(face-italic-p): Return t only for values `italic'
[bpt/emacs.git] / lisp / image.el
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1;;; image.el --- image API
2
3;; Copyright (C) 1998 Free Software Foundation, Inc.
04799cf5 4;; Keywords: multimedia
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5
6;; This file is part of GNU Emacs.
7
8;; GNU Emacs is free software; you can redistribute it and/or modify
9;; it under the terms of the GNU General Public License as published by
10;; the Free Software Foundation; either version 2, or (at your option)
11;; any later version.
12
13;; GNU Emacs is distributed in the hope that it will be useful,
14;; but WITHOUT ANY WARRANTY; without even the implied warranty of
15;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16;; GNU General Public License for more details.
17
18;; You should have received a copy of the GNU General Public License
19;; along with GNU Emacs; see the file COPYING. If not, write to the
20;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21;; Boston, MA 02111-1307, USA.
22
23;;; Commentary:
24
25;;; Code:
26
27(defconst image-type-regexps
28 '(("^/\\*.*XPM.\\*/" . xpm)
29 ("^P[1-6]" . pbm)
30 ("^GIF8" . gif)
31 ("JFIF" . jpeg)
32 ("^\211PNG\r\n" . png)
33 ("^#define" . xbm)
34 ("^\\(MM\0\\*\\)\\|\\(II\\*\0\\)" . tiff)
35 ("^%!PS" . ghostscript))
36 "Alist of (REGEXP . IMAGE-TYPE) pairs used to auto-detect image types.
37When the first bytes of an image file match REGEXP, it is assumed to
38be of image type IMAGE-TYPE.")
39
40
41;;;###autoload
42(defun image-type-from-file-header (file)
43 "Determine the type of image file FILE from its first few bytes.
44Value is a symbol specifying the image type, or nil if type cannot
45be determined."
46 (unless (file-name-directory file)
47 (setq file (concat data-directory file)))
48 (setq file (expand-file-name file))
49 (let ((header (with-temp-buffer
50 (insert-file-contents-literally file nil 0 256)
51 (buffer-string)))
52 (types image-type-regexps)
53 type)
54 (while (and types (null type))
55 (let ((regexp (car (car types)))
56 (image-type (cdr (car types))))
57 (when (string-match regexp header)
58 (setq type image-type))
59 (setq types (cdr types))))
60 type))
61
62
63;;;###autoload
64(defun image-type-available-p (type)
65 "Value is non-nil if image type TYPE is available.
66Image types are symbols like `xbm' or `jpeg'."
67 (not (null (memq type image-types))))
68
69
70;;;###autoload
71(defun create-image (file &optional type &rest props)
72 "Create an image which will be loaded from FILE.
73Optional TYPE is a symbol describing the image type. If TYPE is omitted
74or nil, try to determine the image file type from its first few bytes.
75If that doesn't work, use FILE's extension.as image type.
76Optional PROPS are additional image attributes to assign to the image,
77like, e.g. `:heuristic-mask t'.
78Value is the image created, or nil if images of type TYPE are not supported."
79 (unless (stringp file)
80 (error "Invalid image file name %s" file))
81 (unless (or type
82 (setq type (image-type-from-file-header file)))
83 (let ((extension (file-name-extension file)))
84 (unless extension
85 (error "Cannot determine image type"))
86 (setq type (intern extension))))
87 (unless (symbolp type)
88 (error "Invalid image type %s" type))
89 (when (image-type-available-p type)
90 (append (list 'image :type type :file file) props)))
91
92
93;;;###autoload
94(defun put-image (image pos &optional buffer area)
95 "Put image IMAGE in front of POS in BUFFER.
96IMAGE must be an image created with `create-image' or `defimage'.
97POS may be an integer or marker.
98BUFFER nil or omitted means use the current buffer.
99AREA is where to display the image. AREA nil or omitted means
100display it in the text area, a value of `left-margin' means
101display it in the left marginal area, a value of `right-margin'
102means display it in the right marginal area.
103IMAGE is displayed by putting an overlay into BUFFER with a
104`before-string' that has a `display' property whose value is the
105image."
106 (unless buffer
107 (setq buffer (current-buffer)))
108 (unless (eq (car image) 'image)
109 (error "Not an image: %s" image))
110 (unless (or (null area) (memq area '(left-margin right-margin)))
111 (error "Invalid area %s" area))
112 (let ((overlay (make-overlay pos pos buffer))
113 (string (make-string 1 ?x))
114 (prop (if (null area) image (cons area image))))
115 (put-text-property 0 1 'display prop string)
116 (overlay-put overlay 'put-image t)
117 (overlay-put overlay 'before-string string)))
118
119
120;;;###autoload
121(defun insert-image (image &optional area)
122 "Insert IMAGE into current buffer at point.
123AREA is where to display the image. AREA nil or omitted means
124display it in the text area, a value of `left-margin' means
125display it in the left marginal area, a value of `right-margin'
126means display it in the right marginal area.
127IMAGE is displayed by inserting an \"x\" into the current buffer
128having a `display' property whose value is the image."
129 (unless (eq (car image) 'image)
130 (error "Not an image: %s" image))
131 (unless (or (null area) (memq area '(left-margin right-margin)))
132 (error "Invalid area %s" area))
133 (insert "x")
134 (add-text-properties (1- (point)) (point)
135 (list 'display (if (null area) image (cons area image))
136 'rear-nonsticky (list 'display))))
137
138
139;;;###autoload
140(defun remove-images (start end &optional buffer)
141 "Remove images between START and END in BUFFER.
142Remove only images that were put in BUFFER with calls to `put-image'.
143BUFFER nil or omitted means use the current buffer."
144 (unless buffer
145 (setq buffer (current-buffer)))
146 (let ((overlays (overlays-in start end)))
147 (while overlays
148 (let ((overlay (car overlays)))
149 (when (overlay-get overlay 'put-image)
150 (delete-overlay overlay)
151 (setq overlays (cdr overlays)))))))
152
153
154;;;###autoload
155(defmacro defimage (symbol specs &optional doc)
156 "Define SYMBOL as an image.
157
158SPECS is a list of image specifications. DOC is an optional
159documentation string.
160
161Each image specification in SPECS is a property list. The contents of
162a specification are image type dependent. All specifications must at
163least contain the properties `:type TYPE' and `:file FILE', where TYPE
164is a symbol specifying the image type, e.g. `xbm', and FILE is the
165file to load the image from. The first image specification whose TYPE
166is supported, and FILE exists, is used to define SYMBOL.
167
168Example:
169
170 (defimage test-image ((:type xpm :file \"~/test1.xpm\")
171 (:type xbm :file \"~/test1.xbm\")))"
172 (let (image)
173 (while (and specs (null image))
174 (let* ((spec (car specs))
175 (type (plist-get spec :type))
176 (file (plist-get spec :file)))
177 (when (and (image-type-available-p type) (stringp file))
178 (setq file (expand-file-name file))
179 (unless (file-name-absolute-p file)
180 (setq file (concat data-directory "/" file)))
181 (when (file-exists-p file)
182 (setq image (cons 'image spec))))
183 (setq specs (cdr specs))))
184 `(defvar ,symbol ',image ,doc)))
185
186
187(provide 'image)
188
189 ;; image.el ends here.
190
191
192
193