lisp/gnus/shr.el

   1 ;;; shr.el --- Simple HTML Renderer
   2
   3 ;; Copyright (C) 2010 Free Software Foundation, Inc.
   4
   5 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   6 ;; Keywords: html
   7
   8 ;; This file is part of GNU Emacs.
   9
  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.
  14
  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.
  19
  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/>.
  22
  23 ;;; Commentary:
  24
  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.
  30
  31 ;;; Code:
  32
  33 (eval-when-compile (require 'cl))
  34 (require 'browse-url)
  35 (unless (aref (char-category-set (make-char 'japanese-jisx0208 33 35)) ?>)
  36   (load "kinsoku" nil t))
  37
  38 (defgroup shr nil
  39   "Simple HTML Renderer"
  40   :group 'mail)
  41
  42 (defcustom shr-max-image-proportion 0.9
  43   "How big pictures displayed are in relation to the window they're in.
  44 A value of 0.7 means that they are allowed to take up 70% of the
  45 width and height of the window.  If they are larger than this,
  46 and Emacs supports it, then the images will be rescaled down to
  47 fit these criteria."
  48   :version "24.1"
  49   :group 'shr
  50   :type 'float)
  51
  52 (defcustom shr-blocked-images nil
  53   "Images that have URLs matching this regexp will be blocked."
  54   :version "24.1"
  55   :group 'shr
  56   :type 'regexp)
  57
  58 (defcustom shr-table-horizontal-line ?-
  59   "Character used to draw horizontal table lines."
  60   :group 'shr
  61   :type 'character)
  62
  63 (defcustom shr-table-vertical-line ?|
  64   "Character used to draw vertical table lines."
  65   :group 'shr
  66   :type 'character)
  67
  68 (defcustom shr-table-corner ?+
  69   "Character used to draw table corners."
  70   :group 'shr
  71   :type 'character)
  72
  73 (defcustom shr-hr-line ?-
  74   "Character used to draw hr lines."
  75   :group 'shr
  76   :type 'character)
  77
  78 (defcustom shr-width fill-column
  79   "Frame width to use for rendering."
  80   :type 'integer
  81   :group 'shr)
  82
  83 (defvar shr-content-function nil
  84   "If bound, this should be a function that will return the content.
  85 This is used for cid: URLs, and the function is called with the
  86 cid: URL as the argument.")
  87
  88 ;;; Internal variables.
  89
  90 (defvar shr-folding-mode nil)
  91 (defvar shr-state nil)
  92 (defvar shr-start nil)
  93 (defvar shr-indentation 0)
  94 (defvar shr-inhibit-images nil)
  95 (defvar shr-list-mode nil)
  96 (defvar shr-content-cache nil)
  97 (defvar shr-kinsoku-shorten nil)
  98 (defvar shr-table-depth 0)
  99
 100 (defvar shr-map
 101   (let ((map (make-sparse-keymap)))
 102     (define-key map "a" 'shr-show-alt-text)
 103     (define-key map "i" 'shr-browse-image)
 104     (define-key map "I" 'shr-insert-image)
 105     (define-key map "u" 'shr-copy-url)
 106     (define-key map "v" 'shr-browse-url)
 107     (define-key map "o" 'shr-save-contents)
 108     (define-key map "\r" 'shr-browse-url)
 109     map))
 110
 111 ;; Public functions and commands.
 112
 113 ;;;###autoload
 114 (defun shr-insert-document (dom)
 115   (setq shr-content-cache nil)
 116   (let ((shr-state nil)
 117         (shr-start nil))
 118     (shr-descend (shr-transform-dom dom))))
 119
 120 (defun shr-copy-url ()
 121   "Copy the URL under point to the kill ring.
 122 If called twice, then try to fetch the URL and see whether it
 123 redirects somewhere else."
 124   (interactive)
 125   (let ((url (get-text-property (point) 'shr-url)))
 126     (cond
 127      ((not url)
 128       (message "No URL under point"))
 129      ;; Resolve redirected URLs.
 130      ((equal url (car kill-ring))
 131       (url-retrieve
 132        url
 133        (lambda (a)
 134          (when (and (consp a)
 135                     (eq (car a) :redirect))
 136            (with-temp-buffer
 137              (insert (cadr a))
 138              (goto-char (point-min))
 139              ;; Remove common tracking junk from the URL.
 140              (when (re-search-forward ".utm_.*" nil t)
 141                (replace-match "" t t))
 142              (message "Copied %s" (buffer-string))
 143              (copy-region-as-kill (point-min) (point-max)))))))
 144      ;; Copy the URL to the kill ring.
 145      (t
 146       (with-temp-buffer
 147         (insert url)
 148         (copy-region-as-kill (point-min) (point-max))
 149         (message "Copied %s" url))))))
 150
 151 (defun shr-show-alt-text ()
 152   "Show the ALT text of the image under point."
 153   (interactive)
 154   (let ((text (get-text-property (point) 'shr-alt)))
 155     (if (not text)
 156         (message "No image under point")
 157       (message "%s" text))))
 158
 159 (defun shr-browse-image ()
 160   "Browse the image under point."
