1
2
3
4
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
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
;;; image-converter.el --- Converting images from exotic formats -*- lexical-binding: t -*-
;; Copyright (C) 2019 Free Software Foundation, Inc.
;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; Keywords: images
;; 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 3 of the License, 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. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;; The main interface function here is `image-convert'.
;;; Code:
(require 'cl-generic)
(eval-when-compile (require 'cl-lib))
(defcustom image-converter nil
"Type of the external image converter to use.
The value should a symbol, either `imagemagick', `graphicsmagick',
or `ffmpeg'.
If nil, Emacs will try to find one of the supported converters
installed on the system."
:group 'image
:type 'symbol
:version "27.1")
(defvar image-converter-regexp nil
"A regexp that matches the file name suffixes that can be converted.")
(defvar image-converter--converters
'((graphicsmagick :command ("gm" "convert") :probe ("-list" "format"))
(ffmpeg :command "ffmpeg" :probe "-decoders")
(imagemagick :command "convert" :probe ("-list" "format")))
"List of supported image converters to try.")
(defun image-convert-p (file)
"Return `image-convert' if FILE is an image file that can be converted."
;; Find an installed image converter.
(unless image-converter
(image-converter--find-converter))
(and image-converter
(string-match image-converter-regexp file)
'image-convert))
(defun image-convert (image)
"Convert IMAGE file to the PNG format.
IMAGE can either be a file name, which will make the return value
a string with the image data. It can also be an image object as
returned by `create-image'. If so, it has to be an image object
where created with DATA-P nil (i.e., it has to refer to a file)."
;; Find an installed image converter.
(unless image-converter
(image-converter--find-converter))
(unless image-converter
(error "No external image converters available"))
(when (and (listp image)
(not (plist-get (cdr image) :file)))
(error "Only images that refer to files can be converted"))
(with-temp-buffer
(set-buffer-multibyte nil)
(when-let ((err (image-converter--convert
image-converter
(if (listp image)
(plist-get (cdr image) :file)
image))))
(error "%s" err))
(if (listp image)
;; Return an image object that's the same as we were passed,
;; but ignore the :type and :file values.
(apply #'create-image (buffer-string) 'png t
(cl-loop for (key val) on (cdr image) by #'cddr
unless (memq key '(:type :file))
append (list key val)))
(buffer-string))))
(defun image-converter--value (type elem)
"Return the value of ELEM of image converter TYPE."
(let ((value (plist-get (cdr (assq type image-converter--converters)) elem)))
(if (stringp value)
(list value)
value)))
(cl-defmethod image-converter--probe ((type (eql graphicsmagick)))
"Check whether the system has GraphicsMagick installed."
(with-temp-buffer
(let ((command (image-converter--value type :command))
formats)
(when (zerop (apply #'call-process (car command) nil '(t nil) nil
(append (cdr command)
(image-converter--value type :probe))))
(goto-char (point-min))
(when (re-search-forward "^-" nil t)
(forward-line 1)
;; Lines look like
;; " 8BIM P rw- Photoshop resource format".
(while (re-search-forward "^ *\\([A-Z0-9]+\\) +. +r" nil t)
(push (downcase (match-string 1)) formats)))
(nreverse formats)))))
(cl-defmethod image-converter--probe ((type (eql imagemagick)))
"Check whether the system has ImageMagick installed."
(with-temp-buffer
(let ((command (image-converter--value type :command))
formats)
;; Can't check return value; ImageMagick convert usually returns
;; a non-zero result on "-list format".
(apply #'call-process (car command) nil '(t nil) nil
(append (cdr command) (image-converter--value type :probe)))
(goto-char (point-min))
(when (re-search-forward "^-" nil t)
(forward-line 1)
;; Lines look like
;; " WPG* r-- Word Perfect Graphics".
(while (re-search-forward "^ *\\([A-Z0-9]+\\)\\*? +r" nil t)
(push (downcase (match-string 1)) formats)))
(nreverse formats))))
(cl-defmethod image-converter--probe ((type (eql ffmpeg)))
"Check whether the system has ffmpeg installed."
(with-temp-buffer
(let ((command (image-converter--value type :command))
formats)
(when (zerop (apply #'call-process (car command) nil '(t nil) nil
(append (cdr command)
(image-converter--value type :probe))))
(goto-char (point-min))
(when (re-search-forward "^ *-" nil t)
(forward-line 1)
;; Lines look like
;; " V....D alias_pix Alias/Wavefront PIX image"
(while (re-search-forward "^ *V[^ ]+ +\\([a-z0-9_]+\\)" nil t)
(push (match-string 1) formats)))
(nreverse formats)))))
(defun image-converter--find-converter ()
"Find an installed image converter."
(catch 'done
(dolist (elem image-converter--converters)
(when-let ((formats (image-converter--probe (car elem))))
(setq image-converter (car elem)
image-converter-regexp (concat "\\." (regexp-opt formats) "\\'"))
(throw 'done image-converter)))))
(cl-defmethod image-converter--convert ((type (eql graphicsmagick)) file)
"Convert using GraphicsMagick."
(image-converter--convert-magick type file))
(cl-defmethod image-converter--convert ((type (eql imagemagick)) file)
"Convert using ImageMagick."
(image-converter--convert-magick type file))
(defun image-converter--convert-magick (type file)
(let ((command (image-converter--value type :command)))
(unless (zerop (apply #'call-process (car command)
nil t nil
(append (cdr command)
(list (expand-file-name file) "png:-"))))
;; If the command failed, hopefully the buffer contains the
;; error message.
(buffer-string))))
(cl-defmethod image-converter--convert ((type (eql ffmpeg)) file)
"Convert using ffmpeg."
(let ((command (image-converter--value type :command)))
(unless (zerop (apply #'call-process
(car command)
nil '(t nil) nil
(append (cdr command)
(list "-i" (expand-file-name file)
"-c:v" "png" "-f" "image2pipe" "-"))))
"ffmpeg error when converting")))
(provide 'image-converter)
;;; image-converter.el ends here
|
