Develop Reference

How can I move a list of tkinter lines in a set space?

import time
from tkinter import *
class Template:
def __init__(self):
self.window = Tk()
self.window.title("2D Display")
self.canvas = self.canvas_display()
self.line1 = self.line_creation(650,350,500 * .3, 1000)
self.line3 = self.line_movement_creation(0, 350,2000, 350)
self.horizon = self.canvas.create_line(0,350,2000, 350, width = 2, fill ="white")
self.speedx = 0 # x movement of line3
self.speedy = 9 # y movement of line3
self.active = True
self.pos1 = []
self.move_active() #Code that creates the problem
self.canvas.update()
def canvas_display(self): #canvas
canvas = Canvas(self.window, width=500, height=400, background='black')
canvas.pack(expand=True, fill="both")
canvas.update()
return canvas
Upwards is Initialization
def line_creation(self,x,y,x1,y1): #creation of multple lines
spacing = 0
lines = [] # could list([])
for i in range(11):
id = self.canvas.create_line( x, y, x1 + spacing, y1, width=2, fill="white")
lines.append(id)
spacing += 100
pos1 = self.canvas.coords(id)
self.pos1 = pos1
print(self.pos1)
return lines
This is the creation method for the vertices lines
def line_movement_creation(self,x,y,x1,y1):
spacing1 = 0
lines = []
for i in range(4):
id = self.canvas.create_line(x , y+spacing1, x1, y1 + spacing1, width=2, fill="white")
lines.append(id)
spacing1 += 100
#line = [] equal all horizontal and vertical, 12 - 15 equal horizontal moving lines
return lines
The is the creation for the horizontal lines
def line_update(self): #line movement method
for line in self.line3:
self.canvas.move(line, self.speedx, self.speedy)
#Create variables for all x and y values for the lines
pos = self.canvas.coords(line)
print(pos)
if pos[3] >= 800:
self.canvas.move(line, self.speedx, self.speedy - 460)
def move_active(self):
if self.active:
self.line_update()
self.window.after(40, self.move_active)
This is what moves the lines creating an illusion of movement. I want to take the list of horizontal lines and set them between the outer most vertical lines. So it would stay between the vertical lines. Creating a road like image. I think I need to make a separate list for both but I am not sure. So to clarify I can someone help show me how to make the horizontal lines not attach to the ends of the screen but to inside the horizontal lines Code Demonstration
def run(self):
self.window.mainloop()
if __name__ == '__main__':
Temp = Template()
Temp.run()

So, first I would suggest that you use some game engine like pygame because it is faster and provides a bit more options and other stuff but here it is with tkinter (basically it is some simple trigonometry):
import tkinter as tk
import math
class Canvas(tk.Canvas):
def __init__(self, parent, width=700, height=500, **kwargs):
super().__init__(parent, width=width, height=height, **kwargs)
self.width = width
self.height = height
self.angle = 70
self.speedy = 10
self.change_speed_ms = 50
self.draw_angle(self.angle, 5)
self.lines, self.interval = self.init_lines(amount=5)
self.draw_lines()
#property
def radians(self):
return math.radians(self.angle)
def draw_angle(self, view_angle, lines):
orient = 0
adjacent = self.height // 2
step = view_angle // lines
half = view_angle // 2
for angle in range(orient - half, orient + half + step, step):
rad = math.radians(angle)
delta = math.tan(rad) * adjacent
x1, y1 = self.width // 2, self.height // 2
x2, y2 = x1 + delta, y1 + adjacent
self.create_line(x1, y1, x2, y2)
def init_lines(self, amount=5):
interval = round((self.height // 2) / amount)
coordinate_list = list()
offset = self.height // 2
for y in range(0, self.height // 2 + interval, interval):
delta = math.tan(self.radians / 2) * y
x1 = self.width // 2 - delta
x2 = self.width // 2 + delta
y1 = y2 = y + offset
line = self.create_line(x1, y1, x2, y2)
coordinate_list.append((line, (x1, y1, x2, y2)))
return coordinate_list, interval
def draw_lines(self):
tmp_lst = list()
for id_, (x1, y1, x2, y2) in self.lines:
y1 += self.speedy
if y1 > self.height + self.interval - self.speedy:
y1 = self.height // 2
y = y2 = y1
adjacent = y - self.height // 2
delta = math.tan(self.radians / 2) * adjacent
x1 = self.width // 2 - delta
x2 = self.width // 2 + delta
self.coords(id_, x1, y1, x2, y2)
tmp_lst.append((id_, (x1, y1, x2, y2)))
self.lines = tmp_lst
self.after(self.change_speed_ms, self.draw_lines)
root = tk.Tk()
Canvas(root, highlightthickness=0).pack()
root.mainloop()
So the main method here is Canvas().draw_lines(). First of you get a list of line IDs and their coordinates at set intervals based on the amount of total lines, then you iterate over them, change their y value and accordingly calculate the opposite side of a right-angle triangle using tan and the adjacent side which is known from the current y coordinate and the starting point (the middle).

