1196 lines
47 KiB
Python
1196 lines
47 KiB
Python
# coding: utf-8
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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 2011-2014 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 unicodedata
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from ..css.computed_values import ex_ratio, strut_layout
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from ..formatting_structure import boxes
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from ..text import can_break_text, split_first_line
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from .absolute import AbsolutePlaceholder, absolute_layout
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from .float import avoid_collisions, float_layout
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from .min_max import handle_min_max_height, handle_min_max_width
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from .percentages import resolve_one_percentage, resolve_percentages
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from .preferred import (
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inline_min_content_width, shrink_to_fit, trailing_whitespace_size)
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from .replaced import image_marker_layout
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from .tables import find_in_flow_baseline, table_wrapper_width
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def iter_line_boxes(context, box, position_y, skip_stack, containing_block,
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device_size, absolute_boxes, fixed_boxes,
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first_letter_style):
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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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context, box, position_y, skip_stack, containing_block,
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device_size, absolute_boxes, fixed_boxes, first_letter_style)
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if line:
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position_y = line.position_y + line.height
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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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first_letter_style = None
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def get_next_linebox(context, linebox, position_y, skip_stack,
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containing_block, device_size, absolute_boxes,
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fixed_boxes, first_letter_style):
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"""Return ``(line, resume_at)``."""
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resolve_percentages(linebox, containing_block)
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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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else:
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linebox.text_indent = 0
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first_letter_style = None
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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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skip_stack = first_letter_to_box(linebox, skip_stack, first_letter_style)
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linebox.width = inline_min_content_width(
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context, linebox, skip_stack=skip_stack, first_line=True)
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linebox.height, _ = strut_layout(linebox.style, context)
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linebox.position_y = position_y
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position_x, position_y, available_width = avoid_collisions(
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context, linebox, containing_block, outer=False)
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candidate_height = linebox.height
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excluded_shapes = context.excluded_shapes[:]
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while 1:
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linebox.position_x = position_x
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linebox.position_y = position_y
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max_x = position_x + available_width
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position_x += linebox.text_indent
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line_placeholders = []
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line_absolutes = []
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line_fixed = []
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waiting_floats = []
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(line, resume_at, preserved_line_break, first_letter,
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last_letter) = split_inline_box(
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context, linebox, position_x, max_x, skip_stack, containing_block,
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device_size, line_absolutes, line_fixed, line_placeholders,
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waiting_floats, line_children=[])
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if is_phantom_linebox(line) and not preserved_line_break:
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line.height = 0
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break
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remove_last_whitespace(context, line)
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new_position_x, _, new_available_width = avoid_collisions(
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context, linebox, containing_block, outer=False)
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alignment_available_width = (
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new_available_width + new_position_x - linebox.position_x)
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offset_x = text_align(
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context, line, alignment_available_width,
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last=(resume_at is None or preserved_line_break))
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bottom, top = line_box_verticality(line)
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assert top is not None
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assert bottom 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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line.translate(offset_x, offset_y)
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if line.height <= candidate_height:
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break
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candidate_height = line.height
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new_excluded_shapes = context.excluded_shapes
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context.excluded_shapes = excluded_shapes
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position_x, position_y, available_width = avoid_collisions(
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context, line, containing_block, outer=False)
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if (position_x, position_y) == (
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linebox.position_x, linebox.position_y):
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context.excluded_shapes = new_excluded_shapes
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break
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absolute_boxes.extend(line_absolutes)
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fixed_boxes.extend(line_fixed)
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for placeholder in line_placeholders:
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if placeholder.style._weasy_specified_display.startswith('inline'):
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# Inline-level static position:
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placeholder.translate(0, position_y - placeholder.position_y)
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else:
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# Block-level static position: at the start of the next line
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placeholder.translate(
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line.position_x - placeholder.position_x,
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position_y + line.height - placeholder.position_y)
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float_children = []
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waiting_floats_y = line.position_y + line.height
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for waiting_float in waiting_floats:
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waiting_float.position_y = waiting_floats_y
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waiting_float = float_layout(
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context, waiting_float, containing_block, device_size,
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absolute_boxes, fixed_boxes)
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float_children.append(waiting_float)
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if float_children:
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line.children += tuple(float_children)
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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) if index else 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) if (index or result) else None
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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(context, 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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box.text = new_text
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new_box, resume, _ = split_text_box(context, box, None, 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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else:
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space_width = box.width
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box.width = 0
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box.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 first_letter_to_box(box, skip_stack, first_letter_style):
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"""Create a box for the ::first-letter selector."""
