image.el 13.2 KB
Newer Older
Gerd Moellmann's avatar
Gerd Moellmann committed
1 2
;;; image.el --- image API

3 4
;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003,
;;   2004, 2005 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)


Gerd Moellmann's avatar
Gerd Moellmann committed
36
(defconst image-type-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
(defvar image-load-path
  (list (file-name-as-directory (expand-file-name "images" data-directory))
	data-directory 'load-path)
  "List of locations in which to search for image files.
If an element is a string, it defines a directory to search in.
If an element is a variable symbol, the value of that variable is
used as a list of directories to search.")

60
(defun image-jpeg-p (data)
61 62
  "Value is non-nil if DATA, a string, consists of JFIF image data.
We accept the tag Exif because that is the same format."
63 64 65 66 67 68 69 70 71 72
  (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)
73 74 75
			   (aref data (+ i 2))))
		(code (aref data i)))
	    (when (and (>= code #xe0) (<= code #xef))
76
	      ;; APP0 LEN1 LEN2 "JFIF\0"
77
	      (throw 'jfif
78 79
		     (string-match "JFIF\\|Exif"
				   (substring data i (min (+ i nbytes) len)))))
80
	    (setq i (+ i 1 nbytes))))))))
Gerd Moellmann's avatar
Gerd Moellmann committed
81 82 83


;;;###autoload
84 85 86
(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
87
be determined."
88
  (let ((types image-type-regexps)
Gerd Moellmann's avatar
Gerd Moellmann committed
89 90 91 92
	type)
    (while (and types (null type))
      (let ((regexp (car (car types)))
	    (image-type (cdr (car types))))
93 94 95 96 97
	(when (or (and (symbolp image-type)
		       (string-match regexp data))
		  (and (consp image-type)
		       (funcall (car image-type) data)
		       (setq image-type (cdr image-type))))
Gerd Moellmann's avatar
Gerd Moellmann committed
98 99 100 101 102
	  (setq type image-type))
	(setq types (cdr types))))
    type))


103 104 105 106 107 108 109 110 111
;;;###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."
  (unless (file-name-directory file)
    (setq file (expand-file-name file data-directory)))
  (setq file (expand-file-name file))
  (let ((header (with-temp-buffer
112
		  (set-buffer-multibyte nil)
113 114 115 116 117
		  (insert-file-contents-literally file nil 0 256)
		  (buffer-string))))
    (image-type-from-data header)))


Gerd Moellmann's avatar
Gerd Moellmann committed
118 119
;;;###autoload
(defun image-type-available-p (type)
120
  "Return non-nil if image type TYPE is available.
Gerd Moellmann's avatar
Gerd Moellmann committed
121
Image types are symbols like `xbm' or `jpeg'."
122 123
  (and (fboundp 'init-image-library)
       (init-image-library type image-library-alist)))
Gerd Moellmann's avatar
Gerd Moellmann committed
124 125

;;;###autoload
126 127 128
(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
129
Optional TYPE is a symbol describing the image type.  If TYPE is omitted
130 131
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,
132
use its file extension as image type.
133
Optional DATA-P non-nil means FILE-OR-DATA is a string containing image data.
Gerd Moellmann's avatar
Gerd Moellmann committed
134
Optional PROPS are additional image attributes to assign to the image,
Gerd Moellmann's avatar
Gerd Moellmann committed
135
like, e.g. `:mask MASK'.
Gerd Moellmann's avatar
Gerd Moellmann committed
136
Value is the image created, or nil if images of type TYPE are not supported."
137 138
  (when (and (not data-p) (not (stringp file-or-data)))
    (error "Invalid image file name `%s'" file-or-data))
139 140 141 142 143 144 145 146 147 148 149 150 151 152
  (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
153
  (unless (symbolp type)
154
    (error "Invalid image type `%s'" type))
Gerd Moellmann's avatar
Gerd Moellmann committed
155
  (when (image-type-available-p type)
156 157
    (append (list 'image :type type (if data-p :data :file) file-or-data)
	    props)))
Gerd Moellmann's avatar
Gerd Moellmann committed
158 159 160


;;;###autoload
161
(defun put-image (image pos &optional string area)
162
  "Put image IMAGE in front of POS in the current buffer.
Gerd Moellmann's avatar
Gerd Moellmann committed
163
IMAGE must be an image created with `create-image' or `defimage'.
164 165
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
166
image.  STRING is defaulted if you omit it.
Gerd Moellmann's avatar
Gerd Moellmann committed
167 168 169 170
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'
171
means display it in the right marginal area."
172
  (unless string (setq string "x"))
173
  (let ((buffer (current-buffer)))
174
    (unless (eq (car-safe image) 'image)
175 176 177
      (error "Not an image: %s" image))
    (unless (or (null area) (memq area '(left-margin right-margin)))
      (error "Invalid area %s" area))
178
    (setq string (copy-sequence string))
179
    (let ((overlay (make-overlay pos pos buffer))
180 181
	  (prop (if (null area) image (list (list 'margin area) image))))
      (put-text-property 0 (length string) 'display prop string)
182 183
      (overlay-put overlay 'put-image t)
      (overlay-put overlay 'before-string string))))
Gerd Moellmann's avatar
Gerd Moellmann committed
184 185 186


