"""
weasyprint.draw
---------------
Take an "after layout" box tree and draw it onto a cairo context.
:copyright: Copyright 2011-2019 Simon Sapin and contributors, see AUTHORS.
:license: BSD, see LICENSE for details.
"""
import contextlib
import operator
from math import ceil, floor, hypot, pi, sqrt, tan
import cairocffi as cairo
from .formatting_structure import boxes
from .images import SVGImage
from .layout import replaced
from .layout.backgrounds import BackgroundLayer
from .stacking import StackingContext
from .text import show_first_line
SIDES = ('top', 'right', 'bottom', 'left')
CROP = '''
'''
CROSS = '''
'''
@contextlib.contextmanager
def stacked(context):
"""Save and restore the context when used with the ``with`` keyword."""
context.save()
try:
yield
finally:
context.restore()
def hsv2rgb(hue, saturation, value):
"""Transform a HSV color to a RGB color."""
c = value * saturation
x = c * (1 - abs((hue / 60) % 2 - 1))
m = value - c
if 0 <= hue < 60:
return c + m, x + m, m
elif 60 <= hue < 120:
return x + m, c + m, m
elif 120 <= hue < 180:
return m, c + m, x + m
elif 180 <= hue < 240:
return m, x + m, c + m
elif 240 <= hue < 300:
return x + m, m, c + m
elif 300 <= hue < 360:
return c + m, m, x + m
def rgb2hsv(red, green, blue):
"""Transform a RGB color to a HSV color."""
cmax = max(red, green, blue)
cmin = min(red, green, blue)
delta = cmax - cmin
if delta == 0:
hue = 0
elif cmax == red:
hue = 60 * ((green - blue) / delta % 6)
elif cmax == green:
hue = 60 * ((blue - red) / delta + 2)
elif cmax == blue:
hue = 60 * ((red - green) / delta + 4)
saturation = 0 if delta == 0 else delta / cmax
return hue, saturation, cmax
def get_color(style, key):
value = style[key]
return value if value != 'currentColor' else style['color']
def darken(color):
"""Return a darker color."""
hue, saturation, value = rgb2hsv(color.red, color.green, color.blue)
value /= 1.5
saturation /= 1.25
return hsv2rgb(hue, saturation, value) + (color.alpha,)
def lighten(color):
"""Return a lighter color."""
hue, saturation, value = rgb2hsv(color.red, color.green, color.blue)
value = 1 - (1 - value) / 1.5
if saturation:
saturation = 1 - (1 - saturation) / 1.25
return hsv2rgb(hue, saturation, value) + (color.alpha,)
def draw_page(page, context, enable_hinting):
"""Draw the given PageBox."""
bleed = {
side: page.style['bleed_%s' % side].value
for side in ('top', 'right', 'bottom', 'left')}
marks = page.style['marks']
stacking_context = StackingContext.from_page(page)
draw_background(
context, stacking_context.box.background, enable_hinting,
clip_box=False, bleed=bleed, marks=marks)
draw_background(
context, page.canvas_background, enable_hinting, clip_box=False)
draw_border(context, page, enable_hinting)
draw_stacking_context(context, stacking_context, enable_hinting)
def draw_box_background_and_border(context, page, box, enable_hinting):
draw_background(context, box.background, enable_hinting)
if isinstance(box, boxes.TableBox):
draw_table_backgrounds(context, page, box, enable_hinting)
if box.style['border_collapse'] == 'separate':
draw_border(context, box, enable_hinting)
for row_group in box.children:
for row in row_group.children:
for cell in row.children:
if (cell.style['empty_cells'] == 'show' or
not cell.empty):
draw_border(context, cell, enable_hinting)
else:
draw_collapsed_borders(context, box, enable_hinting)
else:
draw_border(context, box, enable_hinting)
def draw_stacking_context(context, stacking_context, enable_hinting):
"""Draw a ``stacking_context`` on ``context``."""
