Switch to recommended form of GPLv3 permissions notice.
[bpt/emacs.git] / 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 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
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 static char \\1_bits" . xbm)
42 ("\\`\\(?:MM\0\\*\\|II\\*\0\\)" . tiff)
43 ("\\`[\t\n\r ]*%!PS" . postscript)
44 ("\\`\xff\xd8" . (image-jpeg-p . jpeg))
45 (,(let* ((incomment-re "\\(?:[^-]\\|-[^-]\\)")
46 (comment-re (concat "\\(?:!--" incomment-re "*-->[ \t\r\n]*<\\)")))
47 (concat "\\(?:<\\?xml[ \t\r\n]+[^>]*>\\)?[ \t\r\n]*<"
48 comment-re "*"
49 "\\(?:!DOCTYPE[ \t\r\n]+[^>]*>[ \t\r\n]*<[ \t\r\n]*" comment-re "*\\)?"
50 "[Ss][Vv][Gg]"))
51 . svg)
52 )
53 "Alist of (REGEXP . IMAGE-TYPE) pairs used to auto-detect image types.
54 When the first bytes of an image file match REGEXP, it is assumed to
55 be of image type IMAGE-TYPE if IMAGE-TYPE is a symbol. If not a symbol,
56 IMAGE-TYPE must be a pair (PREDICATE . TYPE). PREDICATE is called
57 with one argument, a string containing the image data. If PREDICATE returns
58 a non-nil value, TYPE is the image's type.")
59
60 (defconst image-type-file-name-regexps
61 '(("\\.png\\'" . png)
62 ("\\.gif\\'" . gif)
63 ("\\.jpe?g\\'" . jpeg)
64 ("\\.bmp\\'" . bmp)
65 ("\\.xpm\\'" . xpm)
66 ("\\.pbm\\'" . pbm)
67 ("\\.xbm\\'" . xbm)
68 ("\\.ps\\'" . postscript)
69 ("\\.tiff?\\'" . tiff)
70 ("\\.svgz?\\'" . svg)
71 )
72 "Alist of (REGEXP . IMAGE-TYPE) pairs used to identify image files.
73 When the name of an image file match REGEXP, it is assumed to
74 be of image type IMAGE-TYPE.")
75
76 ;; We rely on `auto-mode-alist' to detect xbm and xpm files, instead
77 ;; of content autodetection. Their contents are just C code, so it is
78 ;; easy to generate false matches.
79 (defvar image-type-auto-detectable
80 '((pbm . t)
81 (xbm . nil)
82 (bmp . maybe)
83 (gif . maybe)
84 (png . maybe)
85 (xpm . nil)
86 (jpeg . maybe)
87 (tiff . maybe)
88 (svg . maybe)
89 (postscript . nil))
90 "Alist of (IMAGE-TYPE . AUTODETECT) pairs used to auto-detect image files.
91 \(See `image-type-auto-detected-p').
92
93 AUTODETECT can be
94 - t always auto-detect.
95 - nil never auto-detect.
96 - maybe auto-detect only if the image type is available
97 (see `image-type-available-p').")
98
99 (defvar image-load-path nil
100 "List of locations in which to search for image files.
101 If an element is a string, it defines a directory to search.
102 If an element is a variable symbol whose value is a string, that
103 value defines a directory to search.
104 If an element is a variable symbol whose value is a list, the
105 value is used as a list of directories to search.")
106
107 (eval-at-startup
108 (setq image-load-path
109 (list (file-name-as-directory (expand-file-name "images" data-directory))
110 'data-directory 'load-path)))
111
112
113 (defun image-load-path-for-library (library image &optional path no-error)
114 "Return a suitable search path for images used by LIBRARY.
115
116 It searches for IMAGE in `image-load-path' (excluding
117 \"`data-directory'/images\") and `load-path', followed by a path
118 suitable for LIBRARY, which includes \"../../etc/images\" and
119 \"../etc/images\" relative to the library file itself, and then
120 in \"`data-directory'/images\".
121
122 Then this function returns a list of directories which contains
123 first the directory in which IMAGE was found, followed by the
124 value of `load-path'. If PATH is given, it is used instead of
125 `load-path'.
126
127 If NO-ERROR is non-nil and a suitable path can't be found, don't
128 signal an error. Instead, return a list of directories as before,
129 except that nil appears in place of the image directory.
130
131 Here is an example that uses a common idiom to provide
132 compatibility with versions of Emacs that lack the variable
133 `image-load-path':
134
135 ;; Shush compiler.
