mirror of
https://github.com/Kozea/WeasyPrint.git
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204 lines
7.2 KiB
Python
204 lines
7.2 KiB
Python
# coding: utf8
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# WeasyPrint converts web documents (HTML, CSS, ...) to PDF.
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# Copyright (C) 2011 Simon Sapin
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as
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# published by the Free Software Foundation, either version 3 of the
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# License, or (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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from __future__ import division
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import sys
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from ..css.values import get_single_keyword, get_single_pixel_value
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from ..formatting_structure import boxes
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from .. import text
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from .percentages import resolve_percentages
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from .inlines import get_new_lineboxes
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def block_level_layout(box):
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if isinstance(box, boxes.BlockBox):
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block_box_layout(box)
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elif isinstance(box, boxes.ReplacedBox):
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from . import replaced_box_layout
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replaced_box_layout(box)
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else:
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raise TypeError('Layout for %s not handled yet' % type(box).__name__)
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def block_box_layout(box):
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resolve_percentages(box)
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block_level_width(box)
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block_level_height(box)
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list_marker_layout(box)
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def list_marker_layout(box):
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# List markers can be either 'inside' or 'outside'.
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# Inside markers are layed out just like normal inline content, but
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# outside markers need specific layout.
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# TODO: implement outside markers in terms of absolute positioning,
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# see CSS3 lists.
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marker = getattr(box, 'outside_list_marker', None)
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if marker:
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resolve_percentages(marker)
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if isinstance(marker, boxes.TextBox):
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text_fragment = text.TextFragment.from_textbox(marker)
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marker.width, marker.height = text_fragment.get_size()
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else:
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# Image marker
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marker.width, marker.height = list_style_image_size(marker)
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# Align the top of the marker box with the top of its list-item’s
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# content-box.
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# TODO: align the baselines of the first lines instead?
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marker.position_y = box.content_box_y()
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# ... and its right with the left of its list-item’s padding box.
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# (Swap left and right for right-to-left text.)
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marker.position_x = box.border_box_x()
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half_em = 0.5 * get_single_pixel_value(box.style.font_size)
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direction = get_single_keyword(box.style.direction)
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if direction == 'ltr':
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marker.margin_right = half_em
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marker.position_x -= marker.margin_width()
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else:
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marker.margin_left = half_em
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marker.position_x += box.border_width()
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def list_style_image_size(marker_box):
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"""
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Return the used (width, height) for an image in `list-style-image`.
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See http://www.w3.org/TR/CSS21/generate.html#propdef-list-style-image
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"""
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image = marker_box.replacement
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width = image.intrinsic_width()
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height = image.intrinsic_width()
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ratio = image.intrinsic_ratio()
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one_em = get_single_pixel_value(marker_box.style.font_size)
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if width is not None and height is not None:
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return width, height
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elif width is not None and ratio is not None:
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return width, width / ratio
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elif height is not None and ratio is not None:
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return height * ratio, height
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elif ratio is not None:
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# ratio >= 1 : width >= height
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if ratio >= 1:
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return one_em, one_em / ratio
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else:
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return one_em * ratio, one_em
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else:
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return (width if width is not None else one_em,
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height if height is not None else one_em)
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def block_level_width(box):
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# cb = containing block
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cb_width, cb_height = box.containing_block_size()
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# http://www.w3.org/TR/CSS21/visudet.html#blockwidth
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# These names are waaay too long
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margin_l = box.margin_left
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margin_r = box.margin_right
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padding_l = box.padding_left
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padding_r = box.padding_right
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border_l = box.border_left_width
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border_r = box.border_right_width
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width = box.width
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# Only margin-left, margin-right and width can be 'auto'.
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# We want: width of containing block ==
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# margin-left + border-left-width + padding-left + width
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# + padding-right + border-right-width + margin-right
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paddings_plus_borders = padding_l + padding_r + border_l + border_r
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if box.width != 'auto':
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total = paddings_plus_borders + width
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if margin_l != 'auto':
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total += margin_l
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if margin_r != 'auto':
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total += margin_r
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if total > cb_width:
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if margin_l == 'auto':
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margin_l = box.margin_left = 0
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if margin_r == 'auto':
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margin_r = box.margin_right = 0
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if width != 'auto' and margin_l != 'auto' and margin_r != 'auto':
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# The equation is over-constrained
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margin_sum = cb_width - paddings_plus_borders - width
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# This is the direction of the containing block, but the containing
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# block for block-level boxes in normal flow is always the parent.
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# TODO: is it?
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if get_single_keyword(box.parent.style.direction) == 'ltr':
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margin_r = box.margin_right = margin_sum - margin_l
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else:
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margin_l = box.margin_left = margin_sum - margin_r
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if width == 'auto':
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if margin_l == 'auto':
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margin_l = box.margin_left = 0
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if margin_r == 'auto':
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margin_r = box.margin_right = 0
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width = box.width = cb_width - (
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paddings_plus_borders + margin_l + margin_r)
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margin_sum = cb_width - paddings_plus_borders - width
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if margin_l == 'auto' and margin_r == 'auto':
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box.margin_left = margin_sum / 2.
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box.margin_right = margin_sum / 2.
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elif margin_l == 'auto' and margin_r != 'auto':
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box.margin_left = margin_sum - margin_r
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elif margin_l != 'auto' and margin_r == 'auto':
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box.margin_right = margin_sum - margin_l
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def block_level_height(box):
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if get_single_keyword(box.style.overflow) != 'visible':
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raise NotImplementedError
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assert isinstance(box, boxes.BlockBox)
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if box.margin_top == 'auto':
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box.margin_top = 0
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if box.margin_bottom == 'auto':
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box.margin_bottom = 0
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position_x = box.content_box_x()
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position_y = box.content_box_y()
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initial_position_y = position_y
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children = list(box.children)
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box.empty()
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for child in children:
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if not child.is_in_normal_flow():
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continue
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# TODO: collapse margins:
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# http://www.w3.org/TR/CSS21/visudet.html#normal-block
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child.position_x = position_x
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child.position_y = position_y
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if isinstance(child, boxes.LineBox):
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for line in get_new_lineboxes(child):
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box.add_child(line)
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position_y += line.height
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else:
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block_level_layout(child)
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position_y += child.margin_height()
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box.add_child(child)
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if box.height == 'auto':
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box.height = position_y - initial_position_y
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