kopia lustrzana https://github.com/inkstitch/inkstitch
103 wiersze
3.0 KiB
Python
103 wiersze
3.0 KiB
Python
from shapely.geometry import LineString, Point as ShapelyPoint
|
|
import math
|
|
|
|
|
|
def cut(line, distance):
|
|
""" Cuts a LineString in two at a distance from its starting point.
|
|
|
|
This is an example in the Shapely documentation.
|
|
"""
|
|
if distance <= 0.0 or distance >= line.length:
|
|
return [LineString(line), None]
|
|
coords = list(line.coords)
|
|
for i, p in enumerate(coords):
|
|
# TODO: I think this doesn't work if the path doubles back on itself
|
|
pd = line.project(ShapelyPoint(p))
|
|
if pd == distance:
|
|
return [
|
|
LineString(coords[:i+1]),
|
|
LineString(coords[i:])]
|
|
if pd > distance:
|
|
cp = line.interpolate(distance)
|
|
return [
|
|
LineString(coords[:i] + [(cp.x, cp.y)]),
|
|
LineString([(cp.x, cp.y)] + coords[i:])]
|
|
|
|
|
|
def cut_path(points, length):
|
|
"""Return a subsection of at the start of the path that is length units long.
|
|
|
|
Given a path denoted by a set of points, walk along it until we've travelled
|
|
the specified length and return a new path up to that point.
|
|
|
|
If the original path isn't that long, just return it as is.
|
|
"""
|
|
|
|
if len(points) < 2:
|
|
return points
|
|
|
|
path = LineString(points)
|
|
subpath, rest = cut(path, length)
|
|
|
|
return [Point(*point) for point in subpath.coords]
|
|
|
|
|
|
class Point:
|
|
def __init__(self, x, y):
|
|
self.x = x
|
|
self.y = y
|
|
|
|
def __add__(self, other):
|
|
return Point(self.x + other.x, self.y + other.y)
|
|
|
|
def __sub__(self, other):
|
|
return Point(self.x - other.x, self.y - other.y)
|
|
|
|
def mul(self, scalar):
|
|
return Point(self.x * scalar, self.y * scalar)
|
|
|
|
def __mul__(self, other):
|
|
if isinstance(other, Point):
|
|
# dot product
|
|
return self.x * other.x + self.y * other.y
|
|
elif isinstance(other, (int, float)):
|
|
return Point(self.x * other, self.y * other)
|
|
else:
|
|
raise ValueError("cannot multiply Point by %s" % type(other))
|
|
|
|
def __rmul__(self, other):
|
|
if isinstance(other, (int, float)):
|
|
return self.__mul__(other)
|
|
else:
|
|
raise ValueError("cannot multiply Point by %s" % type(other))
|
|
|
|
def __repr__(self):
|
|
return "Point(%s,%s)" % (self.x, self.y)
|
|
|
|
def length(self):
|
|
return math.sqrt(math.pow(self.x, 2.0) + math.pow(self.y, 2.0))
|
|
|
|
def unit(self):
|
|
return self.mul(1.0 / self.length())
|
|
|
|
def rotate_left(self):
|
|
return Point(-self.y, self.x)
|
|
|
|
def rotate(self, angle):
|
|
return Point(self.x * math.cos(angle) - self.y * math.sin(angle), self.y * math.cos(angle) + self.x * math.sin(angle))
|
|
|
|
def as_int(self):
|
|
return Point(int(round(self.x)), int(round(self.y)))
|
|
|
|
def as_tuple(self):
|
|
return (self.x, self.y)
|
|
|
|
def __cmp__(self, other):
|
|
return cmp(self.as_tuple(), other.as_tuple())
|
|
|
|
def __getitem__(self, item):
|
|
return self.as_tuple()[item]
|
|
|
|
def __len__(self):
|
|
return 2
|