Add image drag-and-drop and screenshot support to org-mode.

contrib/lisp/org-download.el

@@ -0,0 +1,336 @@
+;;; org-download.el --- Image drag-and-drop for Emacs org-mode
+
+;; Copyright (C) 2014 Free Software Foundation, Inc.
+
+;; Author: Oleh Krehel
+;; Keywords: images, screenshots, download
+;; Homepage: http://orgmode.org
+
+;; 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 <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; This extension facilitates moving images from point A to point B.
+;;
+;; Point A (the source) can be:
+;; 1. An image inside your browser that you can drag to Emacs.
+;; 2. An image on your file system that you can drag to Emacs.
+;; 3. A local or remote image address in kill-ring.
+;;    Use the `org-download-yank' command for this.
+;;    Remember that you can use "0 w" in `dired' to get an address.
+;; 4. An screenshot taken using `gnome-screenshot' or `scrot' or `gm'.
+;;    Use the `org-download-screenshot' command for this.
+;;    Customize the backend with  `org-download-screenshot-method'.
+;;
+;; Point B (the target) is an Emacs `org-mode' buffer where the inline
+;; link will be inserted.  Several customization options will determine
+;; where exactly on the file system the file will be stored.
+;;
+;; They are:
+;; `org-download-method':
+;; a. 'attach => use `org-mode' attachment machinery
+;; b. 'directory => construct the directory in two stages:
+;;    1. first part of the folder name is:
+;;       * either "." (current folder)
+;;       * or `org-download-image-dir' (if it's not nil).
+;;         `org-download-image-dir' becomes buffer-local when set,
+;;         so each file can customize this value, e.g with:
+;;         # -*- mode: Org; org-download-image-dir: ~/Pictures/foo; -*-
+;;    2. second part is:
+;;       * `org-download-heading-lvl' is nil => ""
+;;       * `org-download-heading-lvl' is n => the name of current
+;;         heading with level n. Level count starts with 0,
+;;         i.e. * is 0, ** is 1, *** is 2 etc.
+;;         `org-download-heading-lvl' becomes buffer-local when set,
+;;         so each file can customize this value, e.g with:
+;;         # -*- mode: Org; org-download-heading-lvl: nil; -*-
+;;
+;; `org-download-timestamp':
+;; optionally add a timestamp to the file name.
+;;
+;; Customize `org-download-backend' to choose between `url-retrieve'
+;; (the default) or `wget' or `curl'.
+;;
+;;; Code:
+
+
+(eval-when-compile
+  (require 'cl))
+(require 'url-parse)
+(require 'url-http)
+
+(defgroup org-download nil
+  "Image drag-and-drop for org-mode."
+  :group 'org
+  :prefix "org-download-")
+
+(defcustom org-download-method 'directory
+  "The way images should be stored."
+  :type '(choice
+          (const :tag "Directory" directory)
+          (const :tag "Attachment" attach))
+  :group 'org-download)
+
+(defcustom org-download-image-dir nil
+  "If set, images will be stored in this directory instead of \".\".
+See `org-download--dir-1' for more info."
+  :type '(choice
+          (const :tag "Default" nil)
+          (string :tag "Directory"))
+  :group 'org-download)
+(make-variable-buffer-local 'org-download-image-dir)
+
+(defcustom org-download-heading-lvl 0
+  "Heading level to be used in `org-download--dir-2'."
+  :group 'org-download)
+(make-variable-buffer-local 'org-download-heading-lvl)
+
+(defcustom org-download-backend t
+  "Method to use for downloading."
+  :type '(choice
+          (const :tag "wget" "wget \"%s\" -O \"%s\"")
+          (const :tag "curl" "curl \"%s\" -o \"%s\"")
+          (const :tag "url-retrieve" t))
+  :group 'org-download)
+
+(defcustom org-download-timestamp "_%Y-%m-%d_%H:%M:%S"
+  "This `format-time-string'-style string will be appended to the file name.
+Set this to \"\" if you don't want time stamps."
+  :type 'string
+  :group 'org-download)
+
+(defcustom org-download-screenshot-method "gnome-screenshot -a -f %s"
+  "The tool to capture screenshots."
