337 lines
11 KiB
Python
337 lines
11 KiB
Python
"""Decode HTML into attributed text.
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A subset of HTML 4.01 Transitional is implemented. The following elements are
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supported fully::
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B BLOCKQUOTE BR CENTER CODE DD DIR DL EM FONT H1 H2 H3 H4 H5 H6 I IMG KBD
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LI MENU OL P PRE Q SAMP STRONG SUB SUP TT U UL VAR
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The mark (bullet or number) of a list item is separated from the body of the
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list item with a tab, as the pyglet document model does not allow
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out-of-stream text. This means lists display as expected, but behave a little
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oddly if edited.
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No CSS styling is supported.
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"""
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import re
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from html.parser import HTMLParser
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from html import entities
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import pyglet
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from pyglet.text.formats import structured
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def _hex_color(val):
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return [(val >> 16) & 0xff, (val >> 8) & 0xff, val & 0xff, 255]
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_color_names = {
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'black': _hex_color(0x000000),
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'silver': _hex_color(0xc0c0c0),
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'gray': _hex_color(0x808080),
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'white': _hex_color(0xffffff),
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'maroon': _hex_color(0x800000),
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'red': _hex_color(0xff0000),
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'purple': _hex_color(0x800080),
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'fucsia': _hex_color(0x008000),
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'green': _hex_color(0x00ff00),
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'lime': _hex_color(0xffff00),
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'olive': _hex_color(0x808000),
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'yellow': _hex_color(0xff0000),
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'navy': _hex_color(0x000080),
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'blue': _hex_color(0x0000ff),
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'teal': _hex_color(0x008080),
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'aqua': _hex_color(0x00ffff),
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}
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def _parse_color(value):
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if value.startswith('#'):
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return _hex_color(int(value[1:], 16))
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else:
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try:
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return _color_names[value.lower()]
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except KeyError:
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raise ValueError()
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_whitespace_re = re.compile(u'[\u0020\u0009\u000c\u200b\r\n]+', re.DOTALL)
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_metadata_elements = ['head', 'title']
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_block_elements = ['p', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6',
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'ul', 'ol', 'dir', 'menu',
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'pre', 'dl', 'div', 'center',
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'noscript', 'noframes', 'blockquote', 'form',
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'isindex', 'hr', 'table', 'fieldset', 'address',
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# Incorrect, but we treat list items as blocks:
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'li', 'dd', 'dt', ]
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_block_containers = ['_top_block',
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'body', 'div', 'center', 'object', 'applet',
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'blockquote', 'ins', 'del', 'dd', 'li', 'form',
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'fieldset', 'button', 'th', 'td', 'iframe', 'noscript',
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'noframes',
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# Incorrect, but we treat list items as blocks:
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'ul', 'ol', 'dir', 'menu', 'dl']
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class HTMLDecoder(HTMLParser, structured.StructuredTextDecoder):
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"""Decoder for HTML documents.
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"""
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#: Default style attributes for unstyled text in the HTML document.
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#:
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#: :type: dict
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default_style = {
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'font_name': 'Times New Roman',
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'font_size': 12,
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'margin_bottom': '12pt',
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'bold': False,
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'italic': False,
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}
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#: Map HTML font sizes to actual font sizes, in points.
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#:
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#: :type: dict
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font_sizes = {
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1: 8,
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2: 10,
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3: 12,
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4: 14,
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5: 18,
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6: 24,
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7: 48
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}
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def decode_structured(self, text, location):
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self.location = location
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self._font_size_stack = [3]
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self.list_stack.append(structured.UnorderedListBuilder({}))
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self.strip_leading_space = True
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self.block_begin = True
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self.need_block_begin = False
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self.element_stack = ['_top_block']
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self.in_metadata = False
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self.in_pre = False
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self.push_style('_default', self.default_style)
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self.feed(text)
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self.close()
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def get_image(self, filename):
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return pyglet.image.load(filename, file=self.location.open(filename))
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def prepare_for_data(self):
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if self.need_block_begin:
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self.add_text('\n')
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self.block_begin = True
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self.need_block_begin = False
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def handle_data(self, data):
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if self.in_metadata:
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return
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if self.in_pre:
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self.add_text(data)
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else:
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data = _whitespace_re.sub(' ', data)
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if data.strip():
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self.prepare_for_data()
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if self.block_begin or self.strip_leading_space:
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data = data.lstrip()
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self.block_begin = False
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self.add_text(data)
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self.strip_leading_space = data.endswith(' ')
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def handle_starttag(self, tag, case_attrs):
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if self.in_metadata:
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return
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element = tag.lower()
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attrs = {}
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for key, value in case_attrs:
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attrs[key.lower()] = value
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if element in _metadata_elements:
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self.in_metadata = True
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elif element in _block_elements:
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# Pop off elements until we get to a block container.
