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WeasyPrint/weasyprint/svg/defs.py
2021-07-31 08:29:23 +02:00

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"""
weasyprint.svg.defs
-------------------
Parse and draw definitions: gradients, patterns, masks, uses…
"""
from itertools import cycle
from math import ceil, hypot
import pydyf
from .bounding_box import is_valid_bounding_box
from .utils import color, parse_url, size, transform
def use(svg, node, font_size):
"""Draw use tags."""
from . import NOT_INHERITED_ATTRIBUTES, SVG
x, y = svg.point(node.get('x'), node.get('y'), font_size)
for attribute in ('x', 'y', 'viewBox', 'mask'):
if attribute in node.attrib:
del node.attrib[attribute]
parsed_url = parse_url(node.get_href())
if parsed_url.fragment and not parsed_url.path:
try:
tree = svg.tree.get_child(parsed_url.fragment).copy()
except AttributeError:
return
else:
url = parsed_url.geturl()
try:
bytestring_svg = svg.url_fetcher(url)
use_svg = SVG(bytestring_svg, url)
except TypeError:
return
else:
use_svg.get_intrinsic_size(font_size)
tree = use_svg.tree
if tree.tag in ('svg', 'symbol'):
# Explicitely specified
# http://www.w3.org/TR/SVG11/struct.html#UseElement
tree._etree_node.tag = 'svg'
if 'width' in node.attrib and 'height' in node.attrib:
tree.attrib['width'] = node.attrib['width']
tree.attrib['height'] = node.attrib['height']
# Cascade
for key, value in node.attrib.items():
if key not in NOT_INHERITED_ATTRIBUTES:
if key not in tree.attrib:
tree.attrib[key] = value
svg.stream.push_state()
svg.stream.transform(e=x, f=y)
svg.draw_node(tree, font_size)
svg.stream.pop_state()
def draw_gradient_or_pattern(svg, node, name, font_size, opacity, stroke):
"""Draw given gradient or pattern."""
if name in svg.gradients:
return draw_gradient(
svg, node, svg.gradients[name], font_size, opacity, stroke)
elif name in svg.patterns:
return draw_pattern(
svg, node, svg.patterns[name], font_size, opacity, stroke)
def draw_gradient(svg, node, gradient, font_size, opacity, stroke):
"""Draw given gradient node."""
# TODO: merge with Gradient.draw
from ..document import Matrix
positions = []
colors = []
for child in gradient:
positions.append(max(
positions[-1] if positions else 0,
size(child.get('offset'), font_size, 1)))
stop_opacity = float(child.get('stop-opacity', 1)) * opacity
stop_color = color(child.get('stop-color', 'black'))
if stop_opacity < 1:
stop_color = tuple(
stop_color[:3] + (stop_color[3] * stop_opacity,))
colors.append(stop_color)
if not colors:
return False
elif len(colors) == 1:
red, green, blue, alpha = colors[0]
svg.stream.set_color_rgb(red, green, blue)
if alpha != 1:
svg.stream.set_alpha(alpha, stroke=stroke)
return True
bounding_box = svg.calculate_bounding_box(node, font_size, stroke)
if not is_valid_bounding_box(bounding_box):
return False
x, y = bounding_box[0], bounding_box[1]
matrix = Matrix(e=x, f=y)
if gradient.get('gradientUnits') == 'userSpaceOnUse':
width, height = svg.inner_width, svg.inner_height
else:
width, height = bounding_box[2], bounding_box[3]
spread = gradient.get('spreadMethod', 'pad')
if spread in ('repeat', 'reflect'):
if positions[0] > 0:
positions.insert(0, 0)
colors.insert(0, colors[0])
if positions[-1] < 1:
positions.append(1)
colors.append(colors[-1])
else:
