gtk:spin-button-increments (spinbutton)

spinbutton -- a gtk:spin-button widget
step -- a number coerced to a double float for the increment applied for a button 1 press
page -- a number coerced to a double float for the increment applied for a button 2 press

Gets or sets the current step and page increments used by the spin button. This affects how quickly the value changes when the arrows of the spin button are activated. The values for the page and step increments are stored in the page-increment and step-increment slots of the adjustment associated with the spin button.