mirror of
https://github.com/Kozea/WeasyPrint.git
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788 lines
29 KiB
Python
788 lines
29 KiB
Python
# coding: utf8
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"""
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weasyprint.layout.inline
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------------------------
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Line breaking and layout for inline-level boxes.
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:copyright: Copyright 2011-2012 Simon Sapin and contributors, see AUTHORS.
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:license: BSD, see LICENSE for details.
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"""
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from __future__ import division, unicode_literals
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import functools
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import cairo
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from .markers import image_marker_layout
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from .percentages import resolve_percentages, resolve_one_percentage
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from .preferred import shrink_to_fit
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from ..text import TextFragment
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from ..formatting_structure import boxes
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from ..css.computed_values import used_line_height
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def iter_line_boxes(document, box, position_y, skip_stack,
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containing_block, device_size):
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"""Return an iterator of ``(line, resume_at)``.
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``line`` is a laid-out LineBox with as much content as possible that
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fits in the available width.
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:param linebox: a non-laid-out :class:`LineBox`
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:param position_y: vertical top position of the line box on the page
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:param skip_stack: ``None`` to start at the beginning of ``linebox``,
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or a ``resume_at`` value to continue just after an
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already laid-out line.
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:param containing_block: Containing block of the line box:
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a :class:`BlockContainerBox`
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:param device_size: ``(width, height)`` of the current page.
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"""
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while 1:
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line, resume_at = get_next_linebox(
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document, box, position_y, skip_stack,
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containing_block, device_size)
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if line is None:
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return
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yield line, resume_at
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if resume_at is None:
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return
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skip_stack = resume_at
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position_y += line.height
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def get_next_linebox(document, linebox, position_y, skip_stack,
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containing_block, device_size):
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"""Return ``(line, resume_at)``."""
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position_x = linebox.position_x
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max_x = position_x + containing_block.width
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if skip_stack is None:
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# text-indent only at the start of the first line
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# Other percentages (margins, width, ...) do not apply.
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resolve_one_percentage(linebox, 'text_indent', containing_block.width)
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position_x += linebox.text_indent
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skip_stack = skip_first_whitespace(linebox, skip_stack)
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if skip_stack == 'continue':
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return None, None
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resolve_percentages(linebox, containing_block)
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line, resume_at, preserved_line_break = split_inline_box(
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document, linebox, position_x, max_x, skip_stack, containing_block,
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device_size)
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remove_last_whitespace(document, line)
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bottom, top = inline_box_verticality(line, baseline_y=0)
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last = resume_at is None or preserved_line_break
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offset_x = text_align(document, line, containing_block, last)
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if bottom is None:
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# No children at all
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line.position_y = position_y
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offset_y = 0
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if preserved_line_break:
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# Only the strut.
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line.baseline = line.margin_top
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line.height += line.margin_top + line.margin_bottom
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else:
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line.height = 0
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line.baseline = 0
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else:
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assert top is not None
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line.baseline = -top
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line.position_y = top
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line.height = bottom - top
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offset_y = position_y - top
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line.margin_top = 0
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line.margin_bottom = 0
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if offset_x != 0 or offset_y != 0:
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# This also translates children
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line.translate(offset_x, offset_y)
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return line, resume_at
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def skip_first_whitespace(box, skip_stack):
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"""Return the ``skip_stack`` to start just after the remove spaces
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at the beginning of the line.
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See http://www.w3.org/TR/CSS21/text.html#white-space-model
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"""
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if skip_stack is None:
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index = 0
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next_skip_stack = None
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else:
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index, next_skip_stack = skip_stack
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if isinstance(box, boxes.TextBox):
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assert next_skip_stack is None
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white_space = box.style.white_space
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length = len(box.text)
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if index == length:
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# Starting a the end of the TextBox, no text to see: Continue
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return 'continue'
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if white_space in ('normal', 'nowrap', 'pre-line'):
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while index < length and box.text[index] == ' ':
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index += 1
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return index, None
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if isinstance(box, (boxes.LineBox, boxes.InlineBox)):
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if index == 0 and not box.children:
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return None
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result = skip_first_whitespace(box.children[index], next_skip_stack)
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if result == 'continue':
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index += 1
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if index >= len(box.children):
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return 'continue'
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result = skip_first_whitespace(box.children[index], None)
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return index, result
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assert skip_stack is None, 'unexpected skip inside %s' % box
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return None
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def remove_last_whitespace(document, box):
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"""Remove in place space characters at the end of a line.