Is it possible to undraw a previously drawn shape from a loop? Zelle Graphics Python

I was wondering if it was possible to undraw previously drawn shapes from a loop. I have this function that'll create squares on click however I want to make it so that when the same area is clicked a second time the square will undraw.
from graphics import *
def createGrid():
X = 0
Y = 0
gridSize = 5
for i in range(1, gridSize + 1):
for j in range(1, gridSize + 1):
gridSquare = Rectangle(Point(X, Y), Point(X + 100, Y + 100))
gridSquare.draw(win)
X = X + 100
Y = Y + 100
X = 0
def editMode():
SelectedSquare = []
instruction = input("> ")
if instruction == "s":
selectionMode(SelectedSquare)
def selectionMode(SelectedSquare):
editSquare = Rectangle(Point(0, 0), Point(20, 20))
editSquare.setFill("black")
editSquare.draw(win)
while True:
selection = win.getMouse()
clickXPos = selection.getX()
clickYPos = selection.getY()
if clickXPos > 20 and clickYPos > 20:
PosX, PosY = clickXPos - (clickXPos % 100), clickYPos - (clickYPos % 100)
SelectedSquare = SelectedSquare + [Point(PosX, PosY)]
rect = Rectangle(Point(PosX, PosY), Point(PosX + 100, PosY + 100))
rect.setWidth(5)
rect.draw(win)
else:
editSquare.undraw()
break
win = GraphWin("GRID", 500, 500)
createGrid()
while True:
editMode()
As you can see, on click, there will be a thicker border around the grid square that was selected, I would like to be able to
1) remove the thickened border if clicked a second time
2) be able to remove all thickened borders surrounding grid squares
but I just cannot seem to figure this out, any help would be greatly appreciated!

The general problem seems to be that you have no underlying data structure or logic for your program -- you're drawing the interface first and then trying to make its behaviors define the program.
Below I've patched your code to have the points on the selected squares list remember what rectangle was drawn to highlight them, so if they are selected again, the highlight can be undone and the point removed:
from graphics import *
GRID_SIZE = 5
SQUARE_SIZE = 100
EDIT_BUTTON_SIZE = 20
BORDER_WIDTH = 5
def createGrid():
X, Y = 0, 0
for _ in range(1, GRID_SIZE + 1):
for _ in range(1, GRID_SIZE + 1):
gridSquare = Rectangle(Point(X, Y), Point(X + SQUARE_SIZE, Y + SQUARE_SIZE))
gridSquare.draw(win)
X += SQUARE_SIZE
Y += SQUARE_SIZE
X = 0
def editMode():
selectedSquares = []
instruction = input("> ")
if instruction == "s":
selectionMode(selectedSquares)
def checkSelected(point, squares):
for selected in squares:
if point.getX() == selected.getX() and point.getY() == selected.getY():
return selected
return None
def selectionMode(selectedSquares):
editSquare = Rectangle(Point(0, 0), Point(EDIT_BUTTON_SIZE, EDIT_BUTTON_SIZE))
editSquare.setFill("black")
editSquare.draw(win)
while True:
selection = win.getMouse()
clickXPos = selection.getX()
clickYPos = selection.getY()
if clickXPos <= EDIT_BUTTON_SIZE and clickYPos <= EDIT_BUTTON_SIZE:
break
PosX, PosY = clickXPos - clickXPos % SQUARE_SIZE, clickYPos - clickYPos % SQUARE_SIZE
point = Point(PosX, PosY)
selected = checkSelected(point, selectedSquares)
if selected:
selected.rect.undraw()
selectedSquares.remove(selected)
else:
rect = Rectangle(point, Point(PosX + SQUARE_SIZE, PosY + SQUARE_SIZE))
rect.setWidth(BORDER_WIDTH)
rect.draw(win)
point.rect = rect
selectedSquares.append(point)
editSquare.undraw()
win = GraphWin("GRID", GRID_SIZE * SQUARE_SIZE, GRID_SIZE * SQUARE_SIZE)
createGrid()
while True:
editMode()
But this is only a band-aid -- as you add more functionality the issue of a lack of data structure and spelled out logic will continue to frustrate you.

