a GtkWidget
X position relative to @src_widget
Y position relative to @src_widget
location to store X position relative to @dest_widget
location to store Y position relative to @dest_widget
%FALSE if @src_widget and @dest_widget have no common ancestor. In this case, 0 is stored in *@dest_x and *@dest_y. Otherwise %TRUE.
Translate coordinates relative to @src_widget’s allocation to coordinates relative to @dest_widget’s allocations.
In order to perform this operation, both widget must share a common ancestor.