 161   (interactive)
 162   (let ((url (get-text-property (point) 'image-url)))
 163     (if (not url)
 164         (message "No image under point")
 165       (message "Browsing %s..." url)
 166       (browse-url url))))
 167
 168 (defun shr-insert-image ()
 169   "Insert the image under point into the buffer."
 170   (interactive)
 171   (let ((url (get-text-property (point) 'image-url)))
 172     (if (not url)
 173         (message "No image under point")
 174       (message "Inserting %s..." url)
 175       (url-retrieve url 'shr-image-fetched
 176                     (list (current-buffer) (1- (point)) (point-marker))
 177                     t))))
 178
 179 ;;; Utility functions.
 180
 181 (defun shr-transform-dom (dom)
 182   (let ((result (list (pop dom))))
 183     (dolist (arg (pop dom))
 184       (push (cons (intern (concat ":" (symbol-name (car arg))) obarray)
 185                   (cdr arg))
 186             result))
 187     (dolist (sub dom)
 188       (if (stringp sub)
 189           (push (cons 'text sub) result)
 190         (push (shr-transform-dom sub) result)))
 191     (nreverse result)))
 192
 193 (defun shr-descend (dom)
 194   (let ((function (intern (concat "shr-tag-" (symbol-name (car dom))) obarray))
 195         (style (cdr (assq :style (cdr dom))))
 196         (start (point)))
 197     (when (and style
 198                (string-match "color" style))
 199       (setq style (shr-parse-style style)))
 200     (if (fboundp function)
 201         (funcall function (cdr dom))
 202       (shr-generic (cdr dom)))
 203     (when (consp style)
 204       (shr-insert-background-overlay (cdr (assq 'background-color style))
 205                                      start)
 206       (shr-insert-foreground-overlay (cdr (assq 'color style))
 207                                      start (point)))))
 208
 209 (defun shr-generic (cont)
 210   (dolist (sub cont)
 211     (cond
 212      ((eq (car sub) 'text)
 213       (shr-insert (cdr sub)))
 214      ((listp (cdr sub))
 215       (shr-descend sub)))))
 216
 217 (defun shr-insert (text)
 218   (when (and (eq shr-state 'image)
 219              (not (string-match "\\`[ \t\n]+\\'" text)))
 220     (insert "\n")
 221     (setq shr-state nil))
 222   (cond
 223    ((eq shr-folding-mode 'none)
 224     (insert text))
 225    (t
 226     (when (and (string-match "\\`[ \t\n]" text)
 227                (not (bolp))
 228                (not (eq (char-after (1- (point))) ? )))
 229       (insert " "))
 230     (dolist (elem (split-string text))
 231       (when (and (bolp)
 232                  (> shr-indentation 0))
 233         (shr-indent))
 234       ;; The shr-start is a special variable that is used to pass
 235       ;; upwards the first point in the buffer where the text really
 236       ;; starts.
 237       (unless shr-start
 238         (setq shr-start (point)))
 239       ;; No space is needed behind a wide character categorized as
 240       ;; kinsoku-bol, between characters both categorized as nospace,
 241       ;; or at the beginning of a line.
 242       (let (prev)
 243         (when (and (eq (preceding-char) ? )
 244                    (or (= (line-beginning-position) (1- (point)))
 245                        (and (aref fill-find-break-point-function-table
 246                                   (setq prev (char-after (- (point) 2))))
 247                             (aref (char-category-set prev) ?>))
 248                        (and (aref fill-nospace-between-words-table prev)
 249                             (aref fill-nospace-between-words-table
 250                                   (aref elem 0)))))
 251           (delete-char -1)))
 252       (insert elem)
 253       (let (found)
 254         (while (and (> (current-column) shr-width)
 255                     (progn
 256                       (setq found (shr-find-fill-point))
 257                       (not (or (bolp) (eolp)))))
 258           (when (eq (preceding-char) ? )
 259             (delete-char -1))
 260           (insert "\n")
 261           (unless found
 262             (put-text-property (1- (point)) (point) 'shr-break t)
 263             ;; No space is needed at the beginning of a line.
 264             (when (eq (following-char) ? )
 265               (delete-char 1)))
 266           (when (> shr-indentation 0)
 267             (shr-indent))
 268           (end-of-line))
 269         (insert " ")))
 270     (unless (string-match "[ \t\n]\\'" text)
 271       (delete-char -1)))))
 272
 273 (defun shr-find-fill-point ()
 274   (when (> (move-to-column shr-width) shr-width)
 275     (backward-char 1))
 276   (let (failed)
 277     (while (not
 278             (or (setq failed (= (current-column) shr-indentation))
 279                 (eq (preceding-char) ? )
 280                 (eq (following-char) ? )
 281                 (aref fill-find-break-point-function-table (preceding-char))))
 282       (backward-char 1))
 283     (if failed
 284         ;; There's no breakable point, so we give it up.