Python: PSO clumping <s>and code working only when mouse moves</s>

I'm trying to make a simple PSO (particle-swarm optimization) program.
Below is my current code, and I've been tweaking the weights only to find the "optimization" not working.
import random as ran
import math
# import threading as thr
import pygame as gm
# import pycuda as cuda
# import matplotlib.pyplot as plt
p_max = 10 # Maximum number of particles
rand_max = 100 # Maximum random vector value
# history = 10 # Number of iterations to record as history (including most current)
width = 600
height = 600
func_dict = {
"sphere" : ( lambda x, y: ( (x-(width/2))**2 + (y-(height/2))**2 ) ),
"booth" : ( lambda x, y: (((x-(width/2)) + 2*(y-(height/2)) - 7) ** 2) + ((2*(x-(width/2)) + (y-(height/2)) - 5) ** 2) ),
"matyas" : ( lambda x, y: (0.26 * ((x-(width/2))**2 + (y-(height/2))**2) - 0.48*(x-(width/2))*(y-(height/2))) )
} # (x-(width/2)) and (y-(height/2)) to shift the Zero to the display center
func = "sphere" # Choose function from func_dict
# Weights (0<w<1)
wLocal = 0.4 # Explore weight
wGlobal = 0.8 # Exploit weight
wRandom = 0.02 # Weight of random vector
global_best = [None, None, None] # Initial blank
class particle: # particles
global global_best
def __init__(self):
global global_best
global width, height
global func_dict, func
self.vel_x = 0
self.vel_y = 0
self.pos_x = ran.randint(0, width)
self.pos_y = ran.randint(0, height)
self.pos_z = func_dict[func](self.pos_x, self.pos_y)
self.local_best = [self.pos_x, self.pos_y, self.pos_z]
if (global_best[0] == None) or (global_best[1] == None) or (global_best[2] == None): # Is 1st particle
global_best = self.local_best
def update(self): # Update vectors
global width, height
global rand_max
global wGlobal, wLocal, wRandom
global global_best
self.vel_x = (wGlobal * (global_best[0] - self.pos_x)) + (wLocal * (self.local_best[0] - self.pos_x)) + (wRandom * ran.randint(-rand_max, rand_max))
self.vel_y = (wGlobal * (global_best[1] - self.pos_y)) + (wLocal * (self.local_best[1] - self.pos_y)) + (wRandom * ran.randint(-rand_max, rand_max))
# self.pos_x = (self.pos_x + self.vel_x) % width
# self.pos_y = (self.pos_y + self.vel_y) % height
self.pos_x += self.vel_x
self.pos_y += self.vel_y
if self.pos_x < 0:
self.pos_x = 0
if self.pos_y < 0:
self.pos_y = 0
if self.pos_x > width:
self.pos_x = width
if self.pos_y > height:
self.pos_y = height
self.pos_z = func_dict[func](self.pos_x, self.pos_y)
if self.pos_z < global_best[2]:
global_best = [self.pos_x, self.pos_y, self.pos_z]
particles = [None for _ in range(p_max)]
def initialize():
global_best = [None, None, None]
for foo in range(p_max):
particles[foo] = particle() # create new particles
# def dist(p1, p2): # distance
# return(math.sqrt( ( (p1.pos_x - p2.pos_y)**2) + ((p1.pos_y - p2.pos_y)**2) ) )
# def update(this): # this = particle
# this.vel_x = (wGlobal * (global_best[0] - this.pos_x)) + (wLocal * (this.local_best[0] - this.pos_x)) + (wRandom * ran.randint(0, rand_max))
# this.vel_y = (wGlobal * (global_best[1] - this.pos_y)) + (wLocal * (this.local_best[1] - this.pos_y)) + (wRandom * ran.randint(0, rand_max))
# # this.pos_x = (this.pos_x + this.vel_x) % width
# # this.pos_y = (this.pos_y + this.vel_y) % height
# this.pos_x += this.vel_x
# this.pos_y += this.vel_y
# if this.pos_x < 0:
# this.pos_x = 0
# if this.pos_y < 0:
# this.pos_y = 0
# if this.pos_x > width:
# this.pos_x = width
# if this.pos_y > height:
# this.pos_y = height
# # return this
# def update_multi(things): # things = list() of particles
# these = things
# for item in these:
# item = update(item)
# return these
gm.init()
main = gm.display.set_mode((width, height))
end_program = False
initialize()
main.fill((255, 255, 255))
while end_program == False:
# main.fill((255, 255, 255)) #Comment/Uncomment to leave trace
# plt.plot() # Plot functions
for event in gm.event.get():
if event.type == gm.QUIT:
end_program = True
for foo in range(len(particles)):
particles[foo].update()
gm.draw.circle(main, (0, 0, 0), (int(particles[foo].pos_x), int(particles[foo].pos_y)), 5, 0)
gm.display.flip()
Problem 1: Program only runs when mouse is moving
I'm not sure why but the program only runs fairly quickly for a few iterations but seems to just stop afterwards, but continues when the mouse is moved.
Problem 2: Particles appear to stay local
As I move the mouse around, it kinda runs. What emerges is clumps of traces left when the 2nd # main.fill((255, 255, 255)) is uncommented. The 1st initial traces from before the program stops without the mouse's movement seem more spread out and I'm not sure if that's the global variables or the randoms at work.
Edit: I've fixed the problem where the program only runs when the mouse moves by unindenting:
for foo in range(len(particles)):
particles[foo].update()
gm.draw.circle(main, (0, 0, 0), (int(particles[foo].pos_x), int(particles[foo].pos_y)), 5, 0)
However, the particles still seem to hardly move from their own positions, oscilating locally.