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if first_letter_style and box.children:
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first_letter = ''
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child = box.children[0]
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if isinstance(child, boxes.TextBox):
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if child.element_tag.endswith('::first-letter'):
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letter_box = boxes.InlineBox(
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'%s::first-letter' % box.element_tag,
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first_letter_style.inherit_from(), [child])
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box.children = (
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(letter_box,) + tuple(box.children[1:]))
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elif child.text:
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character_found = False
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if skip_stack:
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child_skip_stack = skip_stack[1]
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if child_skip_stack:
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index = child_skip_stack[0]
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child.text = child.text[index:]
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skip_stack = None
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while child.text:
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next_letter = child.text[0]
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category = unicodedata.category(next_letter)
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if category not in ('Ps', 'Pe', 'Pi', 'Pf', 'Po'):
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if character_found:
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break
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character_found = True
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first_letter += next_letter
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child.text = child.text[1:]
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if first_letter.lstrip('\n'):
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# "This type of initial letter is similar to an
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# inline-level element if its 'float' property is 'none',
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# otherwise it is similar to a floated element."
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if first_letter_style['float'] == 'none':
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letter_box = boxes.InlineBox(
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'%s::first-letter' % box.element_tag,
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first_letter_style, [])
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text_box = boxes.TextBox(
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'%s::first-letter' % box.element_tag,
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letter_box.style.inherit_from(), first_letter)
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letter_box.children = (text_box,)
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box.children = (letter_box,) + tuple(box.children)
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else:
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letter_box = boxes.BlockBox(
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'%s::first-letter' % box.element_tag,
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first_letter_style, [])
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letter_box.first_letter_style = None
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line_box = boxes.LineBox(
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'%s::first-letter' % box.element_tag,
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letter_box.style.inherit_from(), [])
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letter_box.children = (line_box,)
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text_box = boxes.TextBox(
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'%s::first-letter' % box.element_tag,
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letter_box.style.inherit_from(), first_letter)
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line_box.children = (text_box,)
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box.children = (letter_box,) + tuple(box.children)
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if skip_stack and child_skip_stack:
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skip_stack = (skip_stack[0], (
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child_skip_stack[0] + 1, child_skip_stack[1]))
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elif isinstance(child, boxes.ParentBox):
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if skip_stack:
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child_skip_stack = skip_stack[1]
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else:
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child_skip_stack = None
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child_skip_stack = first_letter_to_box(
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child, child_skip_stack, first_letter_style)
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if skip_stack:
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skip_stack = (skip_stack[0], child_skip_stack)
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return skip_stack
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@handle_min_max_width
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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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intrinsic_width, intrinsic_height = box.replacement.get_intrinsic_size(
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box.style.image_resolution, box.style.font_size)
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# This algorithm simply follows the different points of the specification:
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# http://www.w3.org/TR/CSS21/visudet.html#inline-replaced-width
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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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# Point #1
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box.width = intrinsic_width
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elif box.replacement.intrinsic_ratio is not None:
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if intrinsic_height is not None:
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# Point #2 first part
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box.width = intrinsic_height * box.replacement.intrinsic_ratio
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else:
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# Point #3
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# " It is suggested that, if the containing block's width does
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# not itself depend on the replaced element's width, then the
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# used value of 'width' is calculated from the constraint
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# equation used for block-level, non-replaced elements in
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# normal flow. "
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# Whaaaaat? Let's not do this and use a value that may work
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# well at least with inline blocks.
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box.width = (
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box.style.font_size * box.replacement.intrinsic_ratio)
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if box.width == 'auto':
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if box.replacement.intrinsic_ratio is not None:
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# Point #2 second part
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box.width = box.height * box.replacement.intrinsic_ratio
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elif intrinsic_width is not None:
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# Point #4
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box.width = intrinsic_width
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else:
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# Point #5
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device_width, _device_height = device_size
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box.width = min(300, device_width)
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@handle_min_max_height
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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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intrinsic_width, intrinsic_height = box.replacement.get_intrinsic_size(
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box.style.image_resolution, box.style.font_size)
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intrinsic_ratio = box.replacement.intrinsic_ratio
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# Test 'auto' on the computed width, not the used width
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if box.height == 'auto' and box.width == 'auto':
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box.height = intrinsic_height
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elif box.height == 'auto' and intrinsic_ratio:
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box.height = box.width / intrinsic_ratio
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if (box.height == 'auto' and box.width == 'auto' and
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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.height == 'auto':
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box.height = box.width / intrinsic_ratio
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elif box.height == 'auto' and intrinsic_height is not None:
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box.height = intrinsic_height
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elif box.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 inline_replaced_box_layout(box, 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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inline_replaced_box_width_height(box, device_size)
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def inline_replaced_box_width_height(box, device_size):
|
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if box.style.width == 'auto' and box.style.height == 'auto':
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replaced_box_width.without_min_max(box, device_size)
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replaced_box_height.without_min_max(box, device_size)
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min_max_auto_replaced(box)
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else:
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replaced_box_width(box, device_size)
|
||
replaced_box_height(box, device_size)
|
||
|
||
|
||
def min_max_auto_replaced(box):
|
||
"""Resolve {min,max}-{width,height} constraints on replaced elements
|
||
that have 'auto' width and heights.
