Moving balls with minimum distance (Python)-CodePudding

I am trying to write a code where I can move two circles around using left mouse button. Most of the code is working, but I am missing one part; There should be a minimum distance of 100 pixels between the circles (not allowed to bring them closer apart than that). I tried using while length > 70 with the function def mouseMoved(self, event) but it did not work. I hope someone can help me on my way.

from tkinter import * 
import math

class Circle:
def __init__(self, x, y, radius):
    self.x = x
    self.y = y
    self.radius = radius

def isInside(self, x, y):
    return distance(self.x, self.y, x, y) <= self.radius
              
class MainGUI:
def __init__(self):   
    window = Tk() 
    window.title("Two Balls") 

    self.canvas = Canvas(width = 400, height = 250)
    self.canvas.pack()
    
    self.c1 = Circle(20, 20, 20)
    self.c2 = Circle(120, 50, 20)
    self.canvas.create_line(self.c1.x, self.c1.y, self.c2.x, self.c2.y, tags = "line")      
    self.getLength()

    self.paint(self.c1, "red", "c1")
    self.paint(self.c2, "red", "c2")
  
    self.canvas.bind("<B1-Motion>", self.mouseMoved)
    
    window.mainloop() 

def getLength(self):
    length = round(math.sqrt((self.c1.x-self.c2.x)**2   (self.c1.y-self.c2.y)**2), 2)
    self.canvas.create_text((self.c1.x self.c2.x)/2, (self.c1.y self.c2.y)/2, text = length, tags = "text") 
    return length
    
def mouseMoved(self, event):
    self.canvas.delete("line") 
    self.canvas.delete("text")

    if self.c2.isInside(event.x, event.y):
        self.c2.x = event.x
        self.c2.y = event.y 
            
    self.canvas.delete("c2")
    self.paint(self.c2, "red", "c2")

    if self.c1.isInside(event.x, event.y):
        self.c1.x = event.x
        self.c1.y = event.y 
    
    self.canvas.delete("c1")
    self.paint(self.c1, "red", "c1")

    self.canvas.create_line(self.c1.x, self.c1.y, self.c2.x, self.c2.y, tags = "line")
    self.getLength()

def paint(self, c, color, tags = "stable"):
    self.canvas.create_oval(c.x - c.radius, c.y - c.radius, c.x   c.radius, c.y   c.radius, fill = color, tags = tags)

def distance(x1, y1, x2, y2):
return ((x1 - x2) * (x1 - x2)   (y1 - y2) * (y1 - y2)) ** 0.5       
MainGUI()

CodePudding user response：

You need to calculate the distance between the two circles after one of them is moved, perform the actual move only if the distance is greater than 100 pixels:

def mouseMoved(self, event):
    f2 = self.c2.isInside(event.x, event.y)
    f1 = self.c1.isInside(event.x, event.y)

    # Is one of the circles is selected?
    if f1 or f2:
        # calculate the distance between the two circles after one of them is moved
        if f1:
            length = distance(event.x, event.y, self.c2.x, self.c2.y)
        else:
            length = distance(event.x, event.y, self.c1.x, self.c1.y)

        # Only perform the move if the distance > 100 pixels
        if length > 100:
            self.canvas.delete("text")
            self.canvas.delete("line")
            if f2:
                self.c2.x = event.x
                self.c2.y = event.y

                self.canvas.delete("c2")
                self.paint(self.c2, "red", "c2")
            else:
                self.c1.x = event.x
                self.c1.y = event.y

                self.canvas.delete("c1")
                self.paint(self.c1, "red", "c1")

            self.canvas.create_line(self.c1.x, self.c1.y, self.c2.x, self.c2.y, tags="line")
            self.getLength(length)

CodePudding user response：

The problem is with the indentation

from tkinter import * 
import math

class Circle:
  def __init__(self, x, y, radius):
      self.x = x
      self.y = y
      self.radius = radius

  def isInside(self, x, y):
      return distance(self.x, self.y, x, y) <= self.radius
              
class MainGUI:
  def __init__(self):   
      window = Tk() 
      window.title("Two Balls") 

      self.canvas = Canvas(width = 400, height = 250)
      self.canvas.pack()
      
      self.c1 = Circle(20, 20, 20)
      self.c2 = Circle(120, 50, 20)
      self.canvas.create_line(self.c1.x, self.c1.y, self.c2.x, self.c2.y, tags = "line")      
      self.getLength()

      self.paint(self.c1, "red", "c1")
      self.paint(self.c2, "red", "c2")
    
      self.canvas.bind("<B1-Motion>", self.mouseMoved)
      
      window.mainloop() 

  def getLength(self):
      length = round(math.sqrt((self.c1.x-self.c2.x)**2   (self.c1.y-self.c2.y)**2), 2)
      self.canvas.create_text((self.c1.x self.c2.x)/2, (self.c1.y self.c2.y)/2, text = length, tags = "text") 
      return length
      
  def mouseMoved(self, event):
      self.canvas.delete("line") 
      self.canvas.delete("text")

      if self.c2.isInside(event.x, event.y):
          self.c2.x = event.x
          self.c2.y = event.y 
              
      self.canvas.delete("c2")
      self.paint(self.c2, "red", "c2")

      if self.c1.isInside(event.x, event.y):
          self.c1.x = event.x
          self.c1.y = event.y 
      
      self.canvas.delete("c1")
      self.paint(self.c1, "red", "c1")

      self.canvas.create_line(self.c1.x, self.c1.y, self.c2.x, self.c2.y, tags = "line")
      self.getLength()

  def paint(self, c, color, tags = "stable"):
      self.canvas.create_oval(c.x - c.radius, c.y - c.radius, c.x   c.radius, c.y   c.radius, fill = color, tags = tags)

  def distance(x1, y1, x2, y2):
    return ((x1 - x2) * (x1 - x2)   (y1 - y2) * (y1 - y2)) ** 0.5       
    MainGUI()