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1 ;;; image.el --- image API
3 ;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003,
4 ;; 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
6 ;; Maintainer: FSF
7 ;; Keywords: multimedia
9 ;; This file is part of GNU Emacs.
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.
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.
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.
26 ;;; Commentary:
28 ;;; Code:
31 (defgroup image ()
32 "Image support."
33 :group 'multimedia)
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 (,(let* ((incomment-re "\\(?:[^-]\\|-[^-]\\)")
48 (comment-re (concat "\\(?:!--" incomment-re "*-->[ \t\r\n]*<\\)")))
49 (concat "\\(?:<\\?xml[ \t\r\n]+[^>]*>\\)?[ \t\r\n]*<"
50 comment-re "*"
51 "\\(?:!DOCTYPE[ \t\r\n]+[^>]*>[ \t\r\n]*<[ \t\r\n]*" comment-re "*\\)?"
52 "[Ss][Vv][Gg]"))
53 . svg)
55 "Alist of (REGEXP . IMAGE-TYPE) pairs used to auto-detect image types.
56 When the first bytes of an image file match REGEXP, it is assumed to
57 be of image type IMAGE-TYPE if IMAGE-TYPE is a symbol. If not a symbol,
58 IMAGE-TYPE must be a pair (PREDICATE . TYPE). PREDICATE is called
59 with one argument, a string containing the image data. If PREDICATE returns
60 a non-nil value, TYPE is the image's type.")
62 (defconst image-type-file-name-regexps
63 '(("\\.png\\'" . png)
64 ("\\.gif\\'" . gif)
65 ("\\.jpe?g\\'" . jpeg)
66 ("\\.bmp\\'" . bmp)
67 ("\\.xpm\\'" . xpm)
68 ("\\.pbm\\'" . pbm)
69 ("\\.xbm\\'" . xbm)
70 ("\\.ps\\'" . postscript)
71 ("\\.tiff?\\'" . tiff)
72 ("\\.svgz?\\'" . svg)
74 "Alist of (REGEXP . IMAGE-TYPE) pairs used to identify image files.
75 When the name of an image file match REGEXP, it is assumed to
76 be of image type IMAGE-TYPE.")
78 ;; We rely on `auto-mode-alist' to detect xbm and xpm files, instead
79 ;; of content autodetection. Their contents are just C code, so it is
80 ;; easy to generate false matches.
81 (defvar image-type-auto-detectable
82 '((pbm . t)
83 (xbm . nil)
84 (bmp . maybe)
85 (gif . maybe)
86 (png . maybe)
87 (xpm . nil)
88 (jpeg . maybe)
89 (tiff . maybe)
90 (svg . maybe)
91 (postscript . nil))
92 "Alist of (IMAGE-TYPE . AUTODETECT) pairs used to auto-detect image files.
93 \(See `image-type-auto-detected-p').
95 AUTODETECT can be
96 - t always auto-detect.
97 - nil never auto-detect.
98 - maybe auto-detect only if the image type is available
99 (see `image-type-available-p').")
101 (defvar image-load-path nil
102 "List of locations in which to search for image files.
103 If an element is a string, it defines a directory to search.
104 If an element is a variable symbol whose value is a string, that
105 value defines a directory to search.
106 If an element is a variable symbol whose value is a list, the
107 value is used as a list of directories to search.")
109 (eval-at-startup
110 (setq image-load-path
111 (list (file-name-as-directory (expand-file-name "images" data-directory))
112 'data-directory 'load-path)))
115 (defun image-load-path-for-library (library image &optional path no-error)
116 "Return a suitable search path for images used by LIBRARY.
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\".
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'.
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.
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':
137 ;; Shush compiler.
138 (defvar image-load-path)
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))
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))
203 (error "Could not find image %s for library %s" image library)))
205 ;; Return an augmented `path' or `load-path'.
206 (nconc (list image-directory)
207 (delete image-directory (copy-sequence (or path load-path))))))
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 (when (string-match "\\`\xff\xd8" data)
214 (catch 'jfif
215 (let ((len (length data)) (i 2))
216 (while (< i len)
217 (when (/= (aref data i) #xff)
218 (throw 'jfif nil))
219 (setq i (1+ i))
220 (when (>= (+ i 2) len)
221 (throw 'jfif nil))
222 (let ((nbytes (+ (lsh (aref data (+ i 1)) 8)
223 (aref data (+ i 2))))
224 (code (aref data i)))
225 (when (and (>= code #xe0) (<= code #xef))
226 ;; APP0 LEN1 LEN2 "JFIF\0"
227 (throw 'jfif
228 (string-match "JFIF\\|Exif"
229 (substring data i (min (+ i nbytes) len)))))
230 (setq i (+ i 1 nbytes))))))))
233 ;;;###autoload
234 (defun image-type-from-data (data)
235 "Determine the image type from image data DATA.
