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)
58 (defun shr-transform-dom (dom)
59 (let ((result (list (pop dom))))
60 (dolist (arg (pop dom))
61 (push (cons (intern (concat ":" (symbol-name (car arg))) obarray)
66 (push (cons :text sub) result)
67 (push (shr-transform-dom sub) result)))
71 (defun shr-insert-document (dom)
72 (let ((shr-state nil))
73 (shr-descend (shr-transform-dom dom))))
75 (defun shr-descend (dom)
76 (let ((function (intern (concat "shr-" (symbol-name (car dom))) obarray)))
77 (if (fboundp function)
78 (funcall function (cdr dom))
79 (shr-generic (cdr dom)))))
81 (defun shr-generic (cont)
85 (shr-insert (cdr sub)))
96 (shr-fontize-cont cont 'bold))
99 (shr-fontize-cont cont 'italic))
102 (shr-fontize-cont cont 'underline))
105 (shr-fontize-cont cont 'strikethru))
107 (defun shr-fontize-cont (cont type)
108 (let ((start (point)))
110 (shr-add-font start (point) type)))
112 (defun shr-add-font (start end type)
113 (let ((overlay (make-overlay start end)))
114 (overlay-put overlay 'face type)))
117 (let ((start (point))
118 (url (cdr (assq :href cont))))
120 (widget-convert-button
122 :action 'shr-browse-url
124 :keymap widget-keymap
127 (defun shr-browse-url (widget &rest stuff)
128 (browse-url (widget-get widget :url)))
130 (defun shr-img (cont)
131 (let ((start (point-marker)))
132 (let ((alt (cdr (assq :alt cont)))
133 (url (cdr (assq :src cont))))
134 (when (zerop (length alt))
137 ((and shr-blocked-images
138 (string-match shr-blocked-images url))
140 ((url-is-cached (browse-url-url-encode-chars url "[&)$ ]"))
141 (shr-put-image (shr-get-image-data url) (point) alt))
144 (url-retrieve url 'shr-image-fetched
145 (list (current-buffer) start (point-marker))
148 (setq shr-state 'image))))
150 (defun shr-image-fetched (status buffer start end)
151 (when (and (buffer-name buffer)
152 (not (plist-get status :error)))
153 (url-store-in-cache (current-buffer))
154 (when (or (search-forward "\n\n" nil t)
155 (search-forward "\r\n\r\n" nil t))
156 (let ((data (buffer-substring (point) (point-max))))
157 (with-current-buffer buffer
158 (let ((alt (buffer-substring start end))
159 (inhibit-read-only t))
160 (delete-region start end)
161 (shr-put-image data start alt))))))
162 (kill-buffer (current-buffer)))
164 (defun shr-put-image (data point alt)
165 (if (not (display-graphic-p))
167 (let ((image (shr-rescale-image data)))
168 (put-image image point alt))))
170 (defun shr-rescale-image (data)
171 (if (or (not (fboundp 'imagemagick-types))
172 (not (get-buffer-window (current-buffer))))
173 (create-image data nil t)
174 (let* ((image (create-image data nil t))
175 (size (image-size image))
178 (edges (window-inside-pixel-edges
179 (get-buffer-window (current-buffer))))
180 (window-width (truncate (* shr-max-image-proportion
181 (- (nth 2 edges) (nth 0 edges)))))
182 (window-height (truncate (* shr-max-image-proportion
183 (- (nth 3 edges) (nth 1 edges)))))
185 (when (> height window-height)
186 (setq image (or (create-image data 'imagemagick t
187 :height window-height)
189 (setq size (image-size image t)))
190 (when (> (car size) window-width)
192 (create-image data 'imagemagick t
197 (defun shr-pre (cont)
198 (let ((shr-folding-mode nil))
201 (shr-ensure-newline)))
203 (defun shr-blockquote (cont)
206 (defun shr-ensure-newline ()
207 (unless (zerop (current-column))
210 (defun shr-insert (text)
211 (when (eq shr-state 'image)
213 (setq shr-state nil))
215 ((eq shr-folding-mode 'none)
219 (dolist (elem (split-string text))
220 (setq column (current-column))
223 (if (> (+ column (length elem) 1) shr-width)
225 (insert " " elem))))))))
227 (defun shr-get-image-data (url)
228 "Get image data for URL.
229 Return a string with image data."
231 (mm-disable-multibyte)
232 (url-cache-extract (url-cache-create-filename url))
233 (when (or (search-forward "\n\n" nil t)
234 (search-forward "\r\n\r\n" nil t))
235 (buffer-substring (point) (point-max)))))