1 ;;; image.el --- image API
3 ;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003,
4 ;; 2004, 2005, 2006 Free Software Foundation, Inc.
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 2, or (at your option)
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.
36 (defconst image-type-header-regexps
37 '(("\\`/[\t\n\r ]*\\*.*XPM.\\*/" . xpm
)
40 ("\\`\211PNG\r\n" . png
)
41 ("\\`[\t\n\r ]*#define" . xbm
)
42 ("\\`\\(MM\0\\*\\|II\\*\0\\)" . tiff
)
43 ("\\`[\t\n\r ]*%!PS" . postscript
)
44 ("\\`\xff\xd8" .
(image-jpeg-p . jpeg
)))
45 "Alist of (REGEXP . IMAGE-TYPE) pairs used to auto-detect image types.
46 When the first bytes of an image file match REGEXP, it is assumed to
47 be of image type IMAGE-TYPE if IMAGE-TYPE is a symbol. If not a symbol,
48 IMAGE-TYPE must be a pair (PREDICATE . TYPE). PREDICATE is called
49 with one argument, a string containing the image data. If PREDICATE returns
50 a non-nil value, TYPE is the image's type.")
52 (defconst image-type-file-name-regexps
55 ("\\.jpe?g\\'" . jpeg
)
60 ("\\.ps\\'" . postscript
)
61 ("\\.tiff?\\'" . tiff
))
62 "Alist of (REGEXP . IMAGE-TYPE) pairs used to identify image files.
63 When the name of an image file match REGEXP, it is assumed to
64 be of image type IMAGE-TYPE.")
67 (defvar image-load-path nil
68 "List of locations in which to search for image files.
69 If an element is a string, it defines a directory to search.
70 If an element is a variable symbol whose value is a string, that
71 value defines a directory to search.
72 If an element is a variable symbol whose value is a list, the
73 value is used as a list of directories to search.")
77 (list (file-name-as-directory (expand-file-name "images" data-directory
))
78 'data-directory
'load-path
)))
80 (defun image-jpeg-p (data)
81 "Value is non-nil if DATA, a string, consists of JFIF image data.
82 We accept the tag Exif because that is the same format."
83 (when (string-match "\\`\xff\xd8" data
)
85 (let ((len (length data
)) (i 2))
87 (when (/= (aref data i
) #xff
)
90 (when (>= (+ i
2) len
)
92 (let ((nbytes (+ (lsh (aref data
(+ i
1)) 8)
95 (when (and (>= code
#xe0
) (<= code
#xef
))
96 ;; APP0 LEN1 LEN2 "JFIF\0"
98 (string-match "JFIF\\|Exif"
99 (substring data i
(min (+ i nbytes
) len
)))))
100 (setq i
(+ i
1 nbytes
))))))))
104 (defun image-type-from-data (data)
105 "Determine the image type from image data DATA.
106 Value is a symbol specifying the image type or nil if type cannot
108 (let ((types image-type-header-regexps
)
111 (let ((regexp (car (car types
)))
112 (image-type (cdr (car types
))))
113 (if (or (and (symbolp image-type
)
114 (string-match regexp data
))
115 (and (consp image-type
)
116 (funcall (car image-type
) data
)
117 (setq image-type
(cdr image-type
))))
118 (setq type image-type
120 (setq types
(cdr types
)))))
125 (defun image-type-from-buffer ()
126 "Determine the image type from data in the current buffer.
127 Value is a symbol specifying the image type or nil if type cannot
129 (let ((types image-type-header-regexps
)
132 (goto-char (point-min))
134 (let ((regexp (car (car types
)))
135 (image-type (cdr (car types
)))
137 (if (or (and (symbolp image-type
)
139 (and (consp image-type
)
140 (funcall (car image-type
)
146 (+ (point-min) 256))))))
147 (setq image-type
(cdr image-type
))))
148 (setq type image-type
150 (setq types
(cdr types
)))))
156 (defun image-type-from-file-header (file)
157 "Determine the type of image file FILE from its first few bytes.
158 Value is a symbol specifying the image type, or nil if type cannot
160 (unless (or (file-readable-p file
)
161 (file-name-absolute-p file
))
162 (setq file
(image-search-load-path file
)))
164 (file-readable-p file
)
166 (set-buffer-multibyte nil
)
167 (insert-file-contents-literally file nil
0 256)
168 (image-type-from-buffer))))
172 (defun image-type-from-file-name (file)
173 "Determine the type of image file FILE from its name.
174 Value is a symbol specifying the image type, or nil if type cannot
176 (let ((types image-type-file-name-regexps
)
179 (if (string-match (car (car types
)) file
)
180 (setq type
(cdr (car types
))
182 (setq types
(cdr types
))))
187 (defun image-type-available-p (type)
188 "Return non-nil if image type TYPE is available.
