-void RrPaint (RrAppearance *l, Window win, gint w, gint h);
-void RrMinsize (RrAppearance *l, gint *w, gint *h);
+int RrFontMeasureString (const RrFont *f, const gchar *str);
+int RrFontHeight (const RrFont *f);
+int RrFontMaxCharWidth (const RrFont *f);
+
+void RrPaint (RrAppearance *a, Window win, gint w, gint h);
+void RrMinsize (RrAppearance *a, gint *w, gint *h);
+void RrMargins (RrAppearance *a, gint *l, gint *t, gint *r, gint *b);