mirror of
https://github.com/Kozea/WeasyPrint.git
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795 lines
29 KiB
Python
795 lines
29 KiB
Python
# coding: utf8
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"""
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weasyprint.draw
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---------------
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Take an "after layout" box tree and draw it onto a cairo context.
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:copyright: Copyright 2011-2013 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 contextlib
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import math
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import operator
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import cairocffi as cairo
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from .formatting_structure import boxes
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from .stacking import StackingContext
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from .text import show_first_line
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from .compat import xrange
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ARC_TO_BEZIER = 4 * (2 ** .5 - 1) / 3
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@contextlib.contextmanager
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def stacked(context):
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"""Save and restore the context when used with the ``with`` keyword."""
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context.save()
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try:
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yield
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finally:
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context.restore()
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def lighten(color, offset):
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"""Return a lighter color (or darker, for negative offsets)."""
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return (
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color.red + offset,
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color.green + offset,
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color.blue + offset,
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color.alpha)
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def draw_page(page, context, enable_hinting):
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"""Draw the given PageBox."""
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stacking_context = StackingContext.from_page(page)
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draw_background(
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context, stacking_context.box.background, enable_hinting,
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clip_box=False)
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draw_background(
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context, page.canvas_background, enable_hinting, clip_box=False)
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draw_border(context, page, enable_hinting)
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draw_stacking_context(context, stacking_context, enable_hinting)
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def draw_box_background_and_border(context, page, box, enable_hinting):
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draw_background(context, box.background, enable_hinting)
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if not isinstance(box, boxes.TableBox):
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draw_border(context, box, enable_hinting)
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else:
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for column_group in box.column_groups:
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draw_background(context, column_group.background, enable_hinting)
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for column in column_group.children:
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draw_background(context, column.background, enable_hinting)
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for row_group in box.children:
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draw_background(context, row_group.background, enable_hinting)
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for row in row_group.children:
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draw_background(context, row.background, enable_hinting)
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for cell in row.children:
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draw_background(context, cell.background, enable_hinting)
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if box.style.border_collapse == 'separate':
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draw_border(context, box, enable_hinting)
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for row_group in box.children:
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for row in row_group.children:
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for cell in row.children:
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draw_border(context, cell, enable_hinting)
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else:
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draw_collapsed_borders(context, box, enable_hinting)
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def draw_stacking_context(context, stacking_context, enable_hinting):
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"""Draw a ``stacking_context`` on ``context``."""
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# See http://www.w3.org/TR/CSS2/zindex.html
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with stacked(context):
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box = stacking_context.box
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if box.is_absolutely_positioned() and box.style.clip:
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top, right, bottom, left = box.style.clip
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if top == 'auto':
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top = 0
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if right == 'auto':
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right = 0
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if bottom == 'auto':
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bottom = box.border_height()
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if left == 'auto':
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left = box.border_width()
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context.rectangle(
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box.border_box_x() + right,
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box.border_box_y() + top,
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left - right,
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bottom - top)
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context.clip()
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if box.style.opacity < 1:
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context.push_group()
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if box.transformation_matrix:
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context.transform(box.transformation_matrix)
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# Point 1 is done in draw_page
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# Point 2
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if isinstance(box, (boxes.BlockBox, boxes.MarginBox,
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boxes.InlineBlockBox)):
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# The canvas background was removed by set_canvas_background
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draw_box_background_and_border(
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context, stacking_context.page, box, enable_hinting)
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if box.style.overflow != 'visible':
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# Only clip the content and the children:
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# - the background is already clipped
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# - the border must *not* be clipped
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rounded_box_path(context, box.rounded_padding_box())
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context.clip()
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# Point 3
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for child_context in stacking_context.negative_z_contexts:
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draw_stacking_context(context, child_context, enable_hinting)
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# Point 4
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for block in stacking_context.block_level_boxes:
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draw_box_background_and_border(
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context, stacking_context.page, block, enable_hinting)
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# Point 5
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for child_context in stacking_context.float_contexts:
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draw_stacking_context(context, child_context, enable_hinting)
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# Point 6
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if isinstance(box, boxes.InlineBox):
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draw_inline_level(
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context, stacking_context.page, box, enable_hinting)
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# Point 7
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for block in [box] + stacking_context.blocks_and_cells:
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marker_box = getattr(block, 'outside_list_marker', None)
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if marker_box:
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draw_inline_level(
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context, stacking_context.page, marker_box, enable_hinting)
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if isinstance(block, boxes.ReplacedBox):
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draw_replacedbox(context, block)
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else:
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for child in block.children:
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if isinstance(child, boxes.LineBox):
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# TODO: draw inline tables
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draw_inline_level(
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context, stacking_context.page, child,
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enable_hinting)
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# Point 8
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for child_context in stacking_context.zero_z_contexts:
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draw_stacking_context(context, child_context, enable_hinting)
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# Point 9
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for child_context in stacking_context.positive_z_contexts:
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draw_stacking_context(context, child_context, enable_hinting)
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# Point 10
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draw_outlines(context, box, enable_hinting)
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if box.style.opacity < 1:
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context.pop_group_to_source()
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context.paint_with_alpha(box.style.opacity)
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def rounded_box_path(context, radii):
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"""Draw the path of the border radius box.
