Some changes and re-organization for animated gif support.

* lisp/image.el (image-animate-max-time): Moved to image-mode.el.
(create-animated-image): Remove unnecessary function.
(image-animate): Rename from image-animate-start.  New arg.
(image-animate-stop): Removed; just use image-animate-timer.
(image-animate-timer): Use car-safe.
(image-animate-timeout): Rename argument.

* lisp/image-mode.el (image-toggle-animation): New command.
(image-mode-map): Bind it to RET.
(image-mode): Update message.
(image-toggle-display-image): Avoid a spurious cache flush.
(image-transform-rotation): Doc fix.
(image-transform-properties): Return quickly in the normal case.
(image-animate-loop): Rename from image-animate-max-time.

4 files changed, 154 insertions, 124 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 4a56915798c..eaa6ee1b704 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -693,6 +693,14 @@ listing object name completions when being sent text via
 
 *** An API for manipulating SQL product definitions has been added.
 
+** Image mode
+
+*** RET (`image-toggle-animation') toggles animation, if the displayed
+image can be animated.
+
+*** Option `image-animate-loop', if non-nil, loops the animation.
+If nil, `image-toggle-animation' plays the animation once.
+
 ** sregex.el is now obsolete, since rx.el is a strict superset.
 
 ** s-region.el and pc-select are now declared obsolete,
@@ -980,12 +988,14 @@ i.e. via menu entries of the form `(menu-item "--")'.
 
 ** Image API
 
-*** When the image type is one of listed in `image-animated-types'
-and the number of sub-images in the image is more than one, then the
-new function `create-animated-image' creates an animated image where
-sub-images are displayed successively with the duration defined by
-`image-animate-max-time' and the delay between sub-images defined
-by the Graphic Control Extension of the image.
+*** Animated images support (currently animated gifs only).
+
+**** `image-animated-p' returns non-nil if an image can be animated.
+
+**** `image-animate' animates a supplied image spec.
+
+**** `image-animate-timer' returns the timer object for an image that
+is being animated.
 
 *** `image-extension-data' is renamed to `image-metadata'.
 
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index ab80b59e0be..e5911a35db2 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,20 @@
+2011-06-07  Chong Yidong  <cyd@stupidchicken.com>
+
+        * image-mode.el (image-toggle-animation): New command.
+        (image-mode-map): Bind it to RET.
+        (image-mode): Update message.
+        (image-toggle-display-image): Avoid a spurious cache flush.
+        (image-transform-rotation): Doc fix.
+        (image-transform-properties): Return quickly in the normal case.
+        (image-animate-loop): Rename from image-animate-max-time.
+
+        * image.el (image-animate-max-time): Moved to image-mode.el.
+        (create-animated-image): Remove unnecessary function.
+        (image-animate): Rename from image-animate-start.  New arg.
+        (image-animate-stop): Removed; just use image-animate-timer.
+        (image-animate-timer): Use car-safe.
+        (image-animate-timeout): Rename argument.
+
 2011-06-07  Martin Rudalics  <rudalics@gmx.at>
 
