;; Mirror effect - mirrors half of image
;; @param mode string default "left_right"

(define-effect mirror
  ((mode "left_right"))
  (let* ((w (width frame))
         (h (height frame))
         (hw (floor (/ w 2)))
         (hh (floor (/ h 2))))
    (cond
      ((= mode "left_right")
       (let ((left (crop frame 0 0 hw h))
             (result (copy frame)))
         (paste result (flip-h left) hw 0)))

      ((= mode "right_left")
       (let ((right (crop frame hw 0 hw h))
             (result (copy frame)))
         (paste result (flip-h right) 0 0)))

      ((= mode "top_bottom")
       (let ((top (crop frame 0 0 w hh))
             (result (copy frame)))
         (paste result (flip-v top) 0 hh)))

      ((= mode "bottom_top")
       (let ((bottom (crop frame 0 hh w hh))
             (result (copy frame)))
         (paste result (flip-v bottom) 0 0)))

      (else frame))))