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This also reduces the width of the inline parents of the modified text.
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"""
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ancestors = []
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while isinstance(box, (boxes.LineBox, boxes.InlineBox)):
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ancestors.append(box)
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if not box.children:
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return
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box = box.children[-1]
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if not (isinstance(box, boxes.TextBox) and
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box.style.white_space in ('normal', 'nowrap', 'pre-line')):
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return
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new_text = box.text.rstrip(' ')
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if new_text:
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if len(new_text) == len(box.text):
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return
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new_box, resume, _ = split_text_box(document, box, box.width * 2, 0)
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assert new_box is not None
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assert resume is None
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space_width = box.width - new_box.width
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box.width = new_box.width
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box.show_line = new_box.show_line
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else:
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space_width = box.width
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box.width = 0
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box.show_line = lambda x: x # No-op
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box.text = new_text
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for ancestor in ancestors:
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ancestor.width -= space_width
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# TODO: All tabs (U+0009) are rendered as a horizontal shift that
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# lines up the start edge of the next glyph with the next tab stop.
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# Tab stops occur at points that are multiples of 8 times the width
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# of a space (U+0020) rendered in the block's font from the block's
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# starting content edge.
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# TODO: If spaces (U+0020) or tabs (U+0009) at the end of a line have
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# 'white-space' set to 'pre-wrap', UAs may visually collapse them.
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def replaced_box_width(box, device_size):
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"""
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Compute and set the used width for replaced boxes (inline- or block-level)
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"""
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# http://www.w3.org/TR/CSS21/visudet.html#inline-replaced-width
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_surface, intrinsic_width, _intrinsic_height = box.replacement
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# TODO: update this when we have replaced elements that do not
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# always have an intrinsic width. (See commented code below.)
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assert intrinsic_width is not None
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if box.width == 'auto':
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box.width = intrinsic_width
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# Untested code for when we do not always have an intrinsic width.
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# intrinsic_ratio = intrinsic_width / intrinsic_height
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# if box.height == 'auto' and box.width == 'auto':
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# if intrinsic_width is not None:
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# box.width = intrinsic_width
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# elif intrinsic_height is not None and intrinsic_ratio is not None:
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# box.width = intrinsic_ratio * intrinsic_height
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# elif box.height != 'auto' and intrinsic_ratio is not None:
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# box.width = intrinsic_ratio * box.height
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# elif intrinsic_ratio is not None:
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# pass
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# # TODO: Intrinsic ratio only: undefined in CSS 2.1.
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# # " It is suggested that, if the containing block's width does not
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# # itself depend on the replaced element's width, then the used
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# # value of 'width' is calculated from the constraint equation
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# # used for block-level, non-replaced elements in normal flow. "
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# # Still no value
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# if box.width == 'auto':
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# if intrinsic_width is not None:
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# box.width = intrinsic_width
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# else:
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# # Then the used value of 'width' becomes 300px. If 300px is too
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# # wide to fit the device, UAs should use the width of the largest
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# # rectangle that has a 2:1 ratio and fits the device instead.
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# device_width, _device_height = device_size
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# box.width = min(300, device_width)
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def replaced_box_height(box, device_size):
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"""
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Compute and set the used height for replaced boxes (inline- or block-level)
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"""
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# http://www.w3.org/TR/CSS21/visudet.html#inline-replaced-height
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_surface, intrinsic_width, intrinsic_height = box.replacement
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# TODO: update this when we have replaced elements that do not
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# always have intrinsic dimensions. (See commented code below.)
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assert intrinsic_width is not None
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assert intrinsic_height is not None
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if intrinsic_height == 0:
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# Results in box.height == 0 if used, whatever the used width
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# or intrinsic width.