 285         (progn
 286           (end-of-line)
 287           (while (aref fill-find-break-point-function-table (preceding-char))
 288             (backward-char 1))
 289           nil)
 290       (or (eolp)
 291           ;; Don't put kinsoku-bol characters at the beginning of a line,
 292           ;; or kinsoku-eol characters at the end of a line,
 293           (let ((count 4))
 294             (if (or shr-kinsoku-shorten
 295                     (and (aref (char-category-set (preceding-char)) ?<)
 296                          (progn
 297                            (setq count (1- count))
 298                            (backward-char 1)
 299                            t)))
 300                 (while (and
 301                         (>= (setq count (1- count)) 0)
 302                         (not (memq (preceding-char) (list ?\C-@ ?\n ? )))
 303                         (or (aref (char-category-set (preceding-char)) ?<)
 304                             (aref (char-category-set (following-char)) ?>)))
 305                   (backward-char 1))
 306               (while (and (>= (setq count (1- count)) 0)
 307                           (aref (char-category-set (following-char)) ?>)
 308                           (aref fill-find-break-point-function-table
 309                                 (following-char)))
 310                 (forward-char 1)))
 311             (when (eq (following-char) ? )
 312               (forward-char 1))
 313             t)))))
 314
 315 (defun shr-ensure-newline ()
 316   (unless (zerop (current-column))
 317     (insert "\n")))
 318
 319 (defun shr-ensure-paragraph ()
 320   (unless (bobp)
 321     (if (<= (current-column) shr-indentation)
 322         (unless (save-excursion
 323                   (forward-line -1)
 324                   (looking-at " *$"))
 325           (insert "\n"))
 326       (if (save-excursion
 327             (beginning-of-line)
 328             (looking-at " *$"))
 329           (insert "\n")
 330         (insert "\n\n")))))
 331
 332 (defun shr-indent ()
 333   (when (> shr-indentation 0)
 334     (insert (make-string shr-indentation ? ))))
 335
 336 (defun shr-fontize-cont (cont &rest types)
 337   (let (shr-start)
 338     (shr-generic cont)
 339     (dolist (type types)
 340       (shr-add-font (or shr-start (point)) (point) type))))
 341
 342 ;; Add an overlay in the region, but avoid putting the font properties
 343 ;; on blank text at the start of the line, and the newline at the end,
 344 ;; to avoid ugliness.
 345 (defun shr-add-font (start end type)
 346   (save-excursion
 347     (goto-char start)
 348     (while (< (point) end)
 349       (when (bolp)
 350         (skip-chars-forward " "))
 351       (let ((overlay (make-overlay (point) (min (line-end-position) end))))
 352         (overlay-put overlay 'face type))
 353       (if (< (line-end-position) end)
 354           (forward-line 1)
 355         (goto-char end)))))
 356
 357 (defun shr-browse-url ()
 358   "Browse the URL under point."
 359   (interactive)
 360   (let ((url (get-text-property (point) 'shr-url)))
 361     (cond
 362      ((not url)
 363       (message "No link under point"))
 364      ((string-match "^mailto:" url)
 365       (browse-url-mailto url))
 366      (t
 367       (browse-url url)))))
 368
 369 (defun shr-save-contents (directory)
 370   "Save the contents from URL in a file."
 371   (interactive "DSave contents of URL to directory: ")
 372   (let ((url (get-text-property (point) 'shr-url)))
 373     (if (not url)
 374         (message "No link under point")
 375       (url-retrieve (shr-encode-url url)
 376                     'shr-store-contents (list url directory)))))
 377
 378 (defun shr-store-contents (status url directory)
 379   (unless (plist-get status :error)
 380     (when (or (search-forward "\n\n" nil t)
 381               (search-forward "\r\n\r\n" nil t))
 382       (write-region (point) (point-max)
 383                     (expand-file-name (file-name-nondirectory url)
 384                                       directory)))))
 385
 386 (defun shr-image-fetched (status buffer start end)
 387   (when (and (buffer-name buffer)
 388              (not (plist-get status :error)))
 389     (url-store-in-cache (current-buffer))
 390     (when (or (search-forward "\n\n" nil t)
 391               (search-forward "\r\n\r\n" nil t))
 392       (let ((data (buffer-substring (point) (point-max))))
 393         (with-current-buffer buffer
 394           (let ((alt (buffer-substring start end))
 395                 (inhibit-read-only t))
 396             (delete-region start end)
 397             (goto-char start)
 398             (shr-put-image data alt))))))
 399   (kill-buffer (current-buffer)))
 400
 401 (defun shr-put-image (data alt)
 402   (if (display-graphic-p)
 403       (let ((image (ignore-errors
 404                      (shr-rescale-image data))))
 405         (when image
 406           ;; When inserting big-ish pictures, put them at the
 407           ;; beginning of the line.
 408           (when (and (> (current-column) 0)
 409                      (> (car (image-size image t)) 400))
 410             (insert "\n"))
 411           (insert-image image (or alt "*"))))
 412     (insert alt)))
 413
 414 (defun shr-rescale-image (data)
 415   (if (or (not (fboundp 'imagemagick-types))
 416           (not (get-buffer-window (current-buffer))))
 417       (create-image data nil t)
 418     (let* ((image (create-image data nil t))
 419            (size (image-size image t))
 420            (width (car size))
 421            (height (cdr size))
 422            (edges (window-inside-pixel-edges
 423                    (get-buffer-window (current-buffer))))
 424            (window-width (truncate (* shr-max-image-proportion
 425                                       (- (nth 2 edges) (nth 0 edges)))))
 426            (window-height (truncate (* shr-max-image-proportion
 427                                        (- (nth 3 edges) (nth 1 edges)))))
 428            scaled-image)
 429       (when (> height window-height)
 430         (setq image (or (create-image data 'imagemagick t
 431                                       :height window-height)
 432                         image))
 433         (setq size (image-size image t)))
 434       (when (> (car size) window-width)
 435         (setq image (or
 436                      (create-image data 'imagemagick t
 437                                    :width window-width)
 438                      image)))
 439       image)))
 440
 441 ;; url-cache-extract autoloads url-cache.
