Exemple #1
0
    def __init__(self, shortcuts, parent=None, debug_javascript=False):
        QWebPage.__init__(self, parent)
        self.setObjectName("py_bridge")
        self.in_paged_mode = False
        # Use this to pass arbitrary JSON encodable objects between python and
        # javascript. In python get/set the value as: self.bridge_value. In
        # javascript, get/set the value as: py_bridge.value
        self.bridge_value = None
        self.first_load = True

        self.debug_javascript = debug_javascript
        self.anchor_positions = {}
        self.index_anchors = set()
        self.current_language = None
        self.loaded_javascript = False
        self.js_loader = JavaScriptLoader(
                    dynamic_coffeescript=self.debug_javascript)
        self.in_fullscreen_mode = False

        self.setLinkDelegationPolicy(self.DelegateAllLinks)
        self.scroll_marks = []
        self.shortcuts = shortcuts
        pal = self.palette()
        pal.setBrush(QPalette.Background, QColor(0xee, 0xee, 0xee))
        self.setPalette(pal)
        self.page_position = PagePosition(self)

        settings = self.settings()

        # Fonts
        self.all_viewer_plugins = tuple(all_viewer_plugins())
        for pl in self.all_viewer_plugins:
            pl.load_fonts()
        opts = config().parse()
        self.set_font_settings(opts)

        # Security
        settings.setAttribute(QWebSettings.JavaEnabled, False)
        settings.setAttribute(QWebSettings.PluginsEnabled, False)
        settings.setAttribute(QWebSettings.JavascriptCanOpenWindows, False)
        settings.setAttribute(QWebSettings.JavascriptCanAccessClipboard, False)

        # Miscellaneous
        settings.setAttribute(QWebSettings.LinksIncludedInFocusChain, True)
        settings.setAttribute(QWebSettings.DeveloperExtrasEnabled, True)
        self.set_user_stylesheet(opts)
        self.misc_config(opts)

        # Load javascript
        self.mainFrame().javaScriptWindowObjectCleared.connect(
                self.add_window_objects)

        self.turn_off_internal_scrollbars()
Exemple #2
0
    def __init__(self, shortcuts, parent=None, debug_javascript=False):
        QWebPage.__init__(self, parent)
        self.setObjectName("py_bridge")
        self.in_paged_mode = False
        # Use this to pass arbitrary JSON encodable objects between python and
        # javascript. In python get/set the value as: self.bridge_value. In
        # javascript, get/set the value as: py_bridge.value
        self.bridge_value = None
        self.first_load = True

        self.debug_javascript = debug_javascript
        self.anchor_positions = {}
        self.index_anchors = set()
        self.current_language = None
        self.loaded_javascript = False
        self.js_loader = JavaScriptLoader(
                    dynamic_coffeescript=self.debug_javascript)
        self.in_fullscreen_mode = False

        self.setLinkDelegationPolicy(self.DelegateAllLinks)
        self.scroll_marks = []
        self.shortcuts = shortcuts
        pal = self.palette()
        pal.setBrush(QPalette.Background, QColor(0xee, 0xee, 0xee))
        self.setPalette(pal)
        self.page_position = PagePosition(self)

        settings = self.settings()

        # Fonts
        load_builtin_fonts()
        self.all_viewer_plugins = tuple(all_viewer_plugins())
        for pl in self.all_viewer_plugins:
            pl.load_fonts()
        opts = config().parse()
        self.set_font_settings(opts)

        # Security
        settings.setAttribute(QWebSettings.JavaEnabled, False)
        settings.setAttribute(QWebSettings.PluginsEnabled, False)
        settings.setAttribute(QWebSettings.JavascriptCanOpenWindows, False)
        settings.setAttribute(QWebSettings.JavascriptCanAccessClipboard, False)

        # Miscellaneous
        settings.setAttribute(QWebSettings.LinksIncludedInFocusChain, True)
        settings.setAttribute(QWebSettings.DeveloperExtrasEnabled, True)
        self.set_user_stylesheet(opts)
        self.misc_config(opts)