Problem 1 was solved thanks to Marius. I fixed it by simply putting update outside the event loop.
Problem 2 was fixed by adding the local update that I forgot.
if self.pos_z < global_best[2]: # This was not forgotten
global_best = [self.pos_x, self.pos_y, self.pos_z]
if self.pos_z < local_best[2]: # This was forgotten
local_best = [self.pos_x, self.pos_y, self.pos_z]

Misalignment of triangles drawn with tkinter canvas

I wrote this function that draw a grid of triangles:
def create_triangles(side_length):
result = []
half_width = int(side_length / 2)
# height = int(side_length * math.sqrt(3) / 2)
height = side_length
max_width = 15 * side_length
max_height = 10 * height
for i in range(0, max_height, height):
if (i / height) % 2 == 0:
for j in range(0, max_width-half_width, half_width):
if j % side_length == 0:
triangle = (i-height/2, j-half_width, i+height/2, j, i-height/2, j+half_width)
else:
triangle = (i-height/2, j, i+height/2, j+half_width, i+height/2, j-half_width)
result.append(triangle)
else:
for j in range(half_width, max_width, half_width):
if j % side_length == 0:
triangle = (i-height/2, j-2*half_width, i+height/2, j-half_width+2, i-height/2, j)
else:
triangle = (i-height/2, j-half_width, i+height/2, j, i+height/2, j-2*half_width)
result.append(triangle)
return result
The current output is this:
As you can see some triangles are misaligned but I don't understand why.