+  :type '(choice
+          (const :tag "gnome-screenshot" "gnome-screenshot -a -f %s")
+          (const :tag "scrot" "scrot -s %s")
+          (const :tag "gm" "gm import %s"))
+  :group 'org-download)
+
+(defcustom org-download-image-width 0
+  "When non-zero add #+attr_html: :width tag to the image."
+  :type 'integer
+  :group 'org-download)
+
+(defun org-download-get-heading (lvl)
+  "Return the heading of the current entry's LVL level parent."
+  (save-excursion
+    (let ((cur-lvl (org-current-level)))
+      (unless (= cur-lvl 1)
+        (org-up-heading-all (- (1- (org-current-level)) lvl)))
+      (substring-no-properties
+       (org-get-heading)))))
+
+(defun org-download--dir-1 ()
+  "Return the first part of the directory path for `org-download--dir'.
+It's `org-download-image-dir', unless it's nil.  Then it's \".\"."
+  (or org-download-image-dir "."))
+
+(defun org-download--dir-2 ()
+  "Return the second part of the directory path for `org-download--dir'.
+Unless `org-download-heading-lvl' is nil, it's the name of the current
+`org-download-heading-lvl'-leveled heading.  Otherwise it's \"\"."
+  (and org-download-heading-lvl
+       (org-download-get-heading
+        org-download-heading-lvl)))
+
+(defun org-download--dir ()
+  "Return the directory path for image storage.
+
+The path is composed from `org-download--dir-1' and `org-download--dir-2'.
+The directory is created if it didn't exist before."
+  (let* ((part1 (org-download--dir-1))
+         (part2 (org-download--dir-2))
+         (dir (if part2
+                  (format "%s/%s" part1 part2)
+                part1)))
+    (unless (file-exists-p dir)
+      (make-directory dir t))
+    dir))
+
+(defun org-download--fullname (link)
+  "Return the file name where LINK will be saved to.
+
+It's affected by `org-download-timestamp' and `org-download--dir'."
+  (let ((filename
+         (file-name-nondirectory
+          (car (url-path-and-query
+                (url-generic-parse-url link)))))
+        (dir (org-download--dir)))
+    (format "%s/%s%s.%s"
+            dir
+            (file-name-sans-extension filename)
+            (format-time-string org-download-timestamp)
+            (file-name-extension filename))))
+
+(defun org-download--image (link filename)
+  "Save LINK to FILENAME asynchronously and show inline images in current buffer."
+  (when (string-match "^file://\\(.*\\)" link)
+    (setq link (url-unhex-string (match-string 1 link))))
+  (cond ((file-exists-p link)
+         (org-download--image/command "cp \"%s\" \"%s\"" link filename))
+        ((eq org-download-backend t)
+         (org-download--image/url-retrieve link filename))
+        (t
+         (org-download--image/command org-download-backend link filename))))
+
+(defun org-download--image/command (command link filename)
+  "Using COMMAND, save LINK to FILENAME.
+COMMAND is a format-style string with two slots for LINK and FILENAME."
+  (require 'async)
+  (async-start
+   `(lambda() (shell-command
+          ,(format command link
+                   (expand-file-name filename))))
+   (lexical-let ((cur-buf (current-buffer)))
+     (lambda(x)
+       (with-current-buffer cur-buf
+         (org-display-inline-images))))))
+
+(defun org-download--image/url-retrieve (link filename)
+  "Save LINK to FILENAME using `url-retrieve'."
+  (url-retrieve
+   link
+   (lambda (status filename buffer)
+     ;; Write current buffer to FILENAME
+     ;; and update inline images in BUFFER
+     (let ((err (plist-get status :error)))
+       (if err (error
+                "\"%s\" %s" link
+                (downcase (nth 2 (assq (nth 2 err) url-http-codes))))))
+     (delete-region
+      (point-min)
+      (progn
+        (re-search-forward "\n\n" nil 'move)
+        (point)))
+     (let ((coding-system-for-write 'no-conversion))
+       (write-region nil nil filename nil nil nil 'confirm))
+     (with-current-buffer buffer
+       (org-display-inline-images)))
+   (list
+    (expand-file-name filename)
+    (current-buffer))
+   nil t))
+
+(defun org-download-yank ()
+  "Call `org-download-image' with current kill."
