Python - Functions: There's a Name for That(A Better Drawing Program, turtle module, onkeypress method, listen method, event handler)

Teach Your Kids to Code

開発環境

• macOS High Sierra - Apple
• Emacs (Text Editor)
• Python 3.6 (プログラミング言語)

Teach Your Kids to Code: A Parent-Friendly Guide to Python Programming (Bryson Payne(著)、No Starch Press)のChapter 7.(Functions: There's a Name for That)、PROGRAMMING CHALLENGES、#3: A Better Drawing Programを取り組んでみる。

#3: A Better Drawing Program

コード(Emacs)

Python 3

#!/usr/bin/env python3
import turtle

t = turtle.Pen()
t.speed(0)
stretch_wid = 2
stretch_len = 2
outline = 2
t.turtlesize(stretch_wid, stretch_len, outline)

forward_len = 50


def up():
    print(f'up({forward_len})')
    t.forward(forward_len)


def left():
    print('left')
    t.left(45)


def right():
    print('right')
    t.right(45)


def gt():
    print('gt')
    global forward_len
    forward_len += 1


def lt():
    print('lt')
    global forward_len
    if forward_len > 1:
        forward_len -= 1


def wider():
    print('wider')
    global stretch_wid
    stretch_wid += 1
    t.turtlesize(stretch_wid, stretch_len, outline)


def thinner():
    print('thinner')
    global stretch_wid
    if stretch_wid > 1:
        stretch_wid -= 1
        t.turtlesize(stretch_wid, stretch_len, outline)


turtle.onkeypress(up, 'Up')
turtle.onkeypress(left, 'Left')
turtle.onkeypress(right, 'Right')
turtle.onkeypress(gt, '>')
turtle.onkeypress(lt, '<')
turtle.onkeypress(wider, 'W')
turtle.onkeypress(thinner, 'T')

turtle.listen()

input()

入出力結果(Terminal, Jupyter(IPython))

$ ./sample3.py
up(50)
up(50)
up(50)
up(50)
up(50)
left
left
up(50)
up(50)
up(50)
up(50)
up(50)
left
left
up(50)
up(50)
up(50)
up(50)
up(50)
left
left
up(50)
up(50)
up(50)
up(50)
up(50)
right
right
up(50)
up(50)
up(50)
up(50)
up(50)
right
right
up(50)
up(50)
up(50)
up(50)
up(50)
right
right
up(50)
up(50)
up(50)
up(50)
up(50)
left
left
lt
up(49)
lt
lt
lt
lt
lt
lt
lt
lt
lt
up(40)
gt
gt
gt
gt
gt
gt
gt
gt
gt
gt
gt
gt
gt
gt
gt
gt
gt
gt
gt
gt
right
right
up(60)
up(60)
up(60)
up(60)
up(60)
right
up(60)
up(60)
right
up(60)
up(60)
wider
wider
wider
wider
wider
thinner
thinner
thinner
thinner
thinner
q
$