        # Load javascript
        self.mainFrame().javaScriptWindowObjectCleared.connect(
                self.add_window_objects)

        self.turn_off_internal_scrollbars()
Exemple #3
0
class Document(QWebPage):  # {{{

    page_turn = pyqtSignal(object)
    mark_element = pyqtSignal(QWebElement)
    settings_changed = pyqtSignal()

    def set_font_settings(self, opts):
        settings = self.settings()
        apply_settings(settings, opts)

    def do_config(self, parent=None):
        d = ConfigDialog(self.shortcuts, parent)
        if d.exec_() == QDialog.Accepted:
            opts = config().parse()
            self.apply_settings(opts)

    def apply_settings(self, opts):
        with self.page_position:
            self.set_font_settings(opts)
            self.set_user_stylesheet(opts)
            self.misc_config(opts)
            self.settings_changed.emit()
            self.after_load()

    def __init__(self, shortcuts, parent=None, debug_javascript=False):
        QWebPage.__init__(self, parent)
        self.setObjectName("py_bridge")
        self.in_paged_mode = False
        # Use this to pass arbitrary JSON encodable objects between python and
        # javascript. In python get/set the value as: self.bridge_value. In
        # javascript, get/set the value as: py_bridge.value
        self.bridge_value = None
        self.first_load = True

        self.debug_javascript = debug_javascript
        self.anchor_positions = {}
        self.index_anchors = set()
        self.current_language = None
        self.loaded_javascript = False
        self.js_loader = JavaScriptLoader(
                    dynamic_coffeescript=self.debug_javascript)
        self.in_fullscreen_mode = False

        self.setLinkDelegationPolicy(self.DelegateAllLinks)
        self.scroll_marks = []
        self.shortcuts = shortcuts
        pal = self.palette()
        pal.setBrush(QPalette.Background, QColor(0xee, 0xee, 0xee))
        self.setPalette(pal)
        self.page_position = PagePosition(self)

        settings = self.settings()

        # Fonts
        self.all_viewer_plugins = tuple(all_viewer_plugins())
        for pl in self.all_viewer_plugins:
            pl.load_fonts()
        opts = config().parse()
        self.set_font_settings(opts)

        # Security
        settings.setAttribute(QWebSettings.JavaEnabled, False)
        settings.setAttribute(QWebSettings.PluginsEnabled, False)
        settings.setAttribute(QWebSettings.JavascriptCanOpenWindows, False)
        settings.setAttribute(QWebSettings.JavascriptCanAccessClipboard, False)

        # Miscellaneous
        settings.setAttribute(QWebSettings.LinksIncludedInFocusChain, True)
        settings.setAttribute(QWebSettings.DeveloperExtrasEnabled, True)
        self.set_user_stylesheet(opts)
        self.misc_config(opts)

        # Load javascript
        self.mainFrame().javaScriptWindowObjectCleared.connect(
                self.add_window_objects)

        self.turn_off_internal_scrollbars()

    def turn_off_internal_scrollbars(self):
        mf = self.mainFrame()
        mf.setScrollBarPolicy(Qt.Vertical, Qt.ScrollBarAlwaysOff)
        mf.setScrollBarPolicy(Qt.Horizontal, Qt.ScrollBarAlwaysOff)

    def set_user_stylesheet(self, opts):
        bg = opts.background_color or 'white'
        brules = ['background-color: %s !important'%bg]
        prefix = '''
            body { %s  }
        '''%('; '.join(brules))
        if opts.text_color:
            prefix += '\n\nbody, p, div { color: %s !important }'%opts.text_color
        raw = prefix + opts.user_css
        raw = '::selection {background:#ffff00; color:#000;}\n'+raw
        data = 'data:text/css;charset=utf-8;base64,'
        data += b64encode(raw.encode('utf-8'))
        self.settings().setUserStyleSheetUrl(QUrl(data))

    def findText(self, q, flags):
        if self.hyphenatable:
            q = unicode(q)
            hyphenated_q = self.javascript(
                'hyphenate_text(%s, "%s")' % (json.dumps(q, ensure_ascii=False), self.loaded_lang), typ='string')
            if QWebPage.findText(self, hyphenated_q, flags):
                return True
        return QWebPage.findText(self, q, flags)

    def misc_config(self, opts):
        self.hyphenate = opts.hyphenate
        self.hyphenate_default_lang = opts.hyphenate_default_lang
        self.do_fit_images = opts.fit_images
        self.page_flip_duration = opts.page_flip_duration
        self.enable_page_flip = self.page_flip_duration > 0.1
        self.font_magnification_step = opts.font_magnification_step
        self.wheel_flips_pages = opts.wheel_flips_pages
        self.line_scrolling_stops_on_pagebreaks = opts.line_scrolling_stops_on_pagebreaks
        screen_width = QApplication.desktop().screenGeometry().width()
        # Leave some space for the scrollbar and some border
        self.max_fs_width = min(opts.max_fs_width, screen_width-50)
        self.fullscreen_clock = opts.fullscreen_clock
        self.fullscreen_scrollbar = opts.fullscreen_scrollbar
        self.fullscreen_pos = opts.fullscreen_pos
        self.start_in_fullscreen = opts.start_in_fullscreen
        self.show_fullscreen_help = opts.show_fullscreen_help
        self.use_book_margins = opts.use_book_margins
        self.cols_per_screen = opts.cols_per_screen
        self.side_margin = opts.side_margin
        self.top_margin, self.bottom_margin = opts.top_margin, opts.bottom_margin
        self.show_controls = opts.show_controls

