gdk-pixbuf-scale (src dest x y width height xoffset yoffset xscale  yscale interp)

src -- a gdk-pixbuf object
dest -- a gdk-pixbuf object into which to render the results
x -- an integer with the left coordinate for region to render
y -- an integer with the top coordinate for region to render
width -- an integer with the width of the region to render
height -- an integer with the height of the region to render
xoffset -- a double float with the offset in the x direction, currently rounded to an integer
yoffset -- a double float with the offset in the y direction, currently rounded to an integer
xscale -- a double float with the scale factor in the x direction
yscale -- a double float with the scale factor in the y direction
interp -- a gdk-interp-type interpolation type for the transformation

Creates a transformation of the source image src by scaling by xscale and yscale then translating by xoffset and yoffset, then renders the rectangle (x, y, width, height) of the resulting image onto the destination image replacing the previous contents.

Try to use the gdk-pixbuf-scale-simple function first, this function is the industrial-strength power tool you can fall back to if the gdk-pixbuf-scale-simple function is not powerful enough.

If the source rectangle overlaps the destination rectangle on the same pixbuf, it will be overwritten during the scaling which results in rendering artifacts.