lisp/image.el

   1 ;;; image.el --- image API
   2
   3 ;; Copyright (C) 1998-2012  Free Software Foundation, Inc.
   4
   5 ;; Maintainer: FSF
   6 ;; Keywords: multimedia
   7 ;; Package: emacs
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;;; Code:
  27
  28
  29 (defgroup image ()
  30   "Image support."
  31   :group 'multimedia)
  32
  33 (defalias 'image-refresh 'image-flush)
  34
  35 (defconst image-type-header-regexps
  36   `(("\\`/[\t\n\r ]*\\*.*XPM.\\*/" . xpm)
  37     ("\\`P[1-6][[:space:]]+\\(?:#.*[[:space:]]+\\)*[0-9]+[[:space:]]+[0-9]+" . pbm)
  38     ("\\`GIF8[79]a" . gif)
  39     ("\\`\x89PNG\r\n\x1a\n" . png)
  40     ("\\`[\t\n\r ]*#define \\([a-z0-9_]+\\)_width [0-9]+\n\
  41 #define \\1_height [0-9]+\n\\(\
  42 #define \\1_x_hot [0-9]+\n\
  43 #define \\1_y_hot [0-9]+\n\\)?\
  44 static \\(unsigned \\)?char \\1_bits" . xbm)
  45     ("\\`\\(?:MM\0\\*\\|II\\*\0\\)" . tiff)
  46     ("\\`[\t\n\r ]*%!PS" . postscript)
  47     ("\\`\xff\xd8" . jpeg)    ; used to be (image-jpeg-p . jpeg)
  48     (,(let* ((incomment-re "\\(?:[^-]\\|-[^-]\\)")
  49              (comment-re (concat "\\(?:!--" incomment-re "*-->[ \t\r\n]*<\\)")))
  50         (concat "\\(?:<\\?xml[ \t\r\n]+[^>]*>\\)?[ \t\r\n]*<"
  51                 comment-re "*"
  52                 "\\(?:!DOCTYPE[ \t\r\n]+[^>]*>[ \t\r\n]*<[ \t\r\n]*" comment-re "*\\)?"
  53                 "[Ss][Vv][Gg]"))
  54      . svg)
  55     )
  56   "Alist of (REGEXP . IMAGE-TYPE) pairs used to auto-detect image types.
  57 When the first bytes of an image file match REGEXP, it is assumed to
  58 be of image type IMAGE-TYPE if IMAGE-TYPE is a symbol.  If not a symbol,
  59 IMAGE-TYPE must be a pair (PREDICATE . TYPE).  PREDICATE is called
  60 with one argument, a string containing the image data.  If PREDICATE returns
  61 a non-nil value, TYPE is the image's type.")
  62
  63 (defvar image-type-file-name-regexps
  64   '(("\\.png\\'" . png)
  65     ("\\.gif\\'" . gif)
  66     ("\\.jpe?g\\'" . jpeg)
  67     ("\\.bmp\\'" . bmp)
  68     ("\\.xpm\\'" . xpm)
  69     ("\\.pbm\\'" . pbm)
  70     ("\\.xbm\\'" . xbm)
  71     ("\\.ps\\'" . postscript)
  72     ("\\.tiff?\\'" . tiff)
  73     ("\\.svgz?\\'" . svg)
  74     )
  75   "Alist of (REGEXP . IMAGE-TYPE) pairs used to identify image files.
  76 When the name of an image file match REGEXP, it is assumed to
  77 be of image type IMAGE-TYPE.")
  78
  79 ;; We rely on `auto-mode-alist' to detect xbm and xpm files, instead
  80 ;; of content autodetection.  Their contents are just C code, so it is
  81 ;; easy to generate false matches.
  82 (defvar image-type-auto-detectable
  83   '((pbm . t)
  84     (xbm . nil)
  85     (bmp . maybe)
  86     (gif . maybe)
  87     (png . maybe)
  88     (xpm . nil)
  89     (jpeg . maybe)
  90     (tiff . maybe)
  91     (svg . maybe)
  92     (postscript . nil))
  93   "Alist of (IMAGE-TYPE . AUTODETECT) pairs used to auto-detect image files.
  94 \(See `image-type-auto-detected-p').
  95
  96 AUTODETECT can be
  97  - t      always auto-detect.
  98  - nil    never auto-detect.
