lisp/image.el

   1 ;;; image.el --- image API
   2
   3 ;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003,
   4 ;;   2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
   5
   6 ;; Maintainer: FSF
   7 ;; Keywords: multimedia
   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, or (at your option)
  14 ;; 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; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  24 ;; Boston, MA 02110-1301, USA.
  25
  26 ;;; Commentary:
  27
  28 ;;; Code:
  29
  30
  31 (defgroup image ()
  32   "Image support."
  33   :group 'multimedia)
  34
  35
  36 (defconst image-type-header-regexps
  37   '(("\\`/[\t\n\r ]*\\*.*XPM.\\*/" . xpm)
  38     ("\\`P[1-6][[:space:]]+\\(?:#.*[[:space:]]+\\)*[0-9]+[[:space:]]+[0-9]+" . pbm)
  39     ("\\`GIF8[79]a" . gif)
  40     ("\\`\x89PNG\r\n\x1a\n" . png)
  41     ("\\`[\t\n\r ]*#define \\([a-z0-9]+\\)_width [0-9]+\n\
  42 #define \\1_height [0-9]+\n\
  43 static char \\1_bits" . xbm)
  44     ("\\`\\(?:MM\0\\*\\|II\\*\0\\)" . tiff)
  45     ("\\`[\t\n\r ]*%!PS" . postscript)
  46     ("\\`\xff\xd8" . (image-jpeg-p . jpeg)))
  47   "Alist of (REGEXP . IMAGE-TYPE) pairs used to auto-detect image types.
  48 When the first bytes of an image file match REGEXP, it is assumed to
  49 be of image type IMAGE-TYPE if IMAGE-TYPE is a symbol.  If not a symbol,
  50 IMAGE-TYPE must be a pair (PREDICATE . TYPE).  PREDICATE is called
  51 with one argument, a string containing the image data.  If PREDICATE returns
  52 a non-nil value, TYPE is the image's type.")
  53
  54 (defconst image-type-file-name-regexps
  55   '(("\\.png\\'" . png)
  56     ("\\.gif\\'" . gif)
  57     ("\\.jpe?g\\'" . jpeg)
  58     ("\\.bmp\\'" . bmp)
  59     ("\\.xpm\\'" . xpm)
  60     ("\\.pbm\\'" . pbm)
  61     ("\\.xbm\\'" . xbm)
  62     ("\\.ps\\'" . postscript)
  63     ("\\.tiff?\\'" . tiff))
  64   "Alist of (REGEXP . IMAGE-TYPE) pairs used to identify image files.
  65 When the name of an image file match REGEXP, it is assumed to
  66 be of image type IMAGE-TYPE.")
  67
  68 ;; We rely on `auto-mode-alist' to detect xbm and xpm files, instead
  69 ;; of content autodetection.  Their contents are just C code, so it is
  70 ;; easy to generate false matches.
  71 (defvar image-type-auto-detectable
  72   '((pbm . t)
  73     (xbm . nil)
  74     (bmp . maybe)
  75     (gif . maybe)
  76     (png . maybe)
  77     (xpm . nil)
  78     (jpeg . maybe)
  79     (tiff . maybe)
  80     (postscript . nil))
  81   "Alist of (IMAGE-TYPE . AUTODETECT) pairs used to auto-detect image files.
  82 \(See `image-type-auto-detected-p').
  83
  84 AUTODETECT can be
  85  - t      always auto-detect.
  86  - nil    never auto-detect.
  87  - maybe  auto-detect only if the image type is available
  88             (see `image-type-available-p').")
  89
  90 (defvar image-load-path nil
  91   "List of locations in which to search for image files.
  92 If an element is a string, it defines a directory to search.
  93 If an element is a variable symbol whose value is a string, that
  94 value defines a directory to search.
  95 If an element is a variable symbol whose value is a list, the
  96 value is used as a list of directories to search.")
  97
  98 (eval-at-startup
  99  (setq image-load-path
 100        (list (file-name-as-directory (expand-file-name "images" data-directory))
 101              'data-directory 'load-path)))
 102
 103
 104 (defun image-load-path-for-library (library image &optional path no-error)
 105   "Return a suitable search path for images used by LIBRARY.
