* doc/misc/eshell.texi: Fill most of the missing sections.
[emacs.git] / lisp / image.el
blob9979e3ec843fc1d00247df78b7eb900ed3eac926
1 ;;; image.el --- image API
3 ;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003,
4 ;; 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 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 of the License, or
14 ;; (at your option) 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. If not, see <http://www.gnu.org/licenses/>.
24 ;;; Commentary:
26 ;;; Code:
29 (defgroup image ()
30 "Image support."
31 :group 'multimedia)
34 (defconst image-type-header-regexps
35 `(("\\`/[\t\n\r ]*\\*.*XPM.\\*/" . xpm)
36 ("\\`P[1-6][[:space:]]+\\(?:#.*[[:space:]]+\\)*[0-9]+[[:space:]]+[0-9]+" . pbm)
37 ("\\`GIF8[79]a" . gif)
38 ("\\`\x89PNG\r\n\x1a\n" . png)
39 ("\\`[\t\n\r ]*#define \\([a-z0-9_]+\\)_width [0-9]+\n\
40 #define \\1_height [0-9]+\n\\(\
41 #define \\1_x_hot [0-9]+\n\
42 #define \\1_y_hot [0-9]+\n\\)?\
43 static \\(unsigned \\)?char \\1_bits" . xbm)
44 ("\\`\\(?:MM\0\\*\\|II\\*\0\\)" . tiff)
45 ("\\`[\t\n\r ]*%!PS" . postscript)
46 ("\\`\xff\xd8" . jpeg) ; used to be (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 (defcustom image-load-path
102 (list (file-name-as-directory (expand-file-name "images" data-directory))
103 'data-directory 'load-path)
104 "List of locations in which to search for image files.
105 If an element is a string, it defines a directory to search.
106 If an element is a variable symbol whose value is a string, that
107 value defines a directory to search.
108 If an element is a variable symbol whose value is a list, the
109 value is used as a list of directories to search."
110 :type '(repeat (choice directory variable))
111 :initialize 'custom-initialize-delay)
114 (defun image-load-path-for-library (library image &optional path no-error)
115 "Return a suitable search path for images used by LIBRARY.
117 It searches for IMAGE in `image-load-path' (excluding
118 \"`data-directory'/images\") and `load-path', followed by a path
119 suitable for LIBRARY, which includes \"../../etc/images\" and
120 \"../etc/images\" relative to the library file itself, and then
121 in \"`data-directory'/images\".
123 Then this function returns a list of directories which contains
124 first the directory in which IMAGE was found, followed by the
125 value of `load-path'. If PATH is given, it is used instead of
126 `load-path'.
128 If NO-ERROR is non-nil and a suitable path can't be found, don't
129 signal an error. Instead, return a list of directories as before,
130 except that nil appears in place of the image directory.
132 Here is an example that uses a common idiom to provide
133 compatibility with versions of Emacs that lack the variable
134 `image-load-path':
136 ;; Shush compiler.
137 (defvar image-load-path)
139 (let* ((load-path (image-load-path-for-library \"mh-e\" \"mh-logo.xpm\"))
140 (image-load-path (cons (car load-path)
141 (when (boundp 'image-load-path)
142 image-load-path))))
143 (mh-tool-bar-folder-buttons-init))"
144 (unless library (error "No library specified"))
145 (unless image (error "No image specified"))
146 (let (image-directory image-directory-load-path)
147 ;; Check for images in image-load-path or load-path.
148 (let ((img image)
149 (dir (or
150 ;; Images in image-load-path.
151 (image-search-load-path image)
152 ;; Images in load-path.
153 (locate-library image)))
154 parent)
155 ;; Since the image might be in a nested directory (for
156 ;; example, mail/attach.pbm), adjust `image-directory'
157 ;; accordingly.
158 (when dir
159 (setq dir (file-name-directory dir))
160 (while (setq parent (file-name-directory img))
161 (setq img (directory-file-name parent)
162 dir (expand-file-name "../" dir))))
163 (setq image-directory-load-path dir))
165 ;; If `image-directory-load-path' isn't Emacs' image directory,
166 ;; it's probably a user preference, so use it. Then use a
167 ;; relative setting if possible; otherwise, use
168 ;; `image-directory-load-path'.
