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1 | ;;; image-file.el --- Support for visiting image files |
2 | ;; | |
3 | ;; Copyright (C) 2000 Free Software Foundation, Inc. | |
4 | ;; | |
5 | ;; Author: Miles Bader <miles@gnu.org> | |
6 | ;; Keywords: multimedia | |
7 | ||
8 | ;; This file is part of GNU Emacs. | |
9 | ||
10 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
11 | ;; it under the terms of the GNU General Public License as published by | |
12 | ;; the Free Software Foundation; either version 2, or (at your option) | |
13 | ;; any later version. | |
14 | ||
15 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
16 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | ;; GNU General Public License for more details. | |
19 | ||
20 | ;; You should have received a copy of the GNU General Public License | |
21 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
22 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
23 | ;; Boston, MA 02111-1307, USA. | |
24 | ||
25 | ;;; Commentary: | |
26 | ||
27 | ;; Defines a file-name-handler hook that transforms visited (or | |
28 | ;; inserted) image files so that they are by displayed as emacs as | |
29 | ;; images. This is done by putting a `display' text-property on the | |
30 | ;; image data, with the image-data still present underneath; if the | |
31 | ;; resulting buffer file is saved to another name it will correctly save | |
32 | ;; the image data to the new file. | |
33 | ||
34 | ;;; Code: | |
35 | ||
36 | (require 'image) | |
37 | ||
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38 | |
39 | (defcustom image-file-name-extensions | |
40 | '("png" "jpeg" "jpg" "gif" "tiff" "xbm" "xpm") | |
41 | "*A list of image-file filename extensions. | |
42 | Filenames having one of these extensions are considered image files, | |
43 | in addition to those matching `image-file-name-regexps'. | |
44 | ||
45 | See `auto-image-file-mode'; if `auto-image-file-mode' is enabled, | |
46 | setting this variable directly does not take effect unless | |
47 | `auto-image-file-mode' is re-enabled; this happens automatically the | |
48 | variable is set using \\[customize]." | |
49 | :type '(repeat string) | |
50 | :set (lambda (sym val) | |
51 | (set-default sym val) | |
52 | (when auto-image-file-mode | |
53 | ;; Re-initialize the image-file handler | |
54 | (auto-image-file-mode t))) | |
5859e61a | 55 | :initialize 'custom-initialize-default |
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56 | :group 'image) |
57 | ||
75e5b373 | 58 | (defcustom image-file-name-regexps nil |
34a19346 | 59 | "*List of regexps matching image-file filenames. |
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60 | Filenames matching one of these regexps are considered image files, |
61 | in addition to those with an extension in `image-file-name-extensions'. | |
5859e61a | 62 | |
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63 | See `auto-image-file-mode'; if `auto-image-file-mode' is enabled, |
64 | setting this variable directly does not take effect unless | |
65 | `auto-image-file-mode' is re-enabled; this happens automatically the | |
66 | variable is set using \\[customize]." | |
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67 | :type '(repeat regexp) |
68 | :set (lambda (sym val) | |
69 | (set-default sym val) | |
75e5b373 | 70 | (when auto-image-file-mode |
5859e61a | 71 | ;; Re-initialize the image-file handler |
75e5b373 | 72 | (auto-image-file-mode t))) |
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73 | :initialize 'custom-initialize-default |
74 | :group 'image) | |
75 | ||
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76 | |
77 | ;;;###autoload | |
78 | (defun image-file-name-regexp () | |
34a19346 | 79 | "Return a regular expression matching image-file filenames." |
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80 | (let ((exts-regexp |
81 | (and image-file-name-extensions | |
82 | (concat "\\." | |
83 | (regexp-opt image-file-name-extensions t) | |
84 | "\\'")))) | |
