shr.el 8.69 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
;;; shr.el --- Simple HTML Renderer

;; Copyright (C) 2010 Free Software Foundation, Inc.

;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; Keywords: html

;; 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 package takes a HTML parse tree (as provided by
;; libxml-parse-html-region) and renders it in the current buffer.  It
;; does not do CSS, JavaScript or anything advanced: It's geared
;; towards rendering typical short snippets of HTML, like what you'd
;; find in HTML email and the like.

;;; Code:

33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55
(defgroup shr nil
  "Simple HTML Renderer"
  :group 'mail)

(defcustom shr-max-image-proportion 0.9
  "How big pictures displayed are in relation to the window they're in.
A value of 0.7 means that they are allowed to take up 70% of the
width and height of the window.  If they are larger than this,
and Emacs supports it, then the images will be rescaled down to
fit these criteria."
  :version "24.1"
  :group 'shr
  :type 'float)

(defcustom shr-blocked-images nil
  "Images that have URLs matching this regexp will be blocked."
  :version "24.1"
  :group 'shr
  :type 'regexp)

(defvar shr-folding-mode nil)
(defvar shr-state nil)
(defvar shr-start nil)
56
(defvar shr-indentation 0)
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78

(defvar shr-width 70)

(defun shr-transform-dom (dom)
  (let ((result (list (pop dom))))
    (dolist (arg (pop dom))
      (push (cons (intern (concat ":" (symbol-name (car arg))) obarray)
		  (cdr arg))
	    result))
    (dolist (sub dom)
      (if (stringp sub)
	  (push (cons :text sub) result)
	(push (shr-transform-dom sub) result)))
    (nreverse result)))

;;;###autoload
(defun shr-insert-document (dom)
  (let ((shr-state nil)
	(shr-start nil))
    (shr-descend (shr-transform-dom dom))))

(defun shr-descend (dom)
79
  (let ((function (intern (concat "shr-tag-" (symbol-name (car dom))) obarray)))
80 81 82 83 84 85 86 87 88
    (if (fboundp function)
	(funcall function (cdr dom))
      (shr-generic (cdr dom)))))

(defun shr-generic (cont)
  (dolist (sub cont)
    (cond
     ((eq (car sub) :text)
      (shr-insert (cdr sub)))
89
     ((listp (cdr sub))
90 91
      (shr-descend sub)))))

92 93
(defun shr-tag-p (cont)
  (shr-ensure-paragraph)
94
  (shr-generic cont)
95 96 97 98 99 100 101 102 103
  (shr-ensure-paragraph))

(defun shr-ensure-paragraph ()
  (unless (bobp)
    (if (bolp)
	(unless (eql (char-after (- (point) 2)) ?\n)
	  (insert "\n"))
      (if (save-excursion
	    (beginning-of-line)
104
	    (looking-at " *$"))
105 106 107 108
	  (insert "\n")
	(insert "\n\n")))))

(defun shr-tag-b (cont)
109 110
  (shr-fontize-cont cont 'bold))

111
(defun shr-tag-i (cont)
112 113
  (shr-fontize-cont cont 'italic))

114
(defun shr-tag-u (cont)
115 116
  (shr-fontize-cont cont 'underline))

117 118
(defun shr-tag-s (cont)
  (shr-fontize-cont cont 'strike-through))
119

120
(defun shr-fontize-cont (cont &rest types)
121 122
  (let (shr-start)
    (shr-generic cont)
123 124
    (dolist (type types)
      (shr-add-font (or shr-start (point)) (point) type))))
125 126 127 128 129

(defun shr-add-font (start end type)
  (let ((overlay (make-overlay start end)))
    (overlay-put overlay 'face type)))

130
(defun shr-tag-a (cont)
131 132 133 134 135 136 137 138 139 140 141 142 143
  (let ((url (cdr (assq :href cont)))
	shr-start)
    (shr-generic cont)
    (widget-convert-button
     'link shr-start (point)
     :action 'shr-browse-url
     :url url
     :keymap widget-keymap
     :help-echo url)))

(defun shr-browse-url (widget &rest stuff)
  (browse-url (widget-get widget :url)))

144 145 146 147
(defun shr-tag-img (cont)
  (when (and (> (current-column) 0)
	     (not (eq shr-state 'image)))
    (insert "\n"))
148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183
  (let ((start (point-marker)))
    (let ((alt (cdr (assq :alt cont)))
	  (url (cdr (assq :src cont))))
      (when (zerop (length alt))
	(setq alt "[img]"))
      (cond
       ((and shr-blocked-images
	     (string-match shr-blocked-images url))
	(insert alt))
       ((url-is-cached (browse-url-url-encode-chars url "[&)$ ]"))
	(shr-put-image (shr-get-image-data url) (point) alt))
       (t
	(insert alt)
	(url-retrieve url 'shr-image-fetched
		      (list (current-buffer) start (point-marker))
		      t)))
      (insert " ")
      (setq shr-state 'image))))