189 Image types are symbols like `xbm' or `jpeg'."
190 (and (fboundp 'init-image-library
)
191 (init-image-library type image-library-alist
)))
195 (defun create-image (file-or-data &optional type data-p
&rest props
)
197 FILE-OR-DATA is an image file name or image data.
198 Optional TYPE is a symbol describing the image type. If TYPE is omitted
199 or nil, try to determine the image type from its first few bytes
200 of image data. If that doesn't work, and FILE-OR-DATA is a file name,
201 use its file extension as image type.
202 Optional DATA-P non-nil means FILE-OR-DATA is a string containing image data.
203 Optional PROPS are additional image attributes to assign to the image,
204 like, e.g. `:mask MASK'.
205 Value is the image created, or nil if images of type TYPE are not supported.
207 Images should not be larger than specified by `max-image-size'."
208 (when (and (not data-p
) (not (stringp file-or-data
)))
209 (error "Invalid image file name `%s'" file-or-data
))
211 ;; FILE-OR-DATA is a file name.
213 (setq type
(image-type-from-file-header file-or-data
)))
214 (let ((extension (file-name-extension file-or-data
)))
216 (error "Cannot determine image type"))
217 (setq type
(intern extension
)))))
219 ;; FILE-OR-DATA contains image data.
221 (setq type
(image-type-from-data file-or-data
)))))
223 (error "Cannot determine image type"))
224 (unless (symbolp type
)
225 (error "Invalid image type `%s'" type
))
226 (when (image-type-available-p type
)
227 (append (list 'image
:type type
(if data-p
:data
:file
) file-or-data
)
232 (defun put-image (image pos
&optional string area
)
233 "Put image IMAGE in front of POS in the current buffer.
234 IMAGE must be an image created with `create-image' or `defimage'.
235 IMAGE is displayed by putting an overlay into the current buffer with a
236 `before-string' STRING that has a `display' property whose value is the
237 image. STRING is defaulted if you omit it.
238 POS may be an integer or marker.
239 AREA is where to display the image. AREA nil or omitted means
240 display it in the text area, a value of `left-margin' means
241 display it in the left marginal area, a value of `right-margin'
242 means display it in the right marginal area."
243 (unless string
(setq string
"x"))
244 (let ((buffer (current-buffer)))
245 (unless (eq (car-safe image
) 'image
)
246 (error "Not an image: %s" image
))
247 (unless (or (null area
) (memq area
'(left-margin right-margin
)))
248 (error "Invalid area %s" area
))
249 (setq string
(copy-sequence string
))
250 (let ((overlay (make-overlay pos pos buffer
))
251 (prop (if (null area
) image
(list (list 'margin area
) image
))))
252 (put-text-property 0 (length string
) 'display prop string
)
253 (overlay-put overlay
'put-image t
)
254 (overlay-put overlay
'before-string string
))))
258 (defun insert-image (image &optional string area slice
)
259 "Insert IMAGE into current buffer at point.
260 IMAGE is displayed by inserting STRING into the current buffer
261 with a `display' property whose value is the image. STRING is
262 defaulted if you omit it.
263 AREA is where to display the image. AREA nil or omitted means
264 display it in the text area, a value of `left-margin' means
265 display it in the left marginal area, a value of `right-margin'
266 means display it in the right marginal area.
267 SLICE specifies slice of IMAGE to insert. SLICE nil or omitted
268 means insert whole image. SLICE is a list (X Y WIDTH HEIGHT)
269 specifying the X and Y positions and WIDTH and HEIGHT of image area
270 to insert. A float value 0.0 - 1.0 means relative to the width or
271 height of the image; integer values are taken as pixel values."
272 ;; Use a space as least likely to cause trouble when it's a hidden
273 ;; character in the buffer.
274 (unless string
(setq string
" "))
275 (unless (eq (car-safe image
) 'image
)
276 (error "Not an image: %s" image
))
277 (unless (or (null area
) (memq area
'(left-margin right-margin
)))
278 (error "Invalid area %s" area
))
280 (setq image
(list (list 'margin area
) image
))
281 ;; Cons up a new spec equal but not eq to `image' so that
282 ;; inserting it twice in a row (adjacently) displays two copies of
283 ;; the image. Don't try to avoid this by looking at the display
284 ;; properties on either side so that we DTRT more often with
285 ;; cut-and-paste. (Yanking killed image text next to another copy
286 ;; of it loses anyway.)
287 (setq image
(cons 'image
(cdr image
))))
288 (let ((start (point)))
290 (add-text-properties start
(point)
292 (list (cons 'slice slice
) image
)
293 image
) rear-nonsticky
(display)))))
297 (defun insert-sliced-image (image &optional string area rows cols
)
298 "Insert IMAGE into current buffer at point.
