lisp/image-mode.el

   1 ;;; image-mode.el --- support for visiting image files
   2 ;;
   3 ;; Copyright (C) 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
   4 ;;
   5 ;; Author: Richard Stallman <rms@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 3, 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., 51 Franklin Street, Fifth Floor,
  23 ;; Boston, MA 02110-1301, USA.
  24
  25 ;;; Commentary:
  26
  27 ;; Defines a major mode for visiting image files
  28 ;; that allows conversion between viewing the text of the file
  29 ;; and viewing the file as an image.  Viewing the image
  30 ;; works by putting a `display' text-property on the
  31 ;; image data, with the image-data still present underneath; if the
  32 ;; resulting buffer file is saved to another name it will correctly save
  33 ;; the image data to the new file.
  34
  35 ;;; Code:
  36
  37 (require 'image)
  38 (eval-when-compile (require 'cl))
  39
  40 ;;;###autoload (push '("\\.jpe?g\\'"    . image-mode) auto-mode-alist)
  41 ;;;###autoload (push '("\\.png\\'"      . image-mode) auto-mode-alist)
  42 ;;;###autoload (push '("\\.gif\\'"      . image-mode) auto-mode-alist)
  43 ;;;###autoload (push '("\\.tiff?\\'"    . image-mode) auto-mode-alist)
  44 ;;;###autoload (push '("\\.p[bpgn]m\\'" . image-mode) auto-mode-alist)
  45
  46 ;;;###autoload (push '("\\.x[bp]m\\'"   . c-mode)     auto-mode-alist)
  47 ;;;###autoload (push '("\\.x[bp]m\\'"   . image-mode-maybe) auto-mode-alist)
  48
  49 ;;;###autoload (push '("\\.svgz?\\'"    . xml-mode)   auto-mode-alist)
  50 ;;;###autoload (push '("\\.svgz?\\'"    . image-mode-maybe) auto-mode-alist)
  51
  52 ;;; Image mode window-info management.
  53
  54 (defvar image-mode-winprops-alist t)
  55 (make-variable-buffer-local 'image-mode-winprops-alist)
  56
  57 (defvar image-mode-new-window-functions nil
  58   "Special hook run when image data is requested in a new window.
  59 It is called with one argument, the initial WINPROPS.")
  60
  61 (defun image-mode-winprops (&optional window)
  62   "Return winprops of WINDOW.
  63 A winprops object has the shape (WINDOW . ALIST)."
  64   (unless window (setq window (selected-window)))
  65   (let ((winprops (assq window image-mode-winprops-alist)))
  66     ;; For new windows, set defaults from the latest.
  67     (unless winprops
  68       (setq winprops (cons window
  69                            (copy-alist (cdar image-mode-winprops-alist))))
  70       (run-hook-with-args 'image-mode-new-window-functions winprops))
  71     ;; Move window to front.
  72     (setq image-mode-winprops-alist
  73           (cons winprops (delq winprops image-mode-winprops-alist)))
  74     winprops))
  75
  76 (defun image-mode-window-get (prop &optional winprops)
  77   (unless (consp winprops) (setq winprops (image-mode-winprops winprops)))
  78   (cdr (assq prop (cdr winprops))))
  79
  80 (defsetf image-mode-window-get (prop &optional winprops) (val)
  81   `(image-mode-window-put ,prop ,val ,winprops))
  82
  83 (defun image-mode-window-put (prop val &optional winprops)
  84   (unless (consp winprops) (setq winprops (image-mode-winprops winprops)))
  85   (setcdr winprops (cons (cons prop val)
  86                          (delq (assq prop (cdr winprops)) (cdr winprops)))))
  87
  88 (defun image-set-window-vscroll (vscroll)
  89   (setf (image-mode-window-get 'vscroll) vscroll)
  90   (set-window-vscroll (selected-window) vscroll))
  91
  92 (defun image-set-window-hscroll (ncol)
  93   (setf (image-mode-window-get 'hscroll) ncol)
  94   (set-window-hscroll (selected-window) ncol))
  95
  96 (defun image-mode-reapply-winprops ()
  97   (walk-windows
  98    (lambda (win)
  99      (with-current-buffer (window-buffer win)
 100        ;; When set-window-buffer, set hscroll and vscroll to what they were
 101        ;; last time the image was displayed in this window.