As mentioned in the comments, floating points give you incorrect results; You want to make sure that the shared points representing the vertices of two adjacent triangles are concurrent. A simple approach is to reduce the points coordinates to ints, and organize the calculations so errors do not add up.
In the following examples, the misalignment is corrected, every triangle on the canvas is represented by a polygon, and individually drawn; each triangle can therefore be referenced when moused over, or addressed via an index, or a mapping (not implemented).
import tkinter as tk
import math
WIDTH, HEIGHT = 500, 500
class Point:
"""convenience for point arithmetic
"""
def __init__(self, x, y):
self.x, self.y = x, y
def __add__(self, other):
return Point(self.x + other.x, self.y + other.y)
def __iter__(self):
yield self.x
yield self.y
def tile_with_triangles(canvas, side_length=50):
"""tiles the entire surface of the canvas with triangular polygons
"""
triangle_height = int(side_length * math.sqrt(3) / 2)
half_side = side_length // 2
p0 = Point(0, 0)
p1 = Point(0, side_length)
p2 = Point(triangle_height, half_side)
for idx, x in enumerate(range(-triangle_height, WIDTH+1, triangle_height)):
for y in range(-side_length, HEIGHT+1, side_length):
y += half_side * (idx%2 + 1)
offset = Point(x, y)
pa, pb, pc = p0 + offset, p1 + offset,p2 + offset
canvas.create_polygon(*pa, *pb, *pc, outline='black', fill='', activefill='red')
p2 = Point(-triangle_height, half_side) # flip the model triangle
for idx, x in enumerate(range(-triangle_height, WIDTH+triangle_height+1, triangle_height)):
for y in range(-side_length, HEIGHT+1, side_length):
y += half_side * (idx%2 + 1)
offset = Point(x, y)
pa, pb, pc = p0 + offset, p1 + offset,p2 + offset
canvas.create_polygon(*pa, *pb, *pc, outline='black', fill='', activefill='blue')
root = tk.Tk()
canvas = tk.Canvas(root, width=WIDTH, height=HEIGHT, bg='cyan')
canvas.pack()
tile_with_triangles(canvas) #, side_length=10)
root.mainloop()
I added an active fill property that will change the colors of each triangle when you mouse over.