  99  - maybe  auto-detect only if the image type is available
 100             (see `image-type-available-p').")
 101
 102 (defcustom image-load-path
 103   (list (file-name-as-directory (expand-file-name "images" data-directory))
 104         'data-directory 'load-path)
 105   "List of locations in which to search for image files.
 106 If an element is a string, it defines a directory to search.
 107 If an element is a variable symbol whose value is a string, that
 108 value defines a directory to search.
 109 If an element is a variable symbol whose value is a list, the
 110 value is used as a list of directories to search."
 111   :type '(repeat (choice directory variable))
 112   :initialize 'custom-initialize-delay)
 113
 114
 115 (defun image-load-path-for-library (library image &optional path no-error)
 116   "Return a suitable search path for images used by LIBRARY.
 117
 118 It searches for IMAGE in `image-load-path' (excluding
 119 \"`data-directory'/images\") and `load-path', followed by a path
 120 suitable for LIBRARY, which includes \"../../etc/images\" and
 121 \"../etc/images\" relative to the library file itself, and then
 122 in \"`data-directory'/images\".
 123
 124 Then this function returns a list of directories which contains
 125 first the directory in which IMAGE was found, followed by the
 126 value of `load-path'.  If PATH is given, it is used instead of
 127 `load-path'.
 128
 129 If NO-ERROR is non-nil and a suitable path can't be found, don't
 130 signal an error.  Instead, return a list of directories as before,
 131 except that nil appears in place of the image directory.
 132
 133 Here is an example that uses a common idiom to provide
 134 compatibility with versions of Emacs that lack the variable
 135 `image-load-path':
 136
 137     ;; Shush compiler.
 138     (defvar image-load-path)
 139
 140     (let* ((load-path (image-load-path-for-library \"mh-e\" \"mh-logo.xpm\"))
 141            (image-load-path (cons (car load-path)
 142                                   (when (boundp 'image-load-path)
 143                                     image-load-path))))
 144       (mh-tool-bar-folder-buttons-init))"
 145   (unless library (error "No library specified"))
 146   (unless image   (error "No image specified"))
 147   (let (image-directory image-directory-load-path)
 148     ;; Check for images in image-load-path or load-path.
 149     (let ((img image)
 150           (dir (or
 151                 ;; Images in image-load-path.
 152                 (image-search-load-path image)
 153                 ;; Images in load-path.
 154                 (locate-library image)))
 155           parent)
 156       ;; Since the image might be in a nested directory (for
 157       ;; example, mail/attach.pbm), adjust `image-directory'
 158       ;; accordingly.
 159       (when dir
 160         (setq dir (file-name-directory dir))
 161         (while (setq parent (file-name-directory img))
 162           (setq img (directory-file-name parent)
 163                 dir (expand-file-name "../" dir))))
 164       (setq image-directory-load-path dir))
 165
 166     ;; If `image-directory-load-path' isn't Emacs' image directory,
 167     ;; it's probably a user preference, so use it. Then use a
 168     ;; relative setting if possible; otherwise, use
 169     ;; `image-directory-load-path'.
 170     (cond
 171      ;; User-modified image-load-path?
 172      ((and image-directory-load-path
 173            (not (equal image-directory-load-path
 174                        (file-name-as-directory
 175                         (expand-file-name "images" data-directory)))))
 176       (setq image-directory image-directory-load-path))
 177      ;; Try relative setting.
 178      ((let (library-name d1ei d2ei)
 179         ;; First, find library in the load-path.
 180         (setq library-name (locate-library library))
 181         (if (not library-name)
 182             (error "Cannot find library %s in load-path" library))
 183         ;; And then set image-directory relative to that.
 184         (setq
 185          ;; Go down 2 levels.
 186          d2ei (file-name-as-directory
 187                (expand-file-name
 188                 (concat (file-name-directory library-name) "../../etc/images")))
 189          ;; Go down 1 level.
 190          d1ei (file-name-as-directory
 191                (expand-file-name
 192                 (concat (file-name-directory library-name) "../etc/images"))))
 193         (setq image-directory
 194               ;; Set it to nil if image is not found.
 195               (cond ((file-exists-p (expand-file-name image d2ei)) d2ei)
 196                     ((file-exists-p (expand-file-name image d1ei)) d1ei)))))
 197      ;; Use Emacs' image directory.