236 Value is a symbol specifying the image type or nil if type cannot
237 be determined."
238 (let ((types image-type-header-regexps)
239 type)
240 (while types
241 (let ((regexp (car (car types)))
242 (image-type (cdr (car types))))
243 (if (or (and (symbolp image-type)
244 (string-match regexp data))
245 (and (consp image-type)
246 (funcall (car image-type) data)
247 (setq image-type (cdr image-type))))
248 (setq type image-type
249 types nil)
250 (setq types (cdr types)))))
251 type))
254 ;;;###autoload
255 (defun image-type-from-buffer ()
256 "Determine the image type from data in the current buffer.
257 Value is a symbol specifying the image type or nil if type cannot
258 be determined."
259 (let ((types image-type-header-regexps)
260 type
261 (opoint (point)))
262 (goto-char (point-min))
263 (while types
264 (let ((regexp (car (car types)))
265 (image-type (cdr (car types)))
266 data)
267 (if (or (and (symbolp image-type)
268 (looking-at regexp))
269 (and (consp image-type)
270 (funcall (car image-type)
271 (or data
272 (setq data
273 (buffer-substring
274 (point-min)
275 (min (point-max)
276 (+ (point-min) 256))))))
277 (setq image-type (cdr image-type))))
278 (setq type image-type
279 types nil)
280 (setq types (cdr types)))))
281 (goto-char opoint)
282 type))
285 ;;;###autoload
286 (defun image-type-from-file-header (file)
287 "Determine the type of image file FILE from its first few bytes.
288 Value is a symbol specifying the image type, or nil if type cannot
289 be determined."
290 (unless (or (file-readable-p file)
291 (file-name-absolute-p file))
292 (setq file (image-search-load-path file)))
293 (and file
294 (file-readable-p file)
295 (with-temp-buffer
296 (set-buffer-multibyte nil)
297 (insert-file-contents-literally file nil 0 256)
298 (image-type-from-buffer))))
301 ;;;###autoload
302 (defun image-type-from-file-name (file)
303 "Determine the type of image file FILE from its name.
304 Value is a symbol specifying the image type, or nil if type cannot
305 be determined."
306 (assoc-default file image-type-file-name-regexps 'string-match))
309 ;;;###autoload
310 (defun image-type (source &optional type data-p)
311 "Determine and return image type.
312 SOURCE is an image file name or image data.
313 Optional TYPE is a symbol describing the image type. If TYPE is omitted
314 or nil, try to determine the image type from its first few bytes
315 of image data. If that doesn't work, and SOURCE is a file name,
316 use its file extension as image type.
317 Optional DATA-P non-nil means SOURCE is a string containing image data."
318 (when (and (not data-p) (not (stringp source)))
319 (error "Invalid image file name `%s'" source))
320 (unless type
321 (setq type (if data-p
322 (image-type-from-data source)
323 (or (image-type-from-file-header source)
324 (image-type-from-file-name source))))
325 (or type (error "Cannot determine image type")))
326 (or (memq type (and (boundp 'image-types) image-types))
327 (error "Invalid image type `%s'" type))
328 type)
331 ;;;###autoload
332 (defun image-type-available-p (type)
333 "Return non-nil if image type TYPE is available.
334 Image types are symbols like `xbm' or `jpeg'."
335 (and (fboundp 'init-image-library)
336 (init-image-library type image-library-alist)))
339 ;;;###autoload
340 (defun image-type-auto-detected-p ()
341 "Return t if the current buffer contains an auto-detectable image.
342 This function is intended to be used from `magic-fallback-mode-alist'.
344 The buffer is considered to contain an auto-detectable image if
345 its beginning matches an image type in `image-type-header-regexps',
346 and that image type is present in `image-type-auto-detectable' with a
347 non-nil value. If that value is non-nil, but not t, then the image type
348 must be available."
349 (let* ((type (image-type-from-buffer))
350 (auto (and type (cdr (assq type image-type-auto-detectable)))))
351 (and auto
352 (or (eq auto t) (image-type-available-p type)))))
355 ;;;###autoload
356 (defun create-image (file-or-data &optional type data-p &rest props)
357 "Create an image.
358 FILE-OR-DATA is an image file name or image data.
359 Optional TYPE is a symbol describing the image type. If TYPE is omitted
360 or nil, try to determine the image type from its first few bytes
361 of image data. If that doesn't work, and FILE-OR-DATA is a file name,
362 use its file extension as image type.