136 (defvar image-load-path)
137
138 (let* ((load-path (image-load-path-for-library \"mh-e\" \"mh-logo.xpm\"))
139 (image-load-path (cons (car load-path)
140 (when (boundp 'image-load-path)
141 image-load-path))))
142 (mh-tool-bar-folder-buttons-init))"
143 (unless library (error "No library specified"))
144 (unless image (error "No image specified"))
145 (let (image-directory image-directory-load-path)
146 ;; Check for images in image-load-path or load-path.
147 (let ((img image)
148 (dir (or
149 ;; Images in image-load-path.
150 (image-search-load-path image)
151 ;; Images in load-path.
152 (locate-library image)))
153 parent)
154 ;; Since the image might be in a nested directory (for
155 ;; example, mail/attach.pbm), adjust `image-directory'
156 ;; accordingly.
157 (when dir
158 (setq dir (file-name-directory dir))
159 (while (setq parent (file-name-directory img))
160 (setq img (directory-file-name parent)
161 dir (expand-file-name "../" dir))))
162 (setq image-directory-load-path dir))
163
164 ;; If `image-directory-load-path' isn't Emacs' image directory,
165 ;; it's probably a user preference, so use it. Then use a
166 ;; relative setting if possible; otherwise, use
167 ;; `image-directory-load-path'.
168 (cond
169 ;; User-modified image-load-path?
170 ((and image-directory-load-path
171 (not (equal image-directory-load-path
172 (file-name-as-directory
173 (expand-file-name "images" data-directory)))))
174 (setq image-directory image-directory-load-path))
175 ;; Try relative setting.
176 ((let (library-name d1ei d2ei)
177 ;; First, find library in the load-path.
178 (setq library-name (locate-library library))
179 (if (not library-name)
180 (error "Cannot find library %s in load-path" library))
181 ;; And then set image-directory relative to that.
182 (setq
183 ;; Go down 2 levels.
184 d2ei (file-name-as-directory
185 (expand-file-name
186 (concat (file-name-directory library-name) "../../etc/images")))
187 ;; Go down 1 level.
188 d1ei (file-name-as-directory
189 (expand-file-name
190 (concat (file-name-directory library-name) "../etc/images"))))
191 (setq image-directory
192 ;; Set it to nil if image is not found.
193 (cond ((file-exists-p (expand-file-name image d2ei)) d2ei)
194 ((file-exists-p (expand-file-name image d1ei)) d1ei)))))
195 ;; Use Emacs' image directory.
196 (image-directory-load-path
197 (setq image-directory image-directory-load-path))
198 (no-error
199 (message "Could not find image %s for library %s" image library))
200 (t
201 (error "Could not find image %s for library %s" image library)))
202
203 ;; Return an augmented `path' or `load-path'.
204 (nconc (list image-directory)
205 (delete image-directory (copy-sequence (or path load-path))))))
206
207
208 (defun image-jpeg-p (data)
209 "Value is non-nil if DATA, a string, consists of JFIF image data.
210 We accept the tag Exif because that is the same format."
211 (when (string-match "\\`\xff\xd8" data)
212 (catch 'jfif
213 (let ((len (length data)) (i 2))
214 (while (< i len)
215 (when (/= (aref data i) #xff)
216 (throw 'jfif nil))
217 (setq i (1+ i))
218 (when (>= (+ i 2) len)
219 (throw 'jfif nil))
220 (let ((nbytes (+ (lsh (aref data (+ i 1)) 8)
221 (aref data (+ i 2))))
222 (code (aref data i)))
223 (when (and (>= code #xe0) (<= code #xef))
224 ;; APP0 LEN1 LEN2 "JFIF\0"
225 (throw 'jfif
226 (string-match "JFIF\\|Exif"
227 (substring data i (min (+ i nbytes) len)))))
228 (setq i (+ i 1 nbytes))))))))
229
230
231 ;;;###autoload
232 (defun image-type-from-data (data)
233 "Determine the image type from image data DATA.
234 Value is a symbol specifying the image type or nil if type cannot
235 be determined."
236 (let ((types image-type-header-regexps)
237 type)
238 (while types
239 (let ((regexp (car (car types)))
240 (image-type (cdr (car types))))
241 (if (or (and (symbolp image-type)
242 (string-match regexp data))
243 (and (consp image-type)
244 (funcall (car image-type) data)
245 (setq image-type (cdr image-type))))
246 (setq type image-type
247 types nil)
248 (setq types (cdr types)))))
249 type))
250
251
252 ;;;###autoload
253 (defun image-type-from-buffer ()
254 "Determine the image type from data in the current buffer.