 198      (image-directory-load-path
 199       (setq image-directory image-directory-load-path))
 200      (no-error
 201       (message "Could not find image %s for library %s" image library))
 202      (t
 203       (error "Could not find image %s for library %s" image library)))
 204
 205     ;; Return an augmented `path' or `load-path'.
 206     (nconc (list image-directory)
 207            (delete image-directory (copy-sequence (or path load-path))))))
 208
 209
 210 (defun image-jpeg-p (data)
 211   "Value is non-nil if DATA, a string, consists of JFIF image data.
 212 We accept the tag Exif because that is the same format."
 213   (setq data (ignore-errors (string-to-unibyte data)))
 214   (when (and data (string-match-p "\\`\xff\xd8" data))
 215     (catch 'jfif
 216       (let ((len (length data)) (i 2))
 217         (while (< i len)
 218           (when (/= (aref data i) #xff)
 219             (throw 'jfif nil))
 220           (setq i (1+ i))
 221           (when (>= (+ i 2) len)
 222             (throw 'jfif nil))
 223           (let ((nbytes (+ (lsh (aref data (+ i 1)) 8)
 224                            (aref data (+ i 2))))
 225                 (code (aref data i)))
 226             (when (and (>= code #xe0) (<= code #xef))
 227               ;; APP0 LEN1 LEN2 "JFIF\0"
 228               (throw 'jfif
 229                      (string-match-p "JFIF\\|Exif"
 230                                      (substring data i (min (+ i nbytes) len)))))
 231             (setq i (+ i 1 nbytes))))))))
 232
 233
 234 ;;;###autoload
 235 (defun image-type-from-data (data)
 236   "Determine the image type from image data DATA.
 237 Value is a symbol specifying the image type or nil if type cannot
 238 be determined."
 239   (let ((types image-type-header-regexps)
 240         type)
 241     (while types
 242       (let ((regexp (car (car types)))
 243             (image-type (cdr (car types))))
 244         (if (or (and (symbolp image-type)
 245                      (string-match-p regexp data))
 246                 (and (consp image-type)
 247                      (funcall (car image-type) data)
 248                      (setq image-type (cdr image-type))))
 249             (setq type image-type
 250                   types nil)
 251           (setq types (cdr types)))))
 252     type))
 253
 254
 255 ;;;###autoload
 256 (defun image-type-from-buffer ()
 257   "Determine the image type from data in the current buffer.
 258 Value is a symbol specifying the image type or nil if type cannot
 259 be determined."
 260   (let ((types image-type-header-regexps)
 261         type
 262         (opoint (point)))
 263     (goto-char (point-min))
 264     (while types
 265       (let ((regexp (car (car types)))
 266             (image-type (cdr (car types)))
 267             data)
 268         (if (or (and (symbolp image-type)
 269                      (looking-at-p regexp))
 270                 (and (consp image-type)
 271                      (funcall (car image-type)
 272                               (or data
 273                                   (setq data
 274                                         (buffer-substring
 275                                          (point-min)
 276                                          (min (point-max)
 277                                               (+ (point-min) 256))))))
 278                      (setq image-type (cdr image-type))))
 279             (setq type image-type
 280                   types nil)
 281           (setq types (cdr types)))))
 282     (goto-char opoint)
 283     type))
 284
 285
 286 ;;;###autoload
 287 (defun image-type-from-file-header (file)
 288   "Determine the type of image file FILE from its first few bytes.
 289 Value is a symbol specifying the image type, or nil if type cannot
 290 be determined."
 291   (unless (or (file-readable-p file)
 292               (file-name-absolute-p file))
 293     (setq file (image-search-load-path file)))
 294   (and file
 295        (file-readable-p file)
 296        (with-temp-buffer
 297          (set-buffer-multibyte nil)
 298          (insert-file-contents-literally file nil 0 256)
 299          (image-type-from-buffer))))
 300
 301
 302 ;;;###autoload
 303 (defun image-type-from-file-name (file)
 304   "Determine the type of image file FILE from its name.
 305 Value is a symbol specifying the image type, or nil if type cannot
 306 be determined."
 307   (assoc-default file image-type-file-name-regexps 'string-match-p))
 308
 309
 310 ;;;###autoload
 311 (defun image-type (source &optional type data-p)
 312   "Determine and return image type.
