Question

python tkinter制作一个可以被拖动的组件

Answer 1

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://www.cnblogs.com/',
              '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, "<B1-Motion>", self.mouseMove)
        #当鼠标在大圆内移动的时候执行
        #self.draw.tag_bind(self.ball, "<Any-Enter>", 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()

效果