def triangulate_cdt(self):
vertices = list()
#print "preparing constrained delaunay triangulation"
for coord_pair in self.src_polygon.exterior.coords:
vertices.append(coord_pair)
border = [p2t.Point(x, y) for x, y in vertices[1:]]
#print "initializing cdt"
cdt = p2t.CDT(border)
#print "adding holes"
for interior_ring in self.src_polygon.interiors:
hole = list()
for coord_pair in interior_ring.coords:
hole.append(coord_pair)
else:
cdt.add_hole([p2t.Point(x, y) for x, y in hole[1:]])
#print "performing cdt"
triangles = cdt.triangulate()
#print "done"
self.triangles = list()
for t in triangles:
triangle = Polygon([(t.a.x, t.a.y), (t.b.x, t.b.y),
(t.c.x, t.c.y)])
self.triangles.append(triangle)
else:
self.triangles = sorted(self.triangles,
key=attrgetter('area'),
reverse=True)
def to2D(self, point):
"""
Get a 2D point from a 3D point by simply omitting the less significant coordinate
Return an instance of poly2tri point because that's what we'll need
"""
p = point[:self.longest] + point[self.longest + 1:]
return p2t.Point(*p)
def triangulate(self):
""""
Returns triangles that form the same shape as the polygon
:return list of Triangle
"""
p2t_points = [p2t.Point(p[0], p[1]) for p in self.points]
cdt = p2t.CDT(p2t_points)
p2t_triangles = cdt.triangulate()
triangles = [Triangle([t.a.x, t.a.y], [t.b.x, t.b.y], [t.c.x, t.c.y]) for t in p2t_triangles]
return triangles
def cd_triangulate_single_polygon(self, polygon):
u"""
Perform a Constrained Delaunay Triangulation on a single polygon. The
given polygon needs to be continuous (no multi-polygon) but may contain
holes.
"""
# creating a complete list of the polygon's vertices
vertices = list()
for coord_pair in polygon.exterior.coords:
vertices.append(coord_pair)
# creating the necessary data structure for the triangulation (list of
# vertex points) excluding the duplicated start and end vertex
border = [p2t.Point(x, y) for x, y in vertices[1:]]
# initializing triangulation
cdt = p2t.CDT(border)
# adding holes to triangulation configuration
for interior_ring in polygon.interiors:
hole = list()
for coord_pair in interior_ring.coords:
hole.append(coord_pair)
else:
cdt.add_hole([p2t.Point(x, y) for x, y in hole[1:]])
# performing triangulation and returning result
return cdt.triangulate()
def triangulatePolygon( verts, holes = None ): polyline = [] x, y = None, None for i in range( 0, len( verts ), 2 ): xx, yy = verts[i], verts[i+1] if xx == x and yy == y: continue polyline.append( p2t.Point( xx, yy ) ) x = xx y = yy cdt = p2t.CDT( polyline ) if holes: for hole in holes: cdt.add_hole( hole ) triangles = cdt.triangulate() result = [] for t in triangles: result.append( t.a.x ) result.append( t.a.y ) result.append( t.b.x ) result.append( t.b.y ) result.append( t.c.x ) result.append( t.c.y ) return result
def test_points_on_line(self, points, point, on):
points = map(lambda x: p2t.Point(*x), points)
line = polygons.Line(*points)
assert line.is_on(p2t.Point(*point)) == on