 102        (when (listp image-mode-winprops-alist)
 103          (let* ((winprops (image-mode-winprops win))
 104                 (hscroll (image-mode-window-get 'hscroll winprops))
 105                 (vscroll (image-mode-window-get 'vscroll winprops)))
 106            (if hscroll (set-window-hscroll win hscroll))
 107            (if vscroll (set-window-vscroll win vscroll))))))
 108    'nomini
 109    (selected-frame)))
 110
 111 (defun image-mode-setup-winprops ()
 112   ;; Record current scroll settings.
 113   (unless (listp image-mode-winprops-alist)
 114     (setq image-mode-winprops-alist nil))
 115   (add-hook 'window-configuration-change-hook
 116             'image-mode-reapply-winprops nil t))
 117
 118 ;;; Image scrolling functions
 119
 120 (defun image-get-display-property ()
 121   (get-char-property (point-min) 'display
 122                      ;; There might be different images for different displays.
 123                      (if (eq (window-buffer) (current-buffer))
 124                          (selected-window))))
 125
 126 (defun image-forward-hscroll (&optional n)
 127   "Scroll image in current window to the left by N character widths.
 128 Stop if the right edge of the image is reached."
 129   (interactive "p")
 130   (cond ((= n 0) nil)
 131         ((< n 0)
 132          (image-set-window-hscroll (max 0 (+ (window-hscroll) n))))
 133         (t
 134          (let* ((image (image-get-display-property))
 135                 (edges (window-inside-edges))
 136                 (win-width (- (nth 2 edges) (nth 0 edges)))
 137                 (img-width (ceiling (car (image-size image)))))
 138            (image-set-window-hscroll (min (max 0 (- img-width win-width))
 139                                           (+ n (window-hscroll))))))))
 140
 141 (defun image-backward-hscroll (&optional n)
 142   "Scroll image in current window to the right by N character widths.
 143 Stop if the left edge of the image is reached."
 144   (interactive "p")
 145   (image-forward-hscroll (- n)))
 146
 147 (defun image-next-line (&optional n)
 148   "Scroll image in current window upward by N lines.
 149 Stop if the bottom edge of the image is reached."
 150   (interactive "p")
 151   (cond ((= n 0) nil)
 152         ((< n 0)
 153          (image-set-window-vscroll (max 0 (+ (window-vscroll) n))))
 154         (t
 155          (let* ((image (image-get-display-property))
 156                 (edges (window-inside-edges))
 157                 (win-height (- (nth 3 edges) (nth 1 edges)))
 158                 (img-height (ceiling (cdr (image-size image)))))
 159            (image-set-window-vscroll (min (max 0 (- img-height win-height))
 160                                           (+ n (window-vscroll))))))))
 161
 162 (defun image-previous-line (&optional n)
 163   "Scroll image in current window downward by N lines.
 164 Stop if the top edge of the image is reached."
 165   (interactive "p")
 166   (image-next-line (- n)))
 167
 168 (defun image-scroll-up (&optional n)
 169   "Scroll image in current window upward by N lines.
 170 Stop if the bottom edge of the image is reached.
 171 If ARG is omitted or nil, scroll upward by a near full screen.
 172 A near full screen is `next-screen-context-lines' less than a full screen.
 173 Negative ARG means scroll downward.
 174 If ARG is the atom `-', scroll downward by nearly full screen.
 175 When calling from a program, supply as argument a number, nil, or `-'."
 176   (interactive "P")
 177   (cond ((null n)
 178          (let* ((edges (window-inside-edges))
 179                 (win-height (- (nth 3 edges) (nth 1 edges))))
 180            (image-next-line
 181             (max 0 (- win-height next-screen-context-lines)))))
 182         ((eq n '-)
 183          (let* ((edges (window-inside-edges))
 184                 (win-height (- (nth 3 edges) (nth 1 edges))))
 185            (image-next-line
 186             (min 0 (- next-screen-context-lines win-height)))))
 187         (t (image-next-line (prefix-numeric-value n)))))
 188
 189 (defun image-scroll-down (&optional n)
 190   "Scroll image in current window downward by N lines.