         * window.el (get-lru-window, get-largest-window): Move here from
diff --git a/lisp/image-mode.el b/lisp/image-mode.el
index 145a15de246..7082cfc57ad 100644
--- a/lisp/image-mode.el
+++ b/lisp/image-mode.el
@@ -308,6 +308,7 @@ This function assumes the current frame has only one window."
     (define-key map "\C-c\C-c" 'image-toggle-display)
     (define-key map (kbd "SPC")       'image-scroll-up)
     (define-key map (kbd "DEL")       'image-scroll-down)
+    (define-key map (kbd "RET")       'image-toggle-animation)
     (define-key map [remap forward-char] 'image-forward-hscroll)
     (define-key map [remap backward-char] 'image-backward-hscroll)
     (define-key map [remap right-char] 'image-forward-hscroll)
@@ -373,16 +374,26 @@ to toggle between display as an image and display as text."
         (add-hook 'change-major-mode-hook 'image-toggle-display-text nil t)
         (add-hook 'after-revert-hook 'image-after-revert-hook nil t)
         (run-mode-hooks 'image-mode-hook)
-        (message "%s" (concat
-                       (substitute-command-keys
-                        "Type \\[image-toggle-display] to view the image as ")
-                       (if (image-get-display-property)
-                           "text" "an image") ".")))
+        (let ((image (image-get-display-property))
+              (msg1 (substitute-command-keys
+                     "Type \\[image-toggle-display] to view the image as ")))
+          (cond
+           ((null image)
+            (message "%s" (concat msg1 "an image.")))
+           ((image-animated-p image)
+            (message "%s"
+                     (concat msg1 "text, or "
+                             (substitute-command-keys
+                              "\\[image-toggle-animation] to animate."))))
+           (t
+            (message "%s" (concat msg1 "text."))))))
+
     (error
      (image-mode-as-text)
      (funcall
       (if (called-interactively-p 'any) 'error 'message)
       "Cannot display image: %s" (cdr err)))))
+
 ;;;###autoload
 (define-minor-mode image-minor-mode
   "Toggle Image minor mode.
@@ -484,25 +495,20 @@ was inserted."
                             (buffer-substring-no-properties (point-min) (point-max)))
                          filename))
          (type (image-type file-or-data nil data-p))
-         ;; Don't use create-animated-image here; that would start the
-         ;; timer, which works by altering the spec destructively.
-         ;; But we still need to append the transformation properties,
-         ;; which would make a new list.
          (image (create-image file-or-data type data-p))
          (inhibit-read-only t)
          (buffer-undo-list t)
          (modified (buffer-modified-p))
          props)
 
+    ;; Discard any stale image data before looking it up again.
+    (image-flush image)
     (setq image (append image (image-transform-properties image)))
     (setq props
           `(display ,image
                     intangible ,image
                     rear-nonsticky (display intangible)
                     read-only t front-sticky (read-only)))
-    (image-flush image)
-    ;; Begin the animation, if any.
-    (image-animate-start image)
 
     (let ((buffer-file-truename nil)) ; avoid changing dir mtime by lock_file
       (add-text-properties (point-min) (point-max) props)
@@ -545,6 +551,37 @@ the image by calling `image-mode'."
     (image-toggle-display-image)))
 
 
+;;; Animated images
+
+(defcustom image-animate-loop nil
+  "Whether to play animated images on a loop in Image mode."
+  :type 'boolean
+  :version "24.1"
+  :group 'image)
+
+(defun image-toggle-animation ()
+  "Start or stop animating the current image."
+  (interactive)
+  (let ((image (image-get-display-property))
+        animation)
+    (cond
+     ((null image)
+      (error "No image is present"))
+     ((null (setq animation (image-animated-p image)))
+      (message "No image animation."))
+     (t
+      (let ((timer (image-animate-timer image)))
+        (if timer
+            (cancel-timer timer)
+          (let ((index (plist-get (cdr image) :index)))
+            ;; If we're at the end, restart.
+            (and index
+                 (>= index (1- (car animation)))
+                 (setq index nil))
+            (image-animate image index
+                           (if image-animate-loop t)))))))))
+
+
 ;;; Support for bookmark.el
 (declare-function bookmark-make-record-default
                   "bookmark" (&optional no-file no-context posn))
@@ -589,33 +626,38 @@ Its value should be one of the following:
  - `fit-width', meaning to fit the image to the window width.
  - A number, which is a scale factor (the default size is 100).")
 
-(defvar image-transform-rotation 0.0)
+(defvar image-transform-rotation 0.0
+  "Rotation angle for the image in the current Image mode buffer.")
 
-(defun image-transform-properties (display)
-  "Return rescaling/rotation properties for the Image mode buffer.
-These properties are suitable for appending to an image spec;
-they are determined by the variables `image-transform-resize' and
-`image-transform-rotation'.
+(defun image-transform-properties (spec)
+  "Return rescaling/rotation properties for image SPEC.
+These properties are determined by the Image mode variables
+`image-transform-resize' and `image-transform-rotation'.  The
+return value is suitable for appending to an image spec.
 
