Description The GtkCurve widget allows the user to edit a curve covering a range of values. It is typically used to fine-tune color balances in graphics applications like the Gimp. The GtkCurve widget has 3 modes of operation - spline, linear and free. In spline mode the user places points on the curve which are automatically connected together into a smooth curve. In linear mode the user places points on the curve which are connected by straight lines. In free mode the user can draw the points of the curve freely, and they are not connected at all. As of GTK+ 2.20, GtkCurve has been deprecated since it is too specialized.