|
||
"""
|
||
width = box.width
|
||
height = box.height
|
||
min_width = box.min_width
|
||
min_height = box.min_height
|
||
max_width = max(min_width, box.max_width)
|
||
max_height = max(min_height, box.max_height)
|
||
|
||
# (violation_width, violation_height)
|
||
violations = (
|
||
'min' if width < min_width else 'max' if width > max_width else '',
|
||
'min' if height < min_height else 'max' if height > max_height else '')
|
||
|
||
# Work around divisions by zero. These are pathological cases anyway.
|
||
# TODO: is there a cleaner way?
|
||
if width == 0:
|
||
width = 1e-6
|
||
if height == 0:
|
||
height = 1e-6
|
||
|
||
# ('', ''): nothing to do
|
||
if violations == ('max', ''):
|
||
box.width = max_width
|
||
box.height = max(max_width * height / width, min_height)
|
||
elif violations == ('min', ''):
|
||
box.width = min_width
|
||
box.height = min(min_width * height / width, max_height)
|
||
elif violations == ('', 'max'):
|
||
box.width = max(max_height * width / height, min_width)
|
||
box.height = max_height
|
||
elif violations == ('', 'min'):
|
||
box.width = min(min_height * width / height, max_width)
|
||
box.height = min_height
|
||
elif violations == ('max', 'max'):
|
||
if max_width / width <= max_height / height:
|
||
box.width = max_width
|
||
box.height = max(min_height, max_width * height / width)
|
||
else:
|
||
box.width = max(min_width, max_height * width / height)
|
||
box.height = max_height
|
||
elif violations == ('min', 'min'):
|
||
if min_width / width <= min_height / height:
|
||
box.width = min(max_width, min_height * width / height)
|
||
box.height = min_height
|
||
else:
|
||
box.width = min_width
|
||
box.height = min(max_height, min_width * height / width)
|
||
elif violations == ('min', 'max'):
|
||
box.width = min_width
|
||
box.height = max_height
|
||
elif violations == ('max', 'min'):
|
||
box.width = max_width
|
||
box.height = min_height
|
||
|
||
|
||
def atomic_box(context, box, position_x, skip_stack, containing_block,
|
||
device_size, absolute_boxes, fixed_boxes):
|
||
"""Compute the width and the height of the atomic ``box``."""
|
||
if isinstance(box, boxes.ReplacedBox):
|
||
if getattr(box, 'is_list_marker', False):
|
||
image_marker_layout(box)
|
||
else:
|
||
inline_replaced_box_layout(box, device_size)
|
||
box.baseline = box.margin_height()
|
||
elif isinstance(box, boxes.InlineBlockBox):
|
||
if box.is_table_wrapper:
|
||
table_wrapper_width(
|
||
context, box,
|
||
(containing_block.width, containing_block.height))
|
||
box = inline_block_box_layout(
|
||
context, box, position_x, skip_stack, containing_block,
|
||
device_size, absolute_boxes, fixed_boxes)
|
||
else: # pragma: no cover
|
||
raise TypeError('Layout for %s not handled yet' % type(box).__name__)
|
||
return box
|
||
|
||
|
||
def inline_block_box_layout(context, box, position_x, skip_stack,
|
||
containing_block, device_size, absolute_boxes,
|
||
fixed_boxes):
|
||
# Avoid a circular import
|
||
from .blocks import block_container_layout
|
||
|
||
resolve_percentages(box, containing_block)
|
||
|
||
# http://www.w3.org/TR/CSS21/visudet.html#inlineblock-width
|
||
if box.margin_left == 'auto':
|
||
box.margin_left = 0
|
||
if box.margin_right == 'auto':
|
||
box.margin_right = 0
|
||
# http://www.w3.org/TR/CSS21/visudet.html#block-root-margin
|
||
if box.margin_top == 'auto':
|
||
box.margin_top = 0
|
||
if box.margin_bottom == 'auto':
|
||
box.margin_bottom = 0
|
||
|
||
inline_block_width(box, context, containing_block)
|
||
|
||
box.position_x = position_x
|
||
box.position_y = 0
|
||
box, _, _, _, _ = block_container_layout(
|
||
context, box, max_position_y=float('inf'), skip_stack=skip_stack,
|
||
device_size=device_size, page_is_empty=True,
|
||
absolute_boxes=absolute_boxes, fixed_boxes=fixed_boxes)
|
||
box.baseline = inline_block_baseline(box)
|
||
return box
|
||
|
||
|
||
def inline_block_baseline(box):
|
||
"""
|
||
Return the y position of the baseline for an inline block
|
||
from the top of its margin box.