# Add explicit colors at boundaries if needed, because PDF doesnt
# extend color stops that are not displayed
if positions[0] == positions[1]:
if gradient.tag == 'radialGradient':
# Avoid negative radius for radial gradients
positions.insert(0, 0)
else:
positions.insert(0, positions[0] - 1)
colors.insert(0, colors[0])
if positions[-2] == positions[-1]:
positions.append(positions[-1] + 1)
colors.append(colors[-1])
if gradient.tag == 'linearGradient':
shading_type = 2
x1, y1 = (
size(gradient.get('x1', 0), font_size, 1),
size(gradient.get('y1', 0), font_size, 1))
x2, y2 = (
size(gradient.get('x2', '100%'), font_size, 1),
size(gradient.get('y2', 0), font_size, 1))
if gradient.get('gradientUnits') == 'userSpaceOnUse':
x1 -= x
y1 -= y
x2 -= x
y2 -= y
else:
length = min(width, height)
x1 *= length
y1 *= length
x2 *= length
y2 *= length
a = (width / height) if height < width else 1
d = (height / width) if height > width else 1
matrix = Matrix(a=a, d=d) @ matrix
positions, colors, coords = spread_linear_gradient(
spread, positions, colors, x1, y1, x2, y2)
else:
assert gradient.tag == 'radialGradient'
shading_type = 3
cx, cy = (
size(gradient.get('cx', '50%'), font_size, 1),
size(gradient.get('cy', '50%'), font_size, 1))
r = size(gradient.get('r', '50%'), font_size, 1)
fx, fy = (
size(gradient.get('fx', cx), font_size, width),
size(gradient.get('fy', cy), font_size, height))
fr = size(gradient.get('fr', 0), font_size, 1)
if gradient.get('gradientUnits') == 'userSpaceOnUse':
cx -= x
cy -= y
fx -= x
fy -= y
else:
length = min(width, height)
cx *= length
cy *= length
r *= length
fx *= length
fy *= length
fr *= length
a = (width / height) if height < width else 1
d = (height / width) if height > width else 1
matrix = Matrix(a=a, d=d) @ matrix
positions, colors, coords = spread_radial_gradient(
spread, positions, colors, fx, fy, fr, cx, cy, r, width, height)
alphas = [color[3] for color in colors]
alpha_couples = [
(alphas[i], alphas[i + 1])
for i in range(len(alphas) - 1)]
color_couples = [
[colors[i][:3], colors[i + 1][:3], 1]
for i in range(len(colors) - 1)]
# Premultiply colors
for i, alpha in enumerate(alphas):
if alpha == 0:
if i > 0:
color_couples[i - 1][1] = color_couples[i - 1][0]
if i < len(colors) - 1:
color_couples[i][0] = color_couples[i][1]
for i, (a0, a1) in enumerate(alpha_couples):
if 0 not in (a0, a1) and (a0, a1) != (1, 1):
color_couples[i][2] = a0 / a1
if 'gradientTransform' in gradient.attrib:
transform_matrix = transform(
gradient.get('gradientTransform'), font_size,
svg.normalized_diagonal)
matrix = transform_matrix @ matrix
matrix = matrix @ svg.stream.ctm
pattern = svg.stream.add_pattern(width, height, width, height, matrix)
group = pattern.add_group([0, 0, width, height])
shading = group.add_shading()
shading['ShadingType'] = shading_type
shading['ColorSpace'] = '/DeviceRGB'
shading['Domain'] = pydyf.Array([positions[0], positions[-1]])
shading['Coords'] = pydyf.Array(coords)
shading['Function'] = pydyf.Dictionary({
'FunctionType': 3,
'Domain': pydyf.Array([positions[0], positions[-1]]),
'Encode': pydyf.Array((len(colors) - 1) * [0, 1]),
'Bounds': pydyf.Array(positions[1:-1]),
'Functions': pydyf.Array([
pydyf.Dictionary({
'FunctionType': 2,
'Domain': pydyf.Array([positions[0], positions[-1]]),
'C0': pydyf.Array(c0),
'C1': pydyf.Array(c1),
'N': n,
}) for c0, c1, n in color_couples
