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1 | ;;; image.el --- image API |
2 | ||
3 | ;; Copyright (C) 1998 Free Software Foundation, Inc. | |
4 | ||
5 | ;; This file is part of GNU Emacs. | |
6 | ||
7 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
8 | ;; it under the terms of the GNU General Public License as published by | |
9 | ;; the Free Software Foundation; either version 2, or (at your option) | |
10 | ;; any later version. | |
11 | ||
12 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
13 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | ;; GNU General Public License for more details. | |
16 | ||
17 | ;; You should have received a copy of the GNU General Public License | |
18 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
19 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
20 | ;; Boston, MA 02111-1307, USA. | |
21 | ||
22 | ;;; Commentary: | |
23 | ||
24 | ;;; Code: | |
25 | ||
26 | (defconst image-type-regexps | |
27 | '(("^/\\*.*XPM.\\*/" . xpm) | |
28 | ("^P[1-6]" . pbm) | |
29 | ("^GIF8" . gif) | |
30 | ("JFIF" . jpeg) | |
31 | ("^\211PNG\r\n" . png) | |
32 | ("^#define" . xbm) | |
33 | ("^\\(MM\0\\*\\)\\|\\(II\\*\0\\)" . tiff) | |
34 | ("^%!PS" . ghostscript)) | |
35 | "Alist of (REGEXP . IMAGE-TYPE) pairs used to auto-detect image types. | |
36 | When the first bytes of an image file match REGEXP, it is assumed to | |
37 | be of image type IMAGE-TYPE.") | |
38 | ||
39 | ||
40 | ;;;###autoload | |
41 | (defun image-type-from-file-header (file) | |
42 | "Determine the type of image file FILE from its first few bytes. | |
43 | Value is a symbol specifying the image type, or nil if type cannot | |
44 | be determined." | |
45 | (unless (file-name-directory file) | |
46 | (setq file (concat data-directory file))) | |
47 | (setq file (expand-file-name file)) | |
48 | (let ((header (with-temp-buffer | |
49 | (insert-file-contents-literally file nil 0 256) | |
50 | (buffer-string))) | |
51 | (types image-type-regexps) | |
52 | type) | |
53 | (while (and types (null type)) | |
54 | (let ((regexp (car (car types))) | |
55 | (image-type (cdr (car types)))) | |
56 | (when (string-match regexp header) | |
57 | (setq type image-type)) | |
58 | (setq types (cdr types)))) | |
59 | type)) | |
60 | ||
61 | ||
62 | ;;;###autoload | |
63 | (defun image-type-available-p (type) | |
64 | "Value is non-nil if image type TYPE is available. | |
65 | Image types are symbols like `xbm' or `jpeg'." | |
66 | (not (null (memq type image-types)))) | |
67 | ||
68 | ||
69 | ;;;###autoload | |
70 | (defun create-image (file &optional type &rest props) | |
71 | "Create an image which will be loaded from FILE. | |
72 | Optional TYPE is a symbol describing the image type. If TYPE is omitted | |
73 | or nil, try to determine the image file type from its first few bytes. | |
74 | If that doesn't work, use FILE's extension.as image type. | |
75 | Optional PROPS are additional image attributes to assign to the image, | |
76 | like, e.g. `:heuristic-mask t'. | |
77 | Value is the image created, or nil if images of type TYPE are not supported." | |
78 | (unless (stringp file) | |
79 | (error "Invalid image file name %s" file)) | |
80 | (unless (or type | |
81 | (setq type (image-type-from-file-header file))) | |
82 | (let ((extension (file-name-extension file))) | |
83 | (unless extension | |
84 | (error "Cannot determine image type")) | |
85 | (setq type (intern extension)))) | |
86 | (unless (symbolp type) | |
87 | (error "Invalid image type %s" type)) | |
88 | (when (image-type-available-p type) | |
89 | (append (list 'image :type type :file file) props))) | |
90 | ||
91 | ||
92 | ;;;###autoload | |
93 | (defun put-image (image pos &optional buffer area) | |
94 | "Put image IMAGE in front of POS in BUFFER. | |
95 | IMAGE must be an image created with `create-image' or `defimage'. | |
96 | POS may be an integer or marker. | |
97 | BUFFER nil or omitted means use the current buffer. | |
98 | AREA is where to display the image. AREA nil or omitted means | |
