Commit 5859e61a authored by Miles Bader's avatar Miles Bader
Browse files

Initial checkin.

parent 3ed36514
;;; image-file.el --- Support for visiting image files
;; Copyright (C) 2000 Free Software Foundation, Inc.
;; Author: Miles Bader <>
;; Keywords: multimedia
;; 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 2, 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
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING. If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Commentary:
;; Defines a file-name-handler hook that transforms visited (or
;; inserted) image files so that they are by displayed as emacs as
;; images. This is done by putting a `display' text-property on the
;; image data, with the image-data still present underneath; if the
;; resulting buffer file is saved to another name it will correctly save
;; the image data to the new file.
;;; Code:
(require 'image)
(defcustom image-file-handler-enabled nil
"True if visiting an image file will actually display the image.
A file is considered an image file if its filename matches one of the
regexps in `image-file-regexps'.
Setting this variable directly does not take effect;
use either \\[customize] or the function `set-image-file-handler-enabled'."
:type 'boolean
:set (lambda (sym val) (set-image-file-handler-enabled val))
:initialize 'custom-initialize-default
:require 'image-file
:group 'image)
(defcustom image-file-regexps
'("\\.png$" "\\.jpeg$" "\\.jpg$" "\\.gif$" "\\.tiff$" "\\.x[bp]m$")
"*A list of regexps matching files that should be displayed as images.
Setting this variable directly does not take effect until the next time
`set-image-file-handler-enabled' is called (which happens automatically
when using \\[customize]."
:type '(repeat regexp)
:set (lambda (sym val)
(set-default sym val)
(when image-file-handler-enabled
;; Re-initialize the image-file handler
(set-image-file-handler-enabled t)))
:initialize 'custom-initialize-default
:group 'image)
(defun insert-image-file (file &optional visit beg end replace)
"Insert the image file FILE into the current buffer.
Optional arguments VISIT, BEG, END, and REPLACE are interpreted as for
the command `insert-file-contents'."
(let ((rval
(image-file-call-underlying #'insert-file-contents-literally
file visit beg end replace)))
(when (and image-file-handler-enabled (or (null beg) (zerop beg)) (null end))
;; Make image into a picture, but only if the whole file was inserted
(let* ((ibeg (point))
(iend (+ (point) (cadr rval)))
(string-make-unibyte (buffer-substring-no-properties ibeg iend)))
(create-image data nil t))
`(display ,image
intangible ,image
rear-nonsticky (display)
;; This a cheap attempt to make the whole buffer
;; read-only when we're visiting the file.
,@(and visit
(= ibeg (point-min))
(= iend (point-max))
'(read-only t front-sticky (read-only))))))
(add-text-properties ibeg iend props)))
(defun image-file-handler (operation &rest args)
"File name handler for inserting image files.
OPERATION is the operation to perform, on ARGS.
See `file-name-handler-alist' for details."
(if (eq operation 'insert-file-contents)
(apply #'insert-image-file args)
;; We don't handle OPERATION, use another handler or the default
(apply #'image-file-call-underlying operation operation args)))
(defun image-file-call-underlying (function operation &rest args)
"Call FUNCTION with `image-file-handler' and OPERATION inhibited.
Optional argument ARGS are the arguments to call FUNCTION with."
(let ((inhibit-file-name-handlers
(cons 'image-file-handler
(and (eq inhibit-file-name-operation operation)
(inhibit-file-name-operation operation))
(apply function args)))
(defun set-image-file-handler-enabled (enabled)
"Enable or disable visiting image files as real images, as per ENABLED.
The regexp in `image-file-regexp' is used to determine which filenames are
considered image files."
;; Remove existing handler
(let ((existing-entry (rassq 'image-file-handler file-name-handler-alist)))
(when existing-entry
(setq file-name-handler-alist
(delq existing-entry file-name-handler-alist))))
;; Add new handler
(when enabled
(let ((regexp
(concat "\\("
(mapconcat 'identity image-file-regexps "\\|")
(setq file-name-handler-alist
(cons (cons regexp 'image-file-handler) file-name-handler-alist))))
(setq-default image-file-handler-enabled enabled))
(defun enable-image-file-handler ()
"Enable visiting image files as real images.
The regexp in `image-file-regexp' is used to determine which filenames are
considered image files."
(set-image-file-handler-enabled t))
(defun disable-image-file-handler ()
"Disable visiting image files as real images."
(set-image-file-handler-enabled nil))
(provide 'image-file)
;;; image-file.el ends here
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