lisp/image.el

   1 ;;; image.el --- image API
   2
   3 ;; Copyright (C) 1998-2011  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 POS may be an integer or marker.
 393 AREA is where to display the image.  AREA nil or omitted means
 394 display it in the text area, a value of `left-margin' means
 395 display it in the left marginal area, a value of `right-margin'
 396 means display it in the right marginal area."
 397   (unless string (setq string "x"))
 398   (let ((buffer (current-buffer)))
 399     (unless (eq (car-safe image) 'image)
 400       (error "Not an image: %s" image))
 401     (unless (or (null area) (memq area '(left-margin right-margin)))
 402       (error "Invalid area %s" area))
 403     (setq string (copy-sequence string))
 404     (let ((overlay (make-overlay pos pos buffer))
 405           (prop (if (null area) image (list (list 'margin area) image))))
 406       (put-text-property 0 (length string) 'display prop string)
 407       (overlay-put overlay 'put-image t)
 408       (overlay-put overlay 'before-string string))))
 409
 410
 411 ;;;###autoload
 412 (defun insert-image (image &optional string area slice)
 413   "Insert IMAGE into current buffer at point.
 414 IMAGE is displayed by inserting STRING into the current buffer
 415 with a `display' property whose value is the image.  STRING is
 416 defaulted if you omit it.
 417 AREA is where to display the image.  AREA nil or omitted means
 418 display it in the text area, a value of `left-margin' means
 419 display it in the left marginal area, a value of `right-margin'
 420 means display it in the right marginal area.
 421 SLICE specifies slice of IMAGE to insert.  SLICE nil or omitted
 422 means insert whole image.  SLICE is a list (X Y WIDTH HEIGHT)
 423 specifying the X and Y positions and WIDTH and HEIGHT of image area
 424 to insert.  A float value 0.0 - 1.0 means relative to the width or
 425 height of the image; integer values are taken as pixel values."
 426   ;; Use a space as least likely to cause trouble when it's a hidden
 427   ;; character in the buffer.
 428   (unless string (setq string " "))
 429   (unless (eq (car-safe image) 'image)
 430     (error "Not an image: %s" image))
 431   (unless (or (null area) (memq area '(left-margin right-margin)))
 432     (error "Invalid area %s" area))
 433   (if area
 434       (setq image (list (list 'margin area) image))
 435     ;; Cons up a new spec equal but not eq to `image' so that
 436     ;; inserting it twice in a row (adjacently) displays two copies of
 437     ;; the image.  Don't try to avoid this by looking at the display
 438     ;; properties on either side so that we DTRT more often with
 439     ;; cut-and-paste.  (Yanking killed image text next to another copy
 440     ;; of it loses anyway.)
 441     (setq image (cons 'image (cdr image))))
 442   (let ((start (point)))
 443     (insert string)
 444     (add-text-properties start (point)
 445                          `(display ,(if slice
 446                                         (list (cons 'slice slice) image)
 447                                       image) rear-nonsticky (display)))))
 448
 449
 450 ;;;###autoload
 451 (defun insert-sliced-image (image &optional string area rows cols)
 452   "Insert IMAGE into current buffer at point.
 453 IMAGE is displayed by inserting STRING into the current buffer
 454 with a `display' property whose value is the image.  STRING is
 455 defaulted if you omit it.
 456 AREA is where to display the image.  AREA nil or omitted means
 457 display it in the text area, a value of `left-margin' means
 458 display it in the left marginal area, a value of `right-margin'
 459 means display it in the right marginal area.
 460 The image is automatically split into ROWS x COLS slices."
 461   (unless string (setq string " "))
 462   (unless (eq (car-safe image) 'image)
 463     (error "Not an image: %s" image))
 464   (unless (or (null area) (memq area '(left-margin right-margin)))
 465     (error "Invalid area %s" area))
 466   (if area
 467       (setq image (list (list 'margin area) image))
 468     ;; Cons up a new spec equal but not eq to `image' so that
 469     ;; inserting it twice in a row (adjacently) displays two copies of
 470     ;; the image.  Don't try to avoid this by looking at the display
 471     ;; properties on either side so that we DTRT more often with
 472     ;; cut-and-paste.  (Yanking killed image text next to another copy
 473     ;; of it loses anyway.)
