207 lines
7.5 KiB
EmacsLisp
207 lines
7.5 KiB
EmacsLisp
;;; image-file.el --- support for visiting image files -*- lexical-binding:t -*-
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;;
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;; Copyright (C) 2000-2024 Free Software Foundation, Inc.
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;;
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;; Author: Miles Bader <miles@gnu.org>
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;; Keywords: multimedia
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
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;;; Commentary:
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;; Defines a file-name-handler hook that transforms visited (or
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;; inserted) image files so that they are displayed by Emacs as
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;; images. This is done by putting a `display' text-property on the
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;; image data, with the image-data still present underneath; if the
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;; resulting buffer file is saved to another name it will correctly save
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;; the image data to the new file.
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;;; Code:
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(require 'image)
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(require 'image-converter)
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;;;###autoload
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(defcustom image-file-name-extensions
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(purecopy '("png" "jpeg" "jpg" "gif" "tiff" "tif" "xbm" "xpm" "pbm" "pgm" "ppm" "pnm" "svg" "webp"))
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"A list of image-file filename extensions.
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Filenames having one of these extensions are considered image files,
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in addition to those matching `image-file-name-regexps'.
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See `auto-image-file-mode'; if `auto-image-file-mode' is enabled,
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setting this variable directly does not take effect unless
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`auto-image-file-mode' is re-enabled; this happens automatically when
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the variable is set using \\[customize]."
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:type '(repeat string)
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:set (lambda (sym val)
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(set-default sym val)
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(when auto-image-file-mode
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;; Re-initialize the image-file handler
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(auto-image-file-mode t)))
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:initialize 'custom-initialize-default
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:group 'image)
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;;;###autoload
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(defcustom image-file-name-regexps nil
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"List of regexps matching image-file filenames.
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Filenames matching one of these regexps are considered image files,
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in addition to those with an extension in `image-file-name-extensions'.
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See function `auto-image-file-mode'; if `auto-image-file-mode' is
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enabled, setting this variable directly does not take effect unless
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`auto-image-file-mode' is re-enabled; this happens automatically when
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the variable is set using \\[customize]."
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:type '(repeat regexp)
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:set (lambda (sym val)
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(set-default sym val)
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(when auto-image-file-mode
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;; Re-initialize the image-file handler
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(auto-image-file-mode t)))
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:initialize 'custom-initialize-default
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:group 'image)
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;;;###autoload
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(defun image-file-name-regexp ()
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"Return a regular expression matching image-file filenames."
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(let ((exts-regexp
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(and image-file-name-extensions
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(concat "\\."
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(regexp-opt
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(append (mapcar #'upcase image-file-name-extensions)
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image-file-name-extensions
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(mapcar #'upcase
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image-converter-file-name-extensions)
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image-converter-file-name-extensions)
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t)
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"\\'"))))
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(mapconcat
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#'identity
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(delq nil
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(nconc (list exts-regexp
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(car (rassq 'imagemagick image-type-file-name-regexps)))
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(ensure-list image-file-name-regexps)))
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"\\|")))
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;;;###autoload
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(defun insert-image-file (file &optional visit beg end replace)
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"Insert the image file FILE into the current buffer.
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Optional arguments VISIT, BEG, END, and REPLACE are interpreted
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as for the command `insert-file-contents'. Return list of
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absolute file name and number of characters inserted."
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(let ((rval
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(image-file-call-underlying #'insert-file-contents-literally
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'insert-file-contents
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file visit beg end replace)))
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;; Turn the image data into a real image, but only if the whole file
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;; was inserted
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(when (and (or (null beg) (zerop beg)) (null end))
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(let* ((ibeg (point))
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(iend (+ (point) (cadr rval)))
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(visitingp (and visit (= ibeg (point-min)) (= iend (point-max))))
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(image (create-image (encode-coding-region ibeg iend 'binary t)
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nil t))
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(props
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`(display ,image
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yank-handler
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(image-file-yank-handler nil t)
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intangible ,image
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rear-nonsticky (display intangible)
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;; This a cheap attempt to make the whole buffer
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;; read-only when we're visiting the file (as
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;; opposed to just inserting it).
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,@(and visitingp
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'(read-only t front-sticky (read-only))))))
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(add-text-properties ibeg iend props)
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(when visitingp
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;; Inhibit the cursor when the buffer contains only an image,
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;; because cursors look very strange on top of images.
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(setq cursor-type nil)
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;; This just makes the arrow displayed in the right fringe
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;; area look correct when the image is wider than the window.
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(setq truncate-lines t))))
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rval))
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;; We use a yank-handler to make yanked images unique, so that
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;; yanking two copies of the same image next to each other are
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;; recognized as two different images.
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(defun image-file-yank-handler (string)
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"Yank handler for inserting an image into a buffer."
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(let ((len (length string))
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(image (get-text-property 0 'display string)))
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(if (eq yank-excluded-properties t)
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(set-text-properties 0 len () string)
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(remove-list-of-text-properties 0 len yank-excluded-properties string))
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(if (consp image)
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(add-text-properties 0
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(or (next-single-property-change 0 'image-counter string)
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(length string))
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`(display
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,(cons (car image) (cdr image))
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yank-handler
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,(cons 'image-file-yank-handler '(nil t)))
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string))
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(insert string)))
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(put 'image-file-handler 'safe-magic t)
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(defun image-file-handler (operation &rest args)
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"Filename handler for inserting image files.
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OPERATION is the operation to perform, on ARGS.
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See `file-name-handler-alist' for details."
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(if (and (eq operation 'insert-file-contents)
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auto-image-file-mode)
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(apply #'insert-image-file args)
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;; We don't handle OPERATION, use another handler or the default
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(apply #'image-file-call-underlying operation operation args)))
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(defun image-file-call-underlying (function operation &rest args)
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"Call FUNCTION with `image-file-handler' and OPERATION inhibited.
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Optional argument ARGS are the arguments to call FUNCTION with."
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(let ((inhibit-file-name-handlers
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(cons 'image-file-handler
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(and (eq inhibit-file-name-operation operation)
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inhibit-file-name-handlers)))
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(inhibit-file-name-operation operation))
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(apply function args)))
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;;;###autoload
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(define-minor-mode auto-image-file-mode
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"Toggle visiting of image files as images (Auto Image File mode).
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An image file is one whose name has an extension in
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`image-file-name-extensions', or matches a regexp in
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`image-file-name-regexps'."
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:global t
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:group 'image
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;; Remove existing handler
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(let ((existing-entry
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(rassq 'image-file-handler file-name-handler-alist)))
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(when existing-entry
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(setq file-name-handler-alist
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(delq existing-entry file-name-handler-alist))))
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;; Add new handler, if enabled
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(when auto-image-file-mode
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(push (cons (image-file-name-regexp) 'image-file-handler)
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file-name-handler-alist)))
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(provide 'image-file)
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;;; image-file.el ends here
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