|
||
|
||
http://www.w3.org/TR/CSS21/visudet.html#propdef-vertical-align
|
||
|
||
"""
|
||
if box.style.overflow == 'visible':
|
||
result = find_in_flow_baseline(box, last=True)
|
||
if result:
|
||
return result
|
||
return box.position_y + box.margin_height()
|
||
|
||
|
||
@handle_min_max_width
|
||
def inline_block_width(box, context, containing_block):
|
||
if box.width == 'auto':
|
||
box.width = shrink_to_fit(context, box, containing_block.width)
|
||
|
||
|
||
def split_inline_level(context, box, position_x, max_x, skip_stack,
|
||
containing_block, device_size, absolute_boxes,
|
||
fixed_boxes, line_placeholders, waiting_floats,
|
||
line_children):
|
||
"""Fit as much content as possible from an inline-level box in a width.
|
||
|
||
Return ``(new_box, resume_at, preserved_line_break, first_letter,
|
||
last_letter)``. ``resume_at`` is ``None`` if all of the content
|
||
fits. Otherwise it can be passed as a ``skip_stack`` parameter to resume
|
||
where we left off.
|
||
|
||
``new_box`` is non-empty (unless the box is empty) and as big as possible
|
||
while being narrower than ``available_width``, if possible (may overflow
|
||
is no split is possible.)
|
||
|
||
"""
|
||
resolve_percentages(box, containing_block)
|
||
if isinstance(box, boxes.TextBox):
|
||
box.position_x = position_x
|
||
if skip_stack is None:
|
||
skip = 0
|
||
else:
|
||
skip, skip_stack = skip_stack
|
||
skip = skip or 0
|
||
assert skip_stack is None
|
||
|
||
new_box, skip, preserved_line_break = split_text_box(
|
||
context, box, max_x - position_x, skip)
|
||
|
||
if skip is None:
|
||
resume_at = None
|
||
else:
|
||
resume_at = (skip, None)
|
||
if box.text:
|
||
first_letter = box.text[0]
|
||
if skip is None:
|
||
last_letter = box.text[-1]
|
||
else:
|
||
last_letter = box.text[skip - 1]
|
||
else:
|
||
first_letter = last_letter = None
|
||
elif isinstance(box, boxes.InlineBox):
|
||
if box.margin_left == 'auto':
|
||
box.margin_left = 0
|
||
if box.margin_right == 'auto':
|
||
box.margin_right = 0
|
||
(new_box, resume_at, preserved_line_break, first_letter,
|
||
last_letter) = split_inline_box(
|
||
context, box, position_x, max_x, skip_stack, containing_block,
|
||
device_size, absolute_boxes, fixed_boxes, line_placeholders,
|
||
waiting_floats, line_children)
|
||
elif isinstance(box, boxes.AtomicInlineLevelBox):
|
||
new_box = atomic_box(
|
||
context, box, position_x, skip_stack, containing_block,
|
||
device_size, absolute_boxes, fixed_boxes)
|
||
new_box.position_x = position_x
|
||
resume_at = None
|
||
preserved_line_break = False
|
||
# See https://www.w3.org/TR/css-text-3/#line-breaking
|
||
# Atomic inlines behave like ideographic characters.
|
||
first_letter = '\u2e80'
|
||
last_letter = '\u2e80'
|
||
# else: unexpected box type here
|
||
return new_box, resume_at, preserved_line_break, first_letter, last_letter
|
||
|
||
|
||
def split_inline_box(context, box, position_x, max_x, skip_stack,
|
||
containing_block, device_size, absolute_boxes,
|
||
fixed_boxes, line_placeholders, waiting_floats,
|
||
line_children):
|
||
"""Same behavior as split_inline_level."""
