image.el 7.09 KB
Newer Older
Gerd Moellmann's avatar
Gerd Moellmann committed
1 2
;;; image.el --- image API

3
;; Copyright (C) 1998, 1999 Free Software Foundation, Inc.
Dave Love's avatar
Dave Love committed
4
;; Keywords: multimedia
Gerd Moellmann's avatar
Gerd Moellmann committed
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74

;; 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
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;;; Code:

(defconst image-type-regexps
  '(("^/\\*.*XPM.\\*/" . xpm)
    ("^P[1-6]" . pbm)
    ("^GIF8" . gif)
    ("JFIF" . jpeg)
    ("^\211PNG\r\n" . png)
    ("^#define" . xbm)
    ("^\\(MM\0\\*\\)\\|\\(II\\*\0\\)" . tiff)
    ("^%!PS" . ghostscript))
  "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
be of image type IMAGE-TYPE.")


;;;###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 (concat data-directory file)))
  (setq file (expand-file-name file))
  (let ((header (with-temp-buffer
		  (insert-file-contents-literally file nil 0 256)
		  (buffer-string)))
	(types image-type-regexps)
	type)
    (while (and types (null type))
      (let ((regexp (car (car types)))
	    (image-type (cdr (car types))))
	(when (string-match regexp header)
	  (setq type image-type))
	(setq types (cdr types))))
    type))


;;;###autoload
(defun image-type-available-p (type)
  "Value is non-nil if image type TYPE is available.
Image types are symbols like `xbm' or `jpeg'."
  (not (null (memq type image-types))))


;;;###autoload
(defun create-image (file &optional type &rest props)
  "Create an image which will be loaded from FILE.
Optional TYPE is a symbol describing the image type.  If TYPE is omitted
or nil, try to determine the image file type from its first few bytes.
75
If that doesn't work, use FILE's extension as image type.
Gerd Moellmann's avatar
Gerd Moellmann committed
76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93
Optional PROPS are additional image attributes to assign to the image,
like, e.g. `:heuristic-mask t'.
Value is the image created, or nil if images of type TYPE are not supported."
  (unless (stringp file)
    (error "Invalid image file name %s" file))
  (unless (or type
	      (setq type (image-type-from-file-header file)))
    (let ((extension (file-name-extension file)))
      (unless extension
	(error "Cannot determine image type"))
      (setq type (intern extension))))
  (unless (symbolp type)
    (error "Invalid image type %s" type))
  (when (image-type-available-p type)
    (append (list 'image :type type :file file) props)))


;;;###autoload
94
(defun put-image (image pos string &optional area)
95
  "Put image IMAGE in front of POS in the current buffer.
Gerd Moellmann's avatar
Gerd Moellmann committed
96
IMAGE must be an image created with `create-image' or `defimage'.
97 98 99
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
image.
Gerd Moellmann's avatar
Gerd Moellmann committed
100 101 102 103
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'
104
means display it in the right marginal area."
105 106 107 108 109
  (let ((buffer (current-buffer)))
    (unless (eq (car image) 'image)
      (error "Not an image: %s" image))
    (unless (or (null area) (memq area '(left-margin right-margin)))
      (error "Invalid area %s" area))
110
    (setq string (copy-sequence string))
111
    (let ((overlay (make-overlay pos pos buffer))
112 113
	  (prop (if (null area) image (list (list 'margin area) image))))
      (put-text-property 0 (length string) 'display prop string)
114 115
      (overlay-put overlay 'put-image t)
      (overlay-put overlay 'before-string string))))
Gerd Moellmann's avatar
Gerd Moellmann committed
116 117 118


;;;###autoload
119
(defun insert-image (image string &optional area)
Gerd Moellmann's avatar
Gerd Moellmann committed
120
  "Insert IMAGE into current buffer at point.
121 122
IMAGE is displayed by inserting STRING into the current buffer
with a `display' property whose value is the image.
Gerd Moellmann's avatar
Gerd Moellmann committed
123 124 125
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'
126
means display it in the right marginal area."
Gerd Moellmann's avatar
Gerd Moellmann committed
127 128 129 130
  (unless (eq (car image) 'image)
    (error "Not an image: %s" image))
  (unless (or (null area) (memq area '(left-margin right-margin)))
    (error "Invalid area %s" area))
131 132 133 134
  (when area
    (setq image (list (list 'margin area) image)))
  (let ((start (point)))
    (insert string)
135 136
    ;; Copy `image' so that inserting it twice in a row (adjacently)
    ;; displays two copies of the image.
137
    (add-text-properties start (point)
138 139
			 (list 'display (copy-sequence image)
			       'intangible (list t) ; something unique
140
			       'rear-nonsticky (list 'display)))))
141

Gerd Moellmann's avatar
Gerd Moellmann committed
142 143 144 145 146 147 148 149 150 151 152 153

;;;###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)
154 155
	  (delete-overlay overlay)))
      (setq overlays (cdr overlays)))))
Gerd Moellmann's avatar
Gerd Moellmann committed
156 157 158 159 160 161 162 163 164 165 166


;;;###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
167 168 169 170 171 172
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.
Gerd Moellmann's avatar
Gerd Moellmann committed
173 174 175 176 177 178 179 180

Example:

   (defimage test-image ((:type xpm :file \"~/test1.xpm\")
                         (:type xbm :file \"~/test1.xbm\")))"
  (let (image)
    (while (and specs (null image))
      (let* ((spec (car specs))
181
	     (data (plist-get spec :data))
Gerd Moellmann's avatar
Gerd Moellmann committed
182 183
	     (type (plist-get spec :type))
	     (file (plist-get spec :file)))
184 185 186 187 188 189 190 191
	(when (and (image-type-available-p type) ; Image type is supported
		   (or data (stringp file))) ; Data or file was specified
	  (if data
	      (setq image (cons 'image spec))
	    (setq file (expand-file-name file data-directory))
	    (when (file-readable-p file)
	      (setq image (cons 'image (plist-put spec :file file)))))
	  (setq specs (cdr specs)))))
Gerd Moellmann's avatar
Gerd Moellmann committed
192 193 194 195 196
    `(defvar ,symbol ',image ,doc)))


(provide 'image)

Dave Love's avatar
Dave Love committed
197
;;; image.el ends here