]),
})
if spread not in ('repeat', 'reflect'):
shading['Extend'] = pydyf.Array([b'true', b'true'])
if any(alpha != 1 for alpha in alphas):
alpha_stream = group.add_group(
[0, 0, svg.concrete_width, svg.concrete_height])
state = pydyf.Dictionary({
'Type': '/ExtGState',
'SMask': pydyf.Dictionary({
'Type': '/Mask',
'S': '/Luminosity',
'G': alpha_stream,
}),
'ca': 1,
'AIS': 'false',
})
group.set_state(state)
alpha_shading = alpha_stream.add_shading()
alpha_shading['ShadingType'] = shading_type
alpha_shading['ColorSpace'] = '/DeviceGray'
alpha_shading['Domain'] = pydyf.Array(
[positions[0], positions[-1]])
alpha_shading['Coords'] = pydyf.Array(coords)
alpha_shading['Function'] = pydyf.Dictionary({
'FunctionType': 3,
'Domain': pydyf.Array([positions[0], positions[-1]]),
'Encode': pydyf.Array((len(colors) - 1) * [0, 1]),
'Bounds': pydyf.Array(positions[1:-1]),
'Functions': pydyf.Array([
pydyf.Dictionary({
'FunctionType': 2,
'Domain': pydyf.Array([0, 1]),
'C0': pydyf.Array([c0]),
'C1': pydyf.Array([c1]),
'N': 1,
}) for c0, c1 in alpha_couples
]),
})
if spread not in ('repeat', 'reflect'):
alpha_shading['Extend'] = pydyf.Array([b'true', b'true'])
alpha_stream.stream = [f'/{alpha_shading.id} sh']
group.shading(shading.id)
pattern.draw_x_object(group.id)
svg.stream.color_space('Pattern', stroke=stroke)
svg.stream.set_color_special(pattern.id, stroke=stroke)
return True
def spread_linear_gradient(spread, positions, colors, x1, y1, x2, y2):
"""Repeat linear gradient."""
# TODO: merge with LinearGradient.layout
from ..images import gradient_average_color, normalize_stop_positions
first, last, positions = normalize_stop_positions(positions)
if spread in ('repeat', 'reflect'):
# Render as a solid color if the first and last positions are equal
# See https://drafts.csswg.org/css-images-3/#repeating-gradients
if first == last:
average_color = gradient_average_color(colors, positions)
return 1, 'solid', None, [], [average_color]
# Define defined gradient length and steps between positions
stop_length = last - first
assert stop_length > 0
position_steps = [
positions[i + 1] - positions[i]
for i in range(len(positions) - 1)]
# Create cycles used to add colors
if spread == 'repeat':
next_steps = cycle([0] + position_steps)
next_colors = cycle(colors)
previous_steps = cycle([0] + position_steps[::-1])
previous_colors = cycle(colors[::-1])
else:
assert spread == 'reflect'
next_steps = cycle(
[0] + position_steps[::-1] + [0] + position_steps)
next_colors = cycle(colors[::-1] + colors)
previous_steps = cycle(
[0] + position_steps + [0] + position_steps[::-1])
previous_colors = cycle(colors + colors[::-1])
# Add colors after last step
while last < hypot(x2 - x1, y2 - y1):
step = next(next_steps)
colors.append(next(next_colors))
positions.append(positions[-1] + step)
last += step * stop_length
# Add colors before last step
while first > 0:
step = next(previous_steps)
colors.insert(0, next(previous_colors))
positions.insert(0, positions[0] - step)
first -= step * stop_length
x1, x2 = x1 + (x2 - x1) * first, x1 + (x2 - x1) * last
y1, y2 = y1 + (y2 - y1) * first, y1 + (y2 - y1) * last
coords = (x1, y1, x2, y2)
return positions, colors, coords
def spread_radial_gradient(spread, positions, colors, fx, fy, fr, cx, cy, r,
width, height):
"""Repeat radial gradient."""