 191 Stop if the top edge of the image is reached.
 192 If ARG is omitted or nil, scroll downward by a near full screen.
 193 A near full screen is `next-screen-context-lines' less than a full screen.
 194 Negative ARG means scroll upward.
 195 If ARG is the atom `-', scroll upward by nearly full screen.
 196 When calling from a program, supply as argument a number, nil, or `-'."
 197   (interactive "P")
 198   (cond ((null n)
 199          (let* ((edges (window-inside-edges))
 200                 (win-height (- (nth 3 edges) (nth 1 edges))))
 201            (image-next-line
 202             (min 0 (- next-screen-context-lines win-height)))))
 203         ((eq n '-)
 204          (let* ((edges (window-inside-edges))
 205                 (win-height (- (nth 3 edges) (nth 1 edges))))
 206            (image-next-line
 207             (max 0 (- win-height next-screen-context-lines)))))
 208         (t (image-next-line (- (prefix-numeric-value n))))))
 209
 210 (defun image-bol (arg)
 211   "Scroll horizontally to the left edge of the image in the current window.
 212 With argument ARG not nil or 1, move forward ARG - 1 lines first,
 213 stopping if the top or bottom edge of the image is reached."
 214   (interactive "p")
 215   (and arg
 216        (/= (setq arg (prefix-numeric-value arg)) 1)
 217        (image-next-line (- arg 1)))
 218   (image-set-window-hscroll 0))
 219
 220 (defun image-eol (arg)
 221   "Scroll horizontally to the right edge of the image in the current window.
 222 With argument ARG not nil or 1, move forward ARG - 1 lines first,
 223 stopping if the top or bottom edge of the image is reached."
 224   (interactive "p")
 225   (and arg
 226        (/= (setq arg (prefix-numeric-value arg)) 1)
 227        (image-next-line (- arg 1)))
 228   (let* ((image (image-get-display-property))
 229          (edges (window-inside-edges))
 230          (win-width (- (nth 2 edges) (nth 0 edges)))
 231          (img-width (ceiling (car (image-size image)))))
 232     (image-set-window-hscroll (max 0 (- img-width win-width)))))
 233
 234 (defun image-bob ()
 235   "Scroll to the top-left corner of the image in the current window."
 236   (interactive)
 237   (image-set-window-hscroll 0)
 238   (image-set-window-vscroll 0))
 239
 240 (defun image-eob ()
 241   "Scroll to the bottom-right corner of the image in the current window."
 242   (interactive)
 243   (let* ((image (image-get-display-property))
 244          (edges (window-inside-edges))
 245          (win-width (- (nth 2 edges) (nth 0 edges)))
 246          (img-width (ceiling (car (image-size image))))
 247          (win-height (- (nth 3 edges) (nth 1 edges)))
 248          (img-height (ceiling (cdr (image-size image)))))
 249     (image-set-window-hscroll (max 0 (- img-width win-width)))
 250     (image-set-window-vscroll (max 0 (- img-height win-height)))))
 251
 252 ;;; Image Mode setup
 253
 254 (defvar image-type nil
 255   "Current image type.
 256 This variable is used to display the current image type in the mode line.")
 257 (make-variable-buffer-local 'image-type)
 258
 259 (defvar image-mode-map
 260   (let ((map (make-sparse-keymap)))
 261     (define-key map "\C-c\C-c" 'image-toggle-display)
 262     (define-key map [remap forward-char] 'image-forward-hscroll)
 263     (define-key map [remap backward-char] 'image-backward-hscroll)
 264     (define-key map [remap previous-line] 'image-previous-line)
 265     (define-key map [remap next-line] 'image-next-line)
 266     (define-key map [remap scroll-up] 'image-scroll-up)
 267     (define-key map [remap scroll-down] 'image-scroll-down)
 268     (define-key map [remap move-beginning-of-line] 'image-bol)
 269     (define-key map [remap move-end-of-line] 'image-eol)
 270     (define-key map [remap beginning-of-buffer] 'image-bob)
 271     (define-key map [remap end-of-buffer] 'image-eob)
 272     map)
 273   "Major mode keymap for viewing images in Image mode.")
