sketch-a-day/2019/sketch_190210b/sketch_190210b.pyde

97 wiersze
2.6 KiB
Python

"""
Based on Stackoverflow C# rounded corner post
https://stackoverflow.com/questions/24771828/algorithm-for-creating-rounded-corners-in-a-polygon
"""
def setup():
size(500, 500)
def draw():
background(200)
p1 = PVector(100, 400)
p0 = PVector(300, 100)
p2 = PVector(mouseX, mouseY)
r = 50
roundedCorner(p0, p1, p2, r)
def roundedCorner( angularPoint,
p1, p2, radius):
#Vector 1
dx1 = angularPoint.x - p1.x
dy1 = angularPoint.y - p1.y
#Vector 2
dx2 = angularPoint.x - p2.x
dy2 = angularPoint.y - p2.y
#Angle between vector 1 and vector 2 divided by 2
angle = (atan2(dy1, dx1) - atan2(dy2, dx2)) / 2
# The length of segment between angular point and the
# points of intersection with the circle of a given radius
segment = radius / abs(tan(angle))
#Check the segment
length1 = GetLength(dx1, dy1)
length2 = GetLength(dx2, dy2)
length = min(length1, length2)
if segment > length:
segment = length
radius = length * abs(tan(angle))
# Points of intersection are calculated by the proportion between
# the coordinates of the vector, length of vector and the length of the segment.
p1Cross = GetProportionPoint(angularPoint, segment, length1, dx1, dy1)
p2Cross = GetProportionPoint(angularPoint, segment, length2, dx2, dy2)
# Calculation of the coordinates of the circle
# center by the addition of angular vectors.
dx = angularPoint.x * 2 - p1Cross.x - p2Cross.x
dy = angularPoint.y * 2 - p1Cross.y - p2Cross.y
L = GetLength(dx, dy)
d = GetLength(segment, radius)
circlePoint = GetProportionPoint(angularPoint, d, L, dx, dy)
#StartAngle and EndAngle of arc
startAngle = atan2(p1Cross.y - circlePoint.y, p1Cross.x - circlePoint.x)
endAngle = atan2(p2Cross.y - circlePoint.y, p2Cross.x - circlePoint.x)
#Sweep angle
sweepAngle = endAngle - startAngle
#Some additional checks
if sweepAngle < 0:
startAngle = endAngle
sweepAngle = -sweepAngle
if sweepAngle > PI:
sweepAngle = PI - sweepAngle
#Draw result using graphics
noFill()
strokeWeight(3)
line(p1.x, p1.y, p1Cross.x, p1Cross.y)
line(p2.x, p2.y, p2Cross.x, p2Cross.y)
arc(circlePoint.x, circlePoint.y, 2 * radius, 2 * radius,
startAngle, startAngle + sweepAngle)
def GetLength(dx, dy):
return sqrt(dx * dx + dy * dy)
def GetProportionPoint(pt, segment, L, dx, dy):
if L != 0:
factor = segment / L
else:
factor = 0
return PVector(
(pt.x - dx * factor),
(pt.y - dy * factor))