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``widths`` is a tuple of the inner widths (top, right, bottom, left) from
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the border box. Radii are adjusted from these values. Default is (0, 0, 0,
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0).
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Inspired by Cairo Cookbook
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http://cairographics.org/cookbook/roundedrectangles/
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"""
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x, y, w, h, tl, tr, br, bl = radii
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if 0 in tl:
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tl = (0, 0)
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if 0 in tr:
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tr = (0, 0)
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if 0 in br:
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br = (0, 0)
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if 0 in bl:
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bl = (0, 0)
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if (tl, tr, br, bl) == 4 * ((0, 0),):
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# No radius, draw a rectangle
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context.rectangle(x, y, w, h)
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return
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(tlh, tlv), (trh, trv), (brh, brv), (blh, blv) = tl, tr, br, bl
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context.move_to(x + tlh, y)
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context.rel_line_to(w - tlh - trh, 0)
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context.rel_curve_to(
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ARC_TO_BEZIER * trh, 0, trh, ARC_TO_BEZIER * trv, trh, trv)
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context.rel_line_to(0, h - trv - brv)
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context.rel_curve_to(
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0, ARC_TO_BEZIER * brv, -ARC_TO_BEZIER * brh, brv, -brh, brv)
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context.rel_line_to(-w + blh + brh, 0)
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context.rel_curve_to(
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-ARC_TO_BEZIER * blh, 0, -blh, -ARC_TO_BEZIER * blv, -blh, -blv)
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context.rel_line_to(0, -h + tlv + blv)
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context.rel_curve_to(
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0, -ARC_TO_BEZIER * tlv, ARC_TO_BEZIER * tlh, -tlv, tlh, -tlv)
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def draw_background(context, bg, enable_hinting, clip_box=True):
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"""Draw the background color and image to a ``cairo.Context``.
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If ``clip_box`` is set to ``False``, the background is not clipped to the
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border box of the background, but only to the painting area.
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"""
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if bg is None:
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return
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with stacked(context):
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if clip_box:
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rounded_box_path(context, bg.layers[-1].rounded_box)
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context.clip()
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# Background color
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if bg.color.alpha > 0:
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with stacked(context):
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if enable_hinting:
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# Prefer crisp edges on background rectangles.
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context.set_antialias(cairo.ANTIALIAS_NONE)
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painting_area = bg.layers[-1].painting_area
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if painting_area:
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context.rectangle(*painting_area)
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context.clip()
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context.set_source_rgba(*bg.color)
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context.paint()
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# Paint in reversed order: first layer is "closest" to the viewer.