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intrinsic_ratio = float('inf')
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else:
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intrinsic_ratio = intrinsic_width / intrinsic_height
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# Test 'auto' on the computed width, not the used width
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if box.style.height == 'auto' and box.style.width == 'auto':
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box.height = intrinsic_height
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elif box.style.height == 'auto':
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box.height = box.width / intrinsic_ratio
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# Untested code for when we do not always have intrinsic dimensions.
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# if box.style.height == 'auto' and box.style.width == 'auto':
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# if intrinsic_height is not None:
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# box.height = intrinsic_height
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# elif intrinsic_ratio is not None and box.style.height == 'auto':
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# box.height = box.width / intrinsic_ratio
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# elif box.style.height == 'auto' and intrinsic_height is not None:
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# box.height = intrinsic_height
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# elif box.style.height == 'auto':
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# device_width, _device_height = device_size
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# box.height = min(150, device_width / 2)
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def handle_min_max_width(function):
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"""Decorate a function that sets the used width of a box to handle
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{min,max}-width.
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"""
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@functools.wraps(function)
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def wrapper(box, *args):
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computed_margins = box.margin_left, box.margin_right
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function(box, *args)
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if box.width > box.max_width:
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box.width = box.max_width
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box.margin_left, box.margin_right = computed_margins
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function(box, *args)
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if box.width < box.min_width:
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box.width = box.min_width
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box.margin_left, box.margin_right = computed_margins
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function(box, *args)
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return wrapper
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def handle_min_max_height(function):
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"""Decorate a function that sets the used height of a box to handle
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{min,max}-height.
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"""
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@functools.wraps(function)
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def wrapper(box, *args):
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computed_margins = box.margin_top, box.margin_bottom
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function(box, *args)
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if box.height > box.max_height:
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box.height = box.max_height
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box.margin_top, box.margin_bottom = computed_margins
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function(box, *args)
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if box.height < box.min_height:
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box.height = box.min_height
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box.margin_top, box.margin_bottom = computed_margins
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function(box, *args)
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return wrapper
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min_max_replaced_width = handle_min_max_width(replaced_box_width)
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min_max_replaced_height = handle_min_max_height(replaced_box_height)
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def inline_replaced_box_layout(box, containing_block, device_size):
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"""Lay out an inline :class:`boxes.ReplacedBox` ``box``."""
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for side in ['top', 'right', 'bottom', 'left']:
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if getattr(box, 'margin_' + side) == 'auto':
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setattr(box, 'margin_' + side, 0)
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if box.style.width == 'auto' and box.style.height == 'auto':
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replaced_box_width(box, device_size)
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replaced_box_height(box, device_size)
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min_max_auto_replaced(box)
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else:
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min_max_replaced_width(box, device_size)
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min_max_replaced_height(box, device_size)
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def min_max_auto_replaced(box):
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"""Resolve {min,max}-{width,height} constraints on replaced elements
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that have 'auto' width and heights.
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"""
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width = box.width
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height = box.height
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min_width = box.min_width
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min_height = box.min_height
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max_width = max(min_width, box.max_width)
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max_height = max(min_height, box.max_height)
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# (violation_width, violation_height)
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violations = (
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'min' if width < min_width else 'max' if width > max_width else '',
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'min' if height < min_height else 'max' if height > max_height else '')
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# Work around divisions by zero. These are pathological cases anyway.
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if width == 0:
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width = 1e-6
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if height == 0:
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height = 1e-6
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# ('', ''): nothing to do
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if violations == ('max', ''):
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box.width = max_width
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box.height = max(max_width * height / width, min_height)
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elif violations == ('min', ''):
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box.width = min_width
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box.height = min(min_width * height / width, max_height)
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elif violations == ('', 'max'):
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box.width = max(max_height * width / height, min_width)
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box.height = max_height
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elif violations == ('', 'min'):
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box.width = min(min_height * width / height, max_width)
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box.height = min_height
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elif violations == ('max', 'max'):
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if max_width / width <= max_height / height:
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box.width = max_width
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box.height = max(min_height, max_width * height / width)
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else:
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box.width = max(min_width, max_height * width / height)
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box.height = max_height
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elif violations == ('min', 'min'):
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if min_width / width <= min_height / height:
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box.width = min(max_width, min_height * width / height)
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box.height = min_height
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else:
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box.width = min_width
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box.height = min(max_height, min_width * height / width)
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elif violations == ('min', 'max'):
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box.width = min_width
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box.height = max_height
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elif violations == ('max', 'min'):
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box.width = max_width
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box.height = min_height
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def atomic_box(document, box, position_x, skip_stack, containing_block,
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device_size):
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"""Compute the width and the height of the atomic ``box``."""