+  (interactive)
+  (org-download-image (current-kill 0)))
+
+(defun org-download-screenshot ()
+  "Capture screenshot and insert the resulting file.
+The screenshot tool is determined by `org-download-screenshot-method'."
+  (interactive)
+  (let ((link "/tmp/screenshot.png"))
+    (shell-command (format org-download-screenshot-method link))
+    (org-download-image link)))
+
+(defun org-download-image (link)
+  "Save image at address LINK to `org-download--dir'."
+  (interactive "sUrl: ")
+  (let ((filename
+         (if (eq org-download-method 'attach)
+             (let ((org-download-image-dir (progn (require 'org-attach)
+                                                  (org-attach-dir t)))
+                   org-download-heading-lvl)
+               (org-download--fullname link))
+           (org-download--fullname link))))
+    (when (image-type-from-file-name filename)
+      (org-download--image link filename)
+      (when (eq org-download-method 'attach)
+        (org-attach-attach filename nil 'none))
+      (if (looking-back "^[ \t]+")
+          (delete-region (match-beginning 0) (match-end 0))
+        (newline))
+      (insert (format "#+DOWNLOADED: %s @ %s\n%s [[%s]]"
+                      link
+                      (format-time-string "%Y-%m-%d %H:%M:%S")
+                      (if (= org-download-image-width 0)
+                          ""
+                        (format "#+attr_html: :width %dpx\n" org-download-image-width))
+                      filename))
+      (org-display-inline-images))))
+
+(defun org-download--at-comment-p ()
+  "Check if current line begins with #+DOWLOADED:."
+  (save-excursion
+    (move-beginning-of-line nil)
+    (looking-at "#\\+DOWNLOADED:")))
+
+(defun org-download-delete ()
+  "Delete inline image link on current line, and the file that it points to."
+  (interactive)
+  (cond ((org-download--at-comment-p)
+         (delete-region (line-beginning-position)
+                        (line-end-position))
+         (org-download--delete (line-beginning-position)
+                               nil
+                               1))
+        ((region-active-p)
+         (org-download--delete (region-beginning)
+                               (region-end))
+         (delete-region (region-beginning)
+                        (region-end)))
+
+        (t (org-download--delete (line-beginning-position)
+                                 (line-end-position)))))
+
+(defun org-download--delete (beg end &optional times)
+  "Delete inline image links and the files they point to between BEG and END.
+
+When TIMES isn't nil, delete only TIMES links."
+  (unless times
+    (setq times most-positive-fixnum))
+  (save-excursion
+    (goto-char beg)
+    (while (and (>= (decf times) 0)
+                (re-search-forward "\\[\\[\\([^]]*\\)\\]\\]" end t))
+      (let ((str (match-string-no-properties 1)))
+        (delete-region (match-beginning 0)
+                       (match-end 0))
+        (when (file-exists-p str)
+          (delete-file str))))))
+
+(defun org-download-dnd (uri action)
+  "When in `org-mode' and URI points to image, download it.
+Otherwise, pass URI and ACTION back to dnd dispatch."
+  (if (eq major-mode 'org-mode)
+      ;; probably shouldn't redirect
+      (unless (org-download-image uri)
+        (message "not an image URL"))
+    ;; redirect to someone else
+    (let ((dnd-protocol-alist
+           (rassq-delete-all
+            'org-download-dnd
+            (copy-alist dnd-protocol-alist))))
+      (dnd-handle-one-url nil action uri))))
+
+(defun org-download-enable ()
+  "Enable org-download."
+  (unless (eq (cdr (assoc "^\\(https?\\|ftp\\|file\\|nfs\\)://" dnd-protocol-alist))
+              'org-download-dnd)
+    (setq dnd-protocol-alist
+          `(("^\\(https?\\|ftp\\|file\\|nfs\\)://" . org-download-dnd) ,@dnd-protocol-alist))))
+
+(defun org-download-disable ()
+  "Disable org-download."
+  (rassq-delete-all 'org-download-dnd dnd-protocol-alist))
+
+(org-download-enable)
+
+(provide 'org-download)
+
+;;; org-download.el ends here