99 | display it in the text area, a value of `left-margin' means | |
100 | display it in the left marginal area, a value of `right-margin' | |
101 | means display it in the right marginal area. | |
102 | IMAGE is displayed by putting an overlay into BUFFER with a | |
103 | `before-string' that has a `display' property whose value is the | |
104 | image." | |
105 | (unless buffer | |
106 | (setq buffer (current-buffer))) | |
107 | (unless (eq (car image) 'image) | |
108 | (error "Not an image: %s" image)) | |
109 | (unless (or (null area) (memq area '(left-margin right-margin))) | |
110 | (error "Invalid area %s" area)) | |
111 | (let ((overlay (make-overlay pos pos buffer)) | |
112 | (string (make-string 1 ?x)) | |
113 | (prop (if (null area) image (cons area image)))) | |
114 | (put-text-property 0 1 'display prop string) | |
115 | (overlay-put overlay 'put-image t) | |
116 | (overlay-put overlay 'before-string string))) | |
117 | ||
118 | ||
119 | ;;;###autoload | |
120 | (defun insert-image (image &optional area) | |
121 | "Insert IMAGE into current buffer at point. | |
122 | AREA is where to display the image. AREA nil or omitted means | |
123 | display it in the text area, a value of `left-margin' means | |
124 | display it in the left marginal area, a value of `right-margin' | |
125 | means display it in the right marginal area. | |
126 | IMAGE is displayed by inserting an \"x\" into the current buffer | |
127 | having a `display' property whose value is the image." | |
128 | (unless (eq (car image) 'image) | |
129 | (error "Not an image: %s" image)) | |
130 | (unless (or (null area) (memq area '(left-margin right-margin))) | |
131 | (error "Invalid area %s" area)) | |
132 | (insert "x") | |
133 | (add-text-properties (1- (point)) (point) | |
134 | (list 'display (if (null area) image (cons area image)) | |
135 | 'rear-nonsticky (list 'display)))) | |
136 | ||
137 | ||
138 | ;;;###autoload | |
139 | (defun remove-images (start end &optional buffer) | |
140 | "Remove images between START and END in BUFFER. | |
141 | Remove only images that were put in BUFFER with calls to `put-image'. | |
142 | BUFFER nil or omitted means use the current buffer." | |
143 | (unless buffer | |
144 | (setq buffer (current-buffer))) | |
145 | (let ((overlays (overlays-in start end))) | |
146 | (while overlays | |
147 | (let ((overlay (car overlays))) | |
148 | (when (overlay-get overlay 'put-image) | |
149 | (delete-overlay overlay) | |
150 | (setq overlays (cdr overlays))))))) | |
151 | ||
152 | ||
153 | ;;;###autoload | |
154 | (defmacro defimage (symbol specs &optional doc) | |
155 | "Define SYMBOL as an image. | |
156 | ||
157 | SPECS is a list of image specifications. DOC is an optional | |
158 | documentation string. | |
159 | ||
160 | Each image specification in SPECS is a property list. The contents of | |
161 | a specification are image type dependent. All specifications must at | |
162 | least contain the properties `:type TYPE' and `:file FILE', where TYPE | |
163 | is a symbol specifying the image type, e.g. `xbm', and FILE is the | |
164 | file to load the image from. The first image specification whose TYPE | |
165 | is supported, and FILE exists, is used to define SYMBOL. | |
166 | ||
167 | Example: | |
168 | ||
169 | (defimage test-image ((:type xpm :file \"~/test1.xpm\") | |
170 | (:type xbm :file \"~/test1.xbm\")))" | |
171 | (let (image) | |
172 | (while (and specs (null image)) | |
173 | (let* ((spec (car specs)) | |
174 | (type (plist-get spec :type)) | |
175 | (file (plist-get spec :file))) | |
176 | (when (and (image-type-available-p type) (stringp file)) | |
177 | (setq file (expand-file-name file)) | |
178 | (unless (file-name-absolute-p file) | |
179 | (setq file (concat data-directory "/" file))) | |
180 | (when (file-exists-p file) | |
181 | (setq image (cons 'image spec)))) | |
182 | (setq specs (cdr specs)))) | |
183 | `(defvar ,symbol ',image ,doc))) | |
184 | ||
185 | ||
186 | (provide 'image) | |
187 | ||
188 | ;; image.el ends here. | |
189 | ||
190 | ||
191 | ||
192 |