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for layer in reversed(bg.layers):
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draw_background_image(context, layer, bg.image_rendering)
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def draw_background_image(context, layer, image_rendering):
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# Background image
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if layer.image is None:
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return
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painting_x, painting_y, painting_width, painting_height = (
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layer.painting_area)
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positioning_x, positioning_y, positioning_width, positioning_height = (
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layer.positioning_area)
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position_x, position_y = layer.position
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repeat_x, repeat_y = layer.repeat
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image_width, image_height = layer.size
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if repeat_x == 'no-repeat':
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repeat_width = painting_width * 2
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elif repeat_x in ('repeat', 'round'):
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repeat_width = image_width
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else:
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assert repeat_x == 'space'
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n_repeats = math.floor(positioning_width / image_width)
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if n_repeats >= 2:
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repeat_width = (positioning_width - image_width) / (n_repeats - 1)
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position_x = 0 # Ignore background-position for this dimension
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else:
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repeat_width = image_width
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if repeat_y == 'no-repeat':
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repeat_height = painting_height * 2
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elif repeat_y in ('repeat', 'round'):
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repeat_height = image_height
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else:
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assert repeat_y == 'space'
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n_repeats = math.floor(positioning_height / image_height)
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if n_repeats >= 2:
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repeat_height = (
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positioning_height - image_height) / (n_repeats - 1)
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position_y = 0 # Ignore background-position for this dimension
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else:
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repeat_height = image_height
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sub_surface = cairo.PDFSurface(None, repeat_width, repeat_height)
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sub_context = cairo.Context(sub_surface)
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sub_context.rectangle(0, 0, image_width, image_height)
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sub_context.clip()
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layer.image.draw(sub_context, image_width, image_height, image_rendering)
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pattern = cairo.SurfacePattern(sub_surface)
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pattern.set_extend(cairo.EXTEND_REPEAT)
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with stacked(context):
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if not layer.unbounded:
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context.rectangle(painting_x, painting_y,
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painting_width, painting_height)
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context.clip()
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#else: unrestricted, whole page box
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context.translate(positioning_x + position_x,
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positioning_y + position_y)
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context.set_source(pattern)
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context.paint()
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def get_rectangle_edges(x, y, width, height):
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"""Return the 4 edges of a rectangle as a list.
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Edges are in clock-wise order, starting from the top.
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Each edge is returned as ``(start_point, end_point)`` and each point
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as ``(x, y)`` coordinates.
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"""
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# In clock-wise order, starting on top left
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corners = [
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(x, y),
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(x + width, y),
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(x + width, y + height),
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(x, y + height)]
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# clock-wise order, starting on top right
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shifted_corners = corners[1:] + corners[:1]
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return zip(corners, shifted_corners)
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def xy_offset(x, y, offset_x, offset_y, offset):
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"""Increment X and Y coordinates by the given offsets."""
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return x + offset_x * offset, y + offset_y * offset
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def draw_border(context, box, enable_hinting):
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"""Draw the box border to a ``cairo.Context``."""
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# We need a plan to draw beautiful borders, and that's difficult, no need
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# to lie. Let's try to find the cases that we can handle in a smart way.
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# The box is hidden, easy.
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if box.style.visibility == 'hidden':
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return
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sides = ('top', 'right', 'bottom', 'left')
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widths = [getattr(box, 'border_%s_width' % side) for side in sides]
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# No border, return early.
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if all(width == 0 for width in widths):
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return
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colors = [box.style.get_color('border_%s_color' % side) for side in sides]
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styles = [
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colors[i].alpha and box.style['border_%s_style' % side]
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for (i, side) in enumerate(sides)]
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# The 4 sides are solid or double, and they have the same color. Oh yeah!
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# We can draw them so easily!
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if set(styles) in ({'solid'}, {'double'}) and len(set(colors)) == 1:
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style = styles[0]
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color = colors[0]
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context.new_path()
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rounded_box_path(context, box.rounded_padding_box())
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if style == 'double':
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rounded_box_path(context, box.rounded_box(1 / 3))
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rounded_box_path(context, box.rounded_box(2 / 3))
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rounded_box_path(context, box.rounded_border_box())
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context.set_fill_rule(cairo.FILL_RULE_EVEN_ODD)
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context.set_source_rgba(*color)
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context.close_path()
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context.fill()
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return
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# We're not smart enough to find a good way to draw the borders :/. We must
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# draw them side by side.