255 Value is a symbol specifying the image type or nil if type cannot
256 be determined."
257 (let ((types image-type-header-regexps)
258 type
259 (opoint (point)))
260 (goto-char (point-min))
261 (while types
262 (let ((regexp (car (car types)))
263 (image-type (cdr (car types)))
264 data)
265 (if (or (and (symbolp image-type)
266 (looking-at regexp))
267 (and (consp image-type)
268 (funcall (car image-type)
269 (or data
270 (setq data
271 (buffer-substring
272 (point-min)
273 (min (point-max)
274 (+ (point-min) 256))))))
275 (setq image-type (cdr image-type))))
276 (setq type image-type
277 types nil)
278 (setq types (cdr types)))))
279 (goto-char opoint)
280 type))
281
282
283 ;;;###autoload
284 (defun image-type-from-file-header (file)
285 "Determine the type of image file FILE from its first few bytes.
286 Value is a symbol specifying the image type, or nil if type cannot
287 be determined."
288 (unless (or (file-readable-p file)
289 (file-name-absolute-p file))
290 (setq file (image-search-load-path file)))
291 (and file
292 (file-readable-p file)
293 (with-temp-buffer
294 (set-buffer-multibyte nil)
295 (insert-file-contents-literally file nil 0 256)
296 (image-type-from-buffer))))
297
298
299 ;;;###autoload
300 (defun image-type-from-file-name (file)
301 "Determine the type of image file FILE from its name.
302 Value is a symbol specifying the image type, or nil if type cannot
303 be determined."
304 (assoc-default file image-type-file-name-regexps 'string-match))
305
306
307 ;;;###autoload
308 (defun image-type (source &optional type data-p)
309 "Determine and return image type.
310 SOURCE is an image file name or image data.
311 Optional TYPE is a symbol describing the image type. If TYPE is omitted
312 or nil, try to determine the image type from its first few bytes
313 of image data. If that doesn't work, and SOURCE is a file name,
314 use its file extension as image type.
315 Optional DATA-P non-nil means SOURCE is a string containing image data."
316 (when (and (not data-p) (not (stringp source)))
317 (error "Invalid image file name `%s'" source))
318 (unless type
319 (setq type (if data-p
320 (image-type-from-data source)
321 (or (image-type-from-file-header source)
322 (image-type-from-file-name source))))
323 (or type (error "Cannot determine image type")))
324 (or (memq type (and (boundp 'image-types) image-types))
325 (error "Invalid image type `%s'" type))
326 type)
327
328
329 ;;;###autoload
330 (defun image-type-available-p (type)
331 "Return non-nil if image type TYPE is available.
332 Image types are symbols like `xbm' or `jpeg'."
333 (and (fboundp 'init-image-library)
334 (init-image-library type image-library-alist)))
335
336
337 ;;;###autoload
338 (defun image-type-auto-detected-p ()
339 "Return t if the current buffer contains an auto-detectable image.
340 This function is intended to be used from `magic-fallback-mode-alist'.
341
342 The buffer is considered to contain an auto-detectable image if
343 its beginning matches an image type in `image-type-header-regexps',
344 and that image type is present in `image-type-auto-detectable' with a
345 non-nil value. If that value is non-nil, but not t, then the image type
346 must be available."
347 (let* ((type (image-type-from-buffer))
348 (auto (and type (cdr (assq type image-type-auto-detectable)))))
349 (and auto
350 (or (eq auto t) (image-type-available-p type)))))
351
352
353 ;;;###autoload
354 (defun create-image (file-or-data &optional type data-p &rest props)
355 "Create an image.
356 FILE-OR-DATA is an image file name or image data.
357 Optional TYPE is a symbol describing the image type. If TYPE is omitted
358 or nil, try to determine the image type from its first few bytes
359 of image data. If that doesn't work, and FILE-OR-DATA is a file name,
360 use its file extension as image type.
361 Optional DATA-P non-nil means FILE-OR-DATA is a string containing image data.
362 Optional PROPS are additional image attributes to assign to the image,
363 like, e.g. `:mask MASK'.
364 Value is the image created, or nil if images of type TYPE are not supported.
365
366 Images should not be larger than specified by `max-image-size'.
367
368 Image file names that are not absolute are searched for in the
369 \"images\" sub-directory of `data-directory' and
370 `x-bitmap-file-path' (in that order)."
