image.el 19.3 KB
Newer Older
Gerd Moellmann's avatar
Gerd Moellmann committed
1 2
;;; image.el --- image API

3
;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003,
4
;;   2004, 2005, 2006 Free Software Foundation, Inc.
Pavel Janík's avatar
Pavel Janík committed
5 6

;; Maintainer: FSF
Dave Love's avatar
Dave Love committed
7
;; Keywords: multimedia
Gerd Moellmann's avatar
Gerd Moellmann committed
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
Lute Kamstra's avatar
Lute Kamstra committed
23 24
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.
Gerd Moellmann's avatar
Gerd Moellmann committed
25 26 27 28 29

;;; Commentary:

;;; Code:

Miles Bader's avatar
Miles Bader committed
30 31 32 33 34 35

(defgroup image ()
  "Image support."
  :group 'multimedia)


36
(defconst image-type-header-regexps
37
  '(("\\`/[\t\n\r ]*\\*.*XPM.\\*/" . xpm)
38 39 40
    ("\\`P[1-6]" . pbm)
    ("\\`GIF8" . gif)
    ("\\`\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)))
Gerd Moellmann's avatar
Gerd Moellmann committed
45 46
  "Alist of (REGEXP . IMAGE-TYPE) pairs used to auto-detect image types.
When the first bytes of an image file match REGEXP, it is assumed to
47 48 49
be of image type IMAGE-TYPE if IMAGE-TYPE is a symbol.  If not a symbol,
IMAGE-TYPE must be a pair (PREDICATE . TYPE).  PREDICATE is called
with one argument, a string containing the image data.  If PREDICATE returns
50
a non-nil value, TYPE is the image's type.")
51

52 53 54 55 56 57 58 59 60 61 62 63 64 65 66
(defconst image-type-file-name-regexps
  '(("\\.png\\'" . png)
    ("\\.gif\\'" . gif)
    ("\\.jpe?g\\'" . jpeg)
    ("\\.bmp\\'" . bmp)
    ("\\.xpm\\'" . xpm)
    ("\\.pbm\\'" . pbm)
    ("\\.xbm\\'" . xbm)
    ("\\.ps\\'" . postscript)
    ("\\.tiff?\\'" . tiff))
  "Alist of (REGEXP . IMAGE-TYPE) pairs used to identify image files.
When the name of an image file match REGEXP, it is assumed to
be of image type IMAGE-TYPE.")


67
(defvar image-load-path nil
68
  "List of locations in which to search for image files.
69 70 71 72 73
If an element is a string, it defines a directory to search.
If an element is a variable symbol whose value is a string, that
value defines a directory to search.
If an element is a variable symbol whose value is a list, the
value is used as a list of directories to search.")
74

75 76 77 78 79
(eval-at-startup
 (setq image-load-path
       (list (file-name-as-directory (expand-file-name "images" data-directory))
	     'data-directory 'load-path)))

80

81
(defun image-load-path-for-library (library image &optional path no-error)
82 83
  "Return a suitable search path for images relative to LIBRARY.

84 85 86 87 88
First it searches for IMAGE in `image-load-path' (excluding
\"`data-directory'/images\") and `load-path', followed by a path
suitable for LIBRARY, which includes \"../../etc/images\" and
\"../etc/images\" relative to the library file itself, and then
in \"`data-directory'/images\".
89

90 91 92 93
Then this function returns a list of directories which contains
first the directory in which IMAGE was found, followed by the
value of `load-path'. If PATH is given, it is used instead of
`load-path'.
94

95 96 97
If NO-ERROR is non-nil and a suitable path can't be found, don't
signal an error. Instead, return a list of directories as before,
except that nil appears in place of the image directory.
98 99 100 101 102

Here is an example that uses a common idiom to provide
compatibility with versions of Emacs that lack the variable
`image-load-path':

103 104
    ;; Shush compiler.
    (defvar image-load-path)
105 106

    (let* ((load-path (image-load-path-for-library \"mh-e\" \"mh-logo.xpm\"))
107 108 109
           (image-load-path (cons (car load-path)
                                  (when (boundp 'image-load-path)
                                    image-load-path))))
110
      (mh-tool-bar-folder-buttons-init))"
111 112
  (unless library (error "No library specified"))
  (unless image   (error "No image specified"))
113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135
  (let (image-directory image-directory-load-path)
    ;; Check for images in image-load-path or load-path.
    (let ((img image)
          (dir (or
                ;; Images in image-load-path.
                (image-search-load-path image)
                ;; Images in load-path.
                (locate-library image)))
          parent)
      ;; Since the image might be in a nested directory (for
      ;; example, mail/attach.pbm), adjust `image-directory'
      ;; accordingly.
      (when dir
        (setq dir (file-name-directory dir))
        (while (setq parent (file-name-directory img))
          (setq img (directory-file-name parent)
                dir (expand-file-name "../" dir))))
      (setq image-directory-load-path dir))