363 Optional DATA-P non-nil means FILE-OR-DATA is a string containing image data.
364 Optional PROPS are additional image attributes to assign to the image,
365 like, e.g. `:mask MASK'.
366 Value is the image created, or nil if images of type TYPE are not supported.
368 Images should not be larger than specified by `max-image-size'.
370 Image file names that are not absolute are searched for in the
371 \"images\" sub-directory of `data-directory' and
372 `x-bitmap-file-path' (in that order)."
373 ;; It is x_find_image_file in image.c that sets the search path.
374 (setq type (image-type file-or-data type data-p))
375 (when (image-type-available-p type)
376 (append (list 'image :type type (if data-p :data :file) file-or-data)
377 props)))
380 ;;;###autoload
381 (defun put-image (image pos &optional string area)
382 "Put image IMAGE in front of POS in the current buffer.
383 IMAGE must be an image created with `create-image' or `defimage'.
384 IMAGE is displayed by putting an overlay into the current buffer with a
385 `before-string' STRING that has a `display' property whose value is the
386 image. STRING is defaulted if you omit it.
387 POS may be an integer or marker.
388 AREA is where to display the image. AREA nil or omitted means
389 display it in the text area, a value of `left-margin' means
390 display it in the left marginal area, a value of `right-margin'
391 means display it in the right marginal area."
392 (unless string (setq string "x"))
393 (let ((buffer (current-buffer)))
394 (unless (eq (car-safe image) 'image)
395 (error "Not an image: %s" image))
396 (unless (or (null area) (memq area '(left-margin right-margin)))
397 (error "Invalid area %s" area))
398 (setq string (copy-sequence string))
399 (let ((overlay (make-overlay pos pos buffer))
400 (prop (if (null area) image (list (list 'margin area) image))))
401 (put-text-property 0 (length string) 'display prop string)
402 (overlay-put overlay 'put-image t)
403 (overlay-put overlay 'before-string string))))
406 ;;;###autoload
407 (defun insert-image (image &optional string area slice)
408 "Insert IMAGE into current buffer at point.
409 IMAGE is displayed by inserting STRING into the current buffer
410 with a `display' property whose value is the image. STRING is
411 defaulted if you omit it.
412 AREA is where to display the image. AREA nil or omitted means
413 display it in the text area, a value of `left-margin' means
414 display it in the left marginal area, a value of `right-margin'
415 means display it in the right marginal area.
416 SLICE specifies slice of IMAGE to insert. SLICE nil or omitted
417 means insert whole image. SLICE is a list (X Y WIDTH HEIGHT)
418 specifying the X and Y positions and WIDTH and HEIGHT of image area
419 to insert. A float value 0.0 - 1.0 means relative to the width or
420 height of the image; integer values are taken as pixel values."
421 ;; Use a space as least likely to cause trouble when it's a hidden
422 ;; character in the buffer.
423 (unless string (setq string " "))
424 (unless (eq (car-safe image) 'image)
425 (error "Not an image: %s" image))
426 (unless (or (null area) (memq area '(left-margin right-margin)))
427 (error "Invalid area %s" area))
428 (if area
429 (setq image (list (list 'margin area) image))
430 ;; Cons up a new spec equal but not eq to `image' so that
431 ;; inserting it twice in a row (adjacently) displays two copies of
432 ;; the image. Don't try to avoid this by looking at the display
433 ;; properties on either side so that we DTRT more often with
434 ;; cut-and-paste. (Yanking killed image text next to another copy
435 ;; of it loses anyway.)
436 (setq image (cons 'image (cdr image))))
437 (let ((start (point)))
438 (insert string)
439 (add-text-properties start (point)
440 `(display ,(if slice
441 (list (cons 'slice slice) image)
442 image) rear-nonsticky (display)))))
445 ;;;###autoload
446 (defun insert-sliced-image (image &optional string area rows cols)
447 "Insert IMAGE into current buffer at point.
448 IMAGE is displayed by inserting STRING into the current buffer
449 with a `display' property whose value is the image. STRING is
450 defaulted if you omit it.
451 AREA is where to display the image. AREA nil or omitted means
452 display it in the text area, a value of `left-margin' means
453 display it in the left marginal area, a value of `right-margin'
454 means display it in the right marginal area.