 106
 107 It searches for IMAGE in `image-load-path' (excluding
 108 \"`data-directory'/images\") and `load-path', followed by a path
 109 suitable for LIBRARY, which includes \"../../etc/images\" and
 110 \"../etc/images\" relative to the library file itself, and then
 111 in \"`data-directory'/images\".
 112
 113 Then this function returns a list of directories which contains
 114 first the directory in which IMAGE was found, followed by the
 115 value of `load-path'. If PATH is given, it is used instead of
 116 `load-path'.
 117
 118 If NO-ERROR is non-nil and a suitable path can't be found, don't
 119 signal an error. Instead, return a list of directories as before,
 120 except that nil appears in place of the image directory.
 121
 122 Here is an example that uses a common idiom to provide
 123 compatibility with versions of Emacs that lack the variable
 124 `image-load-path':
 125
 126     ;; Shush compiler.
 127     (defvar image-load-path)
 128
 129     (let* ((load-path (image-load-path-for-library \"mh-e\" \"mh-logo.xpm\"))
 130            (image-load-path (cons (car load-path)
 131                                   (when (boundp 'image-load-path)
 132                                     image-load-path))))
 133       (mh-tool-bar-folder-buttons-init))"
 134   (unless library (error "No library specified"))
 135   (unless image   (error "No image specified"))
 136   (let (image-directory image-directory-load-path)
 137     ;; Check for images in image-load-path or load-path.
 138     (let ((img image)
 139           (dir (or
 140                 ;; Images in image-load-path.
 141                 (image-search-load-path image)
 142                 ;; Images in load-path.
 143                 (locate-library image)))
 144           parent)
 145       ;; Since the image might be in a nested directory (for
 146       ;; example, mail/attach.pbm), adjust `image-directory'
 147       ;; accordingly.
 148       (when dir
 149         (setq dir (file-name-directory dir))
 150         (while (setq parent (file-name-directory img))
 151           (setq img (directory-file-name parent)
 152                 dir (expand-file-name "../" dir))))
 153       (setq image-directory-load-path dir))
 154
 155     ;; If `image-directory-load-path' isn't Emacs' image directory,
 156     ;; it's probably a user preference, so use it. Then use a
 157     ;; relative setting if possible; otherwise, use
 158     ;; `image-directory-load-path'.
 159     (cond
 160      ;; User-modified image-load-path?
 161      ((and image-directory-load-path
 162            (not (equal image-directory-load-path
 163                        (file-name-as-directory
 164                         (expand-file-name "images" data-directory)))))
 165       (setq image-directory image-directory-load-path))
 166      ;; Try relative setting.
 167      ((let (library-name d1ei d2ei)
 168         ;; First, find library in the load-path.
 169         (setq library-name (locate-library library))
 170         (if (not library-name)
 171             (error "Cannot find library %s in load-path" library))
 172         ;; And then set image-directory relative to that.
 173         (setq
 174          ;; Go down 2 levels.
 175          d2ei (file-name-as-directory
 176                (expand-file-name
 177                 (concat (file-name-directory library-name) "../../etc/images")))
 178          ;; Go down 1 level.
 179          d1ei (file-name-as-directory
 180                (expand-file-name
 181                 (concat (file-name-directory library-name) "../etc/images"))))
 182         (setq image-directory
 183               ;; Set it to nil if image is not found.
 184               (cond ((file-exists-p (expand-file-name image d2ei)) d2ei)
 185                     ((file-exists-p (expand-file-name image d1ei)) d1ei)))))
 186      ;; Use Emacs' image directory.
 187      (image-directory-load-path
 188       (setq image-directory image-directory-load-path))
 189      (no-error
 190       (message "Could not find image %s for library %s" image library))
 191      (t
 192       (error "Could not find image %s for library %s" image library)))
 193
 194     ;; Return an augmented `path' or `load-path'.