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for side, border_edge, padding_edge in zip(
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['top', 'right', 'bottom', 'left'],
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get_rectangle_edges(
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box.border_box_x(), box.border_box_y(),
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box.border_width(), box.border_height(),
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),
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get_rectangle_edges(
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box.padding_box_x(), box.padding_box_y(),
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box.padding_width(), box.padding_height(),
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),
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):
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width = getattr(box, 'border_%s_width' % side)
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if width == 0:
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continue
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color = box.style.get_color('border_%s_color' % side)
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if color.alpha == 0:
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continue
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style = box.style['border_%s_style' % side]
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draw_border_segment(
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context, enable_hinting, style, width, color, side, border_edge,
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padding_edge)
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def draw_border_segment(context, enable_hinting, style, width, color, side,
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border_edge, padding_edge):
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with stacked(context):
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if enable_hinting and style != 'dotted' and (
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# Borders smaller than 1 device unit would disappear
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# without anti-aliasing.
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math.hypot(*context.user_to_device(width, 0)) >= 1 and
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math.hypot(*context.user_to_device(0, width)) >= 1):
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# Avoid an artifact in the corner joining two solid borders
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# of the same color.
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context.set_antialias(cairo.ANTIALIAS_NONE)
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if style in ('inset', 'outset'):
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do_lighten = (side in ('top', 'left')) ^ (style == 'inset')
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factor = 0.5 if do_lighten else -0.5
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context.set_source_rgba(*lighten(color, factor))
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else:
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context.set_source_rgba(*color)
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x_offset, y_offset = {'top': (0, 1), 'bottom': (0, -1),
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'left': (1, 0), 'right': (-1, 0)}[side]
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if style not in ('dotted', 'dashed'):
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# Clip on the trapezoid shape
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"""
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Clip the angles the trapezoid formed by the border edge (longer)
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and the padding edge (shorter).
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This is on the top side:
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+---------------+ <= border edge ^
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\ / |
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\ / | top border width
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\ / |
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+-------+ <= padding edge v
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<--> <--> <= left and right border widths
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The clip shape is:
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1---------------------------2
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\ /
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\ /
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\ /
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+...................+
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\ /
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\ /
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\ /
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+...........+
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\ /
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\ /
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\ /
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4---3
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"""
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def double_vector(p1, p2):
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x1, y1 = p1
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x2, y2 = p2
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return 2 * x2 - x1, 2 * y2 - y1
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border_start, border_stop = border_edge
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padding_start, padding_stop = padding_edge
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points = [double_vector(padding_start, border_start),
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double_vector(padding_stop, border_stop),
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double_vector(border_stop, padding_stop),
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double_vector(border_start, padding_start)]
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context.move_to(*points[-1])
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for point in points:
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context.line_to(*point)
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context.clip()
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if style in ('groove', 'ridge'):
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# TODO: these would look better with more color stops
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"""
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||
Divide the width in 2 and stroke lines in different colors
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||
+-------------+
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||
1\ /2
|
||
1'\ / 2'
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||
+-------+
|
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"""
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||
do_lighten = (side in ('top', 'left')) ^ (style == 'groove')
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||
factor = 1 if do_lighten else -1
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context.set_line_width(width / 2)
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(x1, y1), (x2, y2) = border_edge
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||
# from the border edge to the center of the first line
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||
x1, y1 = xy_offset(x1, y1, x_offset, y_offset, width / 4)
|
||
x2, y2 = xy_offset(x2, y2, x_offset, y_offset, width / 4)
|
||
context.move_to(x1, y1)
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||
context.line_to(x2, y2)
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||
context.set_source_rgba(*lighten(color, 0.5 * factor))
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||
context.stroke()
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||
# Between the centers of both lines. 1/4 + 1/4 = 1/2
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||
x1, y1 = xy_offset(x1, y1, x_offset, y_offset, width / 2)
|
||
x2, y2 = xy_offset(x2, y2, x_offset, y_offset, width / 2)
|
||
context.move_to(x1, y1)
|
||
context.line_to(x2, y2)
|
||
context.set_source_rgba(*lighten(color, -0.5 * factor))
|
||
context.stroke()
|
||
elif style == 'double':
|
||
"""
|
||
Divide the width in 3 and stroke both outer lines
|
||
+---------------+
|
||
1\ /2
|
||
\ /
|
||
1' \ / 2'
|
||
+-------+
|
||
"""
|
||
context.set_line_width(width / 3)
|
||
(x1, y1), (x2, y2) = border_edge
|
||
# from the border edge to the center of the first line
|
||
x1, y1 = xy_offset(x1, y1, x_offset, y_offset, width / 6)
|
||
x2, y2 = xy_offset(x2, y2, x_offset, y_offset, width / 6)
|
||
context.move_to(x1, y1)
|
||
context.line_to(x2, y2)
|
||
context.stroke()
|
||
# Between the centers of both lines. 1/6 + 1/3 + 1/6 = 2/3
|
||
x1, y1 = xy_offset(x1, y1, x_offset, y_offset, 2 * width / 3)
|
||
x2, y2 = xy_offset(x2, y2, x_offset, y_offset, 2 * width / 3)
|
||
context.move_to(x1, y1)
|
||
context.line_to(x2, y2)
|
||
context.stroke()
|
||
else:
|
||
(x1, y1), (x2, y2) = border_edge
|
||
if style == 'dotted':
