gtk-alignment-set (alignment xalign yalign xscale yscale)

alignment -- a gtk-alignment widget
xalign -- a float with the horizontal alignment of the child widget, from 0.0 (left) to 1.0 (right)
yalign -- a float with the vertical alignment of the child widget, from 0.0 (top) to 1.0 (bottom)
xscale -- a float with the amount that the child widget expands horizontally to fill up unused space, from 0.0 to 1.0, a value of 0.0 indicates that the child widget should never expand, a value of 1.0 indicates that the child widget will expand to fill all of the space allocated for the alignment
yscale -- a float with the amount that the child widget expands vertically to fill up unused space, from 0.0 to 1.0, the values are similar to xscale

Sets the alignment values. The function gtk-alignment-set has been deprecated since version 3.14 and should not be used in newly written code. Use the gtk-widget alignment and margin properties.