# See http://www.w3.org/TR/CSS2/zindex.html
with stacked(context):
box = stacking_context.box
if box.is_absolutely_positioned() and box.style['clip']:
top, right, bottom, left = box.style['clip']
if top == 'auto':
top = 0
if right == 'auto':
right = 0
if bottom == 'auto':
bottom = box.border_height()
if left == 'auto':
left = box.border_width()
context.rectangle(
box.border_box_x() + right,
box.border_box_y() + top,
left - right,
bottom - top)
context.clip()
if box.style['opacity'] < 1:
context.push_group()
if box.transformation_matrix:
try:
box.transformation_matrix.copy().invert()
except cairo.CairoError:
return
else:
context.transform(box.transformation_matrix)
# Point 1 is done in draw_page
# Point 2
if isinstance(box, (boxes.BlockBox, boxes.MarginBox,
boxes.InlineBlockBox, boxes.TableCellBox,
boxes.FlexContainerBox)):
# The canvas background was removed by set_canvas_background
draw_box_background_and_border(
context, stacking_context.page, box, enable_hinting)
with stacked(context):
if box.style['overflow'] != 'visible':
# Only clip the content and the children:
# - the background is already clipped
# - the border must *not* be clipped
rounded_box_path(context, box.rounded_padding_box())
context.clip()
# Point 3
for child_context in stacking_context.negative_z_contexts:
draw_stacking_context(context, child_context, enable_hinting)
# Point 4
for block in stacking_context.block_level_boxes:
draw_box_background_and_border(
context, stacking_context.page, block, enable_hinting)
# Point 5
for child_context in stacking_context.float_contexts:
draw_stacking_context(context, child_context, enable_hinting)
# Point 6
if isinstance(box, boxes.InlineBox):
draw_inline_level(
context, stacking_context.page, box, enable_hinting)
# Point 7
for block in [box] + stacking_context.blocks_and_cells:
if isinstance(block, boxes.ReplacedBox):
draw_replacedbox(context, block)
else:
for child in block.children:
if isinstance(child, boxes.LineBox):
draw_inline_level(
context, stacking_context.page, child,
enable_hinting)
# Point 8
for child_context in stacking_context.zero_z_contexts:
draw_stacking_context(context, child_context, enable_hinting)
# Point 9
for child_context in stacking_context.positive_z_contexts:
draw_stacking_context(context, child_context, enable_hinting)
# Point 10
draw_outlines(context, box, enable_hinting)
if box.style['opacity'] < 1:
context.pop_group_to_source()
context.paint_with_alpha(box.style['opacity'])
def rounded_box_path(context, radii):
"""Draw the path of the border radius box.
``widths`` is a tuple of the inner widths (top, right, bottom, left) from
the border box. Radii are adjusted from these values. Default is (0, 0, 0,
0).
Inspired by cairo cookbook
http://cairographics.org/cookbook/roundedrectangles/
"""
x, y, w, h, tl, tr, br, bl = radii
if 0 in tl:
tl = (0, 0)
if 0 in tr:
tr = (0, 0)
if 0 in br:
br = (0, 0)
if 0 in bl:
bl = (0, 0)
if (tl, tr, br, bl) == 4 * ((0, 0),):
# No radius, draw a rectangle
context.rectangle(x, y, w, h)
return
context.move_to(x, y)
context.new_sub_path()
for i, (w, h, (rx, ry)) in enumerate((
(0, 0, tl), (w, 0, tr), (w, h, br), (0, h, bl))):
context.save()
context.translate(x + w, y + h)
radius = max(rx, ry)
if radius:
context.scale(min(rx / ry, 1), min(ry / rx, 1))
context.arc(
(-1 if w else 1) * radius, (-1 if h else 1) * radius, radius,
(2 + i) * pi / 2, (3 + i) * pi / 2)
context.restore()
def draw_background(context, bg, enable_hinting, clip_box=True, bleed=None,
marks=()):
"""Draw the background color and image to a ``cairo.Context``.
If ``clip_box`` is set to ``False``, the background is not clipped to the
border box of the background, but only to the painting area.