85 | (if image-file-name-regexps | |
86 | (mapconcat 'identity | |
87 | (if exts-regexp | |
88 | (cons exts-regexp image-file-regexps) | |
89 | image-file-regexps) | |
90 | "\\|") | |
91 | exts-regexp))) | |
92 | ||
93 | ||
94 | ;;;###autoload | |
95 | (define-minor-mode auto-image-file-mode | |
96 | "Toggle visiting of image files as images. | |
97 | With prefix argument ARG, turn on if positive, otherwise off. | |
98 | Returns non-nil if the new state is enabled. | |
99 | ||
100 | Image files are those whose name has an extension in | |
101 | `image-file-name-extensions', or matches a regexp in | |
102 | `image-file-name-regexps'." | |
103 | nil | |
104 | nil | |
105 | nil | |
106 | :global t | |
107 | :group 'image | |
108 | ;; Remove existing handler | |
109 | (let ((existing-entry | |
110 | (rassq 'image-file-handler file-name-handler-alist))) | |
111 | (when existing-entry | |
112 | (setq file-name-handler-alist | |
113 | (delq existing-entry file-name-handler-alist)))) | |
114 | ;; Add new handler, if enabled | |
115 | (when auto-image-file-mode | |
116 | (push (cons (image-file-name-regexp) 'image-file-handler) | |
117 | file-name-handler-alist))) | |
118 | ||
119 | ||
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120 | ;;;###autoload |
121 | (defun insert-image-file (file &optional visit beg end replace) | |
122 | "Insert the image file FILE into the current buffer. | |
123 | Optional arguments VISIT, BEG, END, and REPLACE are interpreted as for | |
124 | the command `insert-file-contents'." | |
125 | (let ((rval | |
126 | (image-file-call-underlying #'insert-file-contents-literally | |
127 | 'insert-file-contents | |
128 | file visit beg end replace))) | |
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129 | ;; Turn the image data into a real image, but only if the whole file |
130 | ;; was inserted | |
131 | (when (and (or (null beg) (zerop beg)) (null end)) | |
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132 | (let* ((ibeg (point)) |
133 | (iend (+ (point) (cadr rval))) | |
134 | (data | |
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135 | (string-make-unibyte |
136 | (buffer-substring-no-properties ibeg iend))) | |
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137 | (image |
138 | (create-image data nil t)) | |
139 | (props | |
140 | `(display ,image | |
141 | intangible ,image | |
142 | rear-nonsticky (display) | |
143 | ;; This a cheap attempt to make the whole buffer | |
144 | ;; read-only when we're visiting the file. | |
145 | ,@(and visit | |
146 | (= ibeg (point-min)) | |
147 | (= iend (point-max)) | |
148 | '(read-only t front-sticky (read-only)))))) | |
149 | (add-text-properties ibeg iend props))) | |
150 | rval)) | |
151 | ||
152 | (defun image-file-handler (operation &rest args) | |
34a19346 | 153 | "Filename handler for inserting image files. |
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154 | OPERATION is the operation to perform, on ARGS. |
155 | See `file-name-handler-alist' for details." | |
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156 | (if (and (eq operation 'insert-file-contents) |
157 | auto-image-file-mode) | |
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158 | (apply #'insert-image-file args) |
159 | ;; We don't handle OPERATION, use another handler or the default | |
160 | (apply #'image-file-call-underlying operation operation args))) | |
161 | ||
162 | (defun image-file-call-underlying (function operation &rest args) | |
163 | "Call FUNCTION with `image-file-handler' and OPERATION inhibited. | |
164 | Optional argument ARGS are the arguments to call FUNCTION with." | |
165 | (let ((inhibit-file-name-handlers | |
166 | (cons 'image-file-handler | |
167 | (and (eq inhibit-file-name-operation operation) | |
168 | inhibit-file-name-handlers))) | |
169 | (inhibit-file-name-operation operation)) | |
170 | (apply function args))) | |
171 | ||
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172 | |
173 | (provide 'image-file) | |
174 | ||
175 | ;;; image-file.el ends here |