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""" turtle-example-suite: |
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tdemo_tree.py |
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Displays a 'breadth-first-tree' - in contrast |
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to the classical Logo tree drawing programs, |
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which use a depth-first-algorithm. |
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Uses: |
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(1) a tree-generator, where the drawing is |
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quasi the side-effect, whereas the generator |
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always yields None. |
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(2) Turtle-cloning: At each branching point |
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the current pen is cloned. So in the end |
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there are 1024 turtles. |
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""" |
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from turtle import Turtle, mainloop |
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from time import perf_counter as clock |
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def tree(plist, l, a, f): |
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""" plist is list of pens |
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l is length of branch |
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a is half of the angle between 2 branches |
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f is factor by which branch is shortened |
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from level to level.""" |
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if l > 3: |
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lst = [] |
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for p in plist: |
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p.forward(l) |
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q = p.clone() |
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p.left(a) |
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q.right(a) |
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lst.append(p) |
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lst.append(q) |
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for x in tree(lst, l*f, a, f): |
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yield None |
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def maketree(): |
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p = Turtle() |
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p.setundobuffer(None) |
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p.hideturtle() |
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p.speed(0) |
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p.getscreen().tracer(30,0) |
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p.left(90) |
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p.penup() |
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p.forward(-210) |
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p.pendown() |
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t = tree([p], 200, 65, 0.6375) |
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for x in t: |
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pass |
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def main(): |
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a=clock() |
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maketree() |
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b=clock() |
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return "done: %.2f sec." % (b-a) |
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if __name__ == "__main__": |
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msg = main() |
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print(msg) |
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mainloop() |
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