"""
if bg is None:
return
with stacked(context):
if enable_hinting:
# Prefer crisp edges on background rectangles.
context.set_antialias(cairo.ANTIALIAS_NONE)
if clip_box:
for box in bg.layers[-1].clipped_boxes:
rounded_box_path(context, box)
context.clip()
# Background color
if bg.color.alpha > 0:
with stacked(context):
painting_area = bg.layers[-1].painting_area
if painting_area:
if bleed:
# Painting area is the PDF BleedBox
x, y, width, height = painting_area
painting_area = (
x - bleed['left'], y - bleed['top'],
width + bleed['left'] + bleed['right'],
height + bleed['top'] + bleed['bottom'])
context.rectangle(*painting_area)
context.clip()
context.set_source_rgba(*bg.color)
context.paint()
if bleed and marks:
x, y, width, height = bg.layers[-1].painting_area
x -= bleed['left']
y -= bleed['top']
width += bleed['left'] + bleed['right']
height += bleed['top'] + bleed['bottom']
svg = '''
'
half_bleed = {key: value * 0.5 for key, value in bleed.items()}
image = SVGImage(svg.format(
height=height, width=width,
bleed_left=bleed['left'], bleed_right=bleed['right'],
bleed_top=bleed['top'], bleed_bottom=bleed['bottom'],
half_bleed_left=half_bleed['left'],
half_bleed_right=half_bleed['right'],
half_bleed_top=half_bleed['top'],
half_bleed_bottom=half_bleed['bottom'],
), '', None)
# Painting area is the PDF media box
size = (width, height)
position = (x, y)
repeat = ('no-repeat', 'no-repeat')
unbounded = True
painting_area = position + size
positioning_area = (0, 0, width, height)
clipped_boxes = []
layer = BackgroundLayer(
image, size, position, repeat, unbounded, painting_area,
positioning_area, clipped_boxes)
bg.layers.insert(0, layer)
# Paint in reversed order: first layer is "closest" to the viewer.
for layer in reversed(bg.layers):
draw_background_image(context, layer, bg.image_rendering)
def draw_table_backgrounds(context, page, table, enable_hinting):
"""Draw the background color and image of the table children."""
for column_group in table.column_groups:
draw_background(context, column_group.background, enable_hinting)
for column in column_group.children:
draw_background(context, column.background, enable_hinting)
for row_group in table.children:
draw_background(context, row_group.background, enable_hinting)
for row in row_group.children:
draw_background(context, row.background, enable_hinting)
for cell in row.children:
if (table.style['border_collapse'] == 'collapse' or
cell.style['empty_cells'] == 'show' or
not cell.empty):
draw_background(context, cell.background, enable_hinting)
def draw_background_image(context, layer, image_rendering):
if layer.image is None:
return
painting_x, painting_y, painting_width, painting_height = (
layer.painting_area)
positioning_x, positioning_y, positioning_width, positioning_height = (
layer.positioning_area)
position_x, position_y = layer.position
repeat_x, repeat_y = layer.repeat
image_width, image_height = layer.size
if repeat_x == 'no-repeat':
# We want at least the whole image_width drawn on sub_surface, but we
# want to be sure it will not be repeated on the painting_width.
repeat_width = max(image_width, painting_width)
elif repeat_x in ('repeat', 'round'):
# We repeat the image each image_width.
repeat_width = image_width
else:
assert repeat_x == 'space'
n_repeats = floor(positioning_width / image_width)
if n_repeats >= 2:
# The repeat width is the whole positioning width with one image
# removed, divided by (the number of repeated images - 1). This
# way, we get the width of one image + one space. We ignore
# background-position for this dimension.
repeat_width = (positioning_width - image_width) / (n_repeats - 1)
position_x = 0
else:
# We don't repeat the image.
repeat_width = image_width
# Comments above apply here too.
if repeat_y == 'no-repeat':
repeat_height = max(image_height, painting_height)
elif repeat_y in ('repeat', 'round'):
repeat_height = image_height
else:
assert repeat_y == 'space'
n_repeats = floor(positioning_height / image_height)
if n_repeats >= 2:
repeat_height = (
positioning_height - image_height) / (n_repeats - 1)
position_y = 0
else:
repeat_height = image_height
sub_surface = cairo.PDFSurface(None, repeat_width, repeat_height)
sub_context = cairo.Context(sub_surface)
sub_context.rectangle(0, 0, image_width, image_height)
sub_context.clip()
layer.image.draw(sub_context, image_width, image_height, image_rendering)
pattern = cairo.SurfacePattern(sub_surface)
if repeat_x == repeat_y == 'no-repeat':
pattern.set_extend(cairo.EXTEND_NONE)
else:
pattern.set_extend(cairo.EXTEND_REPEAT)
with stacked(context):
if not layer.unbounded:
context.rectangle(painting_x, painting_y,
painting_width, painting_height)
context.clip()
# else: unrestricted, whole page box
context.translate(positioning_x + position_x,
positioning_y + position_y)
context.set_source(pattern)
context.paint()
def xy_offset(x, y, offset_x, offset_y, offset):
"""Increment X and Y coordinates by the given offsets."""
return x + offset_x * offset, y + offset_y * offset
def styled_color(style, color, side):
if style in ('inset', 'outset'):
do_lighten = (side in ('top', 'left')) ^ (style == 'inset')
return (lighten if do_lighten else darken)(color)
elif style in ('ridge', 'groove'):
if (side in ('top', 'left')) ^ (style == 'ridge'):
return lighten(color), darken(color)
else:
return darken(color), lighten(color)
return color
def draw_border(context, box, enable_hinting):
"""Draw the box border to a ``cairo.Context``."""
# We need a plan to draw beautiful borders, and that's difficult, no need
# to lie. Let's try to find the cases that we can handle in a smart way.
def draw_column_border():
"""Draw column borders."""
columns = (
isinstance(box, boxes.BlockContainerBox) and (
box.style['column_width'] != 'auto' or
box.style['column_count'] != 'auto'))
if columns and box.style['column_rule_width']:
border_widths = (0, 0, 0, box.style['column_rule_width'])
for child in box.children[1:]:
with stacked(context):
position_x = (child.position_x - (
box.style['column_rule_width'] +
box.style['column_gap']) / 2)
border_box = (
position_x, child.position_y,
box.style['column_rule_width'], box.height)
clip_border_segment(
context, enable_hinting,
box.style['column_rule_style'],
box.style['column_rule_width'], 'left', border_box,
border_widths)
draw_rect_border(
context, border_box, border_widths,
box.style['column_rule_style'], styled_color(
box.style['column_rule_style'],
get_color(box.style, 'column_rule_color'), 'left'))
# The box is hidden, easy.
if box.style['visibility'] != 'visible':
draw_column_border()
return
widths = [getattr(box, 'border_%s_width' % side) for side in SIDES]
# No border, return early.
if all(width == 0 for width in widths):
draw_column_border()
return
colors = [get_color(box.style, 'border_%s_color' % side) for side in SIDES]
styles = [
colors[i].alpha and box.style['border_%s_style' % side]
for (i, side) in enumerate(SIDES)]
# The 4 sides are solid or double, and they have the same color. Oh yeah!
# We can draw them so easily!
if set(styles) in (set(('solid',)), set(('double',))) and (
len(set(colors)) == 1):
draw_rounded_border(context, box, styles[0], colors[0])
draw_column_border()
return
# We're not smart enough to find a good way to draw the borders :/. We must
# draw them side by side.
for side, width, color, style in zip(SIDES, widths, colors, styles):
if width == 0 or not color:
continue
with stacked(context):
clip_border_segment(
context, enable_hinting, style, width, side,
box.rounded_border_box()[:4], widths,
box.rounded_border_box()[4:])
draw_rounded_border(
context, box, style, styled_color(style, color, side))
draw_column_border()
def clip_border_segment(context, enable_hinting, style, width, side,
border_box, border_widths=None, radii=None):
"""Clip one segment of box border.
