diff --git a/unix/x0vncserver/PollingManager.h b/unix/x0vncserver/PollingManager.h
index b26e643..3cb1e8b 100644
--- a/unix/x0vncserver/PollingManager.h
+++ b/unix/x0vncserver/PollingManager.h
@@ -68,8 +68,6 @@
   int m_offsetTop;
   int m_width;
   int m_height;
-  int m_widthTiles;
-  int m_heightTiles;
 
 private:
 
@@ -120,6 +118,10 @@
   Image *m_rowImage;            // one row of the framebuffer
   Image *m_columnImage;         // one column of the framebuffer
 
+  int m_widthTiles;		// shortcut for ((m_width + 31) / 32)
+  int m_heightTiles;		// shortcut for ((m_height + 31) / 32)
+  int m_numTiles;		// shortcut for (m_widthTiles * m_heightTiles)
+
   char *m_rateMatrix;
   char *m_videoFlags;
   Rect m_videoRect;