kopia lustrzana https://github.com/villares/sketch-a-day
154 wiersze
5.7 KiB
Python
154 wiersze
5.7 KiB
Python
def b_poly_filleted(p_list, r_list=None, open_poly=False):
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"""
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draws a 'filleted' polygon with variable radius
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dependent on roundedCorner()
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"""
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if not r_list:
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r_list = [0] * len(p_list)
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assert len(p_list) == len(r_list), \
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"Number of points and radii not the same"
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strokeJoin(ROUND)
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beginShape()
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for p0, p1, p2, r in zip(p_list,
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[p_list[-1]] + p_list[:-1],
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[p_list[-2]] + [p_list[-1]] + p_list[:-2],
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[r_list[-1]] + r_list[:-1]
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):
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m1 = (p0[0] + p1[0]) / 2, (p0[1] + p1[1]) / 2
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m2 = (p2[0] + p1[0]) / 2, (p2[1] + p1[1]) / 2
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b_roundedCorner(p1, m1, m2, r)
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endShape(CLOSE)
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def b_roundedCorner(pc, p2, p1, r):
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"""
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Based on Stackoverflow C# rounded corner post
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https://stackoverflow.com/questions/24771828/algorithm-for-creating-rounded-corners-in-a-polygon
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"""
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def GetProportionPoint(pt, segment, L, dx, dy):
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factor = float(segment) / L if L != 0 else segment
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return PVector((pt[0] - dx * factor), (pt[1] - dy * factor))
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# Vector 1
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dx1 = pc[0] - p1[0]
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dy1 = pc[1] - p1[1]
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# Vector 2
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dx2 = pc[0] - p2[0]
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dy2 = pc[1] - p2[1]
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# Angle between vector 1 and vector 2 divided by 2
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angle = (atan2(dy1, dx1) - atan2(dy2, dx2)) / 2
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# The length of segment between angular point and the
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# points of intersection with the circle of a given radius
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tng = abs(tan(angle))
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segment = r / tng if tng != 0 else r
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# Check the segment
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length1 = sqrt(dx1 * dx1 + dy1 * dy1)
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length2 = sqrt(dx2 * dx2 + dy2 * dy2)
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min_len = min(length1, length2)
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if segment > min_len:
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segment = min_len
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max_r = min_len * abs(tan(angle))
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else:
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max_r = r
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# Points of intersection are calculated by the proportion between
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# length of vector and the length of the segment.
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p1Cross = GetProportionPoint(pc, segment, length1, dx1, dy1)
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p2Cross = GetProportionPoint(pc, segment, length2, dx2, dy2)
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# Calculation of the coordinates of the circle
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# center by the addition of angular vectors.
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dx = pc[0] * 2 - p1Cross[0] - p2Cross[0]
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dy = pc[1] * 2 - p1Cross[1] - p2Cross[1]
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L = sqrt(dx * dx + dy * dy)
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d = sqrt(segment * segment + max_r * max_r)
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circlePoint = GetProportionPoint(pc, d, L, dx, dy)
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# StartAngle and EndAngle of arc
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startAngle = atan2(p1Cross[1] - circlePoint[1],
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p1Cross[0] - circlePoint[0])
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endAngle = atan2(p2Cross[1] - circlePoint[1],
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p2Cross[0] - circlePoint[0])
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# Sweep angle
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sweepAngle = endAngle - startAngle
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# Some additional checks
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A, B = False, False
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if sweepAngle < 0:
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A = True
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startAngle, endAngle = endAngle, startAngle
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sweepAngle = -sweepAngle
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# ellipse(pc[0], pc[1], 15, 15) # debug
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if sweepAngle > PI:
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B = True
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startAngle, endAngle = endAngle, startAngle
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sweepAngle = TWO_PI - sweepAngle
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# ellipse(pc[0], pc[1], 25, 25) # debug
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if (A and not B) or (B and not A):
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startAngle, endAngle = endAngle, startAngle
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sweepAngle = -sweepAngle
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# ellipse(pc[0], pc[1], 5, 5) # debug
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b_arc(circlePoint[0], circlePoint[1], 2 * max_r, 2 * max_r,
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startAngle, startAngle + sweepAngle, arc_type=2)
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def b_arc(cx, cy, w, h, startAngle, endAngle, arc_type=0):
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"""
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A bezier approximation of an arc
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using the same signature as the original Processing arc()
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arc_type: 0 "normal" arc, using beginShape() and endShape()
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1 "middle" used in recursive call of smaller arcs
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2 "naked" like normal, but without beginShape() and endShape()
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for use inside a larger PShape
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"""
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theta = endAngle - startAngle
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# Compute raw Bezier coordinates.
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if arc_type != 1 or theta < HALF_PI:
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x0 = cos(theta / 2.0)
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y0 = sin(theta / 2.0)
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x3 = x0
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y3 = 0 - y0
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x1 = (4.0 - x0) / 3.0
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if y0 != 0:
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y1 = ((1.0 - x0) * (3.0 - x0)) / (3.0 * y0) # y0 != 0...
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else:
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y1 = 0
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x2 = x1
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y2 = 0 - y1
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# Compute rotationally-offset Bezier coordinates, using:
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# x' = cos(angle) * x - sin(angle) * y
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# y' = sin(angle) * x + cos(angle) * y
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bezAng = startAngle + theta / 2.0
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cBezAng = cos(bezAng)
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sBezAng = sin(bezAng)
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rx0 = cBezAng * x0 - sBezAng * y0
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ry0 = sBezAng * x0 + cBezAng * y0
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rx1 = cBezAng * x1 - sBezAng * y1
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ry1 = sBezAng * x1 + cBezAng * y1
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rx2 = cBezAng * x2 - sBezAng * y2
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ry2 = sBezAng * x2 + cBezAng * y2
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rx3 = cBezAng * x3 - sBezAng * y3
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ry3 = sBezAng * x3 + cBezAng * y3
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# Compute scaled and translated Bezier coordinates.
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rx, ry = w / 2.0, h / 2.0
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px0 = cx + rx * rx0
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py0 = cy + ry * ry0
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px1 = cx + rx * rx1
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py1 = cy + ry * ry1
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px2 = cx + rx * rx2
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py2 = cy + ry * ry2
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px3 = cx + rx * rx3
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py3 = cy + ry * ry3
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# Debug points... comment this out!
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# stroke(0)
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# ellipse(px3, py3, 15, 15)
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# ellipse(px0, py0, 5, 5)
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# Drawing
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if arc_type == 0: # 'normal' arc (not 'middle' nor 'naked')
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beginShape()
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if arc_type != 1: # if not 'middle'
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vertex(px3, py3)
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if theta < HALF_PI:
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bezierVertex(px2, py2, px1, py1, px0, py0)
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else:
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# to avoid distortion, break into 2 smaller arcs
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b_arc(cx, cy, w, h, startAngle, endAngle - theta / 2.0, arc_type=1)
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b_arc(cx, cy, w, h, startAngle + theta / 2.0, endAngle, arc_type=1)
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if arc_type == 0: # end of a 'normal' arc
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endShape()
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