cairo:scale (cr sx sy)

cr -- a cairo:context-t instance
sx -- a number coerced to a double float for the scale factor for the x dimension
sy -- a number coerced to a double float for the scale factor for the y dimension

Modifies the current transformation matrix (CTM) by scaling the x and y user-space axes by sx and sy respectively. The scaling of the axes takes place after any existing transformation of user space.