 313 SOURCE is an image file name or image data.
 314 Optional TYPE is a symbol describing the image type.  If TYPE is omitted
 315 or nil, try to determine the image type from its first few bytes
 316 of image data.  If that doesn't work, and SOURCE is a file name,
 317 use its file extension as image type.
 318 Optional DATA-P non-nil means SOURCE is a string containing image data."
 319   (when (and (not data-p) (not (stringp source)))
 320     (error "Invalid image file name `%s'" source))
 321   (unless type
 322     (setq type (if data-p
 323                    (image-type-from-data source)
 324                  (or (image-type-from-file-header source)
 325                      (image-type-from-file-name source))))
 326     (or type (error "Cannot determine image type")))
 327   (or (memq type (and (boundp 'image-types) image-types))
 328       (error "Invalid image type `%s'" type))
 329   type)
 330
 331
 332 (define-obsolete-variable-alias
 333     'image-library-alist
 334     'dynamic-library-alist "24.1")
 335
 336 ;;;###autoload
 337 (defun image-type-available-p (type)
 338   "Return non-nil if image type TYPE is available.
 339 Image types are symbols like `xbm' or `jpeg'."
 340   (and (fboundp 'init-image-library)
 341        (init-image-library type dynamic-library-alist)))
 342
 343
 344 ;;;###autoload
 345 (defun image-type-auto-detected-p ()
 346   "Return t if the current buffer contains an auto-detectable image.
 347 This function is intended to be used from `magic-fallback-mode-alist'.
 348
 349 The buffer is considered to contain an auto-detectable image if
 350 its beginning matches an image type in `image-type-header-regexps',
 351 and that image type is present in `image-type-auto-detectable' with a
 352 non-nil value.  If that value is non-nil, but not t, then the image type
 353 must be available."
 354   (let* ((type (image-type-from-buffer))
 355          (auto (and type (cdr (assq type image-type-auto-detectable)))))
 356     (and auto
 357          (or (eq auto t) (image-type-available-p type)))))
 358
 359
 360 ;;;###autoload
 361 (defun create-image (file-or-data &optional type data-p &rest props)
 362   "Create an image.
 363 FILE-OR-DATA is an image file name or image data.
 364 Optional TYPE is a symbol describing the image type.  If TYPE is omitted
 365 or nil, try to determine the image type from its first few bytes
 366 of image data.  If that doesn't work, and FILE-OR-DATA is a file name,
 367 use its file extension as image type.
 368 Optional DATA-P non-nil means FILE-OR-DATA is a string containing image data.
 369 Optional PROPS are additional image attributes to assign to the image,
 370 like, e.g. `:mask MASK'.
 371 Value is the image created, or nil if images of type TYPE are not supported.
 372
 373 Images should not be larger than specified by `max-image-size'.
 374
 375 Image file names that are not absolute are searched for in the
 376 \"images\" sub-directory of `data-directory' and
 377 `x-bitmap-file-path' (in that order)."
 378   ;; It is x_find_image_file in image.c that sets the search path.
 379   (setq type (image-type file-or-data type data-p))
 380   (when (image-type-available-p type)
 381     (append (list 'image :type type (if data-p :data :file) file-or-data)
 382             props)))
 383
 384
 385 ;;;###autoload
 386 (defun put-image (image pos &optional string area)
 387   "Put image IMAGE in front of POS in the current buffer.
 388 IMAGE must be an image created with `create-image' or `defimage'.
 389 IMAGE is displayed by putting an overlay into the current buffer with a
 390 `before-string' STRING that has a `display' property whose value is the
 391 image.  STRING is defaulted if you omit it.
 392 The overlay created will have the `put-image' property set to t.
 393 POS may be an integer or marker.
 394 AREA is where to display the image.  AREA nil or omitted means
 395 display it in the text area, a value of `left-margin' means
 396 display it in the left marginal area, a value of `right-margin'
 397 means display it in the right marginal area."
 398   (unless string (setq string "x"))
 399   (let ((buffer (current-buffer)))
 400     (unless (eq (car-safe image) 'image)
 401       (error "Not an image: %s" image))
 402     (unless (or (null area) (memq area '(left-margin right-margin)))
 403       (error "Invalid area %s" area))
 404     (setq string (copy-sequence string))
 405     (let ((overlay (make-overlay pos pos buffer))
 406           (prop (if (null area) image (list (list 'margin area) image))))
 407       (put-text-property 0 (length string) 'display prop string)
 408       (overlay-put overlay 'put-image t)
 409       (overlay-put overlay 'before-string string))))
 410
 411
 412 ;;;###autoload
 413 (defun insert-image (image &optional string area slice)
 414   "Insert IMAGE into current buffer at point.
