kopia lustrzana https://github.com/villares/sketch-a-day
205 wiersze
6.5 KiB
Python
205 wiersze
6.5 KiB
Python
# Alexandre B A Villares - https://abav.lugaralgum.com/sketch-a-day
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# Circ-circ tangents on a poly using Bezier approximation of arcs
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pts = [(100, 100), (400, 100), (400, 400)]
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rds = [30, 40, 50, 60, 70, 20]
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dragged_pt = -1
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def setup():
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size(500, 500)
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pts.append((250, 150))
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pts.append((250 + 100 * cos(PI / 6.0),
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250 + 100 * sin(PI / 6.0)))
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pts.append((250 - 100 * cos(PI / 6.0),
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250 + 100 * sin(PI / 6.0)))
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def draw():
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background(200)
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fill(255, 100)
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b_poly_arc_augmented(pts, rds)
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fill(0, 0, 100)
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for pt in pts:
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ellipse(pt[0], pt[1], 10, 10)
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def mouseWheel(E):
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global r, d
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for i, pt in enumerate(pts):
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if dist(mouseX, mouseY, pt[0], pt[1]) < 10:
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rds[i] += 5 * E.getAmount()
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def keyPressed():
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if key == "p":
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saveFrame("####.png")
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def mousePressed():
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global dragged_pt
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for i, pt in enumerate(pts):
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if dist(mouseX, mouseY, pt[0], pt[1]) < 10:
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dragged_pt = i
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break
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def mouseDragged():
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if dragged_pt >= 0:
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pts[dragged_pt] = mouseX, mouseY
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def mouseReleased():
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global dragged_pt
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dragged_pt = -1
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def b_poly_arc_augmented(op_list, or_list):
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assert len(op_list) == len(or_list), \
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"Number of points and radii not the same"
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# remove overlapping adjacent points
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p_list, r_list, r2_list = [], [], or_list[:]
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for i1, p1 in enumerate(op_list):
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i2 = (i1 + 1) % len(op_list)
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p2, r2, r1 = op_list[i2], r2_list[i2], r2_list[i1]
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if dist(p1[0], p1[1], p2[0], p2[1]) > 1: # or p1 != p2:
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p_list.append(p1)
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r_list.append(r1)
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else:
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r2_list[i2] = min(r1, r2)
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# reduce radius that won't fit
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for i1, p1 in enumerate(p_list):
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i2 = (i1 + 1) % len(p_list)
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p2, r2, r1 = p_list[i2], r_list[i2], r_list[i1]
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r_list[i1], r_list[i2] = reduce_radius(p1, p2, r1, r2)
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# calculate the tangents
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a_list = []
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for i1, p1 in enumerate(p_list):
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i2 = (i1 + 1) % len(p_list)
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p2, r2, r1 = p_list[i2], r_list[i2], r_list[i1]
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a = circ_circ_tangent(p1, p2, r1, r2)
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a_list.append(a)
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# draw
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beginShape()
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for i1, ia in enumerate(a_list):
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i2 = (i1 + 1) % len(a_list)
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p1, p2, r1, r2 = p_list[i1], p_list[i2], r_list[i1], r_list[i2]
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a1, p11, p12 = ia
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a2, p21, p22 = a_list[i2]
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if a1 and a2:
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start = a1 if a1 < a2 else a1 - TWO_PI
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if r2 < 0:
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a2 = a2 - TWO_PI
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b_arc(p2[0], p2[1], r2 * 2, r2 * 2, start, a2, mode=2)
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else:
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# when the the segment is smaller than the diference between
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# radius, circ_circ_tangent won't renturn the angle
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# ellipse(p2[0], p2[1], r2 * 2, r2 * 2) # debug
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if a1:
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vertex(p12[0], p12[1])
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if a2:
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vertex(p21[0], p21[1])
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endShape(CLOSE)
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def reduce_radius(p1, p2, r1, r2):
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d = dist(p1[0], p1[1], p2[0], p2[1])
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ri = abs(r1 - r2)
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if d - ri < 0:
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if abs(r1) > abs(r2):
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r1 = map(d, ri + 1, 0, r1, r2)
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else:
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r2 = map(d, ri + 1, 0, r2, r1)
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return(r1, r2)
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def circ_circ_tangent(p1, p2, r1, r2):
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d = dist(p1[0], p1[1], p2[0], p2[1])
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ri = r1 - r2
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line_angle = atan2(p1[0] - p2[0], p2[1] - p1[1])
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if d - abs(ri) >= 0:
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theta = asin(ri / float(d))
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x1 = -cos(line_angle + theta) * r1
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y1 = -sin(line_angle + theta) * r1
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x2 = -cos(line_angle + theta) * r2
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y2 = -sin(line_angle + theta) * r2
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return (line_angle + theta,
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(p1[0] - x1, p1[1] - y1),
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(p2[0] - x2, p2[1] - y2))
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else:
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return (None,
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(p1[0], p1[1]),
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(p2[0], p2[1]))
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def b_arc(cx, cy, w, h, start_angle, end_angle, mode=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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mode: 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 = end_angle - start_angle
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# Compute raw Bezier coordinates.
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if mode != 1 or abs(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 = start_angle + 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 mode == 0: # 'normal' arc (not 'middle' nor 'naked')
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beginShape()
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if mode != 1: # if not 'middle'
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vertex(px3, py3)
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if abs(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, start_angle, end_angle - theta / 2.0, mode=1)
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b_arc(cx, cy, w, h, start_angle + theta / 2.0, end_angle, mode=1)
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if mode == 0: # end of a 'normal' arc
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endShape()
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def settings():
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""" print markdown to add at the sketc-a-day page"""
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from os import path
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global SKETCH_NAME
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SKETCH_NAME = path.basename(sketchPath())
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OUTPUT = ".png"
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println(
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"""
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[{0}](https://github.com/villares/sketch-a-day/tree/master/{2}/{0}) [[Py.Processing](https://villares.github.io/como-instalar-o-processing-modo-python/index-EN)]
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""".format(SKETCH_NAME, OUTPUT, year())
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)
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