 474     (setq image (cons 'image (cdr image))))
 475   (let ((x 0.0) (dx (/ 1.0001 (or cols 1)))
 476          (y 0.0) (dy (/ 1.0001 (or rows 1))))
 477     (while (< y 1.0)
 478       (while (< x 1.0)
 479         (let ((start (point)))
 480           (insert string)
 481           (add-text-properties start (point)
 482                                `(display ,(list (list 'slice x y dx dy) image)
 483                                          rear-nonsticky (display)))
 484           (setq x (+ x dx))))
 485       (setq x 0.0
 486             y (+ y dy))
 487       (insert (propertize "\n" 'line-height t)))))
 488
 489
 490
 491 ;;;###autoload
 492 (defun remove-images (start end &optional buffer)
 493   "Remove images between START and END in BUFFER.
 494 Remove only images that were put in BUFFER with calls to `put-image'.
 495 BUFFER nil or omitted means use the current buffer."
 496   (unless buffer
 497     (setq buffer (current-buffer)))
 498   (let ((overlays (overlays-in start end)))
 499     (while overlays
 500       (let ((overlay (car overlays)))
 501         (when (overlay-get overlay 'put-image)
 502           (delete-overlay overlay)))
 503       (setq overlays (cdr overlays)))))
 504
 505 (defun image-search-load-path (file &optional path)
 506   (unless path
 507     (setq path image-load-path))
 508   (let (element found filename)
 509     (while (and (not found) (consp path))
 510       (setq element (car path))
 511       (cond
 512        ((stringp element)
 513         (setq found
 514               (file-readable-p
 515                (setq filename (expand-file-name file element)))))
 516        ((and (symbolp element) (boundp element))
 517         (setq element (symbol-value element))
 518         (cond
 519          ((stringp element)
 520           (setq found
 521                 (file-readable-p
 522                  (setq filename (expand-file-name file element)))))
 523          ((consp element)
 524           (if (setq filename (image-search-load-path file element))
 525               (setq found t))))))
 526       (setq path (cdr path)))
 527     (if found filename)))
 528
 529 ;;;###autoload
 530 (defun find-image (specs)
 531   "Find an image, choosing one of a list of image specifications.
 532
 533 SPECS is a list of image specifications.
 534
 535 Each image specification in SPECS is a property list.  The contents of
 536 a specification are image type dependent.  All specifications must at
 537 least contain the properties `:type TYPE' and either `:file FILE' or
 538 `:data DATA', where TYPE is a symbol specifying the image type,
 539 e.g. `xbm', FILE is the file to load the image from, and DATA is a
 540 string containing the actual image data.  The specification whose TYPE
 541 is supported, and FILE exists, is used to construct the image
 542 specification to be returned.  Return nil if no specification is
 543 satisfied.
 544
 545 The image is looked for in `image-load-path'.
 546
 547 Image files should not be larger than specified by `max-image-size'."
 548   (let (image)
 549     (while (and specs (null image))
 550       (let* ((spec (car specs))
 551              (type (plist-get spec :type))
 552              (data (plist-get spec :data))
 553              (file (plist-get spec :file))
 554              found)
 555         (when (image-type-available-p type)
 556           (cond ((stringp file)
 557                  (if (setq found (image-search-load-path file))
 558                      (setq image
 559                            (cons 'image (plist-put (copy-sequence spec)
 560                                                    :file found)))))
 561                 ((not (null data))
 562                  (setq image (cons 'image spec)))))
 563         (setq specs (cdr specs))))
 564     image))
 565
 566
 567 ;;;###autoload
 568 (defmacro defimage (symbol specs &optional doc)
 569   "Define SYMBOL as an image.
 570
 571 SPECS is a list of image specifications.  DOC is an optional
 572 documentation string.
 573
 574 Each image specification in SPECS is a property list.  The contents of
 575 a specification are image type dependent.  All specifications must at
 576 least contain the properties `:type TYPE' and either `:file FILE' or
 577 `:data DATA', where TYPE is a symbol specifying the image type,
 578 e.g. `xbm', FILE is the file to load the image from, and DATA is a
 579 string containing the actual image data.  The first image
 580 specification whose TYPE is supported, and FILE exists, is used to
 581 define SYMBOL.
 582
 583 Example:
 584
 585    (defimage test-image ((:type xpm :file \"~/test1.xpm\")
 586                          (:type xbm :file \"~/test1.xbm\")))"
 587   (declare (doc-string 3))
 588   `(defvar ,symbol (find-image ',specs) ,doc))
 589
 590 \f
 591 ;;; Animated image API
 592
 593 (defconst image-animated-types '(gif)
 594   "List of supported animated image types.")
 595
 596 (defun image-animated-p (image)
 597   "Return non-nil if image can be animated.
 598 Actually, the return value is a cons (NIMAGES . DELAY), where
 599 NIMAGES is the number of sub-images in the animated image and
 600 DELAY is the delay in second until the next sub-image shall be
 601 displayed."