 442 (declare-function url-cache-create-filename "url-cache" (url))
 443 (autoload 'mm-disable-multibyte "mm-util")
 444 (autoload 'browse-url-mailto "browse-url")
 445
 446 (defun shr-get-image-data (url)
 447   "Get image data for URL.
 448 Return a string with image data."
 449   (with-temp-buffer
 450     (mm-disable-multibyte)
 451     (when (ignore-errors
 452             (url-cache-extract (url-cache-create-filename (shr-encode-url url)))
 453             t)
 454       (when (or (search-forward "\n\n" nil t)
 455                 (search-forward "\r\n\r\n" nil t))
 456         (buffer-substring (point) (point-max))))))
 457
 458 (defun shr-image-displayer (content-function)
 459   "Return a function to display an image.
 460 CONTENT-FUNCTION is a function to retrieve an image for a cid url that
 461 is an argument.  The function to be returned takes three arguments URL,
 462 START, and END."
 463   `(lambda (url start end)
 464      (when url
 465        (if (string-match "\\`cid:" url)
 466            ,(when content-function
 467               `(let ((image (funcall ,content-function
 468                                      (substring url (match-end 0)))))
 469                  (when image
 470                    (goto-char start)
 471                    (shr-put-image image
 472                                   (prog1
 473                                       (buffer-substring-no-properties start end)
 474                                     (delete-region start end))))))
 475          (url-retrieve url 'shr-image-fetched
 476                        (list (current-buffer) start end)
 477                        t)))))
 478
 479 (defun shr-heading (cont &rest types)
 480   (shr-ensure-paragraph)
 481   (apply #'shr-fontize-cont cont types)
 482   (shr-ensure-paragraph))
 483
 484 (autoload 'widget-convert-button "wid-edit")
 485
 486 (defun shr-urlify (start url)
 487   (widget-convert-button
 488    'url-link start (point)
 489    :help-echo url
 490    :keymap shr-map
 491    url)
 492   (put-text-property start (point) 'shr-url url))
 493
 494 (defun shr-encode-url (url)
 495   "Encode URL."
 496   (browse-url-url-encode-chars url "[)$ ]"))
 497
 498 (autoload 'shr-color-visible "shr-color")
 499 (autoload 'shr-color->hexadecimal "shr-color")
 500
 501 (defun shr-color-check (fg bg)
 502   "Check that FG is visible on BG.
 503 Returns (fg bg) with corrected values.
 504 Returns nil if the colors that would be used are the default
 505 ones, in case fg and bg are nil."
 506   (when (or fg bg)
 507     (let ((fixed (cond ((null fg) 'fg)
 508                        ((null bg) 'bg))))
 509       ;; Convert colors to hexadecimal, or set them to default.
 510       (let ((fg (or (shr-color->hexadecimal fg)
 511                     (frame-parameter nil 'foreground-color)))
 512             (bg (or (shr-color->hexadecimal bg)
 513                     (frame-parameter nil 'background-color))))
 514         (cond ((eq fixed 'bg)
 515                ;; Only return the new fg
 516                (list nil (cadr (shr-color-visible bg fg t))))
 517               ((eq fixed 'fg)
 518                ;; Invert args and results and return only the new bg
 519                (list (cadr (shr-color-visible fg bg t)) nil))
 520               (t
 521                (shr-color-visible bg fg)))))))
 522
 523 (defun shr-get-background (pos)
 524   "Return background color at POS."
 525   (dolist (overlay (overlays-in pos (1+ pos)))
 526     (let ((background (plist-get (overlay-get overlay 'face)
 527                                  :background)))
 528       (when background
 529         (return background)))))
 530
 531 (defun shr-insert-foreground-overlay (fg start end)
 532   (when fg
 533     (let ((bg (shr-get-background start)))
 534       (let ((new-colors (shr-color-check fg bg)))
 535         (when new-colors
 536           (overlay-put (make-overlay start end) 'face
 537                        (list :foreground (cadr new-colors))))))))
 538
 539 (defun shr-insert-background-overlay (bg start)
 540   "Insert an overlay with background color BG at START.
 541 The overlay has rear-advance set to t, so it will be used when
 542 text will be inserted at start."
 543   (when bg
 544     (let ((new-colors (shr-color-check nil bg)))
 545       (when new-colors
 546         (overlay-put (make-overlay start start nil nil t) 'face
 547                      (list :background (car new-colors)))))))
 548
 549 ;;; Tag-specific rendering rules.
