title: Gtk how to calculate width of the string in pixels
body: <p>Gtk how should I calculate width of the string in pixels.<br>
  I have created a markup string using <code>g_markup_printf_escaped</code> and I want to calculate width of the string in pixels not in chars.  </p>
  
  <p>Does <code>Pango</code> provides any function to calculate string length in pixels, depending on font type, size and weight?</p>