    def fit_images(self):
        if self.do_fit_images and not self.in_paged_mode:
            self.javascript('setup_image_scaling_handlers()')

    def add_window_objects(self):
        self.mainFrame().addToJavaScriptWindowObject("py_bridge", self)
        self.javascript('''
                py_bridge.__defineGetter__('value', function() {
                    return JSON.parse(this._pass_json_value);
                });
                py_bridge.__defineSetter__('value', function(val) {
                    this._pass_json_value = JSON.stringify(val);
                });
        ''')
        self.loaded_javascript = False

    def load_javascript_libraries(self):
        if self.loaded_javascript:
            return
        self.loaded_javascript = True
        evaljs = self.mainFrame().evaluateJavaScript
        self.loaded_lang = self.js_loader(evaljs, self.current_language,
                self.hyphenate_default_lang)
        mjpath = P(u'viewer/mathjax').replace(os.sep, '/')
        if iswindows:
            mjpath = u'/' + mjpath
        self.javascript(u'window.mathjax.base = %s'%(json.dumps(mjpath,
            ensure_ascii=False)))
        for pl in self.all_viewer_plugins:
            pl.load_javascript(evaljs)
        evaljs('py_bridge.mark_element.connect(window.calibre_extract.mark)')

    @pyqtSignature("")
    def animated_scroll_done(self):
        self.emit(SIGNAL('animated_scroll_done()'))

    @property
    def hyphenatable(self):
        # Qt fails to render soft hyphens correctly on windows xp
        return not isxp and self.hyphenate and getattr(self, 'loaded_lang', '')

    @pyqtSignature("")
    def init_hyphenate(self):
        if self.hyphenatable:
            self.javascript('do_hyphenation("%s")'%self.loaded_lang)

    @pyqtSlot(int)
    def page_turn_requested(self, backwards):
        self.page_turn.emit(bool(backwards))

    def _pass_json_value_getter(self):
        val = json.dumps(self.bridge_value)
        return QString(val)

    def _pass_json_value_setter(self, value):
        self.bridge_value = json.loads(unicode(value))

    _pass_json_value = pyqtProperty(QString, fget=_pass_json_value_getter,
            fset=_pass_json_value_setter)

    def after_load(self, last_loaded_path=None):
        self.javascript('window.paged_display.read_document_margins()')
        self.set_bottom_padding(0)
        self.fit_images()
        self.init_hyphenate()
        self.javascript('full_screen.save_margins()')
        if self.in_fullscreen_mode:
            self.switch_to_fullscreen_mode()
        if self.in_paged_mode:
            self.switch_to_paged_mode(last_loaded_path=last_loaded_path)
        self.read_anchor_positions(use_cache=False)
        evaljs = self.mainFrame().evaluateJavaScript
        for pl in self.all_viewer_plugins:
            pl.run_javascript(evaljs)
        self.javascript('window.mathjax.check_for_math()')
        self.first_load = False

    def colors(self):
        self.javascript('''
            bs = getComputedStyle(document.body);
            py_bridge.value = [bs.backgroundColor, bs.color]
            ''')
        ans = self.bridge_value
        return (ans if isinstance(ans, list) else ['white', 'black'])

    def read_anchor_positions(self, use_cache=True):
        self.bridge_value = tuple(self.index_anchors)
        self.javascript(u'''
            py_bridge.value = book_indexing.anchor_positions(py_bridge.value, %s);
            '''%('true' if use_cache else 'false'))
        self.anchor_positions = self.bridge_value
        if not isinstance(self.anchor_positions, dict):
            # Some weird javascript error happened
            self.anchor_positions = {}
        return {k:tuple(v) for k, v in self.anchor_positions.iteritems()}