169 (cond
170 ;; User-modified image-load-path?
171 ((and image-directory-load-path
172 (not (equal image-directory-load-path
173 (file-name-as-directory
174 (expand-file-name "images" data-directory)))))
175 (setq image-directory image-directory-load-path))
176 ;; Try relative setting.
177 ((let (library-name d1ei d2ei)
178 ;; First, find library in the load-path.
179 (setq library-name (locate-library library))
180 (if (not library-name)
181 (error "Cannot find library %s in load-path" library))
182 ;; And then set image-directory relative to that.
183 (setq
184 ;; Go down 2 levels.
185 d2ei (file-name-as-directory
186 (expand-file-name
187 (concat (file-name-directory library-name) "../../etc/images")))
188 ;; Go down 1 level.
189 d1ei (file-name-as-directory
190 (expand-file-name
191 (concat (file-name-directory library-name) "../etc/images"))))
192 (setq image-directory
193 ;; Set it to nil if image is not found.
194 (cond ((file-exists-p (expand-file-name image d2ei)) d2ei)
195 ((file-exists-p (expand-file-name image d1ei)) d1ei)))))
196 ;; Use Emacs' image directory.
197 (image-directory-load-path
198 (setq image-directory image-directory-load-path))
199 (no-error
200 (message "Could not find image %s for library %s" image library))
202 (error "Could not find image %s for library %s" image library)))
204 ;; Return an augmented `path' or `load-path'.
205 (nconc (list image-directory)
206 (delete image-directory (copy-sequence (or path load-path))))))
209 (defun image-jpeg-p (data)
210 "Value is non-nil if DATA, a string, consists of JFIF image data.
211 We accept the tag Exif because that is the same format."
212 (setq data (ignore-errors (string-to-unibyte data)))
213 (when (and data (string-match-p "\\`\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-p "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-p 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-p 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-p))
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 (defvar image-library-alist)
333 ;;;###autoload
334 (defun image-type-available-p (type)
335 "Return non-nil if image type TYPE is available.
336 Image types are symbols like `xbm' or `jpeg'."
337 (and (fboundp 'init-image-library)
338 (init-image-library type image-library-alist)))
341 ;;;###autoload
342 (defun image-type-auto-detected-p ()
343 "Return t if the current buffer contains an auto-detectable image.
344 This function is intended to be used from `magic-fallback-mode-alist'.
346 The buffer is considered to contain an auto-detectable image if
347 its beginning matches an image type in `image-type-header-regexps',
348 and that image type is present in `image-type-auto-detectable' with a
349 non-nil value. If that value is non-nil, but not t, then the image type
350 must be available."
351 (let* ((type (image-type-from-buffer))
352 (auto (and type (cdr (assq type image-type-auto-detectable)))))
353 (and auto
354 (or (eq auto t) (image-type-available-p type)))))
357 ;;;###autoload
358 (defun create-image (file-or-data &optional type data-p &rest props)
359 "Create an image.
360 FILE-OR-DATA is an image file name or image data.
361 Optional TYPE is a symbol describing the image type. If TYPE is omitted
362 or nil, try to determine the image type from its first few bytes
363 of image data. If that doesn't work, and FILE-OR-DATA is a file name,
364 use its file extension as image type.
365 Optional DATA-P non-nil means FILE-OR-DATA is a string containing image data.
366 Optional PROPS are additional image attributes to assign to the image,
367 like, e.g. `:mask MASK'.
368 Value is the image created, or nil if images of type TYPE are not supported.
370 Images should not be larger than specified by `max-image-size'.
372 Image file names that are not absolute are searched for in the
373 \"images\" sub-directory of `data-directory' and
374 `x-bitmap-file-path' (in that order)."
375 ;; It is x_find_image_file in image.c that sets the search path.
376 (setq type (image-type file-or-data type data-p))
377 (when (image-type-available-p type)
378 (append (list 'image :type type (if data-p :data :file) file-or-data)
379 props)))
382 ;;;###autoload
383 (defun put-image (image pos &optional string area)
384 "Put image IMAGE in front of POS in the current buffer.