371 ;; It is x_find_image_file in image.c that sets the search path.
372 (setq type (image-type file-or-data type data-p))
373 (when (image-type-available-p type)
374 (append (list 'image :type type (if data-p :data :file) file-or-data)
375 props)))
376
377
378 ;;;###autoload
379 (defun put-image (image pos &optional string area)
380 "Put image IMAGE in front of POS in the current buffer.
381 IMAGE must be an image created with `create-image' or `defimage'.
382 IMAGE is displayed by putting an overlay into the current buffer with a
383 `before-string' STRING that has a `display' property whose value is the
384 image. STRING is defaulted if you omit it.
385 POS may be an integer or marker.
386 AREA is where to display the image. AREA nil or omitted means
387 display it in the text area, a value of `left-margin' means
388 display it in the left marginal area, a value of `right-margin'
389 means display it in the right marginal area."
390 (unless string (setq string "x"))
391 (let ((buffer (current-buffer)))
392 (unless (eq (car-safe image) 'image)
393 (error "Not an image: %s" image))
394 (unless (or (null area) (memq area '(left-margin right-margin)))
395 (error "Invalid area %s" area))
396 (setq string (copy-sequence string))
397 (let ((overlay (make-overlay pos pos buffer))
398 (prop (if (null area) image (list (list 'margin area) image))))
399 (put-text-property 0 (length string) 'display prop string)
400 (overlay-put overlay 'put-image t)
401 (overlay-put overlay 'before-string string))))
402
403
404 ;;;###autoload
405 (defun insert-image (image &optional string area slice)
406 "Insert IMAGE into current buffer at point.
407 IMAGE is displayed by inserting STRING into the current buffer
408 with a `display' property whose value is the image. STRING is
409 defaulted if you omit it.
410 AREA is where to display the image. AREA nil or omitted means
411 display it in the text area, a value of `left-margin' means
412 display it in the left marginal area, a value of `right-margin'
413 means display it in the right marginal area.
414 SLICE specifies slice of IMAGE to insert. SLICE nil or omitted
415 means insert whole image. SLICE is a list (X Y WIDTH HEIGHT)
416 specifying the X and Y positions and WIDTH and HEIGHT of image area
417 to insert. A float value 0.0 - 1.0 means relative to the width or
418 height of the image; integer values are taken as pixel values."
419 ;; Use a space as least likely to cause trouble when it's a hidden
420 ;; character in the buffer.
421 (unless string (setq string " "))
422 (unless (eq (car-safe image) 'image)
423 (error "Not an image: %s" image))
424 (unless (or (null area) (memq area '(left-margin right-margin)))
425 (error "Invalid area %s" area))
426 (if area
427 (setq image (list (list 'margin area) image))
428 ;; Cons up a new spec equal but not eq to `image' so that
429 ;; inserting it twice in a row (adjacently) displays two copies of
430 ;; the image. Don't try to avoid this by looking at the display
431 ;; properties on either side so that we DTRT more often with
432 ;; cut-and-paste. (Yanking killed image text next to another copy
433 ;; of it loses anyway.)
434 (setq image (cons 'image (cdr image))))
435 (let ((start (point)))
436 (insert string)
437 (add-text-properties start (point)
438 `(display ,(if slice
439 (list (cons 'slice slice) image)
440 image) rear-nonsticky (display)))))
441
442
443 ;;;###autoload
444 (defun insert-sliced-image (image &optional string area rows cols)
445 "Insert IMAGE into current buffer at point.
446 IMAGE is displayed by inserting STRING into the current buffer
447 with a `display' property whose value is the image. STRING is
448 defaulted if you omit it.
449 AREA is where to display the image. AREA nil or omitted means
450 display it in the text area, a value of `left-margin' means
451 display it in the left marginal area, a value of `right-margin'
452 means display it in the right marginal area.
453 The image is automatically split into ROW x COLS slices."
454 (unless string (setq string " "))
455 (unless (eq (car-safe image) 'image)
456 (error "Not an image: %s" image))
457 (unless (or (null area) (memq area '(left-margin right-margin)))
458 (error "Invalid area %s" area))
459 (if area
460 (setq image (list (list 'margin area) image))
461 ;; Cons up a new spec equal but not eq to `image' so that
462 ;; inserting it twice in a row (adjacently) displays two copies of
463 ;; the image. Don't try to avoid this by looking at the display
464 ;; properties on either side so that we DTRT more often with
465 ;; cut-and-paste. (Yanking killed image text next to another copy
466 ;; of it loses anyway.)