 415 IMAGE is displayed by inserting STRING into the current buffer
 416 with a `display' property whose value is the image.  STRING
 417 defaults to the empty string if you omit it.
 418 AREA is where to display the image.  AREA nil or omitted means
 419 display it in the text area, a value of `left-margin' means
 420 display it in the left marginal area, a value of `right-margin'
 421 means display it in the right marginal area.
 422 SLICE specifies slice of IMAGE to insert.  SLICE nil or omitted
 423 means insert whole image.  SLICE is a list (X Y WIDTH HEIGHT)
 424 specifying the X and Y positions and WIDTH and HEIGHT of image area
 425 to insert.  A float value 0.0 - 1.0 means relative to the width or
 426 height of the image; integer values are taken as pixel values."
 427   ;; Use a space as least likely to cause trouble when it's a hidden
 428   ;; character in the buffer.
 429   (unless string (setq string " "))
 430   (unless (eq (car-safe image) 'image)
 431     (error "Not an image: %s" image))
 432   (unless (or (null area) (memq area '(left-margin right-margin)))
 433     (error "Invalid area %s" area))
 434   (if area
 435       (setq image (list (list 'margin area) image))
 436     ;; Cons up a new spec equal but not eq to `image' so that
 437     ;; inserting it twice in a row (adjacently) displays two copies of
 438     ;; the image.  Don't try to avoid this by looking at the display
 439     ;; properties on either side so that we DTRT more often with
 440     ;; cut-and-paste.  (Yanking killed image text next to another copy
 441     ;; of it loses anyway.)
 442     (setq image (cons 'image (cdr image))))
 443   (let ((start (point)))
 444     (insert string)
 445     (add-text-properties start (point)
 446                          `(display ,(if slice
 447                                         (list (cons 'slice slice) image)
 448                                       image) rear-nonsticky (display)))))
 449
 450
 451 ;;;###autoload
 452 (defun insert-sliced-image (image &optional string area rows cols)
 453   "Insert IMAGE into current buffer at point.
 454 IMAGE is displayed by inserting STRING into the current buffer
 455 with a `display' property whose value is the image.  STRING is
 456 defaulted if you omit it.
 457 AREA is where to display the image.  AREA nil or omitted means
 458 display it in the text area, a value of `left-margin' means
 459 display it in the left marginal area, a value of `right-margin'
 460 means display it in the right marginal area.
 461 The image is automatically split into ROWS x COLS slices."
 462   (unless string (setq string " "))
 463   (unless (eq (car-safe image) 'image)
 464     (error "Not an image: %s" image))
 465   (unless (or (null area) (memq area '(left-margin right-margin)))
 466     (error "Invalid area %s" area))
 467   (if area
 468       (setq image (list (list 'margin area) image))
 469     ;; Cons up a new spec equal but not eq to `image' so that
 470     ;; inserting it twice in a row (adjacently) displays two copies of
 471     ;; the image.  Don't try to avoid this by looking at the display
 472     ;; properties on either side so that we DTRT more often with
 473     ;; cut-and-paste.  (Yanking killed image text next to another copy
 474     ;; of it loses anyway.)
 475     (setq image (cons 'image (cdr image))))
 476   (let ((x 0.0) (dx (/ 1.0001 (or cols 1)))
 477          (y 0.0) (dy (/ 1.0001 (or rows 1))))
 478     (while (< y 1.0)
 479       (while (< x 1.0)
 480         (let ((start (point)))
 481           (insert string)
 482           (add-text-properties start (point)
 483                                `(display ,(list (list 'slice x y dx dy) image)
 484                                          rear-nonsticky (display)))
 485           (setq x (+ x dx))))
 486       (setq x 0.0
 487             y (+ y dy))
 488       (insert (propertize "\n" 'line-height t)))))
 489
 490
 491
 492 ;;;###autoload
 493 (defun remove-images (start end &optional buffer)
 494   "Remove images between START and END in BUFFER.
