A GtkCalendar is a widget consisting of a grid
container displaying a calendar, with an optional label allowing
month/year navigation and an optional header giving abbreviated day names.
Both the day and the month names are supplied by the system locale, and
cannot be overwritten. Unfortunately, under win32 there are severe
problems with internationalization in the GDK source currently used by
PHP-GTK. Non-standard ISO8859-1/2 characters cannot be drawn in this
widget as a result of a wide character conversion failure under Windows.
Multibyte characters are not recognised, and as they are supplied directly
by the system to the widget there is no option to convert them using PHP.
This issue is gradually being addressed by the PHP-GTK development team on
a widget-by-widget basis.
Assuming that your locale and your operating system will allow you to use
this widget's headers, the only other point to keep in mind is that a
marked date is differentiated from the other dates by
being drawn on a slightly bigger base rectangle, making it appear bold
while actually using the same font as the rest of the widget. This is
less effective in some fonts than in others, and can become a very
negligable distinction.