# TODO: merge with RadialGradient._repeat
from ..images import gradient_average_color, normalize_stop_positions
first, last, positions = normalize_stop_positions(positions)
fr, r = fr + (r - fr) * first, fr + (r - fr) * last
if spread in ('repeat', 'reflect'):
# Keep original lists and values, theyre useful
original_colors = colors.copy()
original_positions = positions.copy()
gradient_length = r - fr
# Get the maximum distance between the center and the corners, to find
# how many times we have to repeat the colors outside
max_distance = max(
hypot(width - fx, height - fy),
hypot(width - fx, -fy),
hypot(-fx, height - fy),
hypot(-fx, -fy))
repeat_after = ceil((max_distance - r) / gradient_length)
if repeat_after > 0:
# Repeat colors and extrapolate positions
repeat = 1 + repeat_after
if spread == 'repeat':
colors *= repeat
else:
assert spread == 'reflect'
colors = []
for i in range(repeat):
colors += original_colors[::1 if i % 2 else -1]
positions = [
i + position for i in range(repeat) for position in positions]
r += gradient_length * repeat_after
if fr == 0:
# Inner circle has 0 radius, no need to repeat inside, return
coords = (fx, fy, fr, cx, cy, r)
return positions, colors, coords
# Find how many times we have to repeat the colors inside
repeat_before = fr / gradient_length
# Set the inner circle size to 0
fr = 0
# Find how many times the whole gradient can be repeated
full_repeat = int(repeat_before)
if full_repeat:
# Repeat colors and extrapolate positions
if spread == 'repeat':
colors += original_colors * full_repeat
else:
assert spread == 'reflect'
for i in range(full_repeat):
colors += original_colors[::1 if i % 2 else -1]
positions = [
i - full_repeat + position for i in range(full_repeat)
for position in original_positions] + positions
# Find the ratio of gradient that must be added to reach the center
partial_repeat = repeat_before - full_repeat
if partial_repeat == 0:
# No partial repeat, return
coords = (fx, fy, fr, cx, cy, r)
return positions, colors, coords
# Iterate through positions in reverse order, from the outer
# circle to the original inner circle, to find positions from
# the inner circle (including full repeats) to the center
assert (original_positions[0], original_positions[-1]) == (0, 1)
assert 0 < partial_repeat < 1
reverse = original_positions[::-1]
ratio = 1 - partial_repeat
for i, position in enumerate(reverse, start=1):
if position == ratio:
# The center is a color of the gradient, truncate original
# colors and positions and prepend them
colors = original_colors[-i:] + colors
new_positions = [
position - full_repeat - 1
for position in original_positions[-i:]]
positions = new_positions + positions
coords = (fx, fy, fr, cx, cy, r)
return positions, colors, coords
if position < ratio:
# The center is between two colors of the gradient,
# define the center color as the average of these two
# gradient colors
color = original_colors[-i]
next_color = original_colors[-(i - 1)]
next_position = original_positions[-(i - 1)]
average_colors = [color, color, next_color, next_color]
average_positions = [position, ratio, ratio, next_position]
zero_color = gradient_average_color(
average_colors, average_positions)
colors = [zero_color] + original_colors[-(i - 1):] + colors
new_positions = [
position - 1 - full_repeat for position
in original_positions[-(i - 1):]]
positions = (
[ratio - 1 - full_repeat] + new_positions + positions)
coords = (fx, fy, fr, cx, cy, r)
return positions, colors, coords
def draw_pattern(svg, node, pattern, font_size, opacity, stroke):
"""Draw given gradient node."""