 274
 275 (defvar image-mode-text-map
 276   (let ((map (make-sparse-keymap)))
 277     (define-key map "\C-c\C-c" 'image-toggle-display)
 278     map)
 279   "Major mode keymap for viewing images as text in Image mode.")
 280
 281 (defvar bookmark-make-cell-function)
 282
 283 ;;;###autoload
 284 (defun image-mode ()
 285   "Major mode for image files.
 286 You can use \\<image-mode-map>\\[image-toggle-display]
 287 to toggle between display as an image and display as text."
 288   (interactive)
 289   (kill-all-local-variables)
 290   (setq mode-name "Image[text]")
 291   (setq major-mode 'image-mode)
 292   ;; Use our own bookmarking function for images.
 293   (set (make-local-variable 'bookmark-make-cell-function)
 294        'image-bookmark-make-cell)
 295
 296   ;; Keep track of [vh]scroll when switching buffers
 297   (image-mode-setup-winprops)
 298
 299   (add-hook 'change-major-mode-hook 'image-toggle-display-text nil t)
 300   (if (and (display-images-p)
 301            (not (image-get-display-property)))
 302       (image-toggle-display)
 303     ;; Set next vars when image is already displayed but local
 304     ;; variables were cleared by kill-all-local-variables
 305     (use-local-map image-mode-map)
 306     (setq cursor-type nil truncate-lines t))
 307   (run-mode-hooks 'image-mode-hook)
 308   (if (display-images-p)
 309       (message "%s" (concat
 310                      (substitute-command-keys
 311                       "Type \\[image-toggle-display] to view as ")
 312                      (if (image-get-display-property)
 313                          "text" "an image") "."))))
 314
 315 ;;;###autoload
 316 (define-minor-mode image-minor-mode
 317   "Toggle Image minor mode.
 318 With arg, turn Image minor mode on if arg is positive, off otherwise.
 319 See the command `image-mode' for more information on this mode."
 320   nil (:eval (format " Image[%s]" image-type)) image-mode-text-map
 321   :group 'image
 322   :version "22.1"
 323   (if (not image-minor-mode)
 324       (image-toggle-display-text)
 325     (if (image-get-display-property)
 326         (setq cursor-type nil truncate-lines t)
 327       (setq image-type "text"))
 328     (add-hook 'change-major-mode-hook (lambda () (image-minor-mode -1)) nil t)
 329     (message "%s" (concat (substitute-command-keys
 330                            "Type \\[image-toggle-display] to view the image as ")
 331                           (if (image-get-display-property)
 332                               "text" "an image") "."))))
 333
 334 ;;;###autoload
 335 (defun image-mode-maybe ()
 336   "Set major or minor mode for image files.
 337 Set Image major mode only when there are no other major modes
 338 associated with a filename in `auto-mode-alist'.  When an image
 339 filename matches another major mode in `auto-mode-alist' then
 340 set that major mode and Image minor mode.
 341
 342 See commands `image-mode' and `image-minor-mode' for more
 343 information on these modes."
 344   (interactive)
 345   (let* ((mode-alist
 346           (delq nil (mapcar
 347                      (lambda (elt)
 348                        (unless (memq (or (car-safe (cdr elt)) (cdr elt))
 349                                      '(image-mode image-mode-maybe))
 350                          elt))
 351                      auto-mode-alist))))
 352     (if (assoc-default buffer-file-name mode-alist 'string-match)
 353         (let ((auto-mode-alist mode-alist)
 354               (magic-mode-alist nil))
 355           (set-auto-mode)
 356           (image-minor-mode t))
 357       (image-mode))))
 358
 359 (defun image-toggle-display-text ()
 360   "Showing the text of the image file."
 361   (if (image-get-display-property)
 362       (image-toggle-display)))
 363
 364 (defvar archive-superior-buffer)
 365 (defvar tar-superior-buffer)
 366
 367 (defun image-toggle-display ()
 368   "Start or stop displaying an image file as the actual image.
 369 This command toggles between showing the text of the image file
 370 and showing the image as an image."