455 The image is automatically split into ROW x COLS slices."
456 (unless string (setq string " "))
457 (unless (eq (car-safe image) 'image)
458 (error "Not an image: %s" image))
459 (unless (or (null area) (memq area '(left-margin right-margin)))
460 (error "Invalid area %s" area))
461 (if area
462 (setq image (list (list 'margin area) image))
463 ;; Cons up a new spec equal but not eq to `image' so that
464 ;; inserting it twice in a row (adjacently) displays two copies of
465 ;; the image. Don't try to avoid this by looking at the display
466 ;; properties on either side so that we DTRT more often with
467 ;; cut-and-paste. (Yanking killed image text next to another copy
468 ;; of it loses anyway.)
469 (setq image (cons 'image (cdr image))))
470 (let ((x 0.0) (dx (/ 1.0001 (or cols 1)))
471 (y 0.0) (dy (/ 1.0001 (or rows 1))))
472 (while (< y 1.0)
473 (while (< x 1.0)
474 (let ((start (point)))
475 (insert string)
476 (add-text-properties start (point)
477 `(display ,(list (list 'slice x y dx dy) image)
478 rear-nonsticky (display)))
479 (setq x (+ x dx))))
480 (setq x 0.0
481 y (+ y dy))
482 (insert (propertize "\n" 'line-height t)))))
486 ;;;###autoload
487 (defun remove-images (start end &optional buffer)
488 "Remove images between START and END in BUFFER.
489 Remove only images that were put in BUFFER with calls to `put-image'.
490 BUFFER nil or omitted means use the current buffer."
491 (unless buffer
492 (setq buffer (current-buffer)))
493 (let ((overlays (overlays-in start end)))
494 (while overlays
495 (let ((overlay (car overlays)))
496 (when (overlay-get overlay 'put-image)
497 (delete-overlay overlay)))
498 (setq overlays (cdr overlays)))))
500 (defun image-search-load-path (file &optional path)
501 (unless path
502 (setq path image-load-path))
503 (let (element found filename)
504 (while (and (not found) (consp path))
505 (setq element (car path))
506 (cond
507 ((stringp element)
508 (setq found
509 (file-readable-p
510 (setq filename (expand-file-name file element)))))
511 ((and (symbolp element) (boundp element))
512 (setq element (symbol-value element))
513 (cond
514 ((stringp element)
515 (setq found
516 (file-readable-p
517 (setq filename (expand-file-name file element)))))
518 ((consp element)
519 (if (setq filename (image-search-load-path file element))
520 (setq found t))))))
521 (setq path (cdr path)))
522 (if found filename)))
524 ;;;###autoload
525 (defun find-image (specs)
526 "Find an image, choosing one of a list of image specifications.
528 SPECS is a list of image specifications.
530 Each image specification in SPECS is a property list. The contents of
531 a specification are image type dependent. All specifications must at
532 least contain the properties `:type TYPE' and either `:file FILE' or
533 `:data DATA', where TYPE is a symbol specifying the image type,
534 e.g. `xbm', FILE is the file to load the image from, and DATA is a
535 string containing the actual image data. The specification whose TYPE
536 is supported, and FILE exists, is used to construct the image
537 specification to be returned. Return nil if no specification is
538 satisfied.
540 The image is looked for in `image-load-path'.
542 Image files should not be larger than specified by `max-image-size'."
543 (let (image)
544 (while (and specs (null image))
545 (let* ((spec (car specs))
546 (type (plist-get spec :type))
547 (data (plist-get spec :data))
548 (file (plist-get spec :file))
549 found)
550 (when (image-type-available-p type)
551 (cond ((stringp file)
552 (if (setq found (image-search-load-path file))
553 (setq image
554 (cons 'image (plist-put (copy-sequence spec)
555 :file found)))))
556 ((not (null data))
557 (setq image (cons 'image spec)))))
558 (setq specs (cdr specs))))
559 image))
562 ;;;###autoload
563 (defmacro defimage (symbol specs &optional doc)
564 "Define SYMBOL as an image.
566 SPECS is a list of image specifications. DOC is an optional
567 documentation string.
569 Each image specification in SPECS is a property list. The contents of
570 a specification are image type dependent. All specifications must at
571 least contain the properties `:type TYPE' and either `:file FILE' or
572 `:data DATA', where TYPE is a symbol specifying the image type,
573 e.g. `xbm', FILE is the file to load the image from, and DATA is a
574 string containing the actual image data. The first image
575 specification whose TYPE is supported, and FILE exists, is used to
576 define SYMBOL.
578 Example:
580 (defimage test-image ((:type xpm :file \"~/test1.xpm\")
581 (:type xbm :file \"~/test1.xbm\")))"
582 (declare (doc-string 3))
583 `(defvar ,symbol (find-image ',specs) ,doc))
586 (provide 'image)
588 ;; arch-tag: 8e76a07b-eb48-4f3e-a7a0-1a7ba9f096b3
589 ;;; image.el ends here