the horizontal alignment, from 0 (left) to 1 (right).
the vertical alignment, from 0 (top) to 1 (bottom).
Deprecated: Use #GtkWidget's alignment (#GtkWidget:halign and #GtkWidget:valign) and margin properties or #GtkLabel's #GtkLabel:xalign and #GtkLabel:yalign properties.
Sets the alignment of the widget.