1 ;;; shr.el --- Simple HTML Renderer
3 ;; Copyright (C) 2010 Free Software Foundation, Inc.
5 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
8 ;; This file is part of GNU Emacs.
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 of the License, or
13 ;; (at your option) any later version.
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.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
25 ;; This package takes a HTML parse tree (as provided by
26 ;; libxml-parse-html-region) and renders it in the current buffer. It
27 ;; does not do CSS, JavaScript or anything advanced: It's geared
28 ;; towards rendering typical short snippets of HTML, like what you'd
29 ;; find in HTML email and the like.
34 "Simple HTML Renderer"
37 (defcustom shr-max-image-proportion 0.9
38 "How big pictures displayed are in relation to the window they're in.
39 A value of 0.7 means that they are allowed to take up 70% of the
40 width and height of the window. If they are larger than this,
41 and Emacs supports it, then the images will be rescaled down to
47 (defcustom shr-blocked-images nil
48 "Images that have URLs matching this regexp will be blocked."
53 (defvar shr-folding-mode nil)
54 (defvar shr-state nil)
55 (defvar shr-start nil)
56 (defvar shr-indentation 0)
60 (defun shr-transform-dom (dom)
61 (let ((result (list (pop dom))))
62 (dolist (arg (pop dom))
63 (push (cons (intern (concat ":" (symbol-name (car arg))) obarray)
68 (push (cons :text sub) result)
69 (push (shr-transform-dom sub) result)))
73 (defun shr-insert-document (dom)
76 (shr-descend (shr-transform-dom dom))))
78 (defun shr-descend (dom)
79 (let ((function (intern (concat "shr-tag-" (symbol-name (car dom))) obarray)))
80 (if (fboundp function)
81 (funcall function (cdr dom))
82 (shr-generic (cdr dom)))))
84 (defun shr-generic (cont)
88 (shr-insert (cdr sub)))
92 (defun shr-tag-p (cont)
93 (shr-ensure-paragraph)
98 (defun shr-ensure-paragraph ()
101 (unless (eql (char-after (- (point) 2)) ?\n)
105 (defun shr-tag-b (cont)
106 (shr-fontize-cont cont 'bold))
108 (defun shr-tag-i (cont)
109 (shr-fontize-cont cont 'italic))
111 (defun shr-tag-u (cont)
112 (shr-fontize-cont cont 'underline))
115 (shr-fontize-cont cont 'strikethru))
117 (defun shr-fontize-cont (cont &rest types)
121 (shr-add-font (or shr-start (point)) (point) type))))
123 (defun shr-add-font (start end type)
124 (let ((overlay (make-overlay start end)))
125 (overlay-put overlay 'face type)))
127 (defun shr-tag-a (cont)
128 (let ((url (cdr (assq :href cont)))
131 (widget-convert-button
132 'link shr-start (point)
133 :action 'shr-browse-url
135 :keymap widget-keymap
138 (defun shr-browse-url (widget &rest stuff)
139 (browse-url (widget-get widget :url)))
141 (defun shr-tag-img (cont)
142 (when (and (plusp (current-column))
143 (not (eq shr-state 'image)))
145 (let ((start (point-marker)))
146 (let ((alt (cdr (assq :alt cont)))
147 (url (cdr (assq :src cont))))
148 (when (zerop (length alt))
151 ((and shr-blocked-images
152 (string-match shr-blocked-images url))
154 ((url-is-cached (browse-url-url-encode-chars url "[&)$ ]"))
155 (shr-put-image (shr-get-image-data url) (point) alt))
158 (url-retrieve url 'shr-image-fetched
159 (list (current-buffer) start (point-marker))
162 (setq shr-state 'image))))
164 (defun shr-image-fetched (status buffer start end)
165 (when (and (buffer-name buffer)
166 (not (plist-get status :error)))
167 (url-store-in-cache (current-buffer))
168 (when (or (search-forward "\n\n" nil t)
169 (search-forward "\r\n\r\n" nil t))
170 (let ((data (buffer-substring (point) (point-max))))
171 (with-current-buffer buffer
172 (let ((alt (buffer-substring start end))
173 (inhibit-read-only t))
174 (delete-region start end)
175 (shr-put-image data start alt))))))
176 (kill-buffer (current-buffer)))
178 (defun shr-put-image (data point alt)
179 (if (not (display-graphic-p))
181 (let ((image (ignore-errors
182 (shr-rescale-image data))))
184 (put-image image point alt)))))
186 (defun shr-rescale-image (data)
187 (if (or (not (fboundp 'imagemagick-types))
188 (not (get-buffer-window (current-buffer))))
189 (create-image data nil t)
190 (let* ((image (create-image data nil t))
191 (size (image-size image t))
194 (edges (window-inside-pixel-edges
195 (get-buffer-window (current-buffer))))
196 (window-width (truncate (* shr-max-image-proportion
197 (- (nth 2 edges) (nth 0 edges)))))
198 (window-height (truncate (* shr-max-image-proportion
199 (- (nth 3 edges) (nth 1 edges)))))
201 (when (> height window-height)
202 (setq image (or (create-image data 'imagemagick t
203 :height window-height)
205 (setq size (image-size image t)))
206 (when (> (car size) window-width)
208 (create-image data 'imagemagick t
213 (defun shr-tag-pre (cont)
214 (let ((shr-folding-mode nil))
217 (shr-ensure-newline)))
219 (defun shr-tag-blockquote (cont)
220 (let ((shr-indentation (+ shr-indentation 4)))
223 (defun shr-ensure-newline ()
224 (unless (zerop (current-column))
227 (defun shr-insert (text)
228 (when (eq shr-state 'image)
230 (setq shr-state nil))
232 ((eq shr-folding-mode 'none)
236 (dolist (elem (split-string text))
237 (setq column (current-column))
239 (if (> (+ column (length elem) 1) shr-width)
243 (plusp shr-indentation))
244 (insert (make-string shr-indentation ? )))
245 ;; The shr-start is a special variable that is used to pass
246 ;; upwards the first point in the buffer where the text really
249 (setq shr-start (point)))
252 (defun shr-get-image-data (url)
253 "Get image data for URL.
254 Return a string with image data."
256 (mm-disable-multibyte)
257 (url-cache-extract (url-cache-create-filename url))
258 (when (or (search-forward "\n\n" nil t)
259 (search-forward "\r\n\r\n" nil t))
260 (buffer-substring (point) (point-max)))))
262 (defvar shr-list-mode nil)
264 (defun shr-tag-ul (cont)
265 (let ((shr-list-mode 'ul))
268 (defun shr-tag-ol (cont)
269 (let ((shr-list-mode 1))
272 (defun shr-tag-li (cont)
274 (if (numberp shr-list-mode)
276 (insert (format "%d " shr-list-mode))
277 (setq shr-list-mode (1+ shr-list-mode)))
281 (defun shr-tag-br (cont)
285 (defun shr-tag-h1 (cont)
286 (shr-heading cont 'bold 'underline))
288 (defun shr-tag-h2 (cont)
289 (shr-heading cont 'bold))
291 (defun shr-tag-h3 (cont)
292 (shr-heading cont 'italic))
294 (defun shr-tag-h4 (cont)
297 (defun shr-tag-h5 (cont)
300 (defun shr-heading (cont &rest types)
301 (shr-ensure-paragraph)
302 (apply #'shr-fontize-cont cont types)
303 (shr-ensure-paragraph))