 Recaling and rotation properties only take effect if Emacs is
 compiled with ImageMagick support."
-  (let* ((size (image-size display t))
-         (height
-          (cond
-           ((numberp image-transform-resize)
-            (unless (= image-transform-resize 100)
-              (* image-transform-resize (cdr size))))
-           ((eq image-transform-resize 'fit-height)
-            (- (nth 3 (window-inside-pixel-edges))
-               (nth 1 (window-inside-pixel-edges))))))
-         (width (if (eq image-transform-resize 'fit-width)
-                    (- (nth 2 (window-inside-pixel-edges))
-                       (nth 0 (window-inside-pixel-edges))))))
-    ;;TODO fit-to-* should consider the rotation angle
-    `(,@(if height (list :height height))
-      ,@(if width (list :width width))
-      ,@(if (not (equal 0.0 image-transform-rotation))
-            (list :rotation image-transform-rotation)))))
+  (when (or image-transform-resize
+            (not (equal image-transform-rotation 0.0)))
+    ;; Note: `image-size' looks up and thus caches the untransformed
+    ;; image.  There's no easy way to prevent that.
+    (let* ((size (image-size spec t))
+           (height
+            (cond
+             ((numberp image-transform-resize)
+              (unless (= image-transform-resize 100)
+                (* image-transform-resize (cdr size))))
+             ((eq image-transform-resize 'fit-height)
+              (- (nth 3 (window-inside-pixel-edges))
+                 (nth 1 (window-inside-pixel-edges))))))
+           (width (if (eq image-transform-resize 'fit-width)
+                      (- (nth 2 (window-inside-pixel-edges))
+                         (nth 0 (window-inside-pixel-edges))))))
+      ;;TODO fit-to-* should consider the rotation angle
+      `(,@(if height (list :height height))
+        ,@(if width (list :width width))
+        ,@(if (not (equal 0.0 image-transform-rotation))
+              (list :rotation image-transform-rotation))))))
 
 (defun image-transform-set-scale (scale)
   "Prompt for a number, and resize the current image by that amount.
diff --git a/lisp/image.el b/lisp/image.el
index b9ed10eacf2..e076c2d09f1 100644
--- a/lisp/image.el
+++ b/lisp/image.el
@@ -590,43 +590,45 @@ Example:
 
 ;;; Animated image API
 
-(defcustom image-animate-max-time nil
-  "Time in seconds to animate images.
-If the value is nil, play animations once.
-If the value is t, loop forever."
-  :type '(choice (const :tag "Play once" nil)
-                 (const :tag "Loop forever" t)
-                 integer)
-  :version "24.1"
-  :group 'image)
-
 (defconst image-animated-types '(gif)
   "List of supported animated image types.")
 
-;;;###autoload
-(defun create-animated-image (file-or-data &optional type data-p &rest props)
-  "Create an animated image, and begin animating it.
-FILE-OR-DATA is an image file name or image data.
-Optional TYPE is a symbol describing the image type.  If TYPE is omitted
-or nil, try to determine the image type from its first few bytes
-of image data.  If that doesn't work, and FILE-OR-DATA is a file name,
-use its file extension as image type.
-Optional DATA-P non-nil means FILE-OR-DATA is a string containing image data.
-Optional PROPS are additional image attributes to assign to the image,
-like, e.g. `:mask MASK'.
-Value is the image created, or nil if images of type TYPE are not supported.
+(defun image-animated-p (image)
+  "Return non-nil if image can be animated.
+Actually, the return value is a cons (NIMAGES . DELAY), where
+NIMAGES is the number of sub-images in the animated image and
+DELAY is the delay in 100ths of a second until the next sub-image
+shall be displayed."
+  (cond
+   ((eq (plist-get (cdr image) :type) 'gif)
+    (let* ((metadata (image-metadata image))
+           (images (plist-get metadata 'count))
+           (extdata (plist-get metadata 'extension-data))
+           (anim (plist-get extdata #xF9))
+           (tmo (and (integerp images) (> images 1)
+                     (stringp anim) (>= (length anim) 4)
+                     (+ (aref anim 1) (* (aref anim 2) 256)))))
+      (when tmo
+        (if (eq tmo 0) (setq tmo 10))
+        (cons images tmo))))))
 