    def switch_to_paged_mode(self, onresize=False, last_loaded_path=None):
        if onresize and not self.loaded_javascript:
            return
        self.javascript('''
            window.paged_display.use_document_margins = %s;
            window.paged_display.set_geometry(%d, %d, %d, %d);
            '''%(
            ('true' if self.use_book_margins else 'false'),
            self.cols_per_screen, self.top_margin, self.side_margin,
            self.bottom_margin
            ))
        force_fullscreen_layout = bool(getattr(last_loaded_path,
                                               'is_single_page', False))
        f = 'true' if force_fullscreen_layout else 'false'
        side_margin = self.javascript('window.paged_display.layout(%s)'%f, typ=int)
        # Setup the contents size to ensure that there is a right most margin.
        # Without this WebKit renders the final column with no margin, as the
        # columns extend beyond the boundaries (and margin) of body
        mf = self.mainFrame()
        sz = mf.contentsSize()
        scroll_width = self.javascript('document.body.scrollWidth', int)
        # At this point sz.width() is not reliable, presumably because Qt
        # has not yet been updated
        if scroll_width > self.window_width:
            sz.setWidth(scroll_width+side_margin)
            self.setPreferredContentsSize(sz)
        self.javascript('window.paged_display.fit_images()')

    @property
    def column_boundaries(self):
        if not self.loaded_javascript:
            return (0, 1)
        self.javascript(u'py_bridge.value = paged_display.column_boundaries()')
        return tuple(self.bridge_value)

    def after_resize(self):
        if self.in_paged_mode:
            self.setPreferredContentsSize(QSize())
            self.switch_to_paged_mode(onresize=True)
        self.javascript('window.mathjax.after_resize()')

    def switch_to_fullscreen_mode(self):
        self.in_fullscreen_mode = True
        self.javascript('full_screen.on(%d, %s)'%(self.max_fs_width,
            'true' if self.in_paged_mode else 'false'))

    def switch_to_window_mode(self):
        self.in_fullscreen_mode = False
        self.javascript('full_screen.off(%s)'%('true' if self.in_paged_mode
            else 'false'))

    @pyqtSignature("QString")
    def debug(self, msg):
        prints(msg)

    def reference_mode(self, enable):
        self.javascript(('enter' if enable else 'leave')+'_reference_mode()')

    def set_reference_prefix(self, prefix):
        self.javascript('reference_prefix = "%s"'%prefix)

    def goto(self, ref):
        self.javascript('goto_reference("%s")'%ref)

    def goto_bookmark(self, bm):
        if bm['type'] == 'legacy':
            bm = bm['pos']
            bm = bm.strip()
            if bm.startswith('>'):
                bm = bm[1:].strip()
            self.javascript('scroll_to_bookmark("%s")'%bm)
        elif bm['type'] == 'cfi':
            self.page_position.to_pos(bm['pos'])

    def javascript(self, string, typ=None):
        ans = self.mainFrame().evaluateJavaScript(string)
        if typ in {'int', int}:
            ans = ans.toInt()
            if ans[1]:
                return ans[0]
            return 0
        if typ in {'float', float}:
            ans = ans.toReal()
            return ans[0] if ans[1] else 0.0
        if typ == 'string':
            return unicode(ans.toString())
        return ans

    def javaScriptConsoleMessage(self, msg, lineno, msgid):
        if self.debug_javascript:
            prints(msg)
        else:
            return QWebPage.javaScriptConsoleMessage(self, msg, lineno, msgid)

    def javaScriptAlert(self, frame, msg):
        if self.debug_javascript:
            prints(msg)
        else:
            return QWebPage.javaScriptAlert(self, frame, msg)

    def scroll_by(self, dx=0, dy=0):
        self.mainFrame().scroll(dx, dy)

    def scroll_to(self, x=0, y=0):
        self.mainFrame().setScrollPosition(QPoint(x, y))

    def jump_to_anchor(self, anchor):
        if not self.loaded_javascript:
            return
        self.javascript('window.paged_display.jump_to_anchor("%s")'%anchor)

    def element_ypos(self, elem):
        ans, ok = elem.evaluateJavaScript('$(this).offset().top').toInt()
        if not ok:
            raise ValueError('No ypos found')
        return ans

    def elem_outer_xml(self, elem):
        return unicode(elem.toOuterXml())

    def bookmark(self):
        pos = self.page_position.current_pos
        return {'type':'cfi', 'pos':pos}

    @property
    def at_bottom(self):
        return self.height - self.ypos <= self.window_height

    @property
    def at_top(self):
        return self.ypos <=0

    def test(self):
        pass

    @property
    def ypos(self):
        return self.mainFrame().scrollPosition().y()