The strategy is to remove the zones not needed because of the style or the
side before painting.
"""
if enable_hinting and style != 'dotted' and (
# Borders smaller than 1 device unit would disappear
# without anti-aliasing.
hypot(*context.user_to_device(width, 0)) >= 1 and
hypot(*context.user_to_device(0, width)) >= 1):
# Avoid an artifact in the corner joining two solid borders
# of the same color.
context.set_antialias(cairo.ANTIALIAS_NONE)
bbx, bby, bbw, bbh = border_box
(tlh, tlv), (trh, trv), (brh, brv), (blh, blv) = radii or 4 * ((0, 0),)
bt, br, bb, bl = border_widths or 4 * (width,)
def transition_point(x1, y1, x2, y2):
"""Get the point use for border transition.
The extra boolean returned is ``True`` if the point is in the padding
box (ie. the padding box is rounded).
This point is not specified. We must be sure to be inside the rounded
padding box, and in the zone defined in the "transition zone" allowed
by the specification. We chose the corner of the transition zone. It's
easy to get and gives quite good results, but it seems to be different
from what other browsers do.
"""
return (
((x1, y1), True) if abs(x1) > abs(x2) and abs(y1) > abs(y2)
else ((x2, y2), False))
def corner_half_length(a, b):
"""Return the length of the half of one ellipsis corner.
Inspired by [Ramanujan, S., "Modular Equations and Approximations to
pi" Quart. J. Pure. Appl. Math., vol. 45 (1913-1914), pp. 350-372],
wonderfully explained by Dr Rob.
http://mathforum.org/dr.math/faq/formulas/
"""
x = (a - b) / (a + b)
return pi / 8 * (a + b) * (
1 + 3 * x ** 2 / (10 + sqrt(4 - 3 * x ** 2)))
if side == 'top':
(px1, py1), rounded1 = transition_point(tlh, tlv, bl, bt)
(px2, py2), rounded2 = transition_point(-trh, trv, -br, bt)
width = bt
way = 1
angle = 1
main_offset = bby
elif side == 'right':
(px1, py1), rounded1 = transition_point(-trh, trv, -br, bt)
(px2, py2), rounded2 = transition_point(-brh, -brv, -br, -bb)
width = br
way = 1
angle = 2
main_offset = bbx + bbw
elif side == 'bottom':
(px1, py1), rounded1 = transition_point(blh, -blv, bl, -bb)
(px2, py2), rounded2 = transition_point(-brh, -brv, -br, -bb)
width = bb
way = -1
angle = 3
main_offset = bby + bbh
elif side == 'left':
(px1, py1), rounded1 = transition_point(tlh, tlv, bl, bt)
(px2, py2), rounded2 = transition_point(blh, -blv, bl, -bb)
width = bl
way = -1
angle = 4
main_offset = bbx
if side in ('top', 'bottom'):
a1, b1 = px1 - bl / 2, way * py1 - width / 2
a2, b2 = -px2 - br / 2, way * py2 - width / 2
line_length = bbw - px1 + px2
length = bbw
context.move_to(bbx + bbw, main_offset)
context.rel_line_to(-bbw, 0)
context.rel_line_to(px1, py1)
context.rel_line_to(-px1 + bbw + px2, -py1 + py2)
elif side in ('left', 'right'):
a1, b1 = -way * px1 - width / 2, py1 - bt / 2
a2, b2 = -way * px2 - width / 2, -py2 - bb / 2
line_length = bbh - py1 + py2
length = bbh
context.move_to(main_offset, bby + bbh)
context.rel_line_to(0, -bbh)
context.rel_line_to(px1, py1)
context.rel_line_to(-px1 + px2, -py1 + bbh + py2)
context.set_fill_rule(cairo.FILL_RULE_EVEN_ODD)
if style in ('dotted', 'dashed'):
dash = width if style == 'dotted' else 3 * width
if rounded1 or rounded2:
# At least one of the two corners is rounded
chl1 = corner_half_length(a1, b1)
chl2 = corner_half_length(a2, b2)
length = line_length + chl1 + chl2
dash_length = round(length / dash)
if rounded1 and rounded2:
# 2x dashes
dash = length / (dash_length + dash_length % 2)
else:
# 2x - 1/2 dashes
dash = length / (dash_length + dash_length % 2 - 0.5)
dashes1 = int(ceil((chl1 - dash / 2) / dash))
dashes2 = int(ceil((chl2 - dash / 2) / dash))
line = int(floor(line_length / dash))
def draw_dots(dashes, line, way, x, y, px, py, chl):
if not dashes:
return line + 1, 0
for i in range(0, dashes, 2):
i += 0.5 # half dash
angle1 = (
((2 * angle - way) + i * way * dash / chl) /
4 * pi)
angle2 = (min if way > 0 else max)(
((2 * angle - way) + (i + 1) * way * dash / chl) /
4 * pi,
angle * pi / 2)
if side in ('top', 'bottom'):
context.move_to(x + px, main_offset + py)
context.line_to(
x + px - way * px * 1 / tan(angle2),
main_offset)
context.line_to(
x + px - way * px * 1 / tan(angle1),
main_offset)
elif side in ('left', 'right'):
context.move_to(main_offset + px, y + py)
context.line_to(
main_offset,
y + py + way * py * tan(angle2))
context.line_to(
main_offset,
y + py + way * py * tan(angle1))
if angle2 == angle * pi / 2:
offset = (angle1 - angle2) / ((
((2 * angle - way) + (i + 1) * way * dash / chl) /
4 * pi) - angle1)
line += 1
break
else:
offset = 1 - (
(angle * pi / 2 - angle2) / (angle2 - angle1))
return line, offset
line, offset = draw_dots(
dashes1, line, way, bbx, bby, px1, py1, chl1)
line = draw_dots(
dashes2, line, -way, bbx + bbw, bby + bbh, px2, py2, chl2)[0]
if line_length > 1e-6:
for i in range(0, line, 2):
i += offset
if side in ('top', 'bottom'):
x1 = max(bbx + px1 + i * dash, bbx + px1)
x2 = min(bbx + px1 + (i + 1) * dash, bbx + bbw + px2)
y1 = main_offset - (width if way < 0 else 0)
y2 = y1 + width
elif side in ('left', 'right'):
y1 = max(bby + py1 + i * dash, bby + py1)
y2 = min(bby + py1 + (i + 1) * dash, bby + bbh + py2)
x1 = main_offset - (width if way > 0 else 0)
x2 = x1 + width
context.rectangle(x1, y1, x2 - x1, y2 - y1)
else:
# 2x + 1 dashes
context.clip()
dash = length / (
round(length / dash) - (round(length / dash) + 1) % 2) or 1
for i in range(0, int(round(length / dash)), 2):
if side == 'top':
context.rectangle(
bbx + i * dash, bby, dash, width)
elif side == 'right':
context.rectangle(
bbx + bbw - width, bby + i * dash, width, dash)
elif side == 'bottom':
context.rectangle(
bbx + i * dash, bby + bbh - width, dash, width)
elif side == 'left':
context.rectangle(
bbx, bby + i * dash, width, dash)
context.clip()
def draw_rounded_border(context, box, style, color):
context.set_fill_rule(cairo.FILL_RULE_EVEN_ODD)
rounded_box_path(context, box.rounded_padding_box())
if style in ('ridge', 'groove'):
rounded_box_path(context, box.rounded_box_ratio(1 / 2))
context.set_source_rgba(*color[0])
context.fill()
rounded_box_path(context, box.rounded_box_ratio(1 / 2))
rounded_box_path(context, box.rounded_border_box())
context.set_source_rgba(*color[1])
context.fill()
return
if style == 'double':
rounded_box_path(context, box.rounded_box_ratio(1 / 3))
rounded_box_path(context, box.rounded_box_ratio(2 / 3))