|
||
# Half-way from the extremities of the border and padding
|
||
# edges.
|
||
(px1, py1), (px2, py2) = padding_edge
|
||
x1 = (x1 + px1) / 2
|
||
x2 = (x2 + px2) / 2
|
||
y1 = (y1 + py1) / 2
|
||
y2 = (y2 + py2) / 2
|
||
"""
|
||
+---------------+
|
||
\ /
|
||
1 2
|
||
\ /
|
||
+-------+
|
||
"""
|
||
else: # solid, dashed
|
||
# From the border edge to the middle:
|
||
x1, y1 = xy_offset(x1, y1, x_offset, y_offset, width / 2)
|
||
x2, y2 = xy_offset(x2, y2, x_offset, y_offset, width / 2)
|
||
"""
|
||
+---------------+
|
||
\ /
|
||
1 \ / 2
|
||
\ /
|
||
+-------+
|
||
"""
|
||
|
||
length = ((x2 - x1) ** 2 + (y2 - y1) ** 2) ** 0.5
|
||
dash = 2 * width
|
||
if style == 'dotted':
|
||
if context.user_to_device_distance(width, 0)[0] > 3:
|
||
# Round so that dash is a divisor of length,
|
||
# but not in the dots are too small.
|
||
dash = length / max(1, round(length / dash))
|
||
context.set_line_cap(cairo.LINE_CAP_ROUND)
|
||
context.set_dash([0, dash])
|
||
elif style == 'dashed':
|
||
# Round so that 2*dash is a divisor of length
|
||
dash = length / (2 * max(1, round(length / (2 * dash))))
|
||
context.set_dash([dash])
|
||
# Stroke along the line in === above, as wide as the border
|
||
context.move_to(x1, y1)
|
||
context.line_to(x2, y2)
|
||
context.set_line_width(width)
|
||
context.stroke()
|
||
|
||
|
||
def draw_outlines(context, box, enable_hinting):
|
||
width = box.style.outline_width
|
||
color = box.style.get_color('outline_color')
|
||
style = box.style.outline_style
|
||
if box.style.visibility != 'hidden' and width != 0 and color.alpha != 0:
|
||
border_box = (box.border_box_x(), box.border_box_y(),
|
||
box.border_width(), box.border_height())
|
||
outline_box = (border_box[0] - width, border_box[1] - width,
|
||
border_box[2] + 2 * width, border_box[3] + 2 * width)
|
||
for side, border_edge, padding_edge in zip(
|
||
['top', 'right', 'bottom', 'left'],
|
||
get_rectangle_edges(*outline_box),
|
||
get_rectangle_edges(*border_box),
|
||
):
|
||
draw_border_segment(context, enable_hinting, style, width, color,
|
||
side, border_edge, padding_edge)
|
||
|
||
if isinstance(box, boxes.ParentBox):
|
||
for child in box.children:
|
||
if isinstance(child, boxes.Box):
|
||
draw_outlines(context, child, enable_hinting)
|
||
|
||
|
||
def draw_collapsed_borders(context, table, enable_hinting):
|
||
row_heights = [row.height for row_group in table.children
|
||
for row in row_group.children]
|
||
column_widths = table.column_widths
|
||
if not (row_heights and column_widths):
|
||
# One of the list is empty: don’t bother with empty tables
|
||
return
|
||
row_positions = [row.position_y for row_group in table.children
|
||
for row in row_group.children]
|
||
column_positions = table.column_positions
|
||
grid_height = len(row_heights)
|
||
grid_width = len(column_widths)
|
||
assert grid_width == len(column_positions)