 195     (nconc (list image-directory)
 196            (delete image-directory (copy-sequence (or path load-path))))))
 197
 198
 199 (defun image-jpeg-p (data)
 200   "Value is non-nil if DATA, a string, consists of JFIF image data.
 201 We accept the tag Exif because that is the same format."
 202   (when (string-match "\\`\xff\xd8" data)
 203     (catch 'jfif
 204       (let ((len (length data)) (i 2))
 205         (while (< i len)
 206           (when (/= (aref data i) #xff)
 207             (throw 'jfif nil))
 208           (setq i (1+ i))
 209           (when (>= (+ i 2) len)
 210             (throw 'jfif nil))
 211           (let ((nbytes (+ (lsh (aref data (+ i 1)) 8)
 212                            (aref data (+ i 2))))
 213                 (code (aref data i)))
 214             (when (and (>= code #xe0) (<= code #xef))
 215               ;; APP0 LEN1 LEN2 "JFIF\0"
 216               (throw 'jfif
 217                      (string-match "JFIF\\|Exif"
 218                                    (substring data i (min (+ i nbytes) len)))))
 219             (setq i (+ i 1 nbytes))))))))
 220
 221
 222 ;;;###autoload
 223 (defun image-type-from-data (data)
 224   "Determine the image type from image data DATA.
 225 Value is a symbol specifying the image type or nil if type cannot
 226 be determined."
 227   (let ((types image-type-header-regexps)
 228         type)
 229     (while types
 230       (let ((regexp (car (car types)))
 231             (image-type (cdr (car types))))
 232         (if (or (and (symbolp image-type)
 233                      (string-match regexp data))
 234                 (and (consp image-type)
 235                      (funcall (car image-type) data)
 236                      (setq image-type (cdr image-type))))
 237             (setq type image-type
 238                   types nil)
 239           (setq types (cdr types)))))
 240     type))
 241
 242
 243 ;;;###autoload
 244 (defun image-type-from-buffer ()
 245   "Determine the image type from data in the current buffer.
 246 Value is a symbol specifying the image type or nil if type cannot
 247 be determined."
 248   (let ((types image-type-header-regexps)
 249         type
 250         (opoint (point)))
 251     (goto-char (point-min))
 252     (while types
 253       (let ((regexp (car (car types)))
 254             (image-type (cdr (car types)))
 255             data)
 256         (if (or (and (symbolp image-type)
 257                      (looking-at regexp))
 258                 (and (consp image-type)
 259                      (funcall (car image-type)
 260                               (or data
 261                                   (setq data
 262                                         (buffer-substring
 263                                          (point-min)
 264                                          (min (point-max)
 265                                               (+ (point-min) 256))))))
 266                      (setq image-type (cdr image-type))))
 267             (setq type image-type
 268                   types nil)
 269           (setq types (cdr types)))))
 270     (goto-char opoint)
 271     type))
 272
 273
 274 ;;;###autoload
 275 (defun image-type-from-file-header (file)
 276   "Determine the type of image file FILE from its first few bytes.
 277 Value is a symbol specifying the image type, or nil if type cannot
 278 be determined."
 279   (unless (or (file-readable-p file)
 280               (file-name-absolute-p file))
 281     (setq file (image-search-load-path file)))
 282   (and file
 283        (file-readable-p file)
 284        (with-temp-buffer
 285          (set-buffer-multibyte nil)
 286          (insert-file-contents-literally file nil 0 256)
 287          (image-type-from-buffer))))
 288
 289
 290 ;;;###autoload
 291 (defun image-type-from-file-name (file)
 292   "Determine the type of image file FILE from its name.
 293 Value is a symbol specifying the image type, or nil if type cannot
 294 be determined."
 295   (let ((types image-type-file-name-regexps)
 296         type)
 297     (while types
 298       (if (string-match (car (car types)) file)
 299           (setq type (cdr (car types))
 300                 types nil)
 301         (setq types (cdr types))))
 302     type))
 303
 304
 305 ;;;###autoload
 306 (defun image-type (file-or-data &optional type data-p)
 307   "Determine and return image type.