 550
 551 (defun shr-tag-body (cont)
 552   (let ((start (point))
 553         (fgcolor (cdr (assq :fgcolor cont)))
 554         (bgcolor (cdr (assq :bgcolor cont))))
 555     (shr-insert-background-overlay bgcolor start)
 556     (shr-generic cont)
 557     (shr-insert-foreground-overlay fgcolor start (point))))
 558
 559 (defun shr-tag-p (cont)
 560   (shr-ensure-paragraph)
 561   (shr-indent)
 562   (shr-generic cont)
 563   (shr-ensure-paragraph))
 564
 565 (defun shr-tag-div (cont)
 566   (shr-ensure-newline)
 567   (shr-indent)
 568   (shr-generic cont)
 569   (shr-ensure-newline))
 570
 571 (defun shr-tag-b (cont)
 572   (shr-fontize-cont cont 'bold))
 573
 574 (defun shr-tag-i (cont)
 575   (shr-fontize-cont cont 'italic))
 576
 577 (defun shr-tag-em (cont)
 578   (shr-fontize-cont cont 'bold))
 579
 580 (defun shr-tag-strong (cont)
 581   (shr-fontize-cont cont 'bold))
 582
 583 (defun shr-tag-u (cont)
 584   (shr-fontize-cont cont 'underline))
 585
 586 (defun shr-tag-s (cont)
 587   (shr-fontize-cont cont 'strike-through))
 588
 589 (defun shr-parse-style (style)
 590   (when style
 591     (save-match-data
 592       (when (string-match "\n" style)
 593         (setq style (replace-match " " t t style))))
 594     (let ((plist nil))
 595       (dolist (elem (split-string style ";"))
 596         (when elem
 597           (setq elem (split-string elem ":"))
 598           (when (and (car elem)
 599                      (cadr elem))
 600             (let ((name (replace-regexp-in-string "^ +\\| +$" "" (car elem)))
 601                   (value (replace-regexp-in-string "^ +\\| +$" "" (cadr elem))))
 602               (when (string-match " *!important\\'" value)
 603                 (setq value (substring value 0 (match-beginning 0))))
 604               (push (cons (intern name obarray)
 605                           value)
 606                     plist)))))
 607       plist)))
 608
 609 (defun shr-tag-a (cont)
 610   (let ((url (cdr (assq :href cont)))
 611         (start (point))
 612         shr-start)
 613     (shr-generic cont)
 614     (shr-urlify (or shr-start start) url)))
 615
 616 (defun shr-tag-object (cont)
 617   (let ((start (point))
 618         url)
 619     (dolist (elem cont)
 620       (when (eq (car elem) 'embed)
 621         (setq url (or url (cdr (assq :src (cdr elem))))))
 622       (when (and (eq (car elem) 'param)
 623                  (equal (cdr (assq :name (cdr elem))) "movie"))
 624         (setq url (or url (cdr (assq :value (cdr elem)))))))
 625     (when url
 626       (shr-insert " [multimedia] ")
 627       (shr-urlify start url))
 628     (shr-generic cont)))
 629
 630 (defun shr-tag-video (cont)
 631   (let ((image (cdr (assq :poster cont)))
 632         (url (cdr (assq :src cont)))
 633         (start (point)))
 634     (shr-tag-img nil image)
 635     (shr-urlify start url)))
 636
 637 (defun shr-tag-img (cont &optional url)
 638   (when (or url
 639             (and cont
 640                  (cdr (assq :src cont))))
 641     (when (and (> (current-column) 0)
 642                (not (eq shr-state 'image)))
 643       (insert "\n"))
 644     (let ((alt (cdr (assq :alt cont)))
 645           (url (or url (cdr (assq :src cont)))))
 646       (let ((start (point-marker)))
 647         (when (zerop (length alt))
 648           (setq alt "*"))
 649         (cond
 650          ((or (member (cdr (assq :height cont)) '("0" "1"))
 651               (member (cdr (assq :width cont)) '("0" "1")))
 652           ;; Ignore zero-sized or single-pixel images.