rounded_box_path(context, box.rounded_border_box())
context.set_source_rgba(*color)
context.fill()
def draw_rect_border(context, box, widths, style, color):
context.set_fill_rule(cairo.FILL_RULE_EVEN_ODD)
bbx, bby, bbw, bbh = box
bt, br, bb, bl = widths
context.rectangle(*box)
if style in ('ridge', 'groove'):
context.rectangle(
bbx + bl / 2, bby + bt / 2,
bbw - (bl + br) / 2, bbh - (bt + bb) / 2)
context.set_source_rgba(*color[0])
context.fill()
context.rectangle(
bbx + bl / 2, bby + bt / 2,
bbw - (bl + br) / 2, bbh - (bt + bb) / 2)
context.rectangle(
bbx + bl, bby + bt, bbw - bl - br, bbh - bt - bb)
context.set_source_rgba(*color[1])
context.fill()
return
if style == 'double':
context.rectangle(
bbx + bl / 3, bby + bt / 3,
bbw - (bl + br) / 3, bbh - (bt + bb) / 3)
context.rectangle(
bbx + bl * 2 / 3, bby + bt * 2 / 3,
bbw - (bl + br) * 2 / 3, bbh - (bt + bb) * 2 / 3)
context.rectangle(bbx + bl, bby + bt, bbw - bl - br, bbh - bt - bb)
context.set_source_rgba(*color)
context.fill()
def draw_outlines(context, box, enable_hinting):
width = box.style['outline_width']
color = get_color(box.style, 'outline_color')
style = box.style['outline_style']
if box.style['visibility'] == 'visible' and width and color.alpha:
outline_box = (
box.border_box_x() - width, box.border_box_y() - width,
box.border_width() + 2 * width, box.border_height() + 2 * width)
for side in SIDES:
with stacked(context):
clip_border_segment(
context, enable_hinting, style, width, side, outline_box)
draw_rect_border(
context, outline_box, 4 * (width,), style,
styled_color(style, color, side))
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):
"""Draw borders of table cells when they collapse."""
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 = list(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
pos_x = column_positions[x]
pos_y1 = row_positions[y] - half_max_width(horizontal_borders, [
(y, x - 1), (y, x)], vertical=False)
pos_y2 = row_positions[y + 1] + half_max_width(horizontal_borders, [
(y + 1, x - 1), (y + 1, x)], vertical=False)
segments.append((
score, style, width, color, 'left',
(pos_x - width / 2, pos_y1, 0, pos_y2 - pos_y1)))
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
pos_y = row_positions[y]
# TODO: change signs for rtl when we support rtl tables?
pos_x1 = column_positions[x] - half_max_width(vertical_borders, [
(y - 1, x), (y, x)])
pos_x2 = column_positions[x + 1] + half_max_width(vertical_borders, [
(y - 1, x + 1), (y, x + 1)])
segments.append((
score, style, width, color, 'top',
(pos_x1, pos_y - width / 2, pos_x2 - pos_x1, 0)))
for x in range(grid_width):
add_horizontal(x, 0)
for y in range(grid_height):
add_vertical(0, y)
for x in range(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:
_, style, width, color, side, border_box = segment
if side == 'top':
widths = (width, 0, 0, 0)
else:
widths = (0, 0, 0, width)
with stacked(context):
clip_border_segment(
context, enable_hinting, style, width, side, border_box,
widths)
draw_rect_border(
context, border_box, widths, style,
styled_color(style, color, side))
def draw_replacedbox(context, box):
"""Draw the given :class:`boxes.ReplacedBox` to a ``cairo.context``."""