467 (setq image (cons 'image (cdr image))))
468 (let ((x 0.0) (dx (/ 1.0001 (or cols 1)))
469 (y 0.0) (dy (/ 1.0001 (or rows 1))))
470 (while (< y 1.0)
471 (while (< x 1.0)
472 (let ((start (point)))
473 (insert string)
474 (add-text-properties start (point)
475 `(display ,(list (list 'slice x y dx dy) image)
476 rear-nonsticky (display)))
477 (setq x (+ x dx))))
478 (setq x 0.0
479 y (+ y dy))
480 (insert (propertize "\n" 'line-height t)))))
481
482
483
484 ;;;###autoload
485 (defun remove-images (start end &optional buffer)
486 "Remove images between START and END in BUFFER.
487 Remove only images that were put in BUFFER with calls to `put-image'.
488 BUFFER nil or omitted means use the current buffer."
489 (unless buffer
490 (setq buffer (current-buffer)))
491 (let ((overlays (overlays-in start end)))
492 (while overlays
493 (let ((overlay (car overlays)))
494 (when (overlay-get overlay 'put-image)
495 (delete-overlay overlay)))
496 (setq overlays (cdr overlays)))))
497
498 (defun image-search-load-path (file &optional path)
499 (unless path
500 (setq path image-load-path))
501 (let (element found filename)
502 (while (and (not found) (consp path))
503 (setq element (car path))
504 (cond
505 ((stringp element)
506 (setq found
507 (file-readable-p
508 (setq filename (expand-file-name file element)))))
509 ((and (symbolp element) (boundp element))
510 (setq element (symbol-value element))
511 (cond
512 ((stringp element)
513 (setq found
514 (file-readable-p
515 (setq filename (expand-file-name file element)))))
516 ((consp element)
517 (if (setq filename (image-search-load-path file element))
518 (setq found t))))))
519 (setq path (cdr path)))
520 (if found filename)))
521
522 ;;;###autoload
523 (defun find-image (specs)
524 "Find an image, choosing one of a list of image specifications.
525
526 SPECS is a list of image specifications.
527
528 Each image specification in SPECS is a property list. The contents of
529 a specification are image type dependent. All specifications must at
530 least contain the properties `:type TYPE' and either `:file FILE' or
531 `:data DATA', where TYPE is a symbol specifying the image type,
532 e.g. `xbm', FILE is the file to load the image from, and DATA is a
533 string containing the actual image data. The specification whose TYPE
534 is supported, and FILE exists, is used to construct the image
535 specification to be returned. Return nil if no specification is
536 satisfied.
537
538 The image is looked for in `image-load-path'.
539
540 Image files should not be larger than specified by `max-image-size'."
541 (let (image)
542 (while (and specs (null image))
543 (let* ((spec (car specs))
544 (type (plist-get spec :type))
545 (data (plist-get spec :data))
546 (file (plist-get spec :file))
547 found)
548 (when (image-type-available-p type)
549 (cond ((stringp file)
550 (if (setq found (image-search-load-path file))
551 (setq image
552 (cons 'image (plist-put (copy-sequence spec)
553 :file found)))))
554 ((not (null data))
555 (setq image (cons 'image spec)))))
556 (setq specs (cdr specs))))
557 image))
558
559
560 ;;;###autoload
561 (defmacro defimage (symbol specs &optional doc)
562 "Define SYMBOL as an image.
563
564 SPECS is a list of image specifications. DOC is an optional
565 documentation string.
566
567 Each image specification in SPECS is a property list. The contents of
568 a specification are image type dependent. All specifications must at
569 least contain the properties `:type TYPE' and either `:file FILE' or
570 `:data DATA', where TYPE is a symbol specifying the image type,
571 e.g. `xbm', FILE is the file to load the image from, and DATA is a
572 string containing the actual image data. The first image
573 specification whose TYPE is supported, and FILE exists, is used to
574 define SYMBOL.
575
576 Example:
577
578 (defimage test-image ((:type xpm :file \"~/test1.xpm\")
579 (:type xbm :file \"~/test1.xbm\")))"
580 (declare (doc-string 3))
581 `(defvar ,symbol (find-image ',specs) ,doc))
582
583
584 (provide 'image)
585
586 ;; arch-tag: 8e76a07b-eb48-4f3e-a7a0-1a7ba9f096b3
587 ;;; image.el ends here