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