 308 FILE-OR-DATA is an image file name or image data.
 309 Optional TYPE is a symbol describing the image type.  If TYPE is omitted
 310 or nil, try to determine the image type from its first few bytes
 311 of image data.  If that doesn't work, and FILE-OR-DATA is a file name,
 312 use its file extension as image type.
 313 Optional DATA-P non-nil means FILE-OR-DATA is a string containing image data."
 314   (when (and (not data-p) (not (stringp file-or-data)))
 315     (error "Invalid image file name `%s'" file-or-data))
 316   (unless type
 317     (setq type (if data-p
 318                    (image-type-from-data file-or-data)
 319                  (or (image-type-from-file-header file-or-data)
 320                      (image-type-from-file-name file-or-data))))
 321     (or type(error "Cannot determine image type")))
 322   (or (memq type (and (boundp 'image-types) image-types))
 323       (error "Invalid image type `%s'" type))
 324   type)
 325
 326
 327 ;;;###autoload
 328 (defun image-type-available-p (type)
 329   "Return non-nil if image type TYPE is available.
 330 Image types are symbols like `xbm' or `jpeg'."
 331   (and (fboundp 'init-image-library)
 332        (init-image-library type image-library-alist)))
 333
 334
 335 ;;;###autoload
 336 (defun image-type-auto-detected-p ()
 337   "Return t if the current buffer contains an auto-detectable image.
 338 This function is intended to be used from `magic-fallback-mode-alist'.
 339
 340 The buffer is considered to contain an auto-detectable image if
 341 its beginning matches an image type in `image-type-header-regexps',
 342 and that image type is present in `image-type-auto-detectable'."
 343   (let* ((type (image-type-from-buffer))
 344          (auto (and type (cdr (assq type image-type-auto-detectable)))))
 345     (and auto
 346          (or (eq auto t) (image-type-available-p type)))))
 347
 348
 349 ;;;###autoload
 350 (defun create-image (file-or-data &optional type data-p &rest props)
 351   "Create an image.
 352 FILE-OR-DATA is an image file name or image data.
 353 Optional TYPE is a symbol describing the image type.  If TYPE is omitted
 354 or nil, try to determine the image type from its first few bytes
 355 of image data.  If that doesn't work, and FILE-OR-DATA is a file name,
 356 use its file extension as image type.
 357 Optional DATA-P non-nil means FILE-OR-DATA is a string containing image data.
 358 Optional PROPS are additional image attributes to assign to the image,
 359 like, e.g. `:mask MASK'.
 360 Value is the image created, or nil if images of type TYPE are not supported.
 361
 362 Images should not be larger than specified by `max-image-size'."
 363   (setq type (image-type file-or-data type data-p))
 364   (when (image-type-available-p type)
 365     (append (list 'image :type type (if data-p :data :file) file-or-data)
 366             props)))
 367
 368
 369 ;;;###autoload
 370 (defun put-image (image pos &optional string area)
 371   "Put image IMAGE in front of POS in the current buffer.
 372 IMAGE must be an image created with `create-image' or `defimage'.
 373 IMAGE is displayed by putting an overlay into the current buffer with a
 374 `before-string' STRING that has a `display' property whose value is the
 375 image.  STRING is defaulted if you omit it.
 376 POS may be an integer or marker.
 377 AREA is where to display the image.  AREA nil or omitted means
 378 display it in the text area, a value of `left-margin' means
 379 display it in the left marginal area, a value of `right-margin'
 380 means display it in the right marginal area."
 381   (unless string (setq string "x"))
 382   (let ((buffer (current-buffer)))
 383     (unless (eq (car-safe image) 'image)
 384       (error "Not an image: %s" image))
 385     (unless (or (null area) (memq area '(left-margin right-margin)))
 386       (error "Invalid area %s" area))
 387     (setq string (copy-sequence string))
 388     (let ((overlay (make-overlay pos pos buffer))
 389           (prop (if (null area) image (list (list 'margin area) image))))
 390       (put-text-property 0 (length string) 'display prop string)
 391       (overlay-put overlay 'put-image t)
 392       (overlay-put overlay 'before-string string))))
 393
 394
 395 ;;;###autoload
 396 (defun insert-image (image &optional string area slice)
 397   "Insert IMAGE into current buffer at point.