 653           )
 654          ((and (not shr-inhibit-images)
 655                (string-match "\\`cid:" url))
 656           (let ((url (substring url (match-end 0)))
 657                 image)
 658             (if (or (not shr-content-function)
 659                     (not (setq image (funcall shr-content-function url))))
 660                 (insert alt)
 661               (shr-put-image image alt))))
 662          ((or shr-inhibit-images
 663               (and shr-blocked-images
 664                    (string-match shr-blocked-images url)))
 665           (setq shr-start (point))
 666           (let ((shr-state 'space))
 667             (if (> (string-width alt) 8)
 668                 (shr-insert (truncate-string-to-width alt 8))
 669               (shr-insert alt))))
 670          ((url-is-cached (shr-encode-url url))
 671           (shr-put-image (shr-get-image-data url) alt))
 672          (t
 673           (insert alt)
 674           (ignore-errors
 675             (url-retrieve (shr-encode-url url) 'shr-image-fetched
 676                           (list (current-buffer) start (point-marker))
 677                           t))))
 678         (put-text-property start (point) 'keymap shr-map)
 679         (put-text-property start (point) 'shr-alt alt)
 680         (put-text-property start (point) 'image-url url)
 681         (put-text-property start (point) 'image-displayer
 682                            (shr-image-displayer shr-content-function))
 683         (put-text-property start (point) 'help-echo alt)
 684         (setq shr-state 'image)))))
 685
 686 (defun shr-tag-pre (cont)
 687   (let ((shr-folding-mode 'none))
 688     (shr-ensure-newline)
 689     (shr-indent)
 690     (shr-generic cont)
 691     (shr-ensure-newline)))
 692
 693 (defun shr-tag-blockquote (cont)
 694   (shr-ensure-paragraph)
 695   (shr-indent)
 696   (let ((shr-indentation (+ shr-indentation 4)))
 697     (shr-generic cont))
 698   (shr-ensure-paragraph))
 699
 700 (defun shr-tag-ul (cont)
 701   (shr-ensure-paragraph)
 702   (let ((shr-list-mode 'ul))
 703     (shr-generic cont))
 704   (shr-ensure-paragraph))
 705
 706 (defun shr-tag-ol (cont)
 707   (shr-ensure-paragraph)
 708   (let ((shr-list-mode 1))
 709     (shr-generic cont))
 710   (shr-ensure-paragraph))
 711
 712 (defun shr-tag-li (cont)
 713   (shr-ensure-paragraph)
 714   (shr-indent)
 715   (let* ((bullet
 716           (if (numberp shr-list-mode)
 717               (prog1
 718                   (format "%d " shr-list-mode)
 719                 (setq shr-list-mode (1+ shr-list-mode)))
 720             "* "))
 721          (shr-indentation (+ shr-indentation (length bullet))))
 722     (insert bullet)
 723     (shr-generic cont)))
 724
 725 (defun shr-tag-br (cont)
 726   (unless (bobp)
 727     (insert "\n")
 728     (shr-indent))
 729   (shr-generic cont))
 730
 731 (defun shr-tag-h1 (cont)
 732   (shr-heading cont 'bold 'underline))
 733
 734 (defun shr-tag-h2 (cont)
 735   (shr-heading cont 'bold))
 736
 737 (defun shr-tag-h3 (cont)
 738   (shr-heading cont 'italic))
 739
 740 (defun shr-tag-h4 (cont)
 741   (shr-heading cont))
 742
 743 (defun shr-tag-h5 (cont)
 744   (shr-heading cont))
 745
 746 (defun shr-tag-h6 (cont)
 747   (shr-heading cont))
 748
 749 (defun shr-tag-hr (cont)
 750   (shr-ensure-newline)
 751   (insert (make-string shr-width shr-hr-line) "\n"))
 752
 753 (defun shr-tag-title (cont)
 754   (shr-heading cont 'bold 'underline))
 755
 756 (defun shr-tag-font (cont)
 757   (let ((start (point))
 758         (color (cdr (assq :color cont))))
 759     (shr-generic cont)
 760     (shr-insert-foreground-overlay color start (point))))
 761
 762 ;;; Table rendering algorithm.
 763
 764 ;; Table rendering is the only complicated thing here.  We do this by
 765 ;; first counting how many TDs there are in each TR, and registering
 766 ;; how wide they think they should be ("width=45%", etc).  Then we
 767 ;; render each TD separately (this is done in temporary buffers, so
 768 ;; that we can use all the rendering machinery as if we were in the
 769 ;; main buffer).  Now we know how much space each TD really takes, so
 770 ;; we then render everything again with the new widths, and finally
 771 ;; insert all these boxes into the main buffer.
 772 (defun shr-tag-table-1 (cont)
 773   (setq cont (or (cdr (assq 'tbody cont))
 774                  cont))
 775   (let* ((shr-inhibit-images t)
 776          (shr-table-depth (1+ shr-table-depth))
 777          (shr-kinsoku-shorten t)
 778          ;; Find all suggested widths.
 779          (columns (shr-column-specs cont))
 780          ;; Compute how many characters wide each TD should be.
 781          (suggested-widths (shr-pro-rate-columns columns))
 782          ;; Do a "test rendering" to see how big each TD is (this can
 783          ;; be smaller (if there's little text) or bigger (if there's
 784          ;; unbreakable text).
 785          (sketch (shr-make-table cont suggested-widths))
 786          (sketch-widths (shr-table-widths sketch suggested-widths)))
 787     ;; This probably won't work very well.
 788     (when (> (+ (loop for width across sketch-widths
 789                       summing (1+ width))
 790                 shr-indentation 1)
 791              (frame-width))
 792       (setq truncate-lines t))
 793     ;; Then render the table again with these new "hard" widths.
 794     (shr-insert-table (shr-make-table cont sketch-widths t) sketch-widths))
 795   ;; Finally, insert all the images after the table.  The Emacs buffer
 796   ;; model isn't strong enough to allow us to put the images actually
 797   ;; into the tables.