if box.style['visibility'] != 'visible' or not box.width or not box.height:
return
draw_width, draw_height, draw_x, draw_y = replaced.replacedbox_layout(box)
with stacked(context):
rounded_box_path(context, box.rounded_content_box())
context.clip()
context.translate(draw_x, draw_y)
box.replacement.draw(
context, draw_width, draw_height, box.style['image_rendering'])
def draw_inline_level(context, page, box, enable_hinting, offset_x=0,
text_overflow='clip'):
if isinstance(box, StackingContext):
stacking_context = box
assert isinstance(
stacking_context.box, (boxes.InlineBlockBox, boxes.InlineFlexBox))
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)):
if isinstance(box, boxes.LineBox):
text_overflow = box.text_overflow
for child in box.children:
if isinstance(child, StackingContext):
child_offset_x = offset_x
else:
child_offset_x = (
offset_x + child.position_x - box.position_x)
if isinstance(child, boxes.TextBox):
draw_text(
context, child, enable_hinting,
child_offset_x, text_overflow)
else:
draw_inline_level(
context, page, child, enable_hinting, child_offset_x,
text_overflow)
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, offset_x, text_overflow)
def draw_text(context, textbox, enable_hinting, offset_x=0,
text_overflow='clip'):
"""Draw ``textbox`` to a ``cairo.Context`` from ``PangoCairo.Context``."""
# Pango crashes with font-size: 0
assert textbox.style['font_size']
if textbox.style['visibility'] != 'visible':
return
context.move_to(textbox.position_x, textbox.position_y + textbox.baseline)
context.set_source_rgba(*textbox.style['color'])
textbox.pango_layout.reactivate(textbox.style)
show_first_line(context, textbox, text_overflow)
values = textbox.style['text_decoration_line']
thickness = textbox.style['font_size'] / 18 # Like other browsers do
if enable_hinting and thickness < 1:
thickness = 1
color = textbox.style['text_decoration_color']
if color == 'currentColor':
color = textbox.style['color']
if ('overline' in values or
'line-through' in values or
'underline' in values):
metrics = textbox.pango_layout.get_font_metrics()
if 'overline' in values:
draw_text_decoration(
context, textbox, offset_x,
textbox.baseline - metrics.ascent + thickness / 2,
thickness, enable_hinting, color)
if 'underline' in values:
draw_text_decoration(
context, textbox, offset_x,
textbox.baseline - metrics.underline_position + thickness / 2,
thickness, enable_hinting, color)
if 'line-through' in values:
draw_text_decoration(
context, textbox, offset_x,
textbox.baseline - metrics.strikethrough_position,
thickness, enable_hinting, color)
textbox.pango_layout.deactivate()
def draw_wave(context, x, y, width, offset_x, radius):
context.new_path()
diameter = 2 * radius
wave_index = offset_x // diameter
remain = offset_x - wave_index * diameter
while width > 0:
up = (wave_index % 2 == 0)
center_x = x - remain + radius
alpha1 = (1 + remain / diameter) * pi
alpha2 = (1 + min(1, width / diameter)) * pi
if up:
context.arc(center_x, y, radius, alpha1, alpha2)
else:
context.arc_negative(
center_x, y, radius, -alpha1, -alpha2)
x += diameter - remain
width -= diameter - remain
remain = 0
wave_index += 1
def draw_text_decoration(context, textbox, offset_x, offset_y, thickness,
enable_hinting, color):
"""Draw text-decoration of ``textbox`` to a ``cairo.Context``."""
style = textbox.style['text_decoration_style']
with stacked(context):
if enable_hinting:
context.set_antialias(cairo.ANTIALIAS_NONE)
context.set_source_rgba(*color)
context.set_line_width(thickness)
if style == 'dashed':
context.set_dash([5 * thickness], offset=offset_x)
elif style == 'dotted':
context.set_dash([thickness], offset=offset_x)
if style == 'wavy':
draw_wave(
context,
textbox.position_x, textbox.position_y + offset_y,
textbox.width, offset_x, 0.75 * thickness)
else:
context.move_to(textbox.position_x, textbox.position_y + offset_y)
context.rel_line_to(textbox.width, 0)
if style == 'double':
delta = 2 * thickness
context.move_to(
textbox.position_x, textbox.position_y + offset_y + delta)
context.rel_line_to(textbox.width, 0)
context.stroke()