;;; 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-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)))
(defun shr-insert-document (dom)
(setq dom (shr-transform-dom dom))
(shr-descend dom))
(defun shr-descend (dom)
(let ((function (intern (concat "shr-" (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)))
((consp (cdr sub))
(shr-descend sub)))))
(defun shr-p (cont)
(shr-ensure-newline)
(insert "\n")
(shr-generic cont)
(insert "\n"))
(defun shr-b (cont)
(shr-fontize-cont cont 'bold))
(defun shr-i (cont)
(shr-fontize-cont cont 'italic))
(defun shr-u (cont)
(shr-fontize-cont cont 'underline))
(defun shr-s (cont)
(shr-fontize-cont cont 'strikethru))
(defun shr-fontize-cont (cont type)
(let ((start (point)))
(shr-generic cont)
(shr-add-font start (point) type)))
(defun shr-add-font (start end type)
(put-text-property start end 'face type))
(defun shr-a (cont)
(let ((start (point))
(url (cdr (assq :href cont))))
(shr-generic cont)
(widget-convert-button
'link 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-img (cont)
(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 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)))))
(insert " "))))
(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 (shr-rescale-image data)))
(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))
(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-pre (cont)
(let ((shr-folding-mode nil))
(shr-ensure-newline)
(shr-generic cont)
(shr-ensure-newline)))
(defun shr-blockquote (cont)
(shr-pre cont))
(defun shr-ensure-newline ()
(unless (zerop (current-column))
(insert "\n")))
(defun shr-insert (text)
(cond
((eq shr-folding-mode 'none)
(insert t))
(t
(let (column)
(dolist (elem (split-string text))
(setq column (current-column))
(if (zerop column)
(insert elem)
(if (> (+ column (length elem) 1) shr-width)
(insert "\n" elem)
(insert " " elem))))))))
(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)))))
(provide 'shr)
;;; shr.el ends here