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if isinstance(box, boxes.ReplacedBox):
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if getattr(box, 'is_list_marker', False):
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image_marker_layout(box)
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else:
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inline_replaced_box_layout(box, containing_block, device_size)
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elif isinstance(box, boxes.InlineBlockBox):
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box = inline_block_box_layout(
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document, box, position_x, skip_stack, containing_block,
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device_size)
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else: # pragma: no cover
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raise TypeError('Layout for %s not handled yet' % type(box).__name__)
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return box
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def inline_block_box_layout(document, box, position_x, skip_stack,
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containing_block, device_size):
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# Avoid a circular import
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from .blocks import block_container_layout
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resolve_percentages(box, containing_block)
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# http://www.w3.org/TR/CSS21/visudet.html#inlineblock-width
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if box.margin_left == 'auto':
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box.margin_left = 0
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if box.margin_right == 'auto':
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box.margin_right = 0
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inline_block_width(box, containing_block)
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box.position_x = position_x
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box.position_y = 0
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box, _, _, _, _ = block_container_layout(
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document, box, max_position_y=float('inf'), skip_stack=skip_stack,
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device_size=device_size, page_is_empty=True)
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# TODO: Why this translation?
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box.translate(0, -box.margin_height())
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return box
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@handle_min_max_width
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def inline_block_width(box, containing_block):
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if box.width == 'auto':
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box.width = shrink_to_fit(box, containing_block.width)
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def split_inline_level(document, box, position_x, max_x, skip_stack,
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containing_block, device_size):
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"""Fit as much content as possible from an inline-level box in a width.
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Return ``(new_box, resume_at)``. ``resume_at`` is ``None`` if all of the
|
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content fits. Otherwise it can be passed as a ``skip_stack`` parameter
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to resume where we left off.
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``new_box`` is non-empty (unless the box is empty) and as big as possible
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while being narrower than ``available_width``, if possible (may overflow
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is no split is possible.)
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"""
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resolve_percentages(box, containing_block)
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if isinstance(box, boxes.TextBox):
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box.position_x = position_x
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if skip_stack is None:
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skip = 0
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else:
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skip, skip_stack = skip_stack
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skip = skip or 0
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assert skip_stack is None
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new_box, skip, preserved_line_break = split_text_box(
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document, box, max_x - position_x, skip)
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|
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if skip is None:
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resume_at = None
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else:
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resume_at = (skip, None)
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elif isinstance(box, boxes.InlineBox):
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if box.margin_left == 'auto':
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box.margin_left = 0
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if box.margin_right == 'auto':
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box.margin_right = 0
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new_box, resume_at, preserved_line_break = split_inline_box(
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document, box, position_x, max_x, skip_stack, containing_block,
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device_size)
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elif isinstance(box, boxes.AtomicInlineLevelBox):
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new_box = atomic_box(
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document, box, position_x, skip_stack, containing_block,
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device_size)
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||
new_box.position_x = position_x
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||
new_box.baseline = new_box.margin_height()
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||
resume_at = None
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preserved_line_break = False
|
||
#else: unexpected box type here
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||
return new_box, resume_at, preserved_line_break
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|
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def split_inline_box(document, box, position_x, max_x, skip_stack,
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containing_block, device_size):
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||
"""Same behavior as split_inline_level."""