 495 Remove only images that were put in BUFFER with calls to `put-image'.
 496 BUFFER nil or omitted means use the current buffer."
 497   (unless buffer
 498     (setq buffer (current-buffer)))
 499   (let ((overlays (overlays-in start end)))
 500     (while overlays
 501       (let ((overlay (car overlays)))
 502         (when (overlay-get overlay 'put-image)
 503           (delete-overlay overlay)))
 504       (setq overlays (cdr overlays)))))
 505
 506 (defun image-search-load-path (file &optional path)
 507   (unless path
 508     (setq path image-load-path))
 509   (let (element found filename)
 510     (while (and (not found) (consp path))
 511       (setq element (car path))
 512       (cond
 513        ((stringp element)
 514         (setq found
 515               (file-readable-p
 516                (setq filename (expand-file-name file element)))))
 517        ((and (symbolp element) (boundp element))
 518         (setq element (symbol-value element))
 519         (cond
 520          ((stringp element)
 521           (setq found
 522                 (file-readable-p
 523                  (setq filename (expand-file-name file element)))))
 524          ((consp element)
 525           (if (setq filename (image-search-load-path file element))
 526               (setq found t))))))
 527       (setq path (cdr path)))
 528     (if found filename)))
 529
 530 ;;;###autoload
 531 (defun find-image (specs)
 532   "Find an image, choosing one of a list of image specifications.
 533
 534 SPECS is a list of image specifications.
 535
 536 Each image specification in SPECS is a property list.  The contents of
 537 a specification are image type dependent.  All specifications must at
 538 least contain the properties `:type TYPE' and either `:file FILE' or
 539 `:data DATA', where TYPE is a symbol specifying the image type,
 540 e.g. `xbm', FILE is the file to load the image from, and DATA is a
 541 string containing the actual image data.  The specification whose TYPE
 542 is supported, and FILE exists, is used to construct the image
 543 specification to be returned.  Return nil if no specification is
 544 satisfied.
 545
 546 The image is looked for in `image-load-path'.
 547
 548 Image files should not be larger than specified by `max-image-size'."
 549   (let (image)
 550     (while (and specs (null image))
 551       (let* ((spec (car specs))
 552              (type (plist-get spec :type))
 553              (data (plist-get spec :data))
 554              (file (plist-get spec :file))
 555              found)
 556         (when (image-type-available-p type)
 557           (cond ((stringp file)
 558                  (if (setq found (image-search-load-path file))
 559                      (setq image
 560                            (cons 'image (plist-put (copy-sequence spec)
 561                                                    :file found)))))
 562                 ((not (null data))
 563                  (setq image (cons 'image spec)))))
 564         (setq specs (cdr specs))))
 565     image))
 566
 567
 568 ;;;###autoload
 569 (defmacro defimage (symbol specs &optional doc)
 570   "Define SYMBOL as an image.
 571
 572 SPECS is a list of image specifications.  DOC is an optional
 573 documentation string.
 574
 575 Each image specification in SPECS is a property list.  The contents of
 576 a specification are image type dependent.  All specifications must at
 577 least contain the properties `:type TYPE' and either `:file FILE' or
 578 `:data DATA', where TYPE is a symbol specifying the image type,
 579 e.g. `xbm', FILE is the file to load the image from, and DATA is a
 580 string containing the actual image data.  The first image
 581 specification whose TYPE is supported, and FILE exists, is used to
 582 define SYMBOL.
 583
 584 Example:
 585
 586    (defimage test-image ((:type xpm :file \"~/test1.xpm\")
 587                          (:type xbm :file \"~/test1.xbm\")))"
 588   (declare (doc-string 3))
 589   `(defvar ,symbol (find-image ',specs) ,doc))
 590
 591 \f
 592 ;;; Animated image API
 593
 594 (defconst image-animated-types '(gif)
 595   "List of supported animated image types.")
 596
 597 (defun image-animated-p (image)
 598   "Return non-nil if image can be animated.
 599 Actually, the return value is a cons (NIMAGES . DELAY), where
 600 NIMAGES is the number of sub-images in the animated image and
 601 DELAY is the delay in second until the next sub-image shall be
 602 displayed."
 603   (cond
 604    ((eq (plist-get (cdr image) :type) 'gif)
 605     (let* ((metadata (image-metadata image))
 606            (images (plist-get metadata 'count))
 607            (delay (plist-get metadata 'delay)))
 608       (when (and images (> images 1) (numberp delay))
 609         (if (< delay 0) (setq delay 0.1))
 610         (cons images delay))))))
 611
 612 (defun image-animate (image &optional index limit)
 613   "Start animating IMAGE.