    @property
    def window_height(self):
        return self.javascript('window.innerHeight', 'int')

    @property
    def window_width(self):
        return self.javascript('window.innerWidth', 'int')

    @property
    def xpos(self):
        return self.mainFrame().scrollPosition().x()

    @dynamic_property
    def scroll_fraction(self):
        def fget(self):
            if self.in_paged_mode:
                return self.javascript('''
                ans = 0.0;
                if (window.paged_display) {
                    ans = window.paged_display.current_pos();
                }
                ans;''',  typ='float')
            else:
                try:
                    return abs(float(self.ypos)/(self.height-self.window_height))
                except ZeroDivisionError:
                    return 0.
        def fset(self, val):
            if self.in_paged_mode and self.loaded_javascript:
                self.javascript('paged_display.scroll_to_pos(%f)'%val)
            else:
                npos = val * (self.height - self.window_height)
                if npos < 0:
                    npos = 0
                self.scroll_to(x=self.xpos, y=npos)
        return property(fget=fget, fset=fset)

    @property
    def hscroll_fraction(self):
        try:
            return float(self.xpos)/self.width
        except ZeroDivisionError:
            return 0.

    @property
    def height(self):
        # Note that document.body.offsetHeight does not include top and bottom
        # margins on body and in some cases does not include the top margin on
        # the first element inside body either. See ticket #8791 for an example
        # of the latter.
        q = self.mainFrame().contentsSize().height()
        if q < 0:
            # Don't know if this is still needed, but it can't hurt
            j = self.javascript('document.body.offsetHeight', 'int')
            if j >= 0:
                q = j
        return q

    @property
    def width(self):
        return self.mainFrame().contentsSize().width()  # offsetWidth gives inaccurate results

    def set_bottom_padding(self, amount):
        s = QSize(-1, -1) if amount == 0 else QSize(self.viewportSize().width(),
                self.height+amount)
        self.setPreferredContentsSize(s)

    def extract_node(self):
        return unicode(self.mainFrame().evaluateJavaScript(
            'window.calibre_extract.extract()').toString())
Exemple #4
0
class Document(QWebPage):  # {{{

    page_turn = pyqtSignal(object)
    mark_element = pyqtSignal(QWebElement)
    settings_changed = pyqtSignal()

    def set_font_settings(self, opts):
        settings = self.settings()
        apply_settings(settings, opts)

    def do_config(self, parent=None):
        d = ConfigDialog(self.shortcuts, parent)
        if d.exec_() == QDialog.Accepted:
            opts = config().parse()
            self.apply_settings(opts)

    def apply_settings(self, opts):
        with self.page_position:
            self.set_font_settings(opts)
            self.set_user_stylesheet(opts)
            self.misc_config(opts)
            self.settings_changed.emit()
            self.after_load()

    def __init__(self, shortcuts, parent=None, debug_javascript=False):
        QWebPage.__init__(self, parent)
        self.setObjectName("py_bridge")
        self.in_paged_mode = False
        # Use this to pass arbitrary JSON encodable objects between python and
        # javascript. In python get/set the value as: self.bridge_value. In
        # javascript, get/set the value as: py_bridge.value
        self.bridge_value = None
        self.first_load = True

        self.debug_javascript = debug_javascript
        self.anchor_positions = {}
        self.index_anchors = set()
        self.current_language = None
        self.loaded_javascript = False
        self.js_loader = JavaScriptLoader(
                    dynamic_coffeescript=self.debug_javascript)
        self.in_fullscreen_mode = False

        self.setLinkDelegationPolicy(self.DelegateAllLinks)
        self.scroll_marks = []
        self.shortcuts = shortcuts
        pal = self.palette()
        pal.setBrush(QPalette.Background, QColor(0xee, 0xee, 0xee))
        self.setPalette(pal)
        self.page_position = PagePosition(self)

        settings = self.settings()

        # Fonts
        self.all_viewer_plugins = tuple(all_viewer_plugins())
        for pl in self.all_viewer_plugins:
            pl.load_fonts()
        opts = config().parse()
        self.set_font_settings(opts)

        # Security
        settings.setAttribute(QWebSettings.JavaEnabled, False)
        settings.setAttribute(QWebSettings.PluginsEnabled, False)
        settings.setAttribute(QWebSettings.JavascriptCanOpenWindows, False)
        settings.setAttribute(QWebSettings.JavascriptCanAccessClipboard, False)