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||
initial_position_x = position_x
|
||
assert isinstance(box, (boxes.LineBox, boxes.InlineBox))
|
||
left_spacing = (box.padding_left + box.margin_left +
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box.border_left_width)
|
||
right_spacing = (box.padding_right + box.margin_right +
|
||
box.border_right_width)
|
||
position_x += left_spacing
|
||
content_box_left = position_x
|
||
|
||
children = []
|
||
preserved_line_break = False
|
||
|
||
if skip_stack is None:
|
||
skip = 0
|
||
else:
|
||
skip, skip_stack = skip_stack
|
||
|
||
for index, child in box.enumerate_skip(skip):
|
||
assert child.is_in_normal_flow(), '"Abnormal" flow not supported yet.'
|
||
new_child, resume_at, preserved = split_inline_level(
|
||
document, child, position_x, max_x, skip_stack,
|
||
containing_block, device_size)
|
||
skip_stack = None
|
||
if preserved:
|
||
preserved_line_break = True
|
||
|
||
# TODO: this is non-optimal when last_child is True and
|
||
# width <= remaining_width < width + right_spacing
|
||
# with
|
||
# width = part1.margin_width()
|
||
|
||
# TODO: on the last child, take care of right_spacing
|
||
|
||
if new_child is None:
|
||
# may be None where we would have an empty TextBox
|
||
assert isinstance(child, boxes.TextBox)
|
||
else:
|
||
margin_width = new_child.margin_width()
|
||
new_position_x = position_x + margin_width
|
||
|
||
if (new_position_x > max_x and children):
|
||
# too wide, and the inline is non-empty:
|
||
# put child entirely on the next line.
|
||
resume_at = (index, None)
|
||
break
|
||
else:
|
||
position_x = new_position_x
|
||
children.append(new_child)
|
||
|
||
if resume_at is not None:
|
||
resume_at = (index, resume_at)
|
||
break
|
||
else:
|
||
resume_at = None
|
||
|
||
new_box = box.copy_with_children(children)
|
||
if isinstance(box, boxes.LineBox):
|
||
# Line boxes already have a position_x which may not be the same
|
||
# as content_box_left when text-indent is non-zero.
|
||
# This is important for justified text.
|
||
new_box.width = position_x - new_box.position_x
|
||
else:
|
||
new_box.position_x = initial_position_x
|
||
new_box.width = position_x - content_box_left
|
||
|
||
# Create a "strut":
|
||
# http://www.w3.org/TR/CSS21/visudet.html#strut
|
||
# TODO: cache these results for a given set of styles?
|
||
fragment = TextFragment(
|
||
'', box.style, cairo.Context(document.surface))
|
||
_, _, _, height, baseline, _ = fragment.split_first_line()
|
||
leading = used_line_height(box.style) - height
|
||
half_leading = leading / 2.
|
||
# Set margins to the half leading but also compensate for borders and
|
||
# paddings. We want margin_height() == line_height
|
||
new_box.margin_top = (half_leading - new_box.border_top_width -
|
||
new_box.padding_bottom)
|
||
new_box.margin_bottom = (half_leading - new_box.border_bottom_width -
|
||
new_box.padding_bottom)
|
||
# form the top of the content box
|
||
new_box.baseline = baseline
|
||
# form the top of the margin box
|
||
new_box.baseline += half_leading
|
||
new_box.height = height
|
||
|
||
if resume_at is not None:
|
||
# There is a line break inside this box.
|
||
box.reset_spacing('left')
|
||
new_box.reset_spacing('right')
|
||
return new_box, resume_at, preserved_line_break
|
||
|
||
|
||
def split_text_box(document, box, available_width, skip):
|
||
"""Keep as much text as possible from a TextBox in a limitied width.
|
||
Try not to overflow but always have some text in ``new_box``
|
||
|
||
Return ``(new_box, skip)``. ``skip`` is the number of UTF-8 bytes
|
||
to skip form the start of the TextBox for the next line, or ``None``
|
||
if all of the text fits.
|
||
|
||
Also break an preserved whitespace.
