inkstitch/lib/elements/gradient_fill.py

80 wiersze
3.7 KiB
Python

from math import pi
from inkex import DirectedLineSegment, Transform
from shapely import geometry as shgeo
from shapely.affinity import affine_transform, rotate
from shapely.ops import split
from ..svg import get_correction_transform
def gradient_shapes_and_attributes(element, shape):
# e.g. url(#linearGradient872) -> linearGradient872
color = element.color[5:-1]
xpath = f'.//svg:defs/svg:linearGradient[@id="{color}"]'
gradient = element.node.getroottree().getroot().findone(xpath)
gradient.apply_transform()
point1 = (float(gradient.get('x1')), float(gradient.get('y1')))
point2 = (float(gradient.get('x2')), float(gradient.get('y2')))
# get 90° angle to calculate the splitting angle
line = DirectedLineSegment(point1, point2)
angle = line.angle - (pi / 2)
# Ink/Stitch somehow turns the stitch angle
stitch_angle = angle * -1
# create bbox polygon to calculate the length necessary to make sure that
# the gradient splitter lines will cut the entire design
bbox = element.node.bounding_box()
bbox_polygon = shgeo.Polygon([(bbox.left, bbox.top), (bbox.right, bbox.top),
(bbox.right, bbox.bottom), (bbox.left, bbox.bottom)])
# gradient stops
offsets = gradient.stop_offsets
stop_styles = gradient.stop_styles
# now split the shape according to the gradient stops
polygons = []
colors = []
attributes = []
previous_color = None
end_row_spacing = None
for i, offset in enumerate(offsets):
shape_rest = []
split_point = shgeo.Point(line.point_at_ratio(float(offset)))
length = split_point.hausdorff_distance(bbox_polygon)
split_line = shgeo.LineString([(split_point.x - length - 2, split_point.y),
(split_point.x + length + 2, split_point.y)])
split_line = rotate(split_line, angle, origin=split_point, use_radians=True)
transform = -Transform(get_correction_transform(element.node))
transform = list(transform.to_hexad())
split_line = affine_transform(split_line, transform)
offset_line = split_line.parallel_offset(1, 'right')
polygon = split(shape, split_line)
color = stop_styles[i]['stop-color']
# does this gradient line split the shape
offset_outside_shape = len(polygon.geoms) == 1
for poly in polygon.geoms:
if isinstance(poly, shgeo.Polygon) and element.shape_is_valid(poly):
if poly.intersects(offset_line):
if previous_color:
polygons.append(poly)
colors.append(previous_color)
attributes.append({'angle': stitch_angle, 'end_row_spacing': end_row_spacing, 'color': previous_color})
polygons.append(poly)
attributes.append({'angle': stitch_angle + pi, 'end_row_spacing': end_row_spacing, 'color': color})
else:
shape_rest.append(poly)
shape = shgeo.MultiPolygon(shape_rest)
previous_color = color
end_row_spacing = element.row_spacing * 2
# add left over shape(s)
if shape:
if offset_outside_shape:
for s in shape.geoms:
polygons.append(s)
attributes.append({'color': stop_styles[-2]['stop-color'], 'angle': stitch_angle, 'end_row_spacing': end_row_spacing})
stitch_angle += pi
else:
end_row_spacing = None
for s in shape.geoms:
polygons.append(s)
attributes.append({'color': stop_styles[-1]['stop-color'], 'angle': stitch_angle, 'end_row_spacing': end_row_spacing})
return polygons, attributes