-The minimum delay between successive frames is `image-minimum-frame-delay'."
- (image-show-frame image n t)
- (setq n (1+ n))
- (let* ((time (float-time))
- (animation (image-multi-frame-p image))
- ;; Subtract off the time we took to load the image from the
- ;; stated delay time.
- (delay (max (+ (or (cdr animation) image-default-frame-delay)
- time (- (float-time)))
- image-minimum-frame-delay))
- done)
- (if (>= n count)
- (if limit
- (setq n 0)
- (setq done t)))
- (setq time-elapsed (+ delay time-elapsed))
- (if (numberp limit)
- (setq done (>= time-elapsed limit)))
- (unless done
- (run-with-timer delay nil 'image-animate-timeout
- image n count time-elapsed limit))))
+The minimum delay between successive frames is `image-minimum-frame-delay'.
+
+If the image has a non-nil :speed property, it acts as a multiplier
+for the animation speed. A negative value means to animate in reverse."
+ (when (buffer-live-p (plist-get (cdr image) :animate-buffer))
+ (image-show-frame image n t)
+ (let* ((speed (image-animate-get-speed image))
+ (time (float-time))
+ (animation (image-multi-frame-p image))
+ ;; Subtract off the time we took to load the image from the
+ ;; stated delay time.
+ (delay (max (+ (* (or (cdr animation) image-default-frame-delay)
+ (/ 1 (abs speed)))
+ time (- (float-time)))
+ image-minimum-frame-delay))
+ done)
+ (setq n (if (< speed 0)
+ (1- n)
+ (1+ n)))
+ (if limit
+ (cond ((>= n count) (setq n 0))
+ ((< n 0) (setq n (1- count))))
+ (and (or (>= n count) (< n 0)) (setq done t)))
+ (setq time-elapsed (+ delay time-elapsed))
+ (if (numberp limit)
+ (setq done (>= time-elapsed limit)))
+ (unless done
+ (run-with-timer delay nil 'image-animate-timeout
+ image n count time-elapsed limit)))))