 398 IMAGE is displayed by inserting STRING into the current buffer
 399 with a `display' property whose value is the image.  STRING is
 400 defaulted if you omit it.
 401 AREA is where to display the image.  AREA nil or omitted means
 402 display it in the text area, a value of `left-margin' means
 403 display it in the left marginal area, a value of `right-margin'
 404 means display it in the right marginal area.
 405 SLICE specifies slice of IMAGE to insert.  SLICE nil or omitted
 406 means insert whole image.  SLICE is a list (X Y WIDTH HEIGHT)
 407 specifying the X and Y positions and WIDTH and HEIGHT of image area
 408 to insert.  A float value 0.0 - 1.0 means relative to the width or
 409 height of the image; integer values are taken as pixel values."
 410   ;; Use a space as least likely to cause trouble when it's a hidden
 411   ;; character in the buffer.
 412   (unless string (setq string " "))
 413   (unless (eq (car-safe image) 'image)
 414     (error "Not an image: %s" image))
 415   (unless (or (null area) (memq area '(left-margin right-margin)))
 416     (error "Invalid area %s" area))
 417   (if area
 418       (setq image (list (list 'margin area) image))
 419     ;; Cons up a new spec equal but not eq to `image' so that
 420     ;; inserting it twice in a row (adjacently) displays two copies of
 421     ;; the image.  Don't try to avoid this by looking at the display
 422     ;; properties on either side so that we DTRT more often with
 423     ;; cut-and-paste.  (Yanking killed image text next to another copy
 424     ;; of it loses anyway.)
 425     (setq image (cons 'image (cdr image))))
 426   (let ((start (point)))
 427     (insert string)
 428     (add-text-properties start (point)
 429                          `(display ,(if slice
 430                                         (list (cons 'slice slice) image)
 431                                       image) rear-nonsticky (display)))))
 432
 433
 434 ;;;###autoload
 435 (defun insert-sliced-image (image &optional string area rows cols)
 436   "Insert IMAGE into current buffer at point.
 437 IMAGE is displayed by inserting STRING into the current buffer
 438 with a `display' property whose value is the image.  STRING is
 439 defaulted if you omit it.
 440 AREA is where to display the image.  AREA nil or omitted means
 441 display it in the text area, a value of `left-margin' means
 442 display it in the left marginal area, a value of `right-margin'
 443 means display it in the right marginal area.
 444 The image is automatically split into ROW x COLS slices."
 445   (unless string (setq string " "))
 446   (unless (eq (car-safe image) 'image)
 447     (error "Not an image: %s" image))
 448   (unless (or (null area) (memq area '(left-margin right-margin)))
 449     (error "Invalid area %s" area))
 450   (if area
 451       (setq image (list (list 'margin area) image))
 452     ;; Cons up a new spec equal but not eq to `image' so that
 453     ;; inserting it twice in a row (adjacently) displays two copies of
 454     ;; the image.  Don't try to avoid this by looking at the display
 455     ;; properties on either side so that we DTRT more often with
 456     ;; cut-and-paste.  (Yanking killed image text next to another copy
 457     ;; of it loses anyway.)
 458     (setq image (cons 'image (cdr image))))
 459   (let ((x 0.0) (dx (/ 1.0001 (or cols 1)))
 460          (y 0.0) (dy (/ 1.0001 (or rows 1))))
 461     (while (< y 1.0)
 462       (while (< x 1.0)
 463         (let ((start (point)))
 464           (insert string)
 465           (add-text-properties start (point)
 466                                `(display ,(list (list 'slice x y dx dy) image)
 467                                          rear-nonsticky (display)))
 468           (setq x (+ x dx))))
 469       (setq x 0.0
 470             y (+ y dy))
 471       (insert (propertize "\n" 'line-height t)))))
 472
 473
 474
 475 ;;;###autoload
 476 (defun remove-images (start end &optional buffer)
 477   "Remove images between START and END in BUFFER.
