since 2018-12-27

Python 3.7.2 で「お絵描きソフト」を作る準備。

ウィンドウを開いて、マウスで左ボタンを押してドラッグしている間は輪郭が表示されて、ボタンを離すと長方形を塗りつぶす。

import tkinter
 
canvas = None
begin_x = begin_y = None
rect = None
 
 
def on_button_press(ev):
    global begin_x, begin_y
    begin_x = ev.x
    begin_y = ev.y
 
 
def on_button_motion(ev):
    global rect
    if rect:
        canvas.delete(rect)
    rect = canvas.create_rectangle(begin_x, begin_y, ev.x, ev.y)
 
 
def on_button_release(ev):
    global begin_x, begin_y
    canvas.create_rectangle(begin_x, begin_y, ev.x, ev.y, fill='green')
    begin_x = begin_y = None
 
 
def main():
    global canvas
    root = tkinter.Tk()
    root.title('hello tkinter')
    root.geometry('800x450')
    canvas = tkinter.Canvas(root)
    canvas.pack(expand=1, fill='both')
    root.bind('<Button-1>', on_button_press)
    root.bind('<B1-Motion>', on_button_motion)
    root.bind('<ButtonRelease-1>', on_button_release)
    root.mainloop()
 
 
if __name__ == '__main__':
    main()

since 2020-07-29

• https://d.nishimotz.com/archives/2332
• https://docs.python.org/ja/3/library/tkinter.html
• https://gist.github.com/nishimotz/67b1e1cd245eadb2b2597db650a8c772

since 2020-07-29

• https://pyvideo.org/pycon-us-2013/using-futures-for-async-gui-programming-in-python.html
• https://github.com/fluentpython/asyncio-tkinter
• Fluent Python （日本語版）18章の最後

since 2020-07-29

• Fluent Python （日本語版）377ページあたり
• 20年前の設計という評価