|
||
|
||
# In some cases (shrink-to-fit result being the preferred width)
|
||
# max_x is coming from Pango itself,
|
||
# but floating point errors have accumulated:
|
||
# width2 = (width + X) - X # in some cases, width2 < width
|
||
# Increase the value a bit to compensate and not introduce
|
||
# an unexpected line break. The 1e-9 value comes from PEP 485.
|
||
max_x *= 1 + 1e-9
|
||
|
||
is_start = skip_stack is None
|
||
initial_position_x = position_x
|
||
initial_skip_stack = skip_stack
|
||
assert isinstance(box, (boxes.LineBox, boxes.InlineBox))
|
||
left_spacing = (box.padding_left + box.margin_left +
|
||
box.border_left_width)
|
||
right_spacing = (box.padding_right + box.margin_right +
|
||
box.border_right_width)
|
||
if is_start:
|
||
position_x += left_spacing
|
||
content_box_left = position_x
|
||
|
||
children = []
|
||
waiting_children = []
|
||
preserved_line_break = False
|
||
first_letter = last_letter = None
|
||
float_translate = 0
|
||
float_resume_at = 0
|
||
|
||
if box.style.position == 'relative':
|
||
absolute_boxes = []
|
||
|
||
if is_start:
|
||
skip = 0
|
||
else:
|
||
skip, skip_stack = skip_stack
|
||
|
||
box_children = list(box.enumerate_skip(skip))
|
||
for i, (index, child) in enumerate(box_children):
|
||
child.position_y = box.position_y
|
||
if child.is_absolutely_positioned():
|
||
child.position_x = position_x
|
||
placeholder = AbsolutePlaceholder(child)
|
||
line_placeholders.append(placeholder)
|
||
waiting_children.append((index, placeholder))
|
||
if child.style.position == 'absolute':
|
||
absolute_boxes.append(placeholder)
|
||
else:
|
||
fixed_boxes.append(placeholder)
|
||
continue
|
||
elif child.is_floated():
|
||
child.position_x = position_x
|
||
float_width = shrink_to_fit(
|
||
context, child, containing_block.width)
|
||
|
||
# To retrieve the real available space for floats, we must remove
|
||
# the trailing whitespaces from the line
|
||
non_floating_children = [
|
||
child_ for _, child_ in (children + waiting_children)
|
||
if not child_.is_floated()]
|
||
if non_floating_children:
|
||
float_width -= trailing_whitespace_size(
|
||
context, non_floating_children[-1])
|
||
|
||
if float_width > max_x - position_x or waiting_floats:
|
||
# TODO: the absolute and fixed boxes in the floats must be
|
||
# added here, and not in iter_line_boxes
|
||
waiting_floats.append(child)
|
||
else:
|
||
child = float_layout(
|
||
context, child, containing_block, device_size,
|
||
absolute_boxes, fixed_boxes)
|
||
waiting_children.append((index, child))
|
||
|
||
# Translate previous line children
|
||
if child.style.float == 'left':
|
||
dx = max(child.margin_width(), 0)
|
||
if isinstance(box, boxes.LineBox):
|
||
# The parent is the line, update the current position
|
||
# for the next child. When the parent is not the line
|
||
# (it is an inline block), the current position of the
|
||
# line is updated by the block itself (see next
|
||
# split_inline_level call).
|
||
position_x += dx
|
||
elif child.style.float == 'right':
|
||
dx = min(-child.margin_width(), 0)
|
||
# Update the maximum x position for the next children
|
||
max_x += dx
|
||
# The float_translate variable will be used to translate the
|
||
# current box if it's an inline block that has floats inside.
|
||
float_translate += dx
|
||
for _, old_child in line_children:
|
||
if not old_child.is_in_normal_flow():
|
||
continue
|
||
if ((child.style.float == 'left' and
|
||
box.style.direction == 'ltr') or
|
||
(child.style.float == 'right' and
|
||
box.style.direction == 'rtl')):
|
||
old_child.translate(dx=dx)
|
||
float_resume_at = index + 1
|
||
continue
|
||
|
||
last_child = (i == len(box_children) - 1)
|
||
available_width = max_x
|
||
new_child, resume_at, preserved, first, last = split_inline_level(
|
||
context, child, position_x, available_width, skip_stack,
|
||
containing_block, device_size, absolute_boxes, fixed_boxes,
|
||
line_placeholders, waiting_floats, line_children)
|
||
if last_child and right_spacing and resume_at is None:
|
||
# TODO: we should take care of children added into absolute_boxes,
|
||
# fixed_boxes and other lists.
|
||
available_width -= right_spacing
|
||
new_child, resume_at, preserved, first, last = split_inline_level(
|
||
context, child, position_x, available_width, skip_stack,
|
||
containing_block, device_size, absolute_boxes, fixed_boxes,
|
||
line_placeholders, waiting_floats, line_children)
|
||
|
||
skip_stack = None
|
||
if preserved:
|
||
preserved_line_break = True
|
||
|
||
can_break = None
|
||
if last_letter is True:
|
||
last_letter = ' '
|
||
elif box.style['white_space'] in ('pre', 'nowrap'):
|
||
can_break = False
|
||
if can_break is None:
|
||
if None in (last_letter, first):
|
||
can_break = False
|
||
else:
|
||
can_break = can_break_text(
|
||
last_letter + first, child.style['lang'])
|
||
|
||
if can_break:
|
||
children.extend(waiting_children)
|
||
waiting_children = []
|
||
|
||
if first_letter is None:
|
||
first_letter = first
|
||
if child.trailing_collapsible_space:
|
||
last_letter = True
|
||
else:
|
||
last_letter = last
|
||
|
||
if new_child is None:
|
||
# may be None where we have an empty TextBox
|
||
assert isinstance(child, boxes.TextBox)
|
||
else:
|
||
if isinstance(box, boxes.LineBox):
|
||
line_children.append((index, new_child))