        # Miscellaneous
        settings.setAttribute(QWebSettings.LinksIncludedInFocusChain, True)
        settings.setAttribute(QWebSettings.DeveloperExtrasEnabled, True)
        self.set_user_stylesheet(opts)
        self.misc_config(opts)

        # Load javascript
        self.mainFrame().javaScriptWindowObjectCleared.connect(
                self.add_window_objects)

        self.turn_off_internal_scrollbars()

    def turn_off_internal_scrollbars(self):
        mf = self.mainFrame()
        mf.setScrollBarPolicy(Qt.Vertical, Qt.ScrollBarAlwaysOff)
        mf.setScrollBarPolicy(Qt.Horizontal, Qt.ScrollBarAlwaysOff)

    def set_user_stylesheet(self, opts):
        bg = opts.background_color or 'white'
        brules = ['background-color: %s !important'%bg]
        prefix = '''
            body { %s  }
        '''%('; '.join(brules))
        if opts.text_color:
            prefix += '\n\nbody, p, div { color: %s !important }'%opts.text_color
        raw = prefix + opts.user_css
        raw = '::selection {background:#ffff00; color:#000;}\n'+raw
        data = 'data:text/css;charset=utf-8;base64,'
        data += b64encode(raw.encode('utf-8'))
        self.settings().setUserStyleSheetUrl(QUrl(data))

    def findText(self, q, flags):
        if self.hyphenatable:
            q = unicode(q)
            hyphenated_q = self.javascript(
                'hyphenate_text(%s, "%s")' % (json.dumps(q, ensure_ascii=False), self.loaded_lang), typ='string')
            if QWebPage.findText(self, hyphenated_q, flags):
                return True
        return QWebPage.findText(self, q, flags)

    def misc_config(self, opts):
        self.hyphenate = opts.hyphenate
        self.hyphenate_default_lang = opts.hyphenate_default_lang
        self.do_fit_images = opts.fit_images
        self.page_flip_duration = opts.page_flip_duration
        self.enable_page_flip = self.page_flip_duration > 0.1
        self.font_magnification_step = opts.font_magnification_step
        self.wheel_flips_pages = opts.wheel_flips_pages
        self.line_scrolling_stops_on_pagebreaks = opts.line_scrolling_stops_on_pagebreaks
        screen_width = QApplication.desktop().screenGeometry().width()
        # Leave some space for the scrollbar and some border
        self.max_fs_width = min(opts.max_fs_width, screen_width-50)
        self.fullscreen_clock = opts.fullscreen_clock
        self.fullscreen_scrollbar = opts.fullscreen_scrollbar
        self.fullscreen_pos = opts.fullscreen_pos
        self.start_in_fullscreen = opts.start_in_fullscreen
        self.show_fullscreen_help = opts.show_fullscreen_help
        self.use_book_margins = opts.use_book_margins
        self.cols_per_screen = opts.cols_per_screen
        self.side_margin = opts.side_margin
        self.top_margin, self.bottom_margin = opts.top_margin, opts.bottom_margin
        self.show_controls = opts.show_controls

    def fit_images(self):
        if self.do_fit_images and not self.in_paged_mode:
            self.javascript('setup_image_scaling_handlers()')

    def add_window_objects(self):
        self.mainFrame().addToJavaScriptWindowObject("py_bridge", self)
        self.javascript('''
                py_bridge.__defineGetter__('value', function() {
                    return JSON.parse(this._pass_json_value);
                });
                py_bridge.__defineSetter__('value', function(val) {
                    this._pass_json_value = JSON.stringify(val);
                });
        ''')
        self.loaded_javascript = False

    def load_javascript_libraries(self):
        if self.loaded_javascript:
            return
        self.loaded_javascript = True
        evaljs = self.mainFrame().evaluateJavaScript
        self.loaded_lang = self.js_loader(evaljs, self.current_language,
                self.hyphenate_default_lang)
        mjpath = P(u'viewer/mathjax').replace(os.sep, '/')
        if iswindows:
            mjpath = u'/' + mjpath
        self.javascript(u'window.mathjax.base = %s'%(json.dumps(mjpath,
            ensure_ascii=False)))
        for pl in self.all_viewer_plugins:
            pl.load_javascript(evaljs)
        evaljs('py_bridge.mark_element.connect(window.calibre_extract.mark)')

    @pyqtSignature("")
    def animated_scroll_done(self):
        self.emit(SIGNAL('animated_scroll_done()'))