|
||
# Add the end of the last column, but make a copy from the table attr.
|
||
column_positions += [column_positions[-1] + column_widths[-1]]
|
||
# Add the end of the last row. No copy here, we own this list
|
||
row_positions.append(row_positions[-1] + row_heights[-1])
|
||
vertical_borders, horizontal_borders = table.collapsed_border_grid
|
||
if table.children[0].is_header:
|
||
header_rows = len(table.children[0].children)
|
||
else:
|
||
header_rows = 0
|
||
if table.children[-1].is_footer:
|
||
footer_rows = len(table.children[-1].children)
|
||
else:
|
||
footer_rows = 0
|
||
skipped_rows = table.skipped_rows
|
||
if skipped_rows:
|
||
body_rows_offset = skipped_rows - header_rows
|
||
else:
|
||
body_rows_offset = 0
|
||
if header_rows == 0:
|
||
header_rows = -1
|
||
if footer_rows:
|
||
first_footer_row = grid_height - footer_rows - 1
|
||
else:
|
||
first_footer_row = grid_height + 1
|
||
original_grid_height = len(vertical_borders)
|
||
footer_rows_offset = original_grid_height - grid_height
|
||
|
||
def row_number(y, horizontal):
|
||
if y < (header_rows + int(horizontal)):
|
||
return y
|
||
elif y >= (first_footer_row + int(horizontal)):
|
||
return y + footer_rows_offset
|
||
else:
|
||
return y + body_rows_offset
|
||
|
||
segments = []
|
||
|
||
def half_max_width(border_list, yx_pairs, vertical=True):
|
||
result = 0
|
||
for y, x in yx_pairs:
|
||
if (
|
||
(0 <= y < grid_height and 0 <= x <= grid_width)
|
||
if vertical else
|
||
(0 <= y <= grid_height and 0 <= x < grid_width)
|
||
):
|
||
yy = row_number(y, horizontal=not vertical)
|
||
_, (_, width, _) = border_list[yy][x]
|
||
result = max(result, width)
|
||
return result / 2
|
||
|
||
def add_vertical(x, y):
|
||
yy = row_number(y, horizontal=False)
|
||
score, (style, width, color) = vertical_borders[yy][x]
|
||
if width == 0 or color.alpha == 0:
|
||
return
|
||
half_width = width / 2
|
||
pos_x = column_positions[x]
|
||
pos_y_1 = row_positions[y] - half_max_width(horizontal_borders, [
|
||
(y, x - 1), (y, x)], vertical=False)
|
||
pos_y_2 = row_positions[y + 1] + half_max_width(horizontal_borders, [
|
||
(y + 1, x - 1), (y + 1, x)], vertical=False)
|
||
edge_1 = (pos_x - half_width, pos_y_1), (pos_x - half_width, pos_y_2)
|
||
edge_2 = (pos_x + half_width, pos_y_1), (pos_x + half_width, pos_y_2)
|
||
segments.append((score, style, width, color, 'left', edge_1, edge_2))
|
||
|
||
def add_horizontal(x, y):
|
||
yy = row_number(y, horizontal=True)
|
||
score, (style, width, color) = horizontal_borders[yy][x]
|
||
if width == 0 or color.alpha == 0:
|
||
return
|
||
half_width = width / 2
|
||
pos_y = row_positions[y]
|
||
# TODO: change signs for rtl when we support rtl tables?
|
||
pos_x_1 = column_positions[x] - half_max_width(vertical_borders, [
|
||
(y - 1, x), (y, x)])
|
||
pos_x_2 = column_positions[x + 1] + half_max_width(vertical_borders, [
|
||
(y - 1, x + 1), (y, x + 1)])
|
||
edge_1 = (pos_x_1, pos_y - half_width), (pos_x_2, pos_y - half_width)
|
||
edge_2 = (pos_x_1, pos_y + half_width), (pos_x_2, pos_y + half_width)
|
||
segments.append((score, style, width, color, 'top', edge_1, edge_2))
|
||
|
||
for x in xrange(grid_width):
|
||
add_horizontal(x, 0)
|
||
for y in xrange(grid_height):
|
||
add_vertical(0, y)
|
||
for x in xrange(grid_width):
|
||
add_vertical(x + 1, y)
|
||
add_horizontal(x, y + 1)
|
||
|
||
# Sort bigger scores last (painted later, on top)
|
||
# Since the number of different scores is expected to be small compared
|
||
# to the number of segments, there should be little changes and Timsort
|
||
# should be closer to O(n) than O(n * log(n))
|
||
segments.sort(key=operator.itemgetter(0))
|
||
|
||
for segment in segments:
|
||
draw_border_segment(context, enable_hinting, *segment[1:])
|
||
|
||
|
||
def draw_replacedbox(context, box):
|
||
"""Draw the given :class:`boxes.ReplacedBox` to a ``cairo.context``."""