Spyder; something in our code is causing the kernel to crash

Does Spyder have a good way to detect what is causing a crash?
All the changes we made are in the ArrayPQ class and the node class, the other code works without our changes.
import math
import numpy as np
import numpy.random as rand
import numpy.linalg as linalg
from tkinter import Tk, Frame, Canvas
class ArrayPQ:
def __init__(self, num_balls):
self.collisionNodes = np.array([])
self.pastCollisions = np.zeros(num_balls)
def parent(self, i):
return (i-1) // 2
def right(self, i):
return (i*2) + 1
def left(self, i):
return (i*2) + 2
def insert(self, i, j, value, num_collisions_i, num_collisions_j):
self.pastCollisions[i] = num_collisions_i
self.pastCollisions[j] = num_collisions_j
self.collisionNodes = np.append(self.collisionNodes, node.nodeinit(self, i, j, value, num_collisions_i, num_collisions_j))
self.heapify1(i)
def heapify1(self, i):
l = self.left(i)
r = self.right(i)
end = len(self.collisionNodes)
top = i
if l < end and self.collisionNodes(i) < self.collisionNodes(l):
top = l
if r < end and self.collisionNodes(top) < self.collisionNodes(r):
top = r
if max != i:
self.swap(i, top)
self.heapify1(top)
def heapify2(self, i):
if self.right(i) + len(self.collisionNodes)
def delete(self, i):
self.swap(self, 0, (len(self.collisionNodes) -1))
del self.collisionNodes[len(self.collisionNodes)-1]
self.heapify1(i)
def swap(self, i, j):
self.collisionNodes[i], self.collisionNodes[j] = self.collisionNodes[j],
self.collisionNodes[i]
def get_next(self):
temp = self.collisionsNodes[0]
return temp.BBi, temp.BBj, temp.T, temp.CCi, temp.CCj
class node:
def nodeinit(self, Bi, Bj, T, Ci, Cj):
self.BBi = Bi
self.BBj = Bj
self.TT = T
self.CCi = Ci
self.CCj = Cj
class Painter:
#__init__ performs the construction of a Painter object
def __init__(self, root, scale=500, border=5, refresh_speed=5,
filename='balls.txt', min_radius=5, max_radius=10, num_balls=20):
#width and height are used to set the simulation borders
width = scale + border
height = scale + border
self.time = 0
#setup will set up the necessary graphics window and the ball list
self.setup(root, width, height, border, refresh_speed)
#Check the input parameter 'filename' to load predetermined simulation
#otherwise set up the default simulation
if filename is None:
self.init_balls(max_radius, min_radius, num_balls)
self.num_balls = num_balls
else:
self.num_balls = self.read_balls(scale, filename)
#Create the priority data structure
self.PQ = ArrayPQ(self.num_balls)
#Initialize all possible collision times
self.init_ball_collision_times()
self.init_wall_collision_times()
#draw will draw the graphics to the window
self.draw()
#refresh is a loop method intended to create animations
self.refresh()
#A blank return indicates the end of the function
return
#setup creates the window to display the graphics along with the red border
#of the simulation
def setup(self, root, width, height, border, refresh_speed):
# Draw frame etc
self.app_frame = Frame(root)
self.app_frame.pack()
self.canvas = Canvas(self.app_frame, width = width, height = height)
self.canvas_size = (int(self.canvas.cget('width')),
int(self.canvas.cget('height')))
self.canvas.pack()
self.refresh_speed = refresh_speed
# Work area
self.min_x = border
self.max_x = width - border
self.min_y = border
self.max_y = height - border
#create array to hold the n number of balls
self.balls = []
self.ball_handles = dict()
return
def read_balls(self, scale, filename):
f = open(filename)
num_balls = int(f.readline().strip())
for l in f:
ll = l.strip().split(" ")
x = scale*float(ll[0])
y = scale*float(ll[1])
vx = scale*float(ll[2])
vy = scale*float(ll[3])
radius = scale*float(ll[4])
mass = float(ll[5])
r = int(ll[6])
g = int(ll[7])
b = int(ll[8])
tk_rgb = "#%02x%02x%02x" % (r, g, b)
new_ball = Ball(radius, x, y, vx, vy, mass, tk_rgb)
self.balls.append(new_ball)
return num_balls
def init_balls(self, max_radius, min_radius, num_balls):
for i in np.arange(num_balls):
while(True):
radius = (max_radius - min_radius) * rand.random_sample() +
min_radius
ball_min_x = self.min_x + radius
ball_max_x = self.max_x - radius
x = (ball_max_x - ball_min_x)*rand.random_sample() + ball_min_x
ball_min_y = self.min_y + radius
ball_max_y = self.max_y - radius
y = (ball_max_y - ball_min_y)*rand.random_sample() + ball_min_y
vx = rand.random_sample()
vy = rand.random_sample()
mass = 1.0 # rand.random_sample()
new_ball = Ball(radius, x, y, vx, vy, mass)
if not new_ball.check_overlap(self.balls):
self.balls.append(new_ball)
break
#init_wall_collision_times will set all of the balls' minimum collision time
def init_wall_collision_times(self):
for i in np.arange(len(self.balls)):
bi = self.balls[i]
tix = bi.horizontal_wall_collision_time(self.min_x, self.max_x)
tiy = bi.vertical_wall_collision_time(self.min_y, self.max_y)
self.PQ.insert(i, -1, tix + self.time, self.balls[i].count, -1)
self.PQ.insert(-1, i, tiy + self.time, -1, self.balls[i].count