    ;; If `image-directory-load-path' isn't Emacs' image directory,
    ;; it's probably a user preference, so use it. Then use a
    ;; relative setting if possible; otherwise, use
    ;; `image-directory-load-path'.
136
    (cond
137 138 139 140 141 142
     ;; User-modified image-load-path?
     ((and image-directory-load-path
           (not (equal image-directory-load-path
                       (file-name-as-directory
                        (expand-file-name "images" data-directory)))))
      (setq image-directory image-directory-load-path))
143 144 145 146 147 148 149 150 151
     ;; Try relative setting.
     ((let (library-name d1ei d2ei)
        ;; First, find library in the load-path.
        (setq library-name (locate-library library))
        (if (not library-name)
            (error "Cannot find library %s in load-path" library))
        ;; And then set image-directory relative to that.
        (setq
         ;; Go down 2 levels.
152 153 154
         d2ei (file-name-as-directory
               (expand-file-name
                (concat (file-name-directory library-name) "../../etc/images")))
155
         ;; Go down 1 level.
156 157 158
         d1ei (file-name-as-directory
               (expand-file-name
                (concat (file-name-directory library-name) "../etc/images"))))
159 160 161 162
        (setq image-directory
              ;; Set it to nil if image is not found.
              (cond ((file-exists-p (expand-file-name image d2ei)) d2ei)
                    ((file-exists-p (expand-file-name image d1ei)) d1ei)))))
163 164 165
     ;; Use Emacs' image directory.
     (image-directory-load-path
      (setq image-directory image-directory-load-path))
166 167
     (no-error
      (message "Could not find image %s for library %s" image library))
168 169 170
     (t
      (error "Could not find image %s for library %s" image library)))

171 172 173 174
    ;; Return an augmented `path' or `load-path'.
    (nconc (list image-directory)
           (delete image-directory (copy-sequence (or path load-path))))))

175

176
(defun image-jpeg-p (data)
177 178
  "Value is non-nil if DATA, a string, consists of JFIF image data.
We accept the tag Exif because that is the same format."
179 180 181 182 183 184 185 186 187 188
  (when (string-match "\\`\xff\xd8" data)
    (catch 'jfif
      (let ((len (length data)) (i 2))
	(while (< i len)
	  (when (/= (aref data i) #xff)
	    (throw 'jfif nil))
	  (setq i (1+ i))
	  (when (>= (+ i 2) len)
	    (throw 'jfif nil))
	  (let ((nbytes (+ (lsh (aref data (+ i 1)) 8)
189 190 191
			   (aref data (+ i 2))))
		(code (aref data i)))
	    (when (and (>= code #xe0) (<= code #xef))
192
	      ;; APP0 LEN1 LEN2 "JFIF\0"
193
	      (throw 'jfif
194 195
		     (string-match "JFIF\\|Exif"
				   (substring data i (min (+ i nbytes) len)))))
196
	    (setq i (+ i 1 nbytes))))))))
Gerd Moellmann's avatar
Gerd Moellmann committed
197 198 199


;;;###autoload
200 201 202
(defun image-type-from-data (data)
  "Determine the image type from image data DATA.
Value is a symbol specifying the image type or nil if type cannot
Gerd Moellmann's avatar
Gerd Moellmann committed
203
be determined."
204
  (let ((types image-type-header-regexps)
Gerd Moellmann's avatar
Gerd Moellmann committed
205
	type)
206
    (while types
Gerd Moellmann's avatar
Gerd Moellmann committed
207 208
      (let ((regexp (car (car types)))
	    (image-type (cdr (car types))))
209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247
	(if (or (and (symbolp image-type)
		     (string-match regexp data))
		(and (consp image-type)
		     (funcall (car image-type) data)
		     (setq image-type (cdr image-type))))
	    (setq type image-type
		  types nil)
	  (setq types (cdr types)))))
    type))


;;;###autoload
(defun image-type-from-buffer ()
  "Determine the image type from data in the current buffer.
Value is a symbol specifying the image type or nil if type cannot
be determined."
  (let ((types image-type-header-regexps)
	type
	(opoint (point)))
    (goto-char (point-min))
    (while types
      (let ((regexp (car (car types)))
	    (image-type (cdr (car types)))
	    data)
	(if (or (and (symbolp image-type)
		     (looking-at regexp))
		(and (consp image-type)
		     (funcall (car image-type)
			      (or data
				  (setq data
					(buffer-substring
					 (point-min)
					 (min (point-max)
					      (+ (point-min) 256))))))
		     (setq image-type (cdr image-type))))
	    (setq type image-type
		  types nil)
	  (setq types (cdr types)))))
    (goto-char opoint)
Gerd Moellmann's avatar
Gerd Moellmann committed
248 249 250
    type))


