Create Cloud.py

Author: Chiki1601

Nature/Cloud.py

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+import turtle
+import math
+import random
+
+screen = turtle.Screen()
+screen.setup(1000,1000)
+screen.title("Random Cloud - PythonTurtle.Academy")
+
+turtle.speed(0)
+turtle.hideturtle()
+turtle.up()
+turtle.bgcolor('dodger blue')
+turtle.pencolor('white')
+turtle.pensize(2)
+
+n = 500 # number of points on each ellipse
+# X,Y is the center of ellipse, a is radius on x-axis, b is radius on y-axis
+# ts is the starting angle of the ellipse, te is the ending angle of the ellipse
+# P is the list of coordinates of the points on the ellipse
+def ellipse(X,Y,a,b,ts,te,P):
+    t = ts
+    for i in range(n):
+        x = a*math.cos(t)
+        y = b*math.sin(t)
+        P.append((x+X,y+Y))
+        t += (te-ts)/(n-1)
+
+# computes Euclidean distance between p1 and p2
+def dist(p1,p2):
+    return ((p1[0]-p2[0])**2 + (p1[1]-p2[1])**2)**0.5
+
+# draws an arc from p1 to p2 with extent value ext
+def draw_arc(p1,p2,ext):
+    turtle.up()
+    turtle.goto(p1)
+    turtle.seth(turtle.towards(p2))
+    a = turtle.heading() 
+    b = 360-ext 
+    c = (180-b)/2
+    d = a-c
+    e = d-90
+    r = dist(p1,p2)/2/math.sin(math.radians(b/2)) # r is the radius of the arc
+    turtle.seth(e) # e is initial heading of the circle
+    turtle.down()
+    turtle.circle(r,ext,100)
+    return (turtle.xcor(),turtle.ycor()) # returns the landing position of the circle
+                                         # this position should be extremely close to p2 but may not be exactly the same
+                                         # return this for continuous drawing to the next point
+
+
+def cloud(P):
+    step = n//10 # draw about 10 arcs on top and bottom part of cloud
+    a = 0 # a is index of first point
+    b = a + random.randint(step//2,step*2) # b is index of second point
+    p1 = P[a] # p1 is the position of the first point
+    p2 = P[b] # p2 is the position of the second point
+    turtle.fillcolor('white')
+    turtle.begin_fill()
+    p3 = draw_arc(p1,p2,random.uniform(70,180)) # draws the arc with random extention
+    while b < len(P)-1:
+        p1 = p3 # start from the end of the last arc 
+        if b < len(P)/2: # first half is top, more ragged
+            ext = random.uniform(70,180)
+            b += random.randint(step//2,step*2)
+        else: # second half is bottom, more smooth
+            ext = random.uniform(30,70)
+            b += random.randint(step,step*2)
+        b = min(b,len(P)-1) # make sure to not skip past the last point
+        p2 = P[b] # second point
+        p3 = draw_arc(p1,p2,ext) # draws an arc and return the end position
+    turtle.end_fill()
+
+P = [] # starting from empty list
+ellipse(0,0,300,200,0,math.pi,P) # taller top half
+ellipse(0,0,300,50,math.pi,math.pi*2,P) # shorter bottom half
+cloud(P)