|
||
# TODO: we should try to find a better condition here.
|
||
trailing_whitespace = (
|
||
isinstance(new_child, boxes.TextBox) and
|
||
not new_child.text.strip())
|
||
|
||
margin_width = new_child.margin_width()
|
||
new_position_x = new_child.position_x + margin_width
|
||
|
||
if new_position_x > max_x and not trailing_whitespace:
|
||
if waiting_children:
|
||
# Too wide, let's try to cut inside waiting children,
|
||
# starting from the end.
|
||
# TODO: we should take care of children added into
|
||
# absolute_boxes, fixed_boxes and other lists.
|
||
waiting_children_copy = waiting_children[:]
|
||
break_found = False
|
||
while waiting_children_copy:
|
||
child_index, child = waiting_children_copy.pop()
|
||
# TODO: what about relative children?
|
||
if (child.is_in_normal_flow() and
|
||
can_break_inside(child)):
|
||
break_found = True
|
||
max_x = child.position_x + child.margin_width()
|
||
# TODO: replace -1, we use it to cut the last word
|
||
# of the line.
|
||
max_x -= 1
|
||
child_skip = None
|
||
if initial_skip_stack and initial_skip_stack[1]:
|
||
child_skip = initial_skip_stack[1][1]
|
||
child_new_child, child_resume_at, _, _, _ = (
|
||
split_inline_level(
|
||
context, child, child.position_x, max_x,
|
||
child_skip, box, device_size,
|
||
absolute_boxes, fixed_boxes,
|
||
line_placeholders, waiting_floats,
|
||
line_children))
|
||
children = children + waiting_children_copy
|
||
if child_new_child is None:
|
||
# may be None where we have an empty TextBox
|
||
assert isinstance(child, boxes.TextBox)
|
||
else:
|
||
children += [(child_index, child_new_child)]
|
||
resume_at = (child_index, child_resume_at)
|
||
break
|
||
if break_found:
|
||
break
|
||
if children:
|
||
# too wide, can't break waiting children and the inline is
|
||
# non-empty: put child entirely on the next line.
|
||
resume_at = (children[-1][0] + 1, None)
|
||
break
|
||
|
||
position_x = new_position_x
|
||
waiting_children.append((index, new_child))
|
||
|
||
if resume_at is not None:
|
||
children.extend(waiting_children)
|
||
resume_at = (index, resume_at)
|
||
break
|
||
else:
|
||
children.extend(waiting_children)
|
||
resume_at = None
|
||
|
||
new_box = box.copy_with_children(
|
||
[box_child for index, box_child in children],
|
||
is_start=is_start, is_end=resume_at is None)
|
||
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
|
||
new_box.translate(dx=float_translate, ignore_floats=True)
|
||
|
||
line_height, new_box.baseline = strut_layout(box.style, context)
|
||
new_box.height = box.style.font_size
|
||
half_leading = (line_height - new_box.height) / 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_top)
|
||
new_box.margin_bottom = (half_leading - new_box.border_bottom_width -
|
||
new_box.padding_bottom)
|
||
|
||
if new_box.style.position == 'relative':
|
||
for absolute_box in absolute_boxes:
|
||
absolute_layout(context, absolute_box, new_box, fixed_boxes)
|
||
|
||
if resume_at is not None:
|
||
if resume_at[0] < float_resume_at:
|
||
resume_at = (float_resume_at, None)
|
||
|
||
return new_box, resume_at, preserved_line_break, first_letter, last_letter
|
||
|
||
|
||
def split_text_box(context, box, available_width, skip):
|
||
"""Keep as much text as possible from a TextBox in a limited width.
|
||
|
||
Try not to overflow but always have some text in ``new_box``
|
||
|
||
Return ``(new_box, skip, preserved_line_break)``. ``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 on preserved line breaks.