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while self.element_stack[-1] not in _block_containers:
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self.handle_endtag(self.element_stack[-1])
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if not self.block_begin:
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self.add_text('\n')
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self.block_begin = True
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self.need_block_begin = False
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self.element_stack.append(element)
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style = {}
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if element in ('b', 'strong'):
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style['bold'] = True
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elif element in ('i', 'em', 'var'):
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style['italic'] = True
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elif element in ('tt', 'code', 'samp', 'kbd'):
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style['font_name'] = 'Courier New'
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elif element == 'u':
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color = self.current_style.get('color')
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if color is None:
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color = [0, 0, 0, 255]
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style['underline'] = color
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elif element == 'font':
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if 'face' in attrs:
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style['font_name'] = attrs['face'].split(',')
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if 'size' in attrs:
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size = attrs['size']
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try:
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if size.startswith('+'):
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size = self._font_size_stack[-1] + int(size[1:])
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elif size.startswith('-'):
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size = self._font_size_stack[-1] - int(size[1:])
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else:
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size = int(size)
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except ValueError:
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size = 3
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self._font_size_stack.append(size)
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if size in self.font_sizes:
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style['font_size'] = self.font_sizes.get(size, 3)
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elif 'real_size' in attrs:
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size = int(attrs['real_size'])
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self._font_size_stack.append(size)
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style['font_size'] = size
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else:
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self._font_size_stack.append(self._font_size_stack[-1])
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if 'color' in attrs:
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try:
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style['color'] = _parse_color(attrs['color'])
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except ValueError:
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pass
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elif element == 'sup':
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size = self._font_size_stack[-1] - 1
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style['font_size'] = self.font_sizes.get(size, 1)
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style['baseline'] = '3pt'
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elif element == 'sub':
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size = self._font_size_stack[-1] - 1
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style['font_size'] = self.font_sizes.get(size, 1)
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style['baseline'] = '-3pt'
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elif element == 'h1':
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style['font_size'] = 24
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style['bold'] = True
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style['align'] = 'center'
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elif element == 'h2':
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style['font_size'] = 18
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style['bold'] = True
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elif element == 'h3':
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style['font_size'] = 16
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style['bold'] = True
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elif element == 'h4':
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style['font_size'] = 14
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style['bold'] = True
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elif element == 'h5':
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style['font_size'] = 12
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style['bold'] = True
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elif element == 'h6':
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style['font_size'] = 12
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style['italic'] = True
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elif element == 'br':
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self.add_text(u'\u2028')
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self.strip_leading_space = True
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elif element == 'p':
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if attrs.get('align') in ('left', 'center', 'right'):
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style['align'] = attrs['align']
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elif element == 'center':
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style['align'] = 'center'
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elif element == 'pre':
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style['font_name'] = 'Courier New'
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style['margin_bottom'] = 0
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self.in_pre = True
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elif element == 'blockquote':
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left_margin = self.current_style.get('margin_left') or 0
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right_margin = self.current_style.get('margin_right') or 0
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style['margin_left'] = left_margin + 60
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style['margin_right'] = right_margin + 60
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elif element == 'q':
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self.handle_data(u'\u201c')
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elif element == 'ol':
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try:
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start = int(attrs.get('start', 1))
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except ValueError:
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start = 1
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format = attrs.get('type', '1') + '.'
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builder = structured.OrderedListBuilder(start, format)
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builder.begin(self, style)
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self.list_stack.append(builder)
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elif element in ('ul', 'dir', 'menu'):
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type = attrs.get('type', 'disc').lower()
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if type == 'circle':
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mark = u'\u25cb'
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elif type == 'square':
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mark = u'\u25a1'
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else:
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mark = u'\u25cf'
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builder = structured.UnorderedListBuilder(mark)
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builder.begin(self, style)
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self.list_stack.append(builder)
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elif element == 'li':
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self.list_stack[-1].item(self, style)
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self.strip_leading_space = True
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elif element == 'dl':
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style['margin_bottom'] = 0
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elif element == 'dd':
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left_margin = self.current_style.get('margin_left') or 0
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style['margin_left'] = left_margin + 30
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elif element == 'img':
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image = self.get_image(attrs.get('src'))
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if image:
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width = attrs.get('width')
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if width:
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width = int(width)
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height = attrs.get('height')
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if height:
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height = int(height)
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self.prepare_for_data()
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self.add_element(structured.ImageElement(image, width, height))
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self.strip_leading_space = False
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self.push_style(element, style)
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def handle_endtag(self, tag):
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element = tag.lower()
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if element not in self.element_stack:
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return
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self.pop_style(element)
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while self.element_stack.pop() != element:
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pass
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if element in _metadata_elements:
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self.in_metadata = False
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elif element in _block_elements:
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self.block_begin = False
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self.need_block_begin = True
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if element == 'font' and len(self._font_size_stack) > 1:
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self._font_size_stack.pop()
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elif element == 'pre':
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self.in_pre = False
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elif element == 'q':
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self.handle_data(u'\u201d')
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elif element in ('ul', 'ol'):
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if len(self.list_stack) > 1:
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self.list_stack.pop()
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def handle_entityref(self, name):
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if name in entities.name2codepoint:
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self.handle_data(chr(entities.name2codepoint[name]))
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def handle_charref(self, name):
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name = name.lower()
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try:
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if name.startswith('x'):
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self.handle_data(chr(int(name[1:], 16)))
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else:
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self.handle_data(chr(int(name)))
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except ValueError:
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pass
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