newSubpixbuf 
  open fun newSubpixbuf(srcX: <Error class: unknown class>, srcY: <Error class: unknown class>, width: <Error class: unknown class>, height: <Error class: unknown class>): Pixbuf(source)
Creates a new pixbuf which represents a sub-region of src_pixbuf.
The new pixbuf shares its pixels with the original pixbuf, so writing to one affects both.  The new pixbuf holds a reference to src_pixbuf, so src_pixbuf will not be finalized until the new pixbuf is finalized.
Note that if src_pixbuf is read-only, this function will force it to be mutable.
Return
a new pixbuf
Parameters
srcX 
X coord in @src_pixbuf
srcY 
Y coord in @src_pixbuf
width
width of region in @src_pixbuf
height
height of region in @src_pixbuf