;;; shr.el --- Simple HTML Renderer
;; Copyright (C) 2010 Free Software Foundation, Inc.
;; Author: Lars Magne Ingebrigtsen
;; 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 .
;;; 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:
(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)
(defvar shr-indentation 0)
(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)
(let ((function (intern (concat "shr-tag-" (symbol-name (car dom))) obarray)))
(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)))
((listp (cdr sub))
(shr-descend sub)))))
(defun shr-tag-p (cont)
(shr-ensure-paragraph)
(shr-generic cont)
(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)
(looking-at " *$"))
(insert "\n")
(insert "\n\n")))))
(defun shr-tag-b (cont)
(shr-fontize-cont cont 'bold))
(defun shr-tag-i (cont)
(shr-fontize-cont cont 'italic))
(defun shr-tag-u (cont)
(shr-fontize-cont cont 'underline))
(defun shr-tag-s (cont)
(shr-fontize-cont cont 'strike-through))
(defun shr-fontize-cont (cont &rest types)
(let (shr-start)
(shr-generic cont)
(dolist (type types)
(shr-add-font (or shr-start (point)) (point) type))))
(defun shr-add-font (start end type)
(let ((overlay (make-overlay start end)))
(overlay-put overlay 'face type)))
(defun shr-tag-a (cont)
(let ((url (cdr (assq :href cont)))
shr-start)
(shr-generic cont)
(widget-convert-button
'link shr-start (point)
:action 'shr-browse-url
:url url
:keymap widget-keymap
:help-echo url)))
(defun shr-browse-url (widget &rest stuff)
(browse-url (widget-get widget :url)))
(defun shr-tag-img (cont)
(when (and (> (current-column) 0)
(not (eq shr-state 'image)))
(insert "\n"))
(let ((start (point-marker)))
(let ((alt (cdr (assq :alt cont)))
(url (cdr (assq :src cont))))
(when (zerop (length alt))
(setq alt "[img]"))
(cond
((and shr-blocked-images
(string-match shr-blocked-images url))
(insert alt))
((url-is-cached (browse-url-url-encode-chars url "[&)$ ]"))
(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)
(let ((image (ignore-errors
(shr-rescale-image data))))
(when image
(put-image image point alt)))))
(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))
(size (image-size image t))
(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)))
(defun shr-tag-pre (cont)
(let ((shr-folding-mode 'none))
(shr-ensure-newline)
(shr-generic cont)
(shr-ensure-newline)))
(defun shr-tag-blockquote (cont)
(shr-ensure-paragraph)
(let ((shr-indentation (+ shr-indentation 4)))
(shr-generic cont)))
(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)
(insert text))
(t
(let ((first t)
column)
(when (and (string-match "\\`[ \t\n]" text)
(not (bolp)))
(insert " "))
(dolist (elem (split-string text))
(setq column (current-column))
(when (> column 0)
(cond
((and (or (not first)
(eq shr-state 'space))
(> (+ column (length elem) 1) shr-width))
(insert "\n"))
((not first)
(insert " "))))
(setq first nil)
(when (and (bolp)
(> shr-indentation 0))
(shr-indent))
;; 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)))
(insert elem))
(setq shr-state nil)
(when (and (string-match "[ \t\n]\\'" text)
(not (bolp)))
(insert " ")
(setq shr-state 'space))))))
(defun shr-indent ()
(insert (make-string shr-indentation ? )))
(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)))))
(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)
(let* ((bullet
(if (numberp shr-list-mode)
(prog1
(format "%d " shr-list-mode)
(setq shr-list-mode (1+ shr-list-mode)))
"* "))
(shr-indentation (+ shr-indentation (length bullet))))
(insert bullet)
(shr-generic cont)))
(defun shr-tag-br (cont)
(unless (bobp)
(insert "\n"))
(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))
(defun shr-tag-table (cont)
(shr-ensure-paragraph)
(setq cont (or (cdr (assq 'tbody cont))
cont))
(let* ((columns (shr-column-specs cont))
(suggested-widths (shr-pro-rate-columns columns))
(sketch (shr-make-table cont suggested-widths))
(sketch-widths (shr-table-widths sketch (length suggested-widths))))
(shr-insert-table (shr-make-table cont sketch-widths t) sketch-widths)))
(defun shr-insert-table (table widths)
(shr-insert-table-ruler widths)
(dolist (row table)
(let ((start (point))
(height (let ((max 0))
(dolist (column row)
(setq max (max max (cadr column))))
max)))
(dotimes (i height)
(shr-indent)
(insert "|\n"))
(dolist (column row)
(goto-char start)
(let ((lines (split-string (nth 2 column) "\n")))
(dolist (line lines)
(when (> (length line) 0)
(end-of-line)
(insert line "|")
(forward-line 1)))
;; Add blank lines at padding at the bottom of the TD,
;; possibly.
