python开发之tkinter实现图形随鼠标移动的方法

from tkinter import *
#1.获取到小圆当前的圆心坐标(x1, y1)
#2.获取到小圆移动的圆心坐标(x2, y2)
#3.把小圆从坐标(x1, y1)移动到坐标(x2, y2)
__author__ = {'name' : 'Hongten',
 'mail' : 'hongtenzone@foxmail.com',
 'blog' : 'http://blog.csdn.net/',
 'QQ': '648719819',
 'created' : '2013-09-20'}
class Eay(Frame):
 def createWidgets(self):
 ## The playing field
 self.draw = Canvas(self, width=500, height=500)
 #鼠标位置
 self.mouse_x = 450
 self.mouse_y = 250
 #圆心坐标(x,y)
 self.oval_zero_x = 250
 self.oval_zero_y = 250
 #外面大圆半径
 self.oval_r = 100
 #里面小圆半径
 self.oval_R = 30
 self.oval_r1 = self.oval_r - self.oval_R + 0.5
 self.oval_r2 = self.oval_r - self.oval_R - 0.5
 #小圆
 self.letter_ball_x1 = 250
 self.letter_ball_y1 = 250
 # The ball 外面大圆
 self.ball = self.draw.create_oval((self.oval_zero_x - self.oval_r),
 (self.oval_zero_y - self.oval_r),
 (self.oval_zero_x + self.oval_r),
 (self.oval_zero_y + self.oval_r),
 fill="white")
 self.ball = self.draw.create_oval((self.oval_zero_x - self.oval_r1),
 (self.oval_zero_y - self.oval_r1),
 (self.oval_zero_x + self.oval_r1),
 (self.oval_zero_y + self.oval_r1),
 fill="blue")
 self.ball = self.draw.create_oval((self.oval_zero_x - self.oval_r2),
 (self.oval_zero_y - self.oval_r2),
 (self.oval_zero_x + self.oval_r2),
 (self.oval_zero_y + self.oval_r2),
 fill="white")
 #里面小圆
 self.ball_over = self.draw.create_oval((self.oval_zero_x - self.oval_R),
 (self.oval_zero_y - self.oval_R),
 (self.oval_zero_x + self.oval_R),
 (self.oval_zero_y + self.oval_R),
 fill="red")
 self.draw.pack(side=LEFT)
 def mouseMove(self, event):
 self.mouse_x = event.x
 self.mouse_y = event.y
 if SHOW_LOG:
 print('#' * 50)
 print('鼠标的坐标为：({}, {})'.format(self.mouse_x, self.mouse_y))
 print('小圆当前坐标为：({}, {})'.format(self.letter_ball_x1, self.letter_ball_y1))
 '''获取到小圆移动的圆心坐标(x2, y2)'''
 ax_x = abs(self.mouse_x - self.oval_zero_x)
 ax_y = abs(self.mouse_y - self.oval_zero_y)
 if SHOW_LOG:
 print('坐标A(oval_zero_x, oval_zero_y)到坐标X(mouse_x, mouse_y)的距离为AX')
 print('AX中ax_x = {}, ax_y = {}'.format(ax_x, ax_y))
 ax_len = ((ax_x ** 2) + (ax_y ** 2))**0.5
 if SHOW_LOG:
 print('AX的长度为：{}'.format(ax_len))
 #如果鼠标坐标在(ax_len > |r-R|)
 if ax_len > abs(self.oval_r - self.oval_R):
 ac_len = abs(self.oval_r - self.oval_R)
 if SHOW_LOG:
 print('AC的产度为:{}'.format(ac_len))
 if int(self.mouse_x - self.oval_zero_x) != 0:
 if int(self.mouse_y - self.oval_zero_y) != 0:
 #求直线斜率 y = kx + b
 k = (self.mouse_y - self.oval_zero_y)/(self.mouse_x - self.oval_zero_x)
 if SHOW_LOG:
 print('鼠标到大圆圆心的直线的斜率为：{}'.format(k))
 b = self.mouse_y - (k * self.mouse_x)
 ###################################################
 #小圆移动后的坐标
 #这里有三个条件：
 # 1.小圆的圆心坐标(x1, y1)在直线AC上(y = kx + b)
 # 2.(r-R)^2 = x1^2 + y1^2 由1,2可以得到 => (r-R)^2 = x1^2 + 2*x1*k*b + b^2 => x1有两个值，通过3判断x1的符号，从而求出y1
 # 3.if self.mousex_x > 0:
 # x1 > 0
 #这是一个二元二次方程，方程的解有两组，不过通过鼠标的位置self.mouse_x(self.mouse_y)可以判断圆心坐标x1(y1)
 letter_ball_x2 = ((ac_len * (abs(self.mouse_x - self.oval_zero_x)))/ax_len) + self.letter_ball_x1
 letter_ball_y2 = (letter_ball_x2 * k) + b
 if SHOW_LOG:
 print('小圆当前坐标为：({}, {})'.format(self.letter_ball_x1, self.letter_ball_y1))
 print('小圆移动后坐标为：({}, {})'.format(letter_ball_x2, letter_ball_y2))
 #把小圆从坐标(x1, y1)移动到坐标(x2, y2)
 self.moved_x2 = letter_ball_x2 - self.letter_ball_x1
 self.moved_y2 = letter_ball_y2 - self.letter_ball_y1
 if SHOW_LOG:
 print('需要移动的距离是：({}, {})'.format(int(self.moved_x2), int(self.moved_y2)))
 self.draw.move(self.ball_over, int(self.moved_x2), int(self.moved_y2))
 self.letter_ball_x1 = letter_ball_x2
 self.letter_ball_y1 = letter_ball_y2
 else:
 print('鼠标在X轴上') 
 else:
 print('鼠标在Y轴上')
 else:
 if SHOW_LOG:
 print('小圆的移动后的坐标就是鼠标坐标')
 #小圆移动后的坐标
 letter_ball_x2 = self.mouse_x
 letter_ball_y2 = self.mouse_y
 if SHOW_LOG:
 print('小圆移动后坐标为：({}, {})'.format(letter_ball_x2, letter_ball_y2))
 #把小圆从坐标(x1, y1)移动到坐标(x2, y2)
 self.moved_x2 = letter_ball_x2 - self.letter_ball_x1
 self.moved_y2 = letter_ball_y2 - self.letter_ball_y1
 if SHOW_LOG:
 print('需要移动的距离是：({}, {})'.format(int(self.moved_x2), int(self.moved_y2)))
 self.draw.move(self.ball_over, int(self.moved_x2), int(self.moved_y2))
 self.letter_ball_x1 = letter_ball_x2
 self.letter_ball_y1 = letter_ball_y2
 def move_ball(self, *args):
 #当鼠标在窗口中按下左键拖动的时候执行
 #Widget.bind(self.draw, "", self.mouseMove)
 #当鼠标在大圆内移动的时候执行
 self.draw.tag_bind(self.ball, "", self.mouseMove)
 def __init__(self, master=None):
 global letter_ball_x2
 letter_ball_x2 = 0
 global letter_ball_y2
 letter_ball_y2 = 0
 global SHOW_LOG
 SHOW_LOG = True
 Frame.__init__(self, master)
 Pack.config(self)
 self.createWidgets()
 self.after(10, self.move_ball)
game = Eay()
game.mainloop()