eimp-ephemeral.el

;;; eimp-ephemeral.el --- Ephemeral EIMP transforms  -*- lexical-binding: t; -*-

;; Copyright (C) 2016  Aaron Harris

;; Author: Aaron Harris <meerwolf@gmail.com>
;; Keywords: multimedia

;; Dependencies: `eimp', `noflet'

;; This program 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.

;; This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; By default, applying any EIMP transformation to an image marks the
;; image buffer as modified.  This can be inconvenient if you do not
;; want to save the effect of the transformation.  This module
;; provides the wrapper function `eimp-ephemeral-apply'; any EIMP
;; transformation invoked with this function will not mark the image
;; buffer as modified.

;;; Code:

(require 'eimp) 
(require 'noflet)

(defun eimp-ephemeral-process-sentinel (proc msg)
  "Process sentinel for `eimp-ephemeral-apply'.

As `eimp-mogrify-process-sentinel', but do not mark buffer as
modified."
  (eimp-mogrify-process-sentinel proc msg)
  (let ((buf (process-buffer proc)))
    (when (buffer-live-p buf)
      (with-current-buffer buf
        (set-buffer-modified-p nil)))))

(defun eimp-ephemeral-apply (transform &rest args)
  "Apply TRANSFORM to ARGS, without marking buffer as modified."
  (noflet
    ((set-process-sentinel
      (process sentinel)
      (funcall this-fn process #'eimp-ephemeral-process-sentinel)))
    (apply transform args)))

(provide 'eimp-ephemeral)
;;; eimp-ephemeral.el ends here