Function: image--compute-rotation

image--compute-rotation is a byte-compiled function defined in image.el.gz.

Signature

(image--compute-rotation IMAGE)

Documentation

Return the current rotation of IMAGE, or 0 if no rotation.

Also return nil if rotation is not a multiples of 90 degrees (0, 90,
180[-180] and 270[-90]).

Source Code

;; Defined in /usr/src/emacs/lisp/image.el.gz
(defsubst image--compute-rotation (image)
  "Return the current rotation of IMAGE, or 0 if no rotation.
Also return nil if rotation is not a multiples of 90 degrees (0, 90,
180[-180] and 270[-90])."
  (let ((degrees (or (image-property image :rotation) 0)))
    (and (= 0 (mod degrees 1))
         (car (memql (truncate (mod degrees 360)) '(0 90 180 270))))))