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from __future__ import unicode_literals, print_function, division
from lingpy import log
import numpy as np
import networkx as nx
try:
import matplotlib.patches as mplPatches
except ImportError:
log.missing_module('matplotlib')
from .convex_hull import convex_hull
def perp(a):
"""
code for intersection taken from
http://stackoverflow.com/questions/3252194/numpy-and-line-intersections
"""
b = np.empty_like(a)
b[0] = -a[1]
b[1] = a[0]
return b
# line segment a given by endpoints a1, a2
# line segment b given by endpoints b1, b2
# return
def seg_intersect(nA, nB):
a1 = np.array(nA[0], dtype='float')
a2 = np.array(nA[1], dtype='float')
b1 = np.array(nB[0], dtype='float')
b2 = np.array(nB[1], dtype='float')
da = a2 - a1
db = b2 - b1
dp = a1 - b1
dap = perp(da)
denom = np.dot(dap, db)
num = np.dot(dap, dp)
try:
x, y = (num / denom) * db + b1
except ZeroDivisionError:
return False
# check whether the point is on both lines
x1 = sorted([a1[0], a2[0]])
x2 = sorted([b1[0], b2[0]])
y1 = sorted([a1[1], a2[1]])
y2 = sorted([b1[1], b2[1]])
if x1[0] <= x <= x1[1] and x2[0] <= x <= x2[1]:
if y1[0] <= y <= y1[1] and y2[0] <= y <= y2[1]:
if [x, y] not in [k.tolist() for k in [a1, a2, b1, b2]]:
return True
return False
def getConvexHull(
nodes,
color='orange',
alpha=0.5,
polygon=True
):
if len(nodes) < 3:
return nodes
points = np.array([[i[0] for i in nodes], [i[1] for i in nodes]])
ch_points = convex_hull(points, graphic=False)
if not polygon:
return ch_points
return mplPatches.Polygon(ch_points, closed=True, fill=True, color=color, alpha=alpha,
lw=0)
def getPolygonFromNodes(
nodes,
color='orange',
alpha=0.5,
):
# get all lines
lines = []
for i, nA in enumerate(nodes):
for j, nB in enumerate(nodes):
if i < j:
lines.append((nA, nB))
# get all non-intersecting lines
ni_lines = []
for i, lineA in enumerate(lines):
this_line = lineA
for j, lineB in enumerate(lines):
if i != j:
if seg_intersect(lineA, lineB) and lineA[0].tolist() != lineB[0].tolist() and \
lineA[1].tolist() != lineB[1].tolist():
this_line = False
if this_line:
ni_lines.append(this_line)
# make a graph of the lines
g = nx.Graph()
for a, b in ni_lines:
xA, yA = a
xB, yB = b
absX = abs(xA - xB)
absY = abs(yA - yB)
if absX == 0:
d = absY
elif absY == 0:
d = absX
else:
d = np.sqrt(absX ** 2 + absY ** 2)
g.add_edge(a, b, weight=d)
# sort the lines
start = g.nodes()[0]
paths = [start]
while True:
tmp = g.edge[start].items()
neighbors = [i[0] for i in tmp if i[0] not in paths]
if not neighbors:
break
distances = [i[1]['weight'] for i in tmp if i[0] not in paths]
this_neighbor = neighbors[distances.index(max(distances))]
start = this_neighbor
paths.append(this_neighbor)
return mplPatches.Polygon(paths, closed=True, fill=True, color=color, alpha=alpha,
lw=0)
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