299 IMAGE is displayed by inserting STRING into the current buffer
300 with a `display' property whose value is the image. STRING is
301 defaulted if you omit it.
302 AREA is where to display the image. AREA nil or omitted means
303 display it in the text area, a value of `left-margin' means
304 display it in the left marginal area, a value of `right-margin'
305 means display it in the right marginal area.
306 The image is automatically split into ROW x COLS slices."
307 (unless string
(setq string
" "))
308 (unless (eq (car-safe image
) 'image
)
309 (error "Not an image: %s" image
))
310 (unless (or (null area
) (memq area
'(left-margin right-margin
)))
311 (error "Invalid area %s" area
))
313 (setq image
(list (list 'margin area
) image
))
314 ;; Cons up a new spec equal but not eq to `image' so that
315 ;; inserting it twice in a row (adjacently) displays two copies of
316 ;; the image. Don't try to avoid this by looking at the display
317 ;; properties on either side so that we DTRT more often with
318 ;; cut-and-paste. (Yanking killed image text next to another copy
319 ;; of it loses anyway.)
320 (setq image
(cons 'image
(cdr image
))))
321 (let ((x 0.0) (dx (/ 1.0001 (or cols
1)))
322 (y 0.0) (dy (/ 1.0001 (or rows
1))))
325 (let ((start (point)))
327 (add-text-properties start
(point)
328 `(display ,(list (list 'slice x y dx dy
) image
)
329 rear-nonsticky
(display)))
333 (insert (propertize "\n" 'line-height t
)))))
338 (defun remove-images (start end
&optional buffer
)
339 "Remove images between START and END in BUFFER.
340 Remove only images that were put in BUFFER with calls to `put-image'.
341 BUFFER nil or omitted means use the current buffer."
343 (setq buffer
(current-buffer)))
344 (let ((overlays (overlays-in start end
)))
346 (let ((overlay (car overlays
)))
347 (when (overlay-get overlay
'put-image
)
348 (delete-overlay overlay
)))
349 (setq overlays
(cdr overlays
)))))
351 (defun image-search-load-path (file &optional path
)
353 (setq path image-load-path
))
354 (let (element found filename
)
355 (while (and (not found
) (consp path
))
356 (setq element
(car path
))
361 (setq filename
(expand-file-name file element
)))))
362 ((and (symbolp element
) (boundp element
))
363 (setq element
(symbol-value element
))
368 (setq filename
(expand-file-name file element
)))))
370 (if (setq filename
(image-search-load-path file element
))
372 (setq path
(cdr path
)))
373 (if found filename
)))
376 (defun find-image (specs)
377 "Find an image, choosing one of a list of image specifications.
379 SPECS is a list of image specifications.
381 Each image specification in SPECS is a property list. The contents of
382 a specification are image type dependent. All specifications must at
383 least contain the properties `:type TYPE' and either `:file FILE' or
384 `:data DATA', where TYPE is a symbol specifying the image type,
385 e.g. `xbm', FILE is the file to load the image from, and DATA is a
386 string containing the actual image data. The specification whose TYPE
387 is supported, and FILE exists, is used to construct the image
388 specification to be returned. Return nil if no specification is
391 The image is looked for in `image-load-path'.
393 Image files should not be larger than specified by `max-image-size'."
395 (while (and specs
(null image
))
396 (let* ((spec (car specs
))
397 (type (plist-get spec
:type
))
398 (data (plist-get spec
:data
))
399 (file (plist-get spec
:file
))
401 (when (image-type-available-p type
)
402 (cond ((stringp file
)
403 (if (setq found
(image-search-load-path file
))
405 (cons 'image
(plist-put (copy-sequence spec
)
408 (setq image
(cons 'image spec
)))))
409 (setq specs
(cdr specs
))))
414 (defmacro defimage
(symbol specs
&optional doc
)
415 "Define SYMBOL as an image.
417 SPECS is a list of image specifications. DOC is an optional
418 documentation string.
420 Each image specification in SPECS is a property list. The contents of
421 a specification are image type dependent. All specifications must at
422 least contain the properties `:type TYPE' and either `:file FILE' or
423 `:data DATA', where TYPE is a symbol specifying the image type,
424 e.g. `xbm', FILE is the file to load the image from, and DATA is a
425 string containing the actual image data. The first image
426 specification whose TYPE is supported, and FILE exists, is used to
431 (defimage test-image ((:type xpm :file \"~/test1.xpm\")
432 (:type xbm :file \"~/test1.xbm\")))"
433 (declare (doc-string 3))
434 `(defvar ,symbol
(find-image ',specs
) ,doc
))
439 ;; arch-tag: 8e76a07b-eb48-4f3e-a7a0-1a7ba9f096b3
440 ;;; image.el ends here