|
||
|
||
"""
|
||
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
|
||
layout, length, resume_at, width, height, baseline = split_first_line(
|
||
text, box.style, context, available_width, box.justification_spacing)
|
||
assert resume_at != 0
|
||
|
||
# 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.
|
||
new_text = layout.text_bytes.decode('utf8')
|
||
encoded = text.encode('utf8')
|
||
if resume_at is not None:
|
||
between = encoded[length:resume_at].decode('utf8')
|
||
resume_at = len(encoded[:resume_at].decode('utf8'))
|
||
length = len(encoded[:length].decode('utf8'))
|
||
|
||
if length > 0:
|
||
box = box.copy_with_text(new_text)
|
||
box.width = width
|
||
box.pango_layout = layout
|
||
# "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.
|
||
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
|
||
line_height, _ = strut_layout(box.style, context)
|
||
half_leading = (line_height - height) / 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
|
||
else:
|
||
box = None
|
||
|
||
if resume_at is None:
|
||
preserved_line_break = False
|
||
else:
|
||
preserved_line_break = (length != resume_at) and between.strip(' ')
|
||
if preserved_line_break:
|
||
# See http://unicode.org/reports/tr14/
|
||
# \r is already handled by process_whitespace
|
||
line_breaks = ('\n', '\t', '\f', '\u0085', '\u2028', '\u2029')
|
||
assert between in line_breaks, (
|
||
'Got %r between two lines. '
|
||
'Expected nothing or a preserved line break' % (between,))
|
||
resume_at += skip
|
||
|
||
return box, resume_at, preserved_line_break
|
||
|
||
|
||
def line_box_verticality(box):
|
||
"""Handle ``vertical-align`` within an :class:`LineBox` (or of a
|
||
non-align sub-tree).
|
||
|
||
Place all boxes vertically assuming that the baseline of ``box``
|
||
is at `y = 0`.
|
||
|
||
Return ``(max_y, min_y)``, the maximum and minimum vertical position
|
||
of margin boxes.
|
||
|
||
"""
|
||
top_bottom_subtrees = []
|
||
max_y, min_y = aligned_subtree_verticality(
|
||
box, top_bottom_subtrees, baseline_y=0)
|
||
subtrees_with_min_max = [
|
||
(subtree, sub_max_y, sub_min_y)
|
||
for subtree in top_bottom_subtrees
|
||
for sub_max_y, sub_min_y in [
|
||
(None, None) if subtree.is_floated()
|
||
else aligned_subtree_verticality(
|
||
subtree, top_bottom_subtrees, baseline_y=0)
|
||
]
|
||
]
|
||
|
||
if subtrees_with_min_max:
|
||
sub_positions = [
|
||
sub_max_y - sub_min_y
|
||
for subtree, sub_max_y, sub_min_y in subtrees_with_min_max
|
||
if not subtree.is_floated()]
|
||
if sub_positions:
|
||
highest_sub = max(sub_positions)
|
||
max_y = max(max_y, min_y + highest_sub)
|
||
|
||
for subtree, sub_max_y, sub_min_y in subtrees_with_min_max:
|
||
if subtree.is_floated():
|
||
dy = min_y - subtree.position_y
|
||
elif subtree.style.vertical_align == 'top':
|
||
dy = min_y - sub_min_y
|
||
else:
|
||
assert subtree.style.vertical_align == 'bottom'
|
||
dy = max_y - sub_max_y
|
||
translate_subtree(subtree, dy)
|
||
return max_y, min_y
|
||
|
||
|
||
def translate_subtree(box, dy):
|
||
if isinstance(box, boxes.InlineBox):
|
||
box.position_y += dy
|
||
if box.style.vertical_align in ('top', 'bottom'):
|
||
for child in box.children:
|
||
translate_subtree(child, dy)
|
||
else:
|
||
# Text or atomic boxes
|
||
box.translate(dy=dy)
|
||
|
||
|
||
def aligned_subtree_verticality(box, top_bottom_subtrees, baseline_y):
|
||
max_y, min_y = inline_box_verticality(box, top_bottom_subtrees, baseline_y)
|
||
# Account for the line box itself:
|
||
top = baseline_y - box.baseline
|
||
bottom = top + box.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
|
||
|
||
return max_y, min_y
|
||
|
||
|
||
def inline_box_verticality(box, top_bottom_subtrees, 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
|
||
if not isinstance(box, (boxes.LineBox, boxes.InlineBox)):
|
||
return max_y, min_y
|
||
|
||
for child in box.children:
|
||
if not child.is_in_normal_flow():
|
||
if child.is_floated():
|
||
top_bottom_subtrees.append(child)
|
||
continue
|
||
vertical_align = child.style.vertical_align
|
||
if vertical_align == 'baseline':
|
||
child_baseline_y = baseline_y
|
||
elif vertical_align == 'middle':
|
||
one_ex = box.style.font_size * ex_ratio(box.style)
|
||
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 == 'text-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 == 'text-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
|
||
elif vertical_align in ('top', 'bottom'):