    @property
    def hyphenatable(self):
        # Qt fails to render soft hyphens correctly on windows xp
        return not isxp and self.hyphenate and getattr(self, 'loaded_lang', '')

    @pyqtSignature("")
    def init_hyphenate(self):
        if self.hyphenatable:
            self.javascript('do_hyphenation("%s")'%self.loaded_lang)

    @pyqtSlot(int)
    def page_turn_requested(self, backwards):
        self.page_turn.emit(bool(backwards))

    def _pass_json_value_getter(self):
        val = json.dumps(self.bridge_value)
        return QString(val)

    def _pass_json_value_setter(self, value):
        self.bridge_value = json.loads(unicode(value))

    _pass_json_value = pyqtProperty(QString, fget=_pass_json_value_getter,
            fset=_pass_json_value_setter)

    def after_load(self, last_loaded_path=None):
        self.javascript('window.paged_display.read_document_margins()')
        self.set_bottom_padding(0)
        self.fit_images()
        self.init_hyphenate()
        self.javascript('full_screen.save_margins()')
        if self.in_fullscreen_mode:
            self.switch_to_fullscreen_mode()
        if self.in_paged_mode:
            self.switch_to_paged_mode(last_loaded_path=last_loaded_path)
        self.read_anchor_positions(use_cache=False)
        evaljs = self.mainFrame().evaluateJavaScript
        for pl in self.all_viewer_plugins:
            pl.run_javascript(evaljs)
        self.javascript('window.mathjax.check_for_math()')
        self.first_load = False

    def colors(self):
        self.javascript('''
            bs = getComputedStyle(document.body);
            py_bridge.value = [bs.backgroundColor, bs.color]
            ''')
        ans = self.bridge_value
        return (ans if isinstance(ans, list) else ['white', 'black'])

    def read_anchor_positions(self, use_cache=True):
        self.bridge_value = tuple(self.index_anchors)
        self.javascript(u'''
            py_bridge.value = book_indexing.anchor_positions(py_bridge.value, %s);
            '''%('true' if use_cache else 'false'))
        self.anchor_positions = self.bridge_value
        if not isinstance(self.anchor_positions, dict):
            # Some weird javascript error happened
            self.anchor_positions = {}
        return {k:tuple(v) for k, v in self.anchor_positions.iteritems()}

    def switch_to_paged_mode(self, onresize=False, last_loaded_path=None):
        if onresize and not self.loaded_javascript:
            return
        self.javascript('''
            window.paged_display.use_document_margins = %s;
            window.paged_display.set_geometry(%d, %d, %d, %d);
            '''%(
            ('true' if self.use_book_margins else 'false'),
            self.cols_per_screen, self.top_margin, self.side_margin,
            self.bottom_margin
            ))
        force_fullscreen_layout = bool(getattr(last_loaded_path,
                                               'is_single_page', False))
        f = 'true' if force_fullscreen_layout else 'false'
        side_margin = self.javascript('window.paged_display.layout(%s)'%f, typ=int)
        # Setup the contents size to ensure that there is a right most margin.
        # Without this WebKit renders the final column with no margin, as the
        # columns extend beyond the boundaries (and margin) of body
        mf = self.mainFrame()
        sz = mf.contentsSize()
        scroll_width = self.javascript('document.body.scrollWidth', int)
        # At this point sz.width() is not reliable, presumably because Qt
        # has not yet been updated
        if scroll_width > self.window_width:
            sz.setWidth(scroll_width+side_margin)
            self.setPreferredContentsSize(sz)
        self.javascript('window.paged_display.fit_images()')

    @property
    def column_boundaries(self):
        if not self.loaded_javascript:
            return (0, 1)
        self.javascript(u'py_bridge.value = paged_display.column_boundaries()')
        return tuple(self.bridge_value)

    def after_resize(self):
        if self.in_paged_mode:
            self.setPreferredContentsSize(QSize())
            self.switch_to_paged_mode(onresize=True)
        self.javascript('window.mathjax.after_resize()')

    def switch_to_fullscreen_mode(self):
        self.in_fullscreen_mode = True
        self.javascript('full_screen.on(%d, %s)'%(self.max_fs_width,
            'true' if self.in_paged_mode else 'false'))

    def switch_to_window_mode(self):
        self.in_fullscreen_mode = False
        self.javascript('full_screen.off(%s)'%('true' if self.in_paged_mode
            else 'false'))

