gtk:render-line (context cr x0 y0 x1 y1)

context -- a gtk:style-context object
cr -- a cairo:context-t context
x0 -- a number coerced to a double float for the x coordinate of the origin of the line
y0 -- a number coerced to a double float for the y coordinate of the origin of the line
x1 -- a number coerced to a double float for the x coordinate of the end of the line
y1 -- a number coerced to a double float for the y coordinate of the end of the line

Renders a line from (x0,y0) to (x1,y1). This function is deprecated since 4.10. Please do not use it in newly written code.