|
||
|
||
"""
|
||
assert isinstance(box, boxes.TextBox)
|
||
font_size = box.style.font_size
|
||
text = box.text[skip:]
|
||
if font_size == 0 or not text:
|
||
return None, None, False
|
||
fragment = TextFragment(text, box.style,
|
||
cairo.Context(document.surface), available_width)
|
||
|
||
# XXX ``resume_at`` is an index in UTF-8 bytes, not unicode codepoints.
|
||
show_line, length, width, height, baseline, resume_at = \
|
||
fragment.split_first_line()
|
||
|
||
# Convert ``length`` and ``resume_at`` from UTF-8 indexes in text
|
||
# to Unicode indexes.
|
||
# No need to encode what’s after resume_at (if set) or length (if
|
||
# resume_at is not set). One code point is one or more byte, so
|
||
# UTF-8 indexes are always bigger or equal to Unicode indexes.
|
||
partial_text = text[:resume_at or length]
|
||
utf8_text = partial_text.encode('utf8')
|
||
new_text = utf8_text[:length].decode('utf8')
|
||
new_length = len(new_text)
|
||
if resume_at is not None:
|
||
between = utf8_text[length:resume_at].decode('utf8')
|
||
resume_at = new_length + len(between)
|
||
length = new_length
|
||
|
||
if length > 0:
|
||
box = box.copy_with_text(new_text)
|
||
box.width = width
|
||
box.show_line = show_line
|
||
# "The height of the content area should be based on the font,
|
||
# but this specification does not specify how."
|
||
# http://www.w3.org/TR/CSS21/visudet.html#inline-non-replaced
|
||
# We trust Pango and use the height of the LayoutLine.
|
||
# It is based on font_size (slightly larger), but I’m not sure how.
|
||
# TODO: investigate this
|
||
box.height = height
|
||
# "only the 'line-height' is used when calculating the height
|
||
# of the line box."
|
||
# Set margins so that margin_height() == line_height
|
||
leading = used_line_height(box.style) - height
|
||
half_leading = leading / 2.
|
||
box.margin_top = half_leading
|
||
box.margin_bottom = half_leading
|
||
# form the top of the content box
|
||
box.baseline = baseline
|
||
# form the top of the margin box
|
||
box.baseline += box.margin_top + box.border_top_width + box.padding_top
|
||
else:
|
||
box = None
|
||
|
||
if resume_at is None:
|
||
preserved_line_break = False
|
||
else:
|
||
preserved_line_break = (length != resume_at)
|
||
if preserved_line_break:
|
||
assert between == '\n', ('Got %r between two lines. '
|
||
'Expected nothing or a preserved line break' % (between,))
|
||
resume_at += skip
|
||
|
||
return box, resume_at, preserved_line_break
|
||
|
||
|
||
def inline_box_verticality(box, baseline_y):
|
||
"""Handle ``vertical-align`` within an :class:`InlineBox`.
|
||
|
||
Place all boxes vertically assuming that the baseline of ``box``
|
||
is at `y = baseline_y`.
|
||
|
||
Return ``(max_y, min_y)``, the maximum and minimum vertical position
|
||
of margin boxes.
|
||
|
||
"""
|
||
max_y = None
|
||
min_y = None
|
||
for child in box.children:
|
||
vertical_align = child.style.vertical_align
|
||
if vertical_align == 'baseline':
|
||
child_baseline_y = baseline_y
|
||
elif vertical_align == 'middle':
|
||
# TODO: find ex from font metrics
|
||
one_ex = box.style.font_size * 0.5
|
||
top = baseline_y - (one_ex + child.margin_height()) / 2.
|
||
child_baseline_y = top + child.baseline
|
||
# TODO: actually implement vertical-align: top and bottom
|
||
elif vertical_align in ('text-top', 'top'):
|
||
# align top with the top of the parent’s content area
|
||
top = (baseline_y - box.baseline + box.margin_top +
|
||
box.border_top_width + box.padding_top)
|
||
child_baseline_y = top + child.baseline
|
||
elif vertical_align in ('text-bottom', 'bottom'):
|
||
# align bottom with the bottom of the parent’s content area
|
||
bottom = (baseline_y - box.baseline + box.margin_top +
|
||
box.border_top_width + box.padding_top + box.height)
|
||
child_baseline_y = bottom - child.margin_height() + child.baseline
|
||
else:
|
||
# Numeric value: The child’s baseline is `vertical_align` above
|
||
# (lower y) the parent’s baseline.
|
||
child_baseline_y = baseline_y - vertical_align
|
||
# the child’s `top` is `child.baseline` above (lower y) its baseline.
|
||
top = child_baseline_y - child.baseline
|
||
child.position_y = top
|
||
bottom = top + child.margin_height()
|
||
if min_y is None or top < min_y:
|
||
min_y = top
|
||
if max_y is None or bottom > max_y:
|
||
max_y = bottom
|
||
if isinstance(child, boxes.InlineBox):
|
||
children_max_y, children_min_y = inline_box_verticality(
|
||
child, child_baseline_y)
|
||
if children_max_y is None:
|
||
if (
|
||
child.margin_width() == 0
|
||
# Guard against the case where a negative margin
|
||
# compensates something else.
|
||
and child.margin_left == 0
|
||
and child.margin_right == 0
|
||
):
|
||
# No content, ignore this box’s line-height.
|
||
# See http://www.w3.org/TR/CSS21/visuren.html#phantom-line-box
|
||
child.position_y = child_baseline_y
|
||
child.height = 0
|
||
continue
|
||
else:
|
||
assert children_min_y is not None
|
||
if children_min_y < min_y:
|
||
min_y = children_min_y
|
||
if children_max_y > max_y:
|
||
max_y = children_max_y
|
||
return max_y, min_y
|
||
|
||
|
||
def text_align(document, line, containing_block, last):
|
||
"""Return how much the line should be moved horizontally according to
|
||
the `text-align` property.
|
||
|
||
"""
|
||
align = line.style.text_align
|
||
if align in ('-weasy-start', '-weasy-end'):
|
||
if (align == '-weasy-start') ^ (line.style.direction == 'rtl'):
|
||
align = 'left'
|
||
else:
|
||
align = 'right'
|
||
if align == 'justify' and last:
|
||
align = 'right' if line.style.direction == 'rtl' else 'left'
|
||
if align == 'left':
|
||
return 0
|
||
offset = containing_block.width - line.width
|
||
if align == 'justify':
|
||
justify_line(document, line, offset)
|
||
return 0
|
||
if align == 'center':
|
||
offset /= 2.
|
||
else:
|
||
assert align == 'right'
|
||
return offset
|
||
|
||
|
||
def justify_line(document, line, extra_width):
|
||
nb_spaces = count_spaces(line)
|
||
if nb_spaces == 0:
|
||
# TODO: what should we do with single-word lines?
|
||
return
|
||
add_word_spacing(document, line, extra_width / nb_spaces, 0)
|
||
|
||
|
||
def count_spaces(box):
|
||
if isinstance(box, boxes.TextBox):
|
||
# TODO: remove trailing spaces correctly
|
||
return box.text.count(' ')
|
||
elif isinstance(box, (boxes.LineBox, boxes.InlineBox)):
|
||
return sum(count_spaces(child) for child in box.children)
|
||
else:
|
||
return 0
|
||
|
||
|
||
def add_word_spacing(document, box, extra_word_spacing, x_advance):
|
||
if isinstance(box, boxes.TextBox):
|
||
box.position_x += x_advance
|
||
box.style.word_spacing += extra_word_spacing
|
||
nb_spaces = count_spaces(box)
|
||
if nb_spaces > 0:
|
||
new_box, resume_at, _ = split_text_box(
|
||
document, box, 1e10, 0)
|
||
assert new_box is not None
|
||
assert resume_at is None
|
||
# XXX new_box.width - box.width is always 0???
|
||
#x_advance += new_box.width - box.width
|
||
x_advance += extra_word_spacing * nb_spaces
|
||
box.width = new_box.width
|
||
box.show_line = new_box.show_line
|
||
elif isinstance(box, (boxes.LineBox, boxes.InlineBox)):
|
||
box.position_x += x_advance
|
||
previous_x_advance = x_advance
|
||
for child in box.children:
|
||
x_advance = add_word_spacing(
|
||
document, child, extra_word_spacing, x_advance)
|
||
box.width += x_advance - previous_x_advance
|
||
else:
|
||
# Atomic inline-level box
|
||
box.translate(x_advance, 0)
|
||
return x_advance
|