 798   (when (zerop shr-table-depth)
 799     (dolist (elem (shr-find-elements cont 'img))
 800       (shr-tag-img (cdr elem)))))
 801
 802 (defun shr-tag-table (cont)
 803   (shr-ensure-paragraph)
 804   (let* ((caption (cdr (assq 'caption cont)))
 805          (header (cdr (assq 'thead cont)))
 806          (body (or (cdr (assq 'tbody cont)) cont))
 807          (footer (cdr (assq 'tfoot cont)))
 808          (bgcolor (cdr (assq :bgcolor cont)))
 809          (nheader (if header (shr-max-columns header)))
 810          (nbody (if body (shr-max-columns body)))
 811          (nfooter (if footer (shr-max-columns footer))))
 812     (shr-insert-background-overlay bgcolor (point))
 813     (shr-tag-table-1
 814      (nconc
 815       (if caption `((tr (td ,@caption))))
 816       (if header
 817           (if footer
 818               ;; hader + body + footer
 819               (if (= nheader nbody)
 820                   (if (= nbody nfooter)
 821                       `((tr (td (table (tbody ,@header ,@body ,@footer)))))
 822                     (nconc `((tr (td (table (tbody ,@header ,@body)))))
 823                            (if (= nfooter 1)
 824                                footer
 825                              `((tr (td (table (tbody ,@footer))))))))
 826                 (nconc `((tr (td (table (tbody ,@header)))))
 827                        (if (= nbody nfooter)
 828                            `((tr (td (table (tbody ,@body ,@footer)))))
 829                          (nconc `((tr (td (table (tbody ,@body)))))
 830                                 (if (= nfooter 1)
 831                                     footer
 832                                   `((tr (td (table (tbody ,@footer))))))))))
 833             ;; header + body
 834             (if (= nheader nbody)
 835                 `((tr (td (table (tbody ,@header ,@body)))))
 836               (if (= nheader 1)
 837                   `(,@header (tr (td (table (tbody ,@body)))))
 838                 `((tr (td (table (tbody ,@header))))
 839                   (tr (td (table (tbody ,@body))))))))
 840         (if footer
 841             ;; body + footer
 842             (if (= nbody nfooter)
 843                 `((tr (td (table (tbody ,@body ,@footer)))))
 844               (nconc `((tr (td (table (tbody ,@body)))))
 845                      (if (= nfooter 1)
 846                          footer
 847                        `((tr (td (table (tbody ,@footer))))))))
 848           (if caption
 849               `((tr (td (table (tbody ,@body)))))
 850             body)))))))
 851
 852 (defun shr-find-elements (cont type)
 853   (let (result)
 854     (dolist (elem cont)
 855       (cond ((eq (car elem) type)
 856              (push elem result))
 857             ((consp (cdr elem))
 858              (setq result (nconc (shr-find-elements (cdr elem) type) result)))))
 859     (nreverse result)))
 860
 861 (defun shr-insert-table (table widths)
 862   (shr-insert-table-ruler widths)
 863   (dolist (row table)
 864     (let ((start (point))
 865           (height (let ((max 0))
 866                     (dolist (column row)
 867                       (setq max (max max (cadr column))))
 868                     max)))
 869       (dotimes (i height)
 870         (shr-indent)
 871         (insert shr-table-vertical-line "\n"))
 872       (dolist (column row)
 873         (goto-char start)
 874         (let ((lines (nth 2 column))
 875               (overlay-lines (nth 3 column))
 876               overlay overlay-line)
 877           (dolist (line lines)
 878             (setq overlay-line (pop overlay-lines))
 879             (end-of-line)
 880             (insert line shr-table-vertical-line)
 881             (dolist (overlay overlay-line)
 882               (let ((o (make-overlay (- (point) (nth 0 overlay) 1)
 883                                      (- (point) (nth 1 overlay) 1)))
 884                     (properties (nth 2 overlay)))
 885                 (while properties
 886                   (overlay-put o (pop properties) (pop properties)))))
 887             (forward-line 1))
 888           ;; Add blank lines at padding at the bottom of the TD,
 889           ;; possibly.
 890           (dotimes (i (- height (length lines)))
 891             (end-of-line)
 892             (insert (make-string (string-width (car lines)) ? )
 893                     shr-table-vertical-line)
 894             (forward-line 1)))))
 895     (shr-insert-table-ruler widths)))
 896
 897 (defun shr-insert-table-ruler (widths)
 898   (when (and (bolp)
 899              (> shr-indentation 0))
 900     (shr-indent))
 901   (insert shr-table-corner)
 902   (dotimes (i (length widths))
 903     (insert (make-string (aref widths i) shr-table-horizontal-line)
 904             shr-table-corner))
 905   (insert "\n"))
 906
 907 (defun shr-table-widths (table suggested-widths)
 908   (let* ((length (length suggested-widths))
 909          (widths (make-vector length 0))
 910          (natural-widths (make-vector length 0)))
 911     (dolist (row table)
 912       (let ((i 0))
 913         (dolist (column row)
 914           (aset widths i (max (aref widths i)
 915                               (car column)))
 916           (aset natural-widths i (max (aref natural-widths i)
 917                                       (cadr column)))
 918           (setq i (1+ i)))))
 919     (let ((extra (- (apply '+ (append suggested-widths nil))
 920                     (apply '+ (append widths nil))))
 921           (expanded-columns 0))
 922       (when (> extra 0)
 923         (dotimes (i length)
 924           ;; If the natural width is wider than the rendered width, we
 925           ;; want to allow the column to expand.
