def contours(path):
""" Returns a list of contours in the path, as BezierPath objects.
A contour is a sequence of lines and curves separated from the next contour by a MOVETO.
For example, the glyph "o" has two contours: the inner circle and the outer circle.
"""
contours = []
current_contour = None
empty = True
for i, el in enumerate(path):
if el.cmd == MOVETO:
if not empty:
contours.append(current_contour)
current_contour = BezierPath()
current_contour.moveto(el.x, el.y)
empty = True
elif el.cmd == LINETO:
empty = False
current_contour.lineto(el.x, el.y)
elif el.cmd == CURVETO:
empty = False
current_contour.curveto(el.ctrl1.x, el.ctrl1.y, el.ctrl2.x, el.ctrl2.y, el.x, el.y)
elif el.cmd == CLOSE:
current_contour.closepath()
if not empty:
contours.append(current_contour)
return contours
def findpath(points, curvature=1.0):
""" Constructs a smooth BezierPath from the given list of points.
The curvature parameter offers some control on how separate segments are stitched together:
from straight angles to smooth curves.
Curvature is only useful if the path has more than three points.
"""
# The list of points consists of Point objects,
# but it shouldn't crash on something straightforward
# as someone supplying a list of (x,y)-tuples.
for i, pt in enumerate(points):
if type(pt) == tuple:
points[i] = Point(pt[0], pt[1])
# No points: return nothing.
if len(points) == 0: return None
# One point: return a path with a single MOVETO-point.
if len(points) == 1:
path = BezierPath(None)
path.moveto(points[0].x, points[0].y)
return path
# Two points: path with a single straight line.
if len(points) == 2:
path = BezierPath(None)
path.moveto(points[0].x, points[0].y)
path.lineto(points[1].x, points[1].y)
return path
# Zero curvature means path with straight lines.
curvature = max(0, min(1, curvature))
if curvature == 0:
path = BezierPath(None)
path.moveto(points[0].x, points[0].y)
for i in range(len(points)):
path.lineto(points[i].x, points[i].y)
return path
# Construct the path with curves.
curvature = 4 + (1.0-curvature)*40
# The first point's ctrl1 and ctrl2 and last point's ctrl2
# will be the same as that point's location;
# we cannot infer how the path curvature started or will continue.
dx = {0: 0, len(points)-1: 0}
dy = {0: 0, len(points)-1: 0}
bi = {1: -0.25}
ax = {1: (points[2].x-points[0].x-dx[0]) / 4}
ay = {1: (points[2].y-points[0].y-dy[0]) / 4}
for i in range(2, len(points)-1):
bi[i] = -1 / (curvature + bi[i-1])
ax[i] = -(points[i+1].x-points[i-1].x-ax[i-1]) * bi[i]
ay[i] = -(points[i+1].y-points[i-1].y-ay[i-1]) * bi[i]
r = range(1, len(points)-1)
r.reverse()
for i in r:
dx[i] = ax[i] + dx[i+1] * bi[i]
dy[i] = ay[i] + dy[i+1] * bi[i]
path = BezierPath(None)
path.moveto(points[0].x, points[0].y)
for i in range(len(points)-1):
path.curveto(points[i].x + dx[i],
points[i].y + dy[i],
points[i+1].x - dx[i+1],
points[i+1].y - dy[i+1],
points[i+1].x,
points[i+1].y)
return path
