mirror of
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94 lines
3.0 KiB
Python
94 lines
3.0 KiB
Python
# coding: utf8
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"""
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weasyprint.layout.preferred
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---------------------------
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Preferred and minimum preferred width, aka. the shrink-to-fit algorithm.
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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 cairo
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from ..formatting_structure import boxes
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from ..text import TextFragment
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from .inlines import replaced_box_width
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from .percentages import resolve_percentages
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def shrink_to_fit(box):
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raise NotImplementedError
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def inline_preferred_minimum_width(box):
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"""Return the preferred minimum width for an ``InlineBox``.
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This is the width by breaking at every line-break opportunity.
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*Warning:* only TextBox and InlineReplacedBox children are supported
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for now. (No recursive InlineBox childdren.)
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"""
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widest_line = 0
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for child in box.children:
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if isinstance(child, boxes.AtomicInlineLevelBox):
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# Images are on their own line
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current_line = replaced_preferred_width(child)
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else:
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assert isinstance(child, boxes.TextBox)
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current_line = max(text_lines_width(child, width=0))
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widest_line = max(widest_line, current_line)
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return widest_line
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def inline_preferred_width(box):
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"""Return the preferred width for an ``InlineBox``.
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This is the width by only breaking at forced line breaks.
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*Warning:* only TextBox and InlineReplacedBox children are supported
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for now. (No recursive InlineBox childdren.)
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"""
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widest_line = 0
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current_line = 0
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for child in box.children:
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if isinstance(child, boxes.InlineReplacedBox):
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# No line break around images
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current_line += replaced_preferred_width(child)
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else:
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assert isinstance(child, boxes.TextBox)
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lines = list(text_lines_width(child, width=None))
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assert lines
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# The first text line goes on the current line
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current_line += lines[0]
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if len(lines) > 1:
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# Forced line break
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widest_line = max(widest_line, current_line)
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if len(lines) > 2:
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widest_line = max(widest_line, max(lines[1:-1]))
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current_line = lines[-1]
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widest_line = max(widest_line, current_line)
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return widest_line
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def text_lines_width(box, width):
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"""Return the list of line widths for a ``TextBox``."""
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# TODO: find the real surface, to have correct hinting
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context = cairo.Context(cairo.PDFSurface(None, 1, 1))
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fragment = TextFragment(box.text, box.style, context, width=width)
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return fragment.line_widths()
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def replaced_preferred_width(box):
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"""Return the preferred (minimum) width for an ``InlineReplacedBox``."""
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# TODO: get the actual device size. Or do we really care?
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# TODO: what about percentage widths?
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resolve_percentages(box, containing_block=(0, 0))
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replaced_box_width(box, device_size=None)
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return box.width
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