385 IMAGE must be an image created with `create-image' or `defimage'.
386 IMAGE is displayed by putting an overlay into the current buffer with a
387 `before-string' STRING that has a `display' property whose value is the
388 image. STRING is defaulted if you omit it.
389 POS may be an integer or marker.
390 AREA is where to display the image. AREA nil or omitted means
391 display it in the text area, a value of `left-margin' means
392 display it in the left marginal area, a value of `right-margin'
393 means display it in the right marginal area."
394 (unless string (setq string "x"))
395 (let ((buffer (current-buffer)))
396 (unless (eq (car-safe image) 'image)
397 (error "Not an image: %s" image))
398 (unless (or (null area) (memq area '(left-margin right-margin)))
399 (error "Invalid area %s" area))
400 (setq string (copy-sequence string))
401 (let ((overlay (make-overlay pos pos buffer))
402 (prop (if (null area) image (list (list 'margin area) image))))
403 (put-text-property 0 (length string) 'display prop string)
404 (overlay-put overlay 'put-image t)
405 (overlay-put overlay 'before-string string))))
408 ;;;###autoload
409 (defun insert-image (image &optional string area slice)
410 "Insert IMAGE into current buffer at point.
411 IMAGE is displayed by inserting STRING into the current buffer
412 with a `display' property whose value is the image. STRING is
413 defaulted if you omit it.
414 AREA is where to display the image. AREA nil or omitted means
415 display it in the text area, a value of `left-margin' means
416 display it in the left marginal area, a value of `right-margin'
417 means display it in the right marginal area.
418 SLICE specifies slice of IMAGE to insert. SLICE nil or omitted
419 means insert whole image. SLICE is a list (X Y WIDTH HEIGHT)
420 specifying the X and Y positions and WIDTH and HEIGHT of image area
421 to insert. A float value 0.0 - 1.0 means relative to the width or
422 height of the image; integer values are taken as pixel values."
423 ;; Use a space as least likely to cause trouble when it's a hidden
424 ;; character in the buffer.
425 (unless string (setq string " "))
426 (unless (eq (car-safe image) 'image)
427 (error "Not an image: %s" image))
428 (unless (or (null area) (memq area '(left-margin right-margin)))
429 (error "Invalid area %s" area))
430 (if area
431 (setq image (list (list 'margin area) image))
432 ;; Cons up a new spec equal but not eq to `image' so that
433 ;; inserting it twice in a row (adjacently) displays two copies of
434 ;; the image. Don't try to avoid this by looking at the display
435 ;; properties on either side so that we DTRT more often with
436 ;; cut-and-paste. (Yanking killed image text next to another copy
437 ;; of it loses anyway.)
438 (setq image (cons 'image (cdr image))))
439 (let ((start (point)))
440 (insert string)
441 (add-text-properties start (point)
442 `(display ,(if slice
443 (list (cons 'slice slice) image)
444 image) rear-nonsticky (display)))))
447 ;;;###autoload
448 (defun insert-sliced-image (image &optional string area rows cols)
449 "Insert IMAGE into current buffer at point.
450 IMAGE is displayed by inserting STRING into the current buffer
451 with a `display' property whose value is the image. STRING is
452 defaulted if you omit it.
453 AREA is where to display the image. AREA nil or omitted means
454 display it in the text area, a value of `left-margin' means
455 display it in the left marginal area, a value of `right-margin'
456 means display it in the right marginal area.
457 The image is automatically split into ROWS x COLS slices."
458 (unless string (setq string " "))
459 (unless (eq (car-safe image) 'image)
460 (error "Not an image: %s" image))
461 (unless (or (null area) (memq area '(left-margin right-margin)))
462 (error "Invalid area %s" area))
463 (if area
464 (setq image (list (list 'margin area) image))
465 ;; Cons up a new spec equal but not eq to `image' so that
466 ;; inserting it twice in a row (adjacently) displays two copies of
467 ;; the image. Don't try to avoid this by looking at the display
468 ;; properties on either side so that we DTRT more often with
469 ;; cut-and-paste. (Yanking killed image text next to another copy
470 ;; of it loses anyway.)