 614 Animation occurs by destructively altering the IMAGE spec list.
 615
 616 With optional INDEX, begin animating from that animation frame.
 617 LIMIT specifies how long to animate the image.  If omitted or
 618 nil, play the animation until the end.  If t, loop forever.  If a
 619 number, play until that number of seconds has elapsed."
 620   (let ((animation (image-animated-p image))
 621         timer)
 622     (when animation
 623       (if (setq timer (image-animate-timer image))
 624           (cancel-timer timer))
 625       (run-with-timer 0.2 nil 'image-animate-timeout
 626                       image (or index 0) (car animation)
 627                       0 limit))))
 628
 629 (defun image-animate-timer (image)
 630   "Return the animation timer for image IMAGE."
 631   ;; See cancel-function-timers
 632   (let ((tail timer-list) timer)
 633     (while tail
 634       (setq timer (car tail)
 635             tail (cdr tail))
 636       (if (and (eq (aref timer 5) 'image-animate-timeout)
 637                (eq (car-safe (aref timer 6)) image))
 638           (setq tail nil)
 639         (setq timer nil)))
 640     timer))
 641
 642 (defun image-animate-timeout (image n count time-elapsed limit)
 643   "Display animation frame N of IMAGE.
 644 N=0 refers to the initial animation frame.
 645 COUNT is the total number of frames in the animation.
 646 DELAY is the time between animation frames, in seconds.
 647 TIME-ELAPSED is the total time that has elapsed since
 648 `image-animate-start' was called.
 649 LIMIT determines when to stop.  If t, loop forever.  If nil, stop
 650  after displaying the last animation frame.  Otherwise, stop
 651  after LIMIT seconds have elapsed."
 652   (plist-put (cdr image) :index n)
 653   (force-window-update)
 654   (setq n (1+ n))
 655   (let* ((time (float-time))
 656          (animation (image-animated-p image))
 657          ;; Subtract off the time we took to load the image from the
 658          ;; stated delay time.
 659          (delay (max (+ (cdr animation) time (- (float-time)))
 660                      0.01))
 661          done)
 662     (if (>= n count)
 663         (if limit
 664             (setq n 0)
 665           (setq done t)))
 666     (setq time-elapsed (+ delay time-elapsed))
 667     (if (numberp limit)
 668         (setq done (>= time-elapsed limit)))
 669     (unless done
 670       (run-with-timer delay nil 'image-animate-timeout
 671                       image n count time-elapsed limit))))
 672
 673 \f
 674 (defcustom imagemagick-types-inhibit
 675   '(C HTML HTM TXT PDF)
 676   "ImageMagick types that Emacs should not use ImageMagick to handle.
 677 This should be a list of symbols, each of which has the same
 678 names as one of the format tags used internally by ImageMagick;
 679 see `imagemagick-types'.  Entries in this list are excluded from
 680 being registered by `imagemagick-register-types'.
 681
 682 If Emacs is compiled without ImageMagick, this variable has no effect."
 683   :type '(choice (const :tag "Let ImageMagick handle all types it can" nil)
 684                  (repeat symbol))
 685   :version "24.1"
 686   :group 'image)
 687
 688 ;;;###autoload
 689 (defun imagemagick-register-types ()
 690   "Register file types that can be handled by ImageMagick.
 691 This adds the file types returned by `imagemagick-types'
 692 \(excluding the ones in `imagemagick-types-inhibit') to
 693 `auto-mode-alist' and `image-type-file-name-regexps', so that
 694 Emacs visits them in Image mode.
 695
 696 If Emacs is compiled without ImageMagick support, do nothing."
 697   (when (fboundp 'imagemagick-types)
 698     (let ((im-types '()))
 699       (dolist (im-type (imagemagick-types))
 700         (unless (memq im-type imagemagick-types-inhibit)
 701           (push (downcase (symbol-name im-type)) im-types)))
 702       (let ((extension (concat "\\." (regexp-opt im-types) "\\'")))
 703         (push (cons extension 'image-mode) auto-mode-alist)
 704         (push (cons extension 'imagemagick)
 705               image-type-file-name-regexps)))))
 706
 707 (provide 'image)
 708
 709 ;;; image.el ends here