gtk:render-expander (context cr x y width height)

context -- a gtk:style-context object
cr -- a cairo:context-t context
x -- a number coerced to a double float for the x origin of the rectangle
y -- a number coerced to a double float for the y origin of the rectangle
width -- a number coerced to a double float for a rectangle width
height -- a number coerced to a double float for a rectangle height

Renders an expander as used in the gtk:tree-view widget and gtk:expander widget in the area defined by x, y, width, height. The :active state of the gtk:state-flags flags determines whether the expander is collapsed or expanded.