|
||
if box.style.visibility == 'hidden' or box.width == 0 or box.height == 0:
|
||
return
|
||
|
||
with stacked(context):
|
||
context.translate(box.content_box_x(), box.content_box_y())
|
||
context.rectangle(0, 0, box.width, box.height)
|
||
context.clip()
|
||
box.replacement.draw(
|
||
context, box.width, box.height, box.style.image_rendering)
|
||
|
||
|
||
def draw_inline_level(context, page, box, enable_hinting):
|
||
if isinstance(box, StackingContext):
|
||
stacking_context = box
|
||
assert isinstance(stacking_context.box, boxes.InlineBlockBox)
|
||
draw_stacking_context(context, stacking_context, enable_hinting)
|
||
else:
|
||
draw_background(context, box.background, enable_hinting)
|
||
draw_border(context, box, enable_hinting)
|
||
if isinstance(box, (boxes.InlineBox, boxes.LineBox)):
|
||
for child in box.children:
|
||
if isinstance(child, boxes.TextBox):
|
||
draw_text(context, child, enable_hinting)
|
||
else:
|
||
draw_inline_level(context, page, child, enable_hinting)
|
||
elif isinstance(box, boxes.InlineReplacedBox):
|
||
draw_replacedbox(context, box)
|
||
else:
|
||
assert isinstance(box, boxes.TextBox)
|
||
# Should only happen for list markers
|
||
draw_text(context, box, enable_hinting)
|
||
|
||
|
||
def draw_text(context, textbox, enable_hinting):
|
||
"""Draw ``textbox`` to a ``cairo.Context`` from ``PangoCairo.Context``."""
|
||
# Pango crashes with font-size: 0
|
||
assert textbox.style.font_size
|
||
|
||
if textbox.style.visibility == 'hidden':
|
||
return
|
||
|
||
context.move_to(textbox.position_x, textbox.position_y + textbox.baseline)
|
||
context.set_source_rgba(*textbox.style.color)
|
||
show_first_line(context, textbox.pango_layout, enable_hinting)
|
||
values = textbox.style.text_decoration
|
||
|
||
metrics = textbox.pango_layout.get_font_metrics()
|
||
thickness = textbox.style.font_size / 18 # That's what other browsers do
|
||
if enable_hinting and thickness < 1:
|
||
thickness = 1
|
||
|
||
if 'overline' in values:
|
||
draw_text_decoration(
|
||
context, textbox,
|
||
textbox.baseline - metrics.ascent + thickness / 2,
|
||
thickness, enable_hinting)
|
||
if 'underline' in values:
|
||
draw_text_decoration(
|
||
context, textbox,
|
||
textbox.baseline - metrics.underline_position + thickness / 2,
|
||
thickness, enable_hinting)
|
||
if 'line-through' in values:
|
||
draw_text_decoration(
|
||
context, textbox,
|
||
textbox.baseline - metrics.strikethrough_position,
|
||
thickness, enable_hinting)
|
||
|
||
|
||
def draw_text_decoration(context, textbox, offset_y, thickness,
|
||
enable_hinting):
|
||
"""Draw text-decoration of ``textbox`` to a ``cairo.Context``."""
|
||
with stacked(context):
|
||
if enable_hinting:
|
||
context.set_antialias(cairo.ANTIALIAS_NONE)
|
||
context.set_source_rgba(*textbox.style.color)
|
||
context.set_line_width(thickness)
|
||
context.move_to(textbox.position_x, textbox.position_y + offset_y)
|
||
context.rel_line_to(textbox.width, 0)
|
||
context.stroke()
|