251 252 253 254 255
;;;###autoload
(defun image-type-from-file-header (file)
  "Determine the type of image file FILE from its first few bytes.
Value is a symbol specifying the image type, or nil if type cannot
be determined."
256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279
  (unless (or (file-readable-p file)
	      (file-name-absolute-p file))
    (setq file (image-search-load-path file)))
  (and file
       (file-readable-p file)
       (with-temp-buffer
	 (set-buffer-multibyte nil)
	 (insert-file-contents-literally file nil 0 256)
	 (image-type-from-buffer))))


;;;###autoload
(defun image-type-from-file-name (file)
  "Determine the type of image file FILE from its name.
Value is a symbol specifying the image type, or nil if type cannot
be determined."
  (let ((types image-type-file-name-regexps)
	type)
    (while types
      (if (string-match (car (car types)) file)
	  (setq type (cdr (car types))
		types nil)
	(setq types (cdr types))))
    type))
280 281


Gerd Moellmann's avatar
Gerd Moellmann committed
282 283
;;;###autoload
(defun image-type-available-p (type)
284
  "Return non-nil if image type TYPE is available.
Gerd Moellmann's avatar
Gerd Moellmann committed
285
Image types are symbols like `xbm' or `jpeg'."
286 287
  (and (fboundp 'init-image-library)
       (init-image-library type image-library-alist)))
Gerd Moellmann's avatar
Gerd Moellmann committed
288

289

Gerd Moellmann's avatar
Gerd Moellmann committed
290
;;;###autoload
291 292 293
(defun create-image (file-or-data &optional type data-p &rest props)
  "Create an image.
FILE-OR-DATA is an image file name or image data.
Gerd Moellmann's avatar
Gerd Moellmann committed
294
Optional TYPE is a symbol describing the image type.  If TYPE is omitted
295 296
or nil, try to determine the image type from its first few bytes
of image data.  If that doesn't work, and FILE-OR-DATA is a file name,
297
use its file extension as image type.
298
Optional DATA-P non-nil means FILE-OR-DATA is a string containing image data.
Gerd Moellmann's avatar
Gerd Moellmann committed
299
Optional PROPS are additional image attributes to assign to the image,
Gerd Moellmann's avatar
Gerd Moellmann committed
300
like, e.g. `:mask MASK'.
301 302 303
Value is the image created, or nil if images of type TYPE are not supported.

Images should not be larger than specified by `max-image-size'."
304 305
  (when (and (not data-p) (not (stringp file-or-data)))
    (error "Invalid image file name `%s'" file-or-data))
306 307 308 309 310 311 312 313 314 315 316 317 318 319
  (cond ((null data-p)
	 ;; FILE-OR-DATA is a file name.
	 (unless (or type
		     (setq type (image-type-from-file-header file-or-data)))
	   (let ((extension (file-name-extension file-or-data)))
	     (unless extension
	       (error "Cannot determine image type"))
	     (setq type (intern extension)))))
	(t
	 ;; FILE-OR-DATA contains image data.
	 (unless type
	   (setq type (image-type-from-data file-or-data)))))
  (unless type
    (error "Cannot determine image type"))
Gerd Moellmann's avatar
Gerd Moellmann committed
320
  (unless (symbolp type)
321
    (error "Invalid image type `%s'" type))
Gerd Moellmann's avatar
Gerd Moellmann committed
322
  (when (image-type-available-p type)
323 324
    (append (list 'image :type type (if data-p :data :file) file-or-data)
	    props)))
Gerd Moellmann's avatar
Gerd Moellmann committed
325 326 327


