtmlWindow::HistoryCanBack/Forward

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@8516 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/htwindow.tex

@@ -98,6 +98,21 @@ Returns the related frame.
 Moves back to the previous page. (each page displayed using 
 \helpref{LoadPage}{wxhtmlwindowloadpage} is stored in history list.)
 
+\membersection{wxHtmlWindow::HistoryCanBack}\label{wxhtmlwindowhistorycanback}
+
+\func{bool}{HistoryCanBack}{\void}
+
+Returns true if it is possible to go back in the history (i.e. HistoryBack()
+won't fail).
+
+\membersection{wxHtmlWindow::HistoryCanForward}\label{wxhtmlwindowhistorycanforward}
+
+\func{bool}{HistoryCanForward}{\void}
+
+Returns true if it is possible to go forward in the history (i.e. HistoryBack()
+won't fail).
+
+
 \membersection{wxHtmlWindow::HistoryClear}\label{wxhtmlwindowhistoryclear}
 
 \func{void}{HistoryClear}{\void}

include/wx/html/htmlwin.h

@@ -129,6 +129,9 @@ class WXDLLEXPORT wxHtmlWindow : public wxScrolledWindow
         bool HistoryForward();
                 // Goes to previous/next page (in browsing history)
                 // Returns TRUE if successful, FALSE otherwise
+        bool HistoryCanBack();
+        bool HistoryCanForward();
+        
         void HistoryClear();
                 // Resets history
 

src/html/htmlwin.cpp

@@ -387,6 +387,11 @@ bool wxHtmlWindow::HistoryBack()
     return TRUE;
 }
 
+bool wxHtmlWindow::HistoryCanBack()
+{
+    if (m_HistoryPos < 1) return FALSE;
+    return TRUE ;
+}
 
 
 bool wxHtmlWindow::HistoryForward()
@@ -413,6 +418,12 @@ bool wxHtmlWindow::HistoryForward()
     return TRUE;
 }
 
+bool wxHtmlWindow::HistoryCanForward()
+{
+    if (m_HistoryPos == -1) return FALSE;
+    if (m_HistoryPos >= (int)m_History.GetCount() - 1)return FALSE;
+    return TRUE ;
+}
 
 
 void wxHtmlWindow::HistoryClear()