 602   (cond
 603    ((eq (plist-get (cdr image) :type) 'gif)
 604     (let* ((metadata (image-metadata image))
 605            (images (plist-get metadata 'count))
 606            (delay (plist-get metadata 'delay)))
 607       (when (and images (> images 1) (numberp delay))
 608         (if (< delay 0) (setq delay 0.1))
 609         (cons images delay))))))
 610
 611 (defun image-animate (image &optional index limit)
 612   "Start animating IMAGE.
 613 Animation occurs by destructively altering the IMAGE spec list.
 614
 615 With optional INDEX, begin animating from that animation frame.
 616 LIMIT specifies how long to animate the image.  If omitted or
 617 nil, play the animation until the end.  If t, loop forever.  If a
 618 number, play until that number of seconds has elapsed."
 619   (let ((animation (image-animated-p image))
 620         timer)
 621     (when animation
 622       (if (setq timer (image-animate-timer image))
 623           (cancel-timer timer))
 624       (run-with-timer 0.2 nil 'image-animate-timeout
 625                       image (or index 0) (car animation)
 626                       0 limit))))
 627
 628 (defun image-animate-timer (image)
 629   "Return the animation timer for image IMAGE."
 630   ;; See cancel-function-timers
 631   (let ((tail timer-list) timer)
 632     (while tail
 633       (setq timer (car tail)
 634             tail (cdr tail))
 635       (if (and (eq (aref timer 5) 'image-animate-timeout)
 636                (eq (car-safe (aref timer 6)) image))
 637           (setq tail nil)
 638         (setq timer nil)))
 639     timer))
 640
 641 (defun image-animate-timeout (image n count time-elapsed limit)
 642   "Display animation frame N of IMAGE.
 643 N=0 refers to the initial animation frame.
 644 COUNT is the total number of frames in the animation.
 645 DELAY is the time between animation frames, in seconds.
 646 TIME-ELAPSED is the total time that has elapsed since
 647 `image-animate-start' was called.
 648 LIMIT determines when to stop.  If t, loop forever.  If nil, stop
 649  after displaying the last animation frame.  Otherwise, stop
 650  after LIMIT seconds have elapsed."
 651   (plist-put (cdr image) :index n)
 652   (force-window-update)
 653   (setq n (1+ n))
 654   (let* ((time (float-time))
 655          (animation (image-animated-p image))
 656          ;; Subtract off the time we took to load the image from the
 657          ;; stated delay time.
 658          (delay (max (+ (cdr animation) time (- (float-time)))
 659                      0.01))
 660          done)
 661     (if (>= n count)
 662         (if limit
 663             (setq n 0)
 664           (setq done t)))
 665     (setq time-elapsed (+ delay time-elapsed))
 666     (if (numberp limit)
 667         (setq done (>= time-elapsed limit)))
 668     (unless done
 669       (run-with-timer delay nil 'image-animate-timeout
 670                       image n count time-elapsed limit))))
 671
 672 \f
 673 (defcustom imagemagick-types-inhibit
 674   '(C HTML HTM TXT PDF)
 675   "ImageMagick types that Emacs should not use ImageMagick to handle.
 676 This should be a list of symbols, each of which has the same
 677 names as one of the format tags used internally by ImageMagick;
 678 see `imagemagick-types'.  Entries in this list are excluded from
 679 being registered by `imagemagick-register-types'.
 680
 681 If Emacs is compiled without ImageMagick, this variable has no effect."
 682   :type '(choice (const :tag "Let ImageMagick handle all types it can" nil)
 683                  (repeat symbol))
 684   :version "24.1"
 685   :group 'image)
 686
 687 ;;;###autoload
 688 (defun imagemagick-register-types ()
 689   "Register file types that can be handled by ImageMagick.
 690 This adds the file types returned by `imagemagick-types'
 691 \(excluding the ones in `imagemagick-types-inhibit') to
 692 `auto-mode-alist' and `image-type-file-name-regexps', so that
 693 Emacs visits them in Image mode.
 694
 695 If Emacs is compiled without ImageMagick support, do nothing."
 696   (when (fboundp 'imagemagick-types)
 697     (let ((im-types (imagemagick-types)))
 698       (dolist (im-inhibit imagemagick-types-inhibit)
 699         (setq im-types (delq im-inhibit im-types)))
 700       (dolist (im-type im-types)
 701         (let ((extension
 702                (concat "\\." (downcase (symbol-name im-type))
 703                        "\\'")))
 704           (push (cons extension 'image-mode) auto-mode-alist)
 705           (push (cons extension 'imagemagick)
 706                 image-type-file-name-regexps))))))
 707
 708 (provide 'image)
 709
 710 ;;; image.el ends here