;;;###autoload
187
(defun insert-image (image &optional string area slice)
Gerd Moellmann's avatar
Gerd Moellmann committed
188
  "Insert IMAGE into current buffer at point.
189
IMAGE is displayed by inserting STRING into the current buffer
190 191
with a `display' property whose value is the image.  STRING is
defaulted if you omit it.
Gerd Moellmann's avatar
Gerd Moellmann committed
192 193 194
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'
195 196 197 198 199 200
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."
201 202 203
  ;; Use a space as least likely to cause trouble when it's a hidden
  ;; character in the buffer.
  (unless string (setq string " "))
204
  (unless (eq (car-safe image) 'image)
Gerd Moellmann's avatar
Gerd Moellmann committed
205 206 207
    (error "Not an image: %s" image))
  (unless (or (null area) (memq area '(left-margin right-margin)))
    (error "Invalid area %s" area))
208 209 210 211 212 213 214 215 216
  (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))))
217 218 219
  (let ((start (point)))
    (insert string)
    (add-text-properties start (point)
220 221 222 223 224
			 `(display ,(if slice
					(list (cons 'slice slice) image)
				      image) rear-nonsticky (display)))))


225
;;;###autoload
226
(defun insert-sliced-image (image &optional string area rows cols)
227 228 229 230 231 232 233 234 235
  "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."
236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261
  (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))
262
      (insert (propertize "\n" 'line-height t)))))
263

264

Gerd Moellmann's avatar
Gerd Moellmann committed
265 266 267 268 269 270 271 272 273 274 275 276

;;;###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)
277 278
	  (delete-overlay overlay)))
      (setq overlays (cdr overlays)))))
Gerd Moellmann's avatar
Gerd Moellmann committed
279

280 281 282 283 284 285 286 287 288 289 290 291 292 293
(defun image-search-load-path (file path)
  (let (found pathname)
    (while (and (not found) (consp path))
      (cond
       ((stringp (car path))
	(setq found
	      (file-readable-p
	       (setq pathname (expand-file-name file (car path))))))
       ((and (symbolp (car path)) (boundp (car path)))
	(if (setq pathname (image-search-load-path
			    file (symbol-value (car path))))
	    (setq found t))))
      (setq path (cdr path)))
    (if found pathname)))
Gerd Moellmann's avatar
Gerd Moellmann committed
294 295

;;;###autoload
Gerd Moellmann's avatar
Gerd Moellmann committed
296 297
(defun find-image (specs)
  "Find an image, choosing one of a list of image specifications.
Gerd Moellmann's avatar
Gerd Moellmann committed
298

299
SPECS is a list of image specifications.
Gerd Moellmann's avatar
Gerd Moellmann committed
300 301 302

Each image specification in SPECS is a property list.  The contents of
a specification are image type dependent.  All specifications must at
303 304 305
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
306 307 308 309 310
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.

311
The image is looked for in `image-load-path'."
Gerd Moellmann's avatar
Gerd Moellmann committed
312 313 314 315
  (let (image)
    (while (and specs (null image))
      (let* ((spec (car specs))
	     (type (plist-get spec :type))
316
	     (data (plist-get spec :data))
317 318
	     (file (plist-get spec :file))
	     found)
319 320
	(when (image-type-available-p type)
	  (cond ((stringp file)
321 322 323 324 325
		 (if (setq found (image-search-load-path
				  file image-load-path))
		     (setq image
			   (cons 'image (plist-put (copy-sequence spec)
						   :file found)))))
326
		((not (null data))
327 328
		 (setq image (cons 'image spec)))))
	(setq specs (cdr specs))))
Gerd Moellmann's avatar
Gerd Moellmann committed
329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352
    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\")))"
  `(defvar ,symbol (find-image ',specs) ,doc))
Gerd Moellmann's avatar
Gerd Moellmann committed
353 354 355 356


(provide 'image)

Miles Bader's avatar
Miles Bader committed
357
;;; arch-tag: 8e76a07b-eb48-4f3e-a7a0-1a7ba9f096b3
Dave Love's avatar
Dave Love committed
358
;;; image.el ends here