cairo:matrix-scale (matrix sx sy)

matrix -- a cairo:matrix-t instance
sx -- a number coerced to a double float for the scale factor in the x direction
sy -- a number coerced to a double float for the scale factor in the y direction

The cairo:matrix-t instance with the applied scaling.

Applies scaling by sx and sy to the transformation in the matrix. The effect of the new transformation is to first scale the coordinates by sx and sy, then apply the original transformation to the coordinates.