 371   (interactive)
 372   (if (image-get-display-property)
 373       (let ((inhibit-read-only t)
 374             (buffer-undo-list t)
 375             (modified (buffer-modified-p)))
 376         (remove-list-of-text-properties (point-min) (point-max)
 377                                         '(display intangible read-nonsticky
 378                                                   read-only front-sticky))
 379         (set-buffer-modified-p modified)
 380         (kill-local-variable 'cursor-type)
 381         (kill-local-variable 'truncate-lines)
 382         (kill-local-variable 'auto-hscroll-mode)
 383         (use-local-map image-mode-text-map)
 384         (setq image-type "text")
 385         (if (eq major-mode 'image-mode)
 386             (setq mode-name "Image[text]"))
 387         (if (called-interactively-p)
 388             (message "Repeat this command to go back to displaying the image")))
 389     ;; Turn the image data into a real image, but only if the whole file
 390     ;; was inserted
 391     (let* ((filename (buffer-file-name))
 392            (data-p (not (and filename
 393                              (file-readable-p filename)
 394                              (not (file-remote-p filename))
 395                              (not (buffer-modified-p))
 396                              (not (and (boundp 'archive-superior-buffer)
 397                                        archive-superior-buffer))
 398                              (not (and (boundp 'tar-superior-buffer)
 399                                        tar-superior-buffer)))))
 400            (file-or-data (if data-p
 401                              (string-make-unibyte
 402                               (buffer-substring-no-properties (point-min) (point-max)))
 403                            filename))
 404            (type (image-type file-or-data nil data-p))
 405            (image (create-image file-or-data type data-p))
 406            (props
 407             `(display ,image
 408                       intangible ,image
 409                       rear-nonsticky (display intangible)
 410                       read-only t front-sticky (read-only)))
 411            (inhibit-read-only t)
 412            (buffer-undo-list t)
 413            (modified (buffer-modified-p)))
 414       (image-refresh image)
 415       (add-text-properties (point-min) (point-max) props)
 416       (set-buffer-modified-p modified)
 417       ;; Inhibit the cursor when the buffer contains only an image,
 418       ;; because cursors look very strange on top of images.
 419       (setq cursor-type nil)
 420       ;; This just makes the arrow displayed in the right fringe
 421       ;; area look correct when the image is wider than the window.
 422       (setq truncate-lines t)
 423       ;; Allow navigation of large images
 424       (set (make-local-variable 'auto-hscroll-mode) nil)
 425       (use-local-map image-mode-map)
 426       (setq image-type type)
 427       (if (eq major-mode 'image-mode)
 428           (setq mode-name (format "Image[%s]" type)))
 429       (if (called-interactively-p)
 430           (message "Repeat this command to go back to displaying the file as text")))))
 431
 432 ;;; Support for bookmark.el
 433
 434 (defun image-bookmark-make-cell (annotation &rest args)
 435   (let ((the-record
 436          `((filename   . ,(buffer-file-name))
 437            (image-type . ,image-type)
 438            (position   . ,(point))
 439            (handler    . image-bookmark-jump))))
 440
 441     ;; Take no chances with text properties
 442     (set-text-properties 0 (length annotation) nil annotation)
 443
 444     (when annotation
 445       (nconc the-record (list (cons 'annotation annotation))))
 446
 447     ;; Finally, return the completed record.
 448     the-record))
 449
 450 (declare-function bookmark-get-filename        "bookmark" (bookmark))
 451 (declare-function bookmark-get-bookmark-record "bookmark" (bookmark))
 452 (declare-function bookmark-get-position        "bookmark" (bookmark))
 453
 454 ;;;###autoload
 455 (defun image-bookmark-jump (bmk)
 456   ;; This implements the `handler' function interface for record type
 457   ;; returned by `bookmark-make-cell-function', which see.
 458   (save-window-excursion
 459     (let ((filename (bookmark-get-filename bmk))
 460           (type (cdr (assq 'image-type (bookmark-get-bookmark-record bmk))))
 461           (pos  (bookmark-get-position bmk)))
 462       (find-file filename)
 463       (when (not (string= image-type type))
 464         (image-toggle-display))
 465       (when (string= image-type "text")
 466         (goto-char pos))
 467       `((buffer ,(current-buffer)) (position ,(point))))))
 468
 469 (provide 'image-mode)
 470
 471 ;; arch-tag: b5b2b7e6-26a7-4b79-96e3-1546b5c4c6cb
 472 ;;; image-mode.el ends here