(defun shr-image-fetched (status buffer start end)
  (when (and (buffer-name buffer)
	     (not (plist-get status :error)))
    (url-store-in-cache (current-buffer))
    (when (or (search-forward "\n\n" nil t)
	      (search-forward "\r\n\r\n" nil t))
      (let ((data (buffer-substring (point) (point-max))))
        (with-current-buffer buffer
          (let ((alt (buffer-substring start end))
		(inhibit-read-only t))
	    (delete-region start end)
	    (shr-put-image data start alt))))))
  (kill-buffer (current-buffer)))

(defun shr-put-image (data point alt)
  (if (not (display-graphic-p))
      (insert alt)
184 185 186 187
    (let ((image (ignore-errors
		   (shr-rescale-image data))))
      (when image
	(put-image image point alt)))))
188 189 190 191 192 193

(defun shr-rescale-image (data)
  (if (or (not (fboundp 'imagemagick-types))
	  (not (get-buffer-window (current-buffer))))
      (create-image data nil t)
    (let* ((image (create-image data nil t))
194
	   (size (image-size image t))
195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215
	   (width (car size))
	   (height (cdr size))
	   (edges (window-inside-pixel-edges
		   (get-buffer-window (current-buffer))))
	   (window-width (truncate (* shr-max-image-proportion
				      (- (nth 2 edges) (nth 0 edges)))))
	   (window-height (truncate (* shr-max-image-proportion
				       (- (nth 3 edges) (nth 1 edges)))))
	   scaled-image)
      (when (> height window-height)
	(setq image (or (create-image data 'imagemagick t
				      :height window-height)
			image))
	(setq size (image-size image t)))
      (when (> (car size) window-width)
	(setq image (or
		     (create-image data 'imagemagick t
				   :width window-width)
		     image)))
      image)))

216
(defun shr-tag-pre (cont)
217
  (let ((shr-folding-mode 'none))
218 219 220 221
    (shr-ensure-newline)
    (shr-generic cont)
    (shr-ensure-newline)))

222 223
(defun shr-tag-blockquote (cont)
  (let ((shr-indentation (+ shr-indentation 4)))
224
    (shr-generic cont)))
225 226 227 228 229 230 231 232 233 234 235

(defun shr-ensure-newline ()
  (unless (zerop (current-column))
    (insert "\n")))

(defun shr-insert (text)
  (when (eq shr-state 'image)
    (insert "\n")
    (setq shr-state nil))
  (cond
   ((eq shr-folding-mode 'none)
236
    (insert text))
237
   (t
238 239
    (let ((first t)
	  column)
240
      (when (and (string-match "\\`[ \t\n]" text)
241 242
		 (not (bolp)))
	(insert " "))
243 244
      (dolist (elem (split-string text))
	(setq column (current-column))
245
	(when (> column 0)
246
	  (cond
247 248 249
	   ((and (or (not first)
		     (eq shr-state 'space))
		 (> (+ column (length elem) 1) shr-width))
250 251 252 253 254 255 256
	    (insert "\n"))
	   ((not first)
	    (insert " "))))
	(setq first nil)
	(when (and (bolp)
		   (> shr-indentation 0))
	  (insert (make-string shr-indentation ? )))
257 258 259 260 261
	;; The shr-start is a special variable that is used to pass
	;; upwards the first point in the buffer where the text really
	;; starts.
	(unless shr-start
	  (setq shr-start (point)))
262
	(insert elem))
263
      (setq shr-state nil)
264
      (when (and (string-match "[ \t\n]\\'" text)
265
		 (not (bolp)))
266 267
	(insert " ")
	(setq shr-state 'space))))))
268 269 270 271 272 273 274 275 276 277 278

(defun shr-get-image-data (url)
  "Get image data for URL.
Return a string with image data."
  (with-temp-buffer
    (mm-disable-multibyte)
    (url-cache-extract (url-cache-create-filename url))
    (when (or (search-forward "\n\n" nil t)
              (search-forward "\r\n\r\n" nil t))
      (buffer-substring (point) (point-max)))))

279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299
(defvar shr-list-mode nil)

(defun shr-tag-ul (cont)
  (shr-ensure-paragraph)
  (let ((shr-list-mode 'ul))
    (shr-generic cont)))

(defun shr-tag-ol (cont)
  (let ((shr-list-mode 1))
    (shr-generic cont)))

(defun shr-tag-li (cont)
  (shr-ensure-newline)
  (if (numberp shr-list-mode)
      (progn
	(insert (format "%d " shr-list-mode))
	(setq shr-list-mode (1+ shr-list-mode)))
    (insert "* "))
  (shr-generic cont))

(defun shr-tag-br (cont)
300 301
  (unless (bobp)
    (insert "\n"))
302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326
  (shr-generic cont))

(defun shr-tag-h1 (cont)
  (shr-heading cont 'bold 'underline))

(defun shr-tag-h2 (cont)
  (shr-heading cont 'bold))

(defun shr-tag-h3 (cont)
  (shr-heading cont 'italic))

(defun shr-tag-h4 (cont)
  (shr-heading cont))

(defun shr-tag-h5 (cont)
  (shr-heading cont))

(defun shr-tag-h6 (cont)
  (shr-heading cont))

(defun shr-heading (cont &rest types)
  (shr-ensure-paragraph)
  (apply #'shr-fontize-cont cont types)
  (shr-ensure-paragraph))

327
(provide 'shr)
328 329

;;; shr.el ends here