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WeasyPrint/weasyprint/layout/percentages.py

107 lines
3.8 KiB
Python

# coding: utf8
"""
weasyprint.layout.percentages
-----------------------------
Resolve percentages into fixed values.
:copyright: Copyright 2011-2012 Simon Sapin and contributors, see AUTHORS.
:license: BSD, see LICENSE for details.
"""
from __future__ import division, unicode_literals
from ..formatting_structure import boxes
def resolve_one_percentage(box, property_name, refer_to):
"""Set a used length value from a computed length value.
``refer_to`` is the length for 100%. If ``refer_to`` is not a number, it
just replaces percentages.
"""
# box.style has computed values
value = box.style[property_name]
if value == 'auto':
result = value
elif value.unit == 'px':
result = value.value
else:
assert value.unit == '%'
result = value.value * refer_to / 100.
# box attributes are used values
setattr(box, property_name, result)
def resolve_position_percentages(box, containing_block):
cb_width, cb_height = containing_block
resolve_one_percentage(box, 'left', cb_width)
resolve_one_percentage(box, 'right', cb_width)
resolve_one_percentage(box, 'top', cb_height)
resolve_one_percentage(box, 'bottom', cb_height)
def resolve_percentages(box, containing_block):
"""Set used values as attributes of the box object."""
if isinstance(containing_block, boxes.Box):
# cb is short for containing block
cb_width = containing_block.width
cb_height = containing_block.height
else:
cb_width, cb_height = containing_block
if isinstance(box, boxes.PageBox):
maybe_height = cb_height
else:
maybe_height = cb_width
resolve_one_percentage(box, 'margin_left', cb_width)
resolve_one_percentage(box, 'margin_right', cb_width)
resolve_one_percentage(box, 'margin_top', maybe_height)
resolve_one_percentage(box, 'margin_bottom', maybe_height)
resolve_one_percentage(box, 'padding_left', cb_width)
resolve_one_percentage(box, 'padding_right', cb_width)
resolve_one_percentage(box, 'padding_top', maybe_height)
resolve_one_percentage(box, 'padding_bottom', maybe_height)
resolve_one_percentage(box, 'width', cb_width)
resolve_one_percentage(box, 'min_width', cb_width)
resolve_one_percentage(box, 'max_width', cb_width)
# XXX later: top, bottom, left and right on positioned elements
if cb_height == 'auto':
# Special handling when the height of the containing block
# depends on its content.
height = box.style.height
if height == 'auto' or height.unit == '%':
box.height = 'auto'
else:
assert height.unit == 'px'
box.height = height.value
resolve_one_percentage(box, 'min_height', 0)
resolve_one_percentage(box, 'max_height', float('inf'))
else:
resolve_one_percentage(box, 'height', cb_height)
resolve_one_percentage(box, 'min_height', cb_height)
resolve_one_percentage(box, 'max_height', cb_height)
# Used value == computed value
for side in ['top', 'right', 'bottom', 'left']:
prop = 'border_{0}_width'.format(side)
setattr(box, prop, box.style[prop])
if box.style.box_sizing == 'border-box':
if box.width != 'auto':
box.width -= (box.padding_left + box.padding_right +
box.border_left_width + box.border_right_width)
if box.height != 'auto':
box.height -= (box.padding_top + box.padding_bottom +
box.border_top_width + box.border_bottom_width)
elif box.style.box_sizing == 'padding-box':
if box.width != 'auto':
box.width -= box.padding_left + box.padding_right
if box.height != 'auto':
box.height -= box.padding_top + box.padding_bottom
else:
assert box.style.box_sizing == 'content-box'