132 lines
4.8 KiB
Python
132 lines
4.8 KiB
Python
"""
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weasyprint.layout.replaced
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--------------------------
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Layout for images and other replaced elements.
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http://dev.w3.org/csswg/css-images-3/#sizing
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:copyright: Copyright 2011-2019 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 .percentages import percentage
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def default_image_sizing(intrinsic_width, intrinsic_height, intrinsic_ratio,
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specified_width, specified_height,
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default_width, default_height):
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"""Default sizing algorithm for the concrete object size.
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http://dev.w3.org/csswg/css-images-3/#default-sizing
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Return a ``(concrete_width, concrete_height)`` tuple.
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"""
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if specified_width == 'auto':
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specified_width = None
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if specified_height == 'auto':
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specified_height = None
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if specified_width is not None and specified_height is not None:
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return specified_width, specified_height
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elif specified_width is not None:
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return specified_width, (
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specified_width / intrinsic_ratio if intrinsic_ratio is not None
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else intrinsic_height if intrinsic_height is not None
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else default_height)
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elif specified_height is not None:
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return (
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specified_height * intrinsic_ratio if intrinsic_ratio is not None
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else intrinsic_width if intrinsic_width is not None
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else default_width
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), specified_height
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else:
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if intrinsic_width is not None or intrinsic_height is not None:
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return default_image_sizing(
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intrinsic_width, intrinsic_height, intrinsic_ratio,
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intrinsic_width, intrinsic_height, default_width,
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default_height)
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else:
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return contain_constraint_image_sizing(
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default_width, default_height, intrinsic_ratio)
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def contain_constraint_image_sizing(
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constraint_width, constraint_height, intrinsic_ratio):
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"""Cover constraint sizing algorithm for the concrete object size.
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http://dev.w3.org/csswg/css-images-3/#contain-constraint
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Return a ``(concrete_width, concrete_height)`` tuple.
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"""
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return _constraint_image_sizing(
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constraint_width, constraint_height, intrinsic_ratio, cover=False)
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def cover_constraint_image_sizing(
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constraint_width, constraint_height, intrinsic_ratio):
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"""Cover constraint sizing algorithm for the concrete object size.
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http://dev.w3.org/csswg/css-images-3/#cover-constraint
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Return a ``(concrete_width, concrete_height)`` tuple.
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"""
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return _constraint_image_sizing(
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constraint_width, constraint_height, intrinsic_ratio, cover=True)
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def _constraint_image_sizing(
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constraint_width, constraint_height, intrinsic_ratio, cover):
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if intrinsic_ratio is None:
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return constraint_width, constraint_height
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elif cover ^ (constraint_width > constraint_height * intrinsic_ratio):
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return constraint_height * intrinsic_ratio, constraint_height
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else:
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return constraint_width, constraint_width / intrinsic_ratio
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def replacedbox_layout(box):
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# TODO: respect box-sizing ?
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object_fit = box.style['object_fit']
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position = box.style['object_position']
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image = box.replacement
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intrinsic_width, intrinsic_height = image.get_intrinsic_size(
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box.style['image_resolution'], box.style['font_size'])
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if None in (intrinsic_width, intrinsic_height):
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intrinsic_width, intrinsic_height = contain_constraint_image_sizing(
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box.width, box.height, box.replacement.intrinsic_ratio)
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if object_fit == 'fill':
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draw_width, draw_height = box.width, box.height
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else:
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if object_fit == 'contain' or object_fit == 'scale-down':
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draw_width, draw_height = contain_constraint_image_sizing(
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box.width, box.height, box.replacement.intrinsic_ratio)
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elif object_fit == 'cover':
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draw_width, draw_height = cover_constraint_image_sizing(
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box.width, box.height, box.replacement.intrinsic_ratio)
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else:
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assert object_fit == 'none', object_fit
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draw_width, draw_height = intrinsic_width, intrinsic_height
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if object_fit == 'scale-down':
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draw_width = min(draw_width, intrinsic_width)
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draw_height = min(draw_height, intrinsic_height)
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origin_x, position_x, origin_y, position_y = position[0]
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ref_x = box.width - draw_width
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ref_y = box.height - draw_height
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position_x = percentage(position_x, ref_x)
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position_y = percentage(position_y, ref_y)
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if origin_x == 'right':
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position_x = ref_x - position_x
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if origin_y == 'bottom':
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position_y = ref_y - position_y
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position_x += box.content_box_x()
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position_y += box.content_box_y()
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return draw_width, draw_height, position_x, position_y
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