diff --git a/3rdparty/fonts/fnt.cxx b/3rdparty/fonts/fnt.cxx
index 05197ba..71595ad 100644
--- a/3rdparty/fonts/fnt.cxx
+++ b/3rdparty/fonts/fnt.cxx
@@ -190,7 +190,7 @@ void fntTexFont::getBBox ( const char *s,
     if ( (cc & 0XE0) == 0XE0) {
       SG_LOG(SG_GUI,SG_ALERT, "UTF8 cc=" << cc);
 
-      int x = cc << 4;
+      int x = (cc & 0X0F) << 4;
 
       SG_LOG(SG_GUI,SG_ALERT, "UTF8 cc<<4 " << x);
 
@@ -199,9 +199,9 @@ void fntTexFont::getBBox ( const char *s,
 
       SG_LOG(SG_GUI,SG_ALERT, "UTF81 cc=" << cc);
 
-      x= x + ((cc>>2) & 0x0F);
+      x= x + ((cc & 0x3C) >>2 ) ;
 
-      int y = (cc & 0x03) * 0X3F;
+      int y = (cc & 0x03) << 6 ;
 
       cc =  (unsigned char) *(s++) ;