 926           (when (> (aref natural-widths i) (aref widths i))
 927             (setq expanded-columns (1+ expanded-columns))))
 928         (dotimes (i length)
 929           (when (> (aref natural-widths i) (aref widths i))
 930             (aset widths i (min
 931                             (1+ (aref natural-widths i))
 932                             (+ (/ extra expanded-columns)
 933                                (aref widths i))))))))
 934     widths))
 935
 936 (defun shr-make-table (cont widths &optional fill)
 937   (let ((trs nil))
 938     (dolist (row cont)
 939       (when (eq (car row) 'tr)
 940         (let ((tds nil)
 941               (columns (cdr row))
 942               (i 0)
 943               column)
 944           (while (< i (length widths))
 945             (setq column (pop columns))
 946             (when (or (memq (car column) '(td th))
 947                       (null column))
 948               (push (shr-render-td (cdr column) (aref widths i) fill)
 949                     tds)
 950               (setq i (1+ i))))
 951           (push (nreverse tds) trs))))
 952     (nreverse trs)))
 953
 954 (defun shr-render-td (cont width fill)
 955   (let ((background (shr-get-background (point))))
 956     (with-temp-buffer
 957       (let ((cache (cdr (assoc (cons width cont) shr-content-cache))))
 958         (if cache
 959             (insert cache)
 960           (shr-insert-background-overlay (or (cdr (assq :bgcolor cont))
 961                                              background)
 962                                          (point))
 963           (let ((shr-width width)
 964                 (shr-indentation 0))
 965             (shr-generic cont))
 966           (delete-region
 967            (point)
 968            (+ (point)
 969               (skip-chars-backward " \t\n")))
 970           (push (cons (cons width cont) (buffer-string))
 971                 shr-content-cache)))
 972       (goto-char (point-min))
 973       (let ((max 0))
 974         (while (not (eobp))
 975           (end-of-line)
 976           (setq max (max max (current-column)))
 977           (forward-line 1))
 978         (when fill
 979           (goto-char (point-min))
 980           ;; If the buffer is totally empty, then put a single blank
 981           ;; line here.
 982           (if (zerop (buffer-size))
 983               (insert (make-string width ? ))
 984             ;; Otherwise, fill the buffer.
 985             (while (not (eobp))
 986               (end-of-line)
 987               (when (> (- width (current-column)) 0)
 988                 (insert (make-string (- width (current-column)) ? )))
 989               (forward-line 1))))
 990         (if fill
 991             (list max
 992                   (count-lines (point-min) (point-max))
 993                   (split-string (buffer-string) "\n")
 994                   (shr-collect-overlays))
 995           (list max
 996                 (shr-natural-width)))))))
 997
 998 (defun shr-natural-width ()
 999   (goto-char (point-min))
1000   (let ((current 0)
1001         (max 0))
1002     (while (not (eobp))
1003       (end-of-line)
1004       (setq current (+ current (current-column)))
1005       (unless (get-text-property (point) 'shr-break)
1006         (setq max (max max current)
1007               current 0))
1008       (forward-line 1))
1009     max))
1010
1011 (defun shr-collect-overlays ()
1012   (save-excursion
1013     (goto-char (point-min))
1014     (let ((overlays nil))
1015       (while (not (eobp))
1016         (push (shr-overlays-in-region (point) (line-end-position))
1017               overlays)
1018         (forward-line 1))
1019       (nreverse overlays))))
1020
1021 (defun shr-overlays-in-region (start end)
1022   (let (result)
1023     (dolist (overlay (overlays-in start end))
1024       (push (list (if (> start (overlay-start overlay))
1025                       (- end start)
1026                     (- end (overlay-start overlay)))
1027                   (if (< end (overlay-end overlay))
1028                       0
1029                     (- end (overlay-end overlay)))
1030                   (overlay-properties overlay))
1031             result))
1032     (nreverse result)))
1033
1034 (defun shr-pro-rate-columns (columns)
1035   (let ((total-percentage 0)
1036         (widths (make-vector (length columns) 0)))
1037     (dotimes (i (length columns))
1038       (setq total-percentage (+ total-percentage (aref columns i))))
1039     (setq total-percentage (/ 1.0 total-percentage))
1040     (dotimes (i (length columns))
1041       (aset widths i (max (truncate (* (aref columns i)
1042                                        total-percentage
1043                                        (- shr-width (1+ (length columns)))))
1044                           10)))
1045     widths))
1046
1047 ;; Return a summary of the number and shape of the TDs in the table.
1048 (defun shr-column-specs (cont)
1049   (let ((columns (make-vector (shr-max-columns cont) 1)))
1050     (dolist (row cont)
1051       (when (eq (car row) 'tr)
1052         (let ((i 0))
1053           (dolist (column (cdr row))
1054             (when (memq (car column) '(td th))
1055               (let ((width (cdr (assq :width (cdr column)))))
1056                 (when (and width
1057                            (string-match "\\([0-9]+\\)%" width))
1058                   (aset columns i
1059                         (/ (string-to-number (match-string 1 width))
1060                            100.0))))
1061               (setq i (1+ i)))))))
1062     columns))
1063
1064 (defun shr-count (cont elem)
1065   (let ((i 0))
1066     (dolist (sub cont)
1067       (when (eq (car sub) elem)
1068         (setq i (1+ i))))
1069     i))
1070
1071 (defun shr-max-columns (cont)
1072   (let ((max 0))
1073     (dolist (row cont)
1074       (when (eq (car row) 'tr)
1075         (setq max (max max (+ (shr-count (cdr row) 'td)
1076                               (shr-count (cdr row) 'th))))))
1077     max))
1078
1079 (provide 'shr)
1080
1081 ;;; shr.el ends here