;;;###autoload
328
(defun put-image (image pos &optional string area)
329
  "Put image IMAGE in front of POS in the current buffer.
Gerd Moellmann's avatar
Gerd Moellmann committed
330
IMAGE must be an image created with `create-image' or `defimage'.
331 332
IMAGE is displayed by putting an overlay into the current buffer with a
`before-string' STRING that has a `display' property whose value is the
333
image.  STRING is defaulted if you omit it.
Gerd Moellmann's avatar
Gerd Moellmann committed
334 335 336 337
POS may be an integer or marker.
AREA is where to display the image.  AREA nil or omitted means
display it in the text area, a value of `left-margin' means
display it in the left marginal area, a value of `right-margin'
338
means display it in the right marginal area."
339
  (unless string (setq string "x"))
340
  (let ((buffer (current-buffer)))
341
    (unless (eq (car-safe image) 'image)
342 343 344
      (error "Not an image: %s" image))
    (unless (or (null area) (memq area '(left-margin right-margin)))
      (error "Invalid area %s" area))
345
    (setq string (copy-sequence string))
346
    (let ((overlay (make-overlay pos pos buffer))
347 348
	  (prop (if (null area) image (list (list 'margin area) image))))
      (put-text-property 0 (length string) 'display prop string)
349 350
      (overlay-put overlay 'put-image t)
      (overlay-put overlay 'before-string string))))
Gerd Moellmann's avatar
Gerd Moellmann committed
351 352 353


;;;###autoload
354
(defun insert-image (image &optional string area slice)
Gerd Moellmann's avatar
Gerd Moellmann committed
355
  "Insert IMAGE into current buffer at point.
356
IMAGE is displayed by inserting STRING into the current buffer
357 358
with a `display' property whose value is the image.  STRING is
defaulted if you omit it.
Gerd Moellmann's avatar
Gerd Moellmann committed
359 360 361
AREA is where to display the image.  AREA nil or omitted means
display it in the text area, a value of `left-margin' means
display it in the left marginal area, a value of `right-margin'
362 363 364 365 366 367
means display it in the right marginal area.
SLICE specifies slice of IMAGE to insert.  SLICE nil or omitted
means insert whole image.  SLICE is a list (X Y WIDTH HEIGHT)
specifying the X and Y positions and WIDTH and HEIGHT of image area
to insert.  A float value 0.0 - 1.0 means relative to the width or
height of the image; integer values are taken as pixel values."
368 369 370
  ;; Use a space as least likely to cause trouble when it's a hidden
  ;; character in the buffer.
  (unless string (setq string " "))
371
  (unless (eq (car-safe image) 'image)
Gerd Moellmann's avatar
Gerd Moellmann committed
372 373 374
    (error "Not an image: %s" image))
  (unless (or (null area) (memq area '(left-margin right-margin)))
    (error "Invalid area %s" area))
375 376 377 378 379 380 381 382 383
  (if area
      (setq image (list (list 'margin area) image))
    ;; Cons up a new spec equal but not eq to `image' so that
    ;; inserting it twice in a row (adjacently) displays two copies of
    ;; the image.  Don't try to avoid this by looking at the display
    ;; properties on either side so that we DTRT more often with
    ;; cut-and-paste.  (Yanking killed image text next to another copy
    ;; of it loses anyway.)
    (setq image (cons 'image (cdr image))))
384 385 386
  (let ((start (point)))
    (insert string)
    (add-text-properties start (point)
387 388 389 390 391
			 `(display ,(if slice
					(list (cons 'slice slice) image)
				      image) rear-nonsticky (display)))))


392
;;;###autoload
393
(defun insert-sliced-image (image &optional string area rows cols)
394 395 396 397 398 399 400 401 402
  "Insert IMAGE into current buffer at point.
IMAGE is displayed by inserting STRING into the current buffer
with a `display' property whose value is the image.  STRING is
defaulted if you omit it.
AREA is where to display the image.  AREA nil or omitted means
display it in the text area, a value of `left-margin' means
display it in the left marginal area, a value of `right-margin'
means display it in the right marginal area.
The image is automatically split into ROW x COLS slices."
403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428
  (unless string (setq string " "))
  (unless (eq (car-safe image) 'image)
    (error "Not an image: %s" image))
  (unless (or (null area) (memq area '(left-margin right-margin)))
    (error "Invalid area %s" area))
  (if area
      (setq image (list (list 'margin area) image))
    ;; Cons up a new spec equal but not eq to `image' so that
    ;; inserting it twice in a row (adjacently) displays two copies of
    ;; the image.  Don't try to avoid this by looking at the display
    ;; properties on either side so that we DTRT more often with
    ;; cut-and-paste.  (Yanking killed image text next to another copy
    ;; of it loses anyway.)
    (setq image (cons 'image (cdr image))))
  (let ((x 0.0) (dx (/ 1.0001 (or cols 1)))
	 (y 0.0) (dy (/ 1.0001 (or rows 1))))
    (while (< y 1.0)
      (while (< x 1.0)
	(let ((start (point)))
	  (insert string)
	  (add-text-properties start (point)
			       `(display ,(list (list 'slice x y dx dy) image)
					 rear-nonsticky (display)))
	  (setq x (+ x dx))))
      (setq x 0.0
	    y (+ y dy))
429
      (insert (propertize "\n" 'line-height t)))))
430