471 (setq image (cons 'image (cdr image))))
472 (let ((x 0.0) (dx (/ 1.0001 (or cols 1)))
473 (y 0.0) (dy (/ 1.0001 (or rows 1))))
474 (while (< y 1.0)
475 (while (< x 1.0)
476 (let ((start (point)))
477 (insert string)
478 (add-text-properties start (point)
479 `(display ,(list (list 'slice x y dx dy) image)
480 rear-nonsticky (display)))
481 (setq x (+ x dx))))
482 (setq x 0.0
483 y (+ y dy))
484 (insert (propertize "\n" 'line-height t)))))
488 ;;;###autoload
489 (defun remove-images (start end &optional buffer)
490 "Remove images between START and END in BUFFER.
491 Remove only images that were put in BUFFER with calls to `put-image'.
492 BUFFER nil or omitted means use the current buffer."
493 (unless buffer
494 (setq buffer (current-buffer)))
495 (let ((overlays (overlays-in start end)))
496 (while overlays
497 (let ((overlay (car overlays)))
498 (when (overlay-get overlay 'put-image)
499 (delete-overlay overlay)))
500 (setq overlays (cdr overlays)))))
502 (defun image-search-load-path (file &optional path)
503 (unless path
504 (setq path image-load-path))
505 (let (element found filename)
506 (while (and (not found) (consp path))
507 (setq element (car path))
508 (cond
509 ((stringp element)
510 (setq found
511 (file-readable-p
512 (setq filename (expand-file-name file element)))))
513 ((and (symbolp element) (boundp element))
514 (setq element (symbol-value element))
515 (cond
516 ((stringp element)
517 (setq found
518 (file-readable-p
519 (setq filename (expand-file-name file element)))))
520 ((consp element)
521 (if (setq filename (image-search-load-path file element))
522 (setq found t))))))
523 (setq path (cdr path)))
524 (if found filename)))
526 ;;;###autoload
527 (defun find-image (specs)
528 "Find an image, choosing one of a list of image specifications.
530 SPECS is a list of image specifications.
532 Each image specification in SPECS is a property list. The contents of
533 a specification are image type dependent. All specifications must at
534 least contain the properties `:type TYPE' and either `:file FILE' or
535 `:data DATA', where TYPE is a symbol specifying the image type,
536 e.g. `xbm', FILE is the file to load the image from, and DATA is a
537 string containing the actual image data. The specification whose TYPE
538 is supported, and FILE exists, is used to construct the image
539 specification to be returned. Return nil if no specification is
540 satisfied.
542 The image is looked for in `image-load-path'.
544 Image files should not be larger than specified by `max-image-size'."
545 (let (image)
546 (while (and specs (null image))
547 (let* ((spec (car specs))
548 (type (plist-get spec :type))
549 (data (plist-get spec :data))
550 (file (plist-get spec :file))
551 found)
552 (when (image-type-available-p type)
553 (cond ((stringp file)
554 (if (setq found (image-search-load-path file))
555 (setq image
556 (cons 'image (plist-put (copy-sequence spec)
557 :file found)))))
558 ((not (null data))
559 (setq image (cons 'image spec)))))
560 (setq specs (cdr specs))))
561 image))
564 ;;;###autoload
565 (defmacro defimage (symbol specs &optional doc)
566 "Define SYMBOL as an image.
568 SPECS is a list of image specifications. DOC is an optional
569 documentation string.
571 Each image specification in SPECS is a property list. The contents of
572 a specification are image type dependent. All specifications must at
573 least contain the properties `:type TYPE' and either `:file FILE' or
574 `:data DATA', where TYPE is a symbol specifying the image type,
575 e.g. `xbm', FILE is the file to load the image from, and DATA is a
576 string containing the actual image data. The first image
577 specification whose TYPE is supported, and FILE exists, is used to
578 define SYMBOL.
580 Example:
582 (defimage test-image ((:type xpm :file \"~/test1.xpm\")
583 (:type xbm :file \"~/test1.xbm\")))"
584 (declare (doc-string 3))
585 `(defvar ,symbol (find-image ',specs) ,doc))
588 (provide 'image)
590 ;; arch-tag: 8e76a07b-eb48-4f3e-a7a0-1a7ba9f096b3
591 ;;; image.el ends here