(dotimes (i (- height (length lines)))
(end-of-line)
(insert (make-string (length (car lines)) ? ) "|")
(forward-line 1)))))
(shr-insert-table-ruler widths)))
(defun shr-insert-table-ruler (widths)
(shr-indent)
(insert "+")
(dotimes (i (length widths))
(insert (make-string (aref widths i) ?-) ?+))
(insert "\n"))
(defun shr-table-widths (table length)
(let ((widths (make-vector length 0)))
(dolist (row table)
(let ((i 0))
(dolist (column row)
(aset widths i (max (aref widths i)
(car column)))
(incf i))))
widths))
(defun shr-make-table (cons widths &optional fill)
(let ((trs nil))
(dolist (row cont)
(when (eq (car row) 'tr)
(let ((i 0)
(tds nil))
(dolist (column (cdr row))
(when (memq (car column) '(td th))
(push (shr-render-td (cdr column) (aref widths i) fill)
tds)
(setq i (1+ i))))
(push (nreverse tds) trs))))
(nreverse trs)))
(defun shr-render-td (cont width fill)
(with-temp-buffer
(let ((shr-width width))
(shr-generic cont))
(while (re-search-backward "\n *$" nil t)
(delete-region (match-beginning 0) (match-end 0)))
(goto-char (point-min))
(let ((max 0))
(while (not (eobp))
(end-of-line)
(setq max (max max (current-column)))
(forward-line 1))
(when fill
(goto-char (point-min))
(while (not (eobp))
(end-of-line)
(insert (make-string (- width (current-column)) ? ))
(forward-line 1)))
(list max (count-lines (point-min) (point-max)) (buffer-string)))))
(defun shr-pro-rate-columns (columns)
(let ((total-percentage 0)
(widths (make-vector (length columns) 0)))
(dotimes (i (length columns))
(incf total-percentage (aref columns i)))
(setq total-percentage (/ 1.0 total-percentage))
(dotimes (i (length columns))
(aset widths i (max (truncate (* (aref columns i)
total-percentage
shr-width))
10)))
widths))
;; Return a summary of the number and shape of the TDs in the table.
(defun shr-column-specs (cont)
(let ((columns (make-vector (shr-max-columns cont) 1)))
(dolist (row cont)
(when (eq (car row) 'tr)
(let ((i 0))
(dolist (column (cdr row))
(when (memq (car column) '(td th))
(let ((width (cdr (assq :width (cdr column)))))
(when (and width
(string-match "\\([0-9]+\\)%" width))
(aset columns i
(/ (string-to-number (match-string 1 width))
100.0)))))
(setq i (1+ i))))))
columns))
(defun shr-count (cont elem)
(let ((i 0))
(dolist (sub cont)
(when (eq (car sub) elem)
(setq i (1+ i))))
i))
(defun shr-max-columns (cont)
(let ((max 0))
(dolist (row cont)
(when (eq (car row) 'tr)
(setq max (max max (shr-count (cdr row) 'td)))))
max))
(provide 'shr)
;;; shr.el ends here