如何使tkinter對象在細胞路徑中移動？

Question

我正在嘗試使用tkinter製作太陽能系統。問題是我不能讓行星在太陽周圍的圓形（或橢圓形）路徑中移動。有任何想法嗎？

Answer 1

使用sinus，cosinus來計算行星的位置從sun

x = sun_x - distance * math.sin(math.radians(angle)) 
y = sun_y - distance * math.cos(math.radians(angle)) 

依賴的angle和distance並使用root.after(milliseconds, function_name)來執行功能，這將改變角度，並計算出新的位置。

工作例如在中心sun和earth走動sun和moon走動earth

#!/usr/bin/env python3 

import tkinter as tk 
import math 

# --- functions --- 

def calculate_position(data): 
    #unpack data 
    center_x, center_y, radius, distance, angle, angle_speed, x, y = data 

    # calculate new position of object 
    x = center_x - distance * math.sin(math.radians(-angle)) 
    y = center_y - distance * math.cos(math.radians(-angle)) 

    # save positon so other object can use it as its center of rotation 
    data[6] = x 
    data[7] = y 

    # calcuate oval coordinates 
    x1 = x - radius 
    y1 = y - radius 
    x2 = x + radius 
    y2 = y + radius 

    return x1, y1, x2, y2 

def create_object(data): 
    # calculate oval coordinates 
    x1, y1, x2, y2 = calculate_position(data) 

    # create oval 
    return c.create_oval(x1, y1, x2, y2) 

def move_object(object_id, data): 
    # calculate oval coordinates 
    x1, y1, x2, y2 = calculate_position(data) 

    # move oval 
    c.coords(object_id, x1, y1, x2, y2) 

def animate(): 
    # move earth - angle += angle_speed 
    earth[4] += earth[5] 
    move_object(e_id, earth) 

    # moon uses earth position as center of rotation 
    moon[0] = earth[6] 
    moon[1] = earth[7] 

    # move move - angle += angle_speed 
    moon[4] += moon[5] 
    move_object(m_id, moon) 

    # animate again after 100ms 
    root.after(100, animate) 

# --- main --- 

# canvas size 
WIDTH = 500 
HEIGHT = 500 

# center of solar system 
center_x = WIDTH//2 
center_y = HEIGHT//2 

# objects data 
# [center of rotation x and y, radius, distance from center, current angle, angle speed, current positon x and y] 
sun = [center_x, center_y, 30, 0, 0, 0, 0, 0] 
earth = [center_x, center_y, 10, 100, 0, 1, 0, 0] 
moon = [0, 0, 5, 40, 0, 3, 0, 0] 

# - init - 
root = tk.Tk() 
root.title("Solar System") 

# - canvas - 
c = tk.Canvas(root, width=WIDTH, heigh=HEIGHT) 
c.pack() 

# create sun and earth 
s_id = create_object(sun) 
e_id = create_object(earth) 

# moon uses earth position as center of rotation 
moon[0] = earth[6] 
moon[1] = earth[7] 

# create moon 
m_id = create_object(moon) 

# start animation 
animate() 

# - start program - 
root.mainloop() 

GitHub上：furas/python-examples/tkinter/canvas-solar-system