-Images should not be larger than specified by `max-image-size'."
-  (setq type (image-type file-or-data type data-p))
-  (when (image-type-available-p type)
-    (let* ((animate (memq type image-animated-types))
-           (image
-            (append (list 'image :type type (if data-p :data :file) file-or-data)
-                    (if animate '(:index 0))
-                    props)))
-      (if animate
-          (image-animate-start image))
-      image)))
+(defun image-animate (image &optional index limit)
+  "Start animating IMAGE.
+Animation occurs by destructively altering the IMAGE spec list.
+
+With optional INDEX, begin animating from that animation frame.
+LIMIT specifies how long to animate the image.  If omitted or
+nil, play the animation until the end.  If t, loop forever.  If a
+number, play until that number of seconds has elapsed."
+  (let ((anim (image-animated-p image))
+        delay timer)
+    (when anim
+      (if (setq timer (image-animate-timer image))
+          (cancel-timer timer))
+      (setq delay (max (* (cdr anim) 0.01) 0.025))
+      (run-with-timer 0.2 nil #'image-animate-timeout
+                      image (or index 0) (car anim)
+                      delay 0 limit))))
 
 (defun image-animate-timer (image)
   "Return the animation timer for image IMAGE."
@@ -635,78 +637,37 @@ Images should not be larger than specified by `max-image-size'."
     (while tail
       (setq timer (car tail)
             tail (cdr tail))
-      (if (and (eq (aref timer 5) #'image-animate-timeout)
-               (consp (aref timer 6))
-               (eq (car (aref timer 6)) image))
+      (if (and (eq (aref timer 5) 'image-animate-timeout)
+               (eq (car-safe (aref timer 6)) image))
           (setq tail nil)
         (setq timer nil)))
     timer))
 
-(defun image-animate-start (image)
-  "Start animating the image IMAGE.
-The variable `image-animate-max-time' determines how long to
-animate for."
-  (let ((anim (image-animated-p image))
-        delay ; in seconds
-        timer)
-    (when anim
-      (if (setq timer (image-animate-timer image))
-          (cancel-timer timer))
-      (setq delay (max (* (cdr anim) 0.01) 0.025))
-      (run-with-timer 0.2 nil #'image-animate-timeout
-                      image 0 (car anim)
-                      delay 0 image-animate-max-time))))
-
-(defun image-animate-stop (image)
-  "Stop animation of image."
-  (let ((timer (image-animate-timer image)))
-    (when timer
-      (cancel-timer timer))))
-
-(defun image-animate-timeout (image n count delay time-elapsed max)
+(defun image-animate-timeout (image n count delay time-elapsed limit)
   "Display animation frame N of IMAGE.
 N=0 refers to the initial animation frame.
 COUNT is the total number of frames in the animation.
 DELAY is the time between animation frames, in seconds.
 TIME-ELAPSED is the total time that has elapsed since
 `image-animate-start' was called.
-MAX determines when to stop.  If t, loop forever.  If nil, stop
+LIMIT determines when to stop.  If t, loop forever.  If nil, stop
  after displaying the last animation frame.  Otherwise, stop
- after MAX seconds have elapsed."
+ after LIMIT seconds have elapsed."
   (let (done)
     (plist-put (cdr image) :index n)
     (force-window-update)
     (setq n (1+ n))
     (if (>= n count)
-        (if max
+        (if limit
             (setq n 0)
           (setq done t)))
     (setq time-elapsed (+ delay time-elapsed))
-    (if (numberp max)
-        (setq done (>= time-elapsed max)))
+    (if (numberp limit)
+        (setq done (>= time-elapsed limit)))
     (unless done
       (run-with-timer delay nil 'image-animate-timeout
                       image n count delay
-                      time-elapsed max))))
-
-(defun image-animated-p (image)
-  "Return non-nil if image is animated.
-Actually, return value is a cons (IMAGES . DELAY) where IMAGES
-is the number of sub-images in the animated image, and DELAY
-is the delay in 100ths of a second until the next sub-image
-shall be displayed."
-  (cond
-   ((eq (plist-get (cdr image) :type) 'gif)
-    (let* ((metadata (image-metadata image))
-           (images (plist-get metadata 'count))
-           (extdata (plist-get metadata 'extension-data))
-           (anim (plist-get extdata #xF9))
-           (tmo (and (integerp images) (> images 1)
-                     (stringp anim) (>= (length anim) 4)
-                     (+ (aref anim 1) (* (aref anim 2) 256)))))
-      (when tmo
-        (if (eq tmo 0) (setq tmo 10))
-        (cons images tmo))))))
+                      time-elapsed limit))))
 
 
 (defcustom imagemagick-types-inhibit