    @pyqtSignature("QString")
    def debug(self, msg):
        prints(msg)

    def reference_mode(self, enable):
        self.javascript(('enter' if enable else 'leave')+'_reference_mode()')

    def set_reference_prefix(self, prefix):
        self.javascript('reference_prefix = "%s"'%prefix)

    def goto(self, ref):
        self.javascript('goto_reference("%s")'%ref)

    def goto_bookmark(self, bm):
        if bm['type'] == 'legacy':
            bm = bm['pos']
            bm = bm.strip()
            if bm.startswith('>'):
                bm = bm[1:].strip()
            self.javascript('scroll_to_bookmark("%s")'%bm)
        elif bm['type'] == 'cfi':
            self.page_position.to_pos(bm['pos'])

    def javascript(self, string, typ=None):
        ans = self.mainFrame().evaluateJavaScript(string)
        if typ in {'int', int}:
            ans = ans.toInt()
            if ans[1]:
                return ans[0]
            return 0
        if typ in {'float', float}:
            ans = ans.toReal()
            return ans[0] if ans[1] else 0.0
        if typ == 'string':
            return unicode(ans.toString())
        return ans

    def javaScriptConsoleMessage(self, msg, lineno, msgid):
        if self.debug_javascript:
            prints(msg)
        else:
            return QWebPage.javaScriptConsoleMessage(self, msg, lineno, msgid)

    def javaScriptAlert(self, frame, msg):
        if self.debug_javascript:
            prints(msg)
        else:
            return QWebPage.javaScriptAlert(self, frame, msg)

    def scroll_by(self, dx=0, dy=0):
        self.mainFrame().scroll(dx, dy)

    def scroll_to(self, x=0, y=0):
        self.mainFrame().setScrollPosition(QPoint(x, y))

    def jump_to_anchor(self, anchor):
        if not self.loaded_javascript:
            return
        self.javascript('window.paged_display.jump_to_anchor("%s")'%anchor)

    def element_ypos(self, elem):
        ans, ok = elem.evaluateJavaScript('$(this).offset().top').toInt()
        if not ok:
            raise ValueError('No ypos found')
        return ans

    def elem_outer_xml(self, elem):
        return unicode(elem.toOuterXml())

    def bookmark(self):
        pos = self.page_position.current_pos
        return {'type':'cfi', 'pos':pos}

    @property
    def at_bottom(self):
        return self.height - self.ypos <= self.window_height

    @property
    def at_top(self):
        return self.ypos <=0

    def test(self):
        pass

    @property
    def ypos(self):
        return self.mainFrame().scrollPosition().y()

    @property
    def window_height(self):
        return self.javascript('window.innerHeight', 'int')

    @property
    def window_width(self):
        return self.javascript('window.innerWidth', 'int')

    @property
    def xpos(self):
        return self.mainFrame().scrollPosition().x()

    @dynamic_property
    def scroll_fraction(self):
        def fget(self):
            if self.in_paged_mode:
                return self.javascript('''
                ans = 0.0;
                if (window.paged_display) {
                    ans = window.paged_display.current_pos();
                }
                ans;''',  typ='float')
            else:
                try:
                    return abs(float(self.ypos)/(self.height-self.window_height))
                except ZeroDivisionError:
                    return 0.
        def fset(self, val):
            if self.in_paged_mode and self.loaded_javascript:
                self.javascript('paged_display.scroll_to_pos(%f)'%val)
            else:
                npos = val * (self.height - self.window_height)
                if npos < 0:
                    npos = 0
                self.scroll_to(x=self.xpos, y=npos)
        return property(fget=fget, fset=fset)

    @property
    def hscroll_fraction(self):
        try:
            return float(self.xpos)/self.width
        except ZeroDivisionError:
            return 0.

    @property
    def height(self):
        # Note that document.body.offsetHeight does not include top and bottom
        # margins on body and in some cases does not include the top margin on
        # the first element inside body either. See ticket #8791 for an example
        # of the latter.
        q = self.mainFrame().contentsSize().height()
        if q < 0:
            # Don't know if this is still needed, but it can't hurt
            j = self.javascript('document.body.offsetHeight', 'int')
            if j >= 0:
                q = j
        return q

    @property
    def width(self):
        return self.mainFrame().contentsSize().width()  # offsetWidth gives inaccurate results

    def set_bottom_padding(self, amount):
        s = QSize(-1, -1) if amount == 0 else QSize(self.viewportSize().width(),
                self.height+amount)
        self.setPreferredContentsSize(s)

    def extract_node(self):
        return unicode(self.mainFrame().evaluateJavaScript(
            'window.calibre_extract.extract()').toString())