 478 Remove only images that were put in BUFFER with calls to `put-image'.
 479 BUFFER nil or omitted means use the current buffer."
 480   (unless buffer
 481     (setq buffer (current-buffer)))
 482   (let ((overlays (overlays-in start end)))
 483     (while overlays
 484       (let ((overlay (car overlays)))
 485         (when (overlay-get overlay 'put-image)
 486           (delete-overlay overlay)))
 487       (setq overlays (cdr overlays)))))
 488
 489 (defun image-search-load-path (file &optional path)
 490   (unless path
 491     (setq path image-load-path))
 492   (let (element found filename)
 493     (while (and (not found) (consp path))
 494       (setq element (car path))
 495       (cond
 496        ((stringp element)
 497         (setq found
 498               (file-readable-p
 499                (setq filename (expand-file-name file element)))))
 500        ((and (symbolp element) (boundp element))
 501         (setq element (symbol-value element))
 502         (cond
 503          ((stringp element)
 504           (setq found
 505                 (file-readable-p
 506                  (setq filename (expand-file-name file element)))))
 507          ((consp element)
 508           (if (setq filename (image-search-load-path file element))
 509               (setq found t))))))
 510       (setq path (cdr path)))
 511     (if found filename)))
 512
 513 ;;;###autoload
 514 (defun find-image (specs)
 515   "Find an image, choosing one of a list of image specifications.
 516
 517 SPECS is a list of image specifications.
 518
 519 Each image specification in SPECS is a property list.  The contents of
 520 a specification are image type dependent.  All specifications must at
 521 least contain the properties `:type TYPE' and either `:file FILE' or
 522 `:data DATA', where TYPE is a symbol specifying the image type,
 523 e.g. `xbm', FILE is the file to load the image from, and DATA is a
 524 string containing the actual image data.  The specification whose TYPE
 525 is supported, and FILE exists, is used to construct the image
 526 specification to be returned.  Return nil if no specification is
 527 satisfied.
 528
 529 The image is looked for in `image-load-path'.
 530
 531 Image files should not be larger than specified by `max-image-size'."
 532   (let (image)
 533     (while (and specs (null image))
 534       (let* ((spec (car specs))
 535              (type (plist-get spec :type))
 536              (data (plist-get spec :data))
 537              (file (plist-get spec :file))
 538              found)
 539         (when (image-type-available-p type)
 540           (cond ((stringp file)
 541                  (if (setq found (image-search-load-path file))
 542                      (setq image
 543                            (cons 'image (plist-put (copy-sequence spec)
 544                                                    :file found)))))
 545                 ((not (null data))
 546                  (setq image (cons 'image spec)))))
 547         (setq specs (cdr specs))))
 548     image))
 549
 550
 551 ;;;###autoload
 552 (defmacro defimage (symbol specs &optional doc)
 553   "Define SYMBOL as an image.
 554
 555 SPECS is a list of image specifications.  DOC is an optional
 556 documentation string.
 557
 558 Each image specification in SPECS is a property list.  The contents of
 559 a specification are image type dependent.  All specifications must at
 560 least contain the properties `:type TYPE' and either `:file FILE' or
 561 `:data DATA', where TYPE is a symbol specifying the image type,
 562 e.g. `xbm', FILE is the file to load the image from, and DATA is a
 563 string containing the actual image data.  The first image
 564 specification whose TYPE is supported, and FILE exists, is used to
 565 define SYMBOL.
 566
 567 Example:
 568
 569    (defimage test-image ((:type xpm :file \"~/test1.xpm\")
 570                          (:type xbm :file \"~/test1.xbm\")))"
 571   (declare (doc-string 3))
 572   `(defvar ,symbol (find-image ',specs) ,doc))
 573
 574
 575 (provide 'image)
 576
 577 ;; arch-tag: 8e76a07b-eb48-4f3e-a7a0-1a7ba9f096b3
 578 ;;; image.el ends here