|
||
# Later, we will assume for this subtree that its baseline
|
||
# is at y=0.
|
||
child_baseline_y = 0
|
||
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
|
||
if isinstance(child, boxes.InlineBlockBox):
|
||
# This also includes table wrappers for inline tables.
|
||
child.translate(dy=top - child.position_y)
|
||
else:
|
||
child.position_y = top
|
||
# grand-children for inline boxes are handled below
|
||
|
||
if vertical_align in ('top', 'bottom'):
|
||
# top or bottom are special, they need to be handled in
|
||
# a later pass.
|
||
top_bottom_subtrees.append(child)
|
||
continue
|
||
|
||
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, top_bottom_subtrees, child_baseline_y)
|
||
if children_min_y is not None and children_min_y < min_y:
|
||
min_y = children_min_y
|
||
if children_max_y is not None and children_max_y > max_y:
|
||
max_y = children_max_y
|
||
return max_y, min_y
|
||
|
||
|
||
def text_align(context, line, available_width, last):
|
||
"""Return how much the line should be moved horizontally according to
|
||
the `text-align` property.
|
||
|
||
"""
|
||
align = line.style.text_align
|
||
space_collapse = line.style.white_space in ('normal', 'nowrap', 'pre-line')
|
||
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 = available_width - line.width
|
||
if align == 'justify':
|
||
if space_collapse:
|
||
# Justification of texts where white space is not collapsing is
|
||
# - forbidden by CSS 2, and
|
||
# - not required by CSS 3 Text.
|
||
justify_line(context, line, offset)
|
||
return 0
|
||
if align == 'center':
|
||
offset /= 2.
|
||
else:
|
||
assert align == 'right'
|
||
return offset
|
||
|
||
|
||
def justify_line(context, line, extra_width):
|
||
# TODO: We should use a better alorithm here, see
|
||
# https://www.w3.org/TR/css-text-3/#justify-algos
|
||
nb_spaces = count_spaces(line)
|
||
if nb_spaces == 0:
|
||
return
|
||
add_word_spacing(context, 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(context, box, justification_spacing, x_advance):
|
||
if isinstance(box, boxes.TextBox):
|
||
box.justification_spacing = justification_spacing
|
||
box.position_x += x_advance
|
||
nb_spaces = count_spaces(box)
|
||
if nb_spaces > 0:
|
||
layout, _, resume_at, width, _, _ = split_first_line(
|
||
box.text, box.style, context, float('inf'),
|
||
box.justification_spacing)
|
||
assert resume_at is None
|
||
# XXX new_box.width - box.width is always 0???
|
||
# x_advance += new_box.width - box.width
|
||
x_advance += justification_spacing * nb_spaces
|
||
box.width = width
|
||
box.pango_layout = layout
|
||
elif isinstance(box, (boxes.LineBox, boxes.InlineBox)):
|
||
box.position_x += x_advance
|
||
previous_x_advance = x_advance
|
||
for child in box.children:
|
||
if child.is_in_normal_flow():
|
||
x_advance = add_word_spacing(
|
||
context, child, justification_spacing, x_advance)
|
||
box.width += x_advance - previous_x_advance
|
||
else:
|
||
# Atomic inline-level box
|
||
box.translate(x_advance, 0)
|
||
return x_advance
|
||
|
||
|
||
def is_phantom_linebox(linebox):
|
||
"""http://www.w3.org/TR/CSS21/visuren.html#phantom-line-box"""
|
||
for child in linebox.children:
|
||
if isinstance(child, boxes.InlineBox):
|
||
if not is_phantom_linebox(child):
|
||
return False
|
||
for side in ('top', 'right', 'bottom', 'left'):
|
||
if (getattr(child.style['margin_%s' % side], 'value', None) or
|
||
child.style['border_%s_width' % side] or
|
||
child.style['padding_%s' % side].value):
|
||
return False
|
||
elif child.is_in_normal_flow():
|
||
return False
|
||
return True
|
||
|
||
|
||
def can_break_inside(box):
|
||
# See https://www.w3.org/TR/css-text-3/#white-space-property
|
||
text_wrap = box.style['white_space'] in ('normal', 'pre-wrap', 'pre-line')
|
||
if isinstance(box, boxes.AtomicInlineLevelBox):
|
||
return False
|
||
elif isinstance(box, boxes.TextBox):
|
||
if text_wrap:
|
||
return can_break_text(box.text, box.style['lang'])
|
||
else:
|
||
return False
|
||
elif isinstance(box, boxes.ParentBox):
|
||
if text_wrap:
|
||
return any(can_break_inside(child) for child in box.children)
|
||
else:
|
||
return False
|
||
return False
|