from ..document import Matrix
from . import Pattern
pattern._etree_node.tag = 'svg'
bounding_box = svg.calculate_bounding_box(node, font_size, stroke)
if not is_valid_bounding_box(bounding_box):
return False
x, y = bounding_box[0], bounding_box[1]
matrix = Matrix(e=x, f=y)
if pattern.get('patternUnits') == 'userSpaceOnUse':
width, height = svg.inner_width, svg.inner_height
else:
width, height = bounding_box[2], bounding_box[3]
if pattern.get('patternUnits') == 'userSpaceOnUse':
x = size(pattern.get('x'), font_size, 1)
y = size(pattern.get('y'), font_size, 1)
pattern_width = size(pattern.get('width', 0), font_size, 1)
pattern_height = size(pattern.get('height', 0), font_size, 1)
else:
x = size(pattern.get('x'), font_size, 1) * width
y = size(pattern.get('y'), font_size, 1) * height
pattern_width = (
size(pattern.attrib.pop('width', '1'), font_size, 1) * width)
pattern_height = (
size(pattern.attrib.pop('height', '1'), font_size, 1) * height)
if 'viewBox' not in pattern:
pattern.attrib['width'] = pattern_width
pattern.attrib['height'] = pattern_height
if pattern.get('patternContentUnits') == 'objectBoundingBox':
pattern.attrib['transform'] = f'scale({width}, {height})'
# Fail if pattern has an invalid size
if pattern_width == 0 or pattern_height == 0:
return False
if 'patternTransform' in pattern.attrib:
transform_matrix = transform(
pattern.get('patternTransform'), font_size, svg.inner_diagonal)
matrix = transform_matrix @ matrix
matrix = matrix @ svg.stream.ctm
stream_pattern = svg.stream.add_pattern(
pattern_width, pattern_height, pattern_width, pattern_height, matrix)
stream_pattern.set_alpha(opacity)
group = stream_pattern.add_group([0, 0, pattern_width, pattern_height])
Pattern(pattern, svg).draw(
group, pattern_width, pattern_height, svg.base_url,
svg.url_fetcher, svg.context)
stream_pattern.draw_x_object(group.id)
svg.stream.color_space('Pattern', stroke=stroke)
svg.stream.set_color_special(stream_pattern.id, stroke=stroke)
return True
def apply_filters(svg, node, filter_node, font_size):
"""Apply filters defined in given filter node."""
for child in filter_node:
if child.tag == 'feOffset':
if filter_node.get('primitiveUnits') == 'objectBoundingBox':
bounding_box = svg.calculate_bounding_box(node, font_size)
if is_valid_bounding_box(bounding_box):
_, _, width, height = bounding_box
dx = size(child.get('dx', 0), font_size, 1) * width
dy = size(child.get('dy', 0), font_size, 1) * height
else:
dx = dy = 0
else:
dx, dy = svg.point(
child.get('dx', 0), child.get('dy', 0), font_size)
svg.stream.transform(e=dx, f=dy)
elif child.tag == 'feBlend':
mode = child.get('mode', 'normal')
mode = mode.replace('-', ' ').title().replace(' ', '')
blend_mode = pydyf.Dictionary({
'Type': '/ExtGState',
'BM': f'/{mode}',
})
svg.stream.set_state(blend_mode)
def paint_mask(svg, node, mask, font_size):
"""Apply given mask node."""
mask._etree_node.tag = 'g'
if mask.get('maskUnits') == 'userSpaceOnUse':
width_ref, height_ref = svg.inner_width, svg.inner_height
else:
width_ref, height_ref = svg.point(
node.get('width'), node.get('height'), font_size)
mask.attrib['x'] = size(mask.get('x', '-10%'), font_size, width_ref)
mask.attrib['y'] = size(mask.get('y', '-10%'), font_size, height_ref)
mask.attrib['height'] = size(
mask.get('height', '120%'), font_size, height_ref)
mask.attrib['width'] = size(
mask.get('width', '120%'), font_size, width_ref)
if mask.get('maskUnits') == 'userSpaceOnUse':
x, y = mask.get('x'), mask.get('y')
width, height = mask.get('width'), mask.get('height')
mask.attrib['viewBox'] = f'{x} {y} {width} {height}'
else:
x, y = 0, 0
width, height = width_ref, height_ref
alpha_stream = svg.stream.add_group([x, y, width, height])
state = pydyf.Dictionary({
'Type': '/ExtGState',
'SMask': pydyf.Dictionary({
'Type': '/Mask',
'S': '/Luminance',
'G': alpha_stream,
}),
'ca': 1,
'AIS': 'false',
})
svg.stream.set_state(state)
svg_stream = svg.stream
svg.stream = alpha_stream
svg.draw_node(mask, font_size)
svg.stream = svg_stream
def clip_path(svg, node, font_size):
"""Store a clip path definition."""
if 'id' in node.attrib:
svg.paths[node.attrib['id']] = node