431

Gerd Moellmann's avatar
Gerd Moellmann committed
432 433 434 435 436 437 438 439 440 441 442 443

;;;###autoload
(defun remove-images (start end &optional buffer)
  "Remove images between START and END in BUFFER.
Remove only images that were put in BUFFER with calls to `put-image'.
BUFFER nil or omitted means use the current buffer."
  (unless buffer
    (setq buffer (current-buffer)))
  (let ((overlays (overlays-in start end)))
    (while overlays
      (let ((overlay (car overlays)))
	(when (overlay-get overlay 'put-image)
444 445
	  (delete-overlay overlay)))
      (setq overlays (cdr overlays)))))
Gerd Moellmann's avatar
Gerd Moellmann committed
446

447 448 449 450
(defun image-search-load-path (file &optional path)
  (unless path
    (setq path image-load-path))
  (let (element found filename)
451
    (while (and (not found) (consp path))
452
      (setq element (car path))
453
      (cond
454
       ((stringp element)
455 456
	(setq found
	      (file-readable-p
457
	       (setq filename (expand-file-name file element)))))
458 459 460 461 462 463
       ((and (symbolp element) (boundp element))
	(setq element (symbol-value element))
	(cond
	 ((stringp element)
	  (setq found
		(file-readable-p
464
		 (setq filename (expand-file-name file element)))))
465
	 ((consp element)
466
	  (if (setq filename (image-search-load-path file element))
467
	      (setq found t))))))
468
      (setq path (cdr path)))
469
    (if found filename)))
Gerd Moellmann's avatar
Gerd Moellmann committed
470 471

;;;###autoload
Gerd Moellmann's avatar
Gerd Moellmann committed
472 473
(defun find-image (specs)
  "Find an image, choosing one of a list of image specifications.
Gerd Moellmann's avatar
Gerd Moellmann committed
474

475
SPECS is a list of image specifications.
Gerd Moellmann's avatar
Gerd Moellmann committed
476 477 478

Each image specification in SPECS is a property list.  The contents of
a specification are image type dependent.  All specifications must at
479 480 481
least contain the properties `:type TYPE' and either `:file FILE' or
`:data DATA', where TYPE is a symbol specifying the image type,
e.g. `xbm', FILE is the file to load the image from, and DATA is a
482 483 484 485 486
string containing the actual image data.  The specification whose TYPE
is supported, and FILE exists, is used to construct the image
specification to be returned.  Return nil if no specification is
satisfied.

487 488 489
The image is looked for in `image-load-path'.

Image files should not be larger than specified by `max-image-size'."
Gerd Moellmann's avatar
Gerd Moellmann committed
490 491 492 493
  (let (image)
    (while (and specs (null image))
      (let* ((spec (car specs))
	     (type (plist-get spec :type))
494
	     (data (plist-get spec :data))
495 496
	     (file (plist-get spec :file))
	     found)
497 498
	(when (image-type-available-p type)
	  (cond ((stringp file)
499
		 (if (setq found (image-search-load-path file))
500 501 502
		     (setq image
			   (cons 'image (plist-put (copy-sequence spec)
						   :file found)))))
503
		((not (null data))
504 505
		 (setq image (cons 'image spec)))))
	(setq specs (cdr specs))))
Gerd Moellmann's avatar
Gerd Moellmann committed
506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528
    image))


;;;###autoload
(defmacro defimage (symbol specs &optional doc)
  "Define SYMBOL as an image.

SPECS is a list of image specifications.  DOC is an optional
documentation string.

Each image specification in SPECS is a property list.  The contents of
a specification are image type dependent.  All specifications must at
least contain the properties `:type TYPE' and either `:file FILE' or
`:data DATA', where TYPE is a symbol specifying the image type,
e.g. `xbm', FILE is the file to load the image from, and DATA is a
string containing the actual image data.  The first image
specification whose TYPE is supported, and FILE exists, is used to
define SYMBOL.

Example:

   (defimage test-image ((:type xpm :file \"~/test1.xpm\")
                         (:type xbm :file \"~/test1.xbm\")))"
529
  (declare (doc-string 3))
Gerd Moellmann's avatar
Gerd Moellmann committed
530
  `(defvar ,symbol (find-image ',specs) ,doc))
Gerd Moellmann's avatar
Gerd Moellmann committed
531 532 533 534


(provide 'image)

535
;; arch-tag: 8e76a07b-eb48-4f3e-a7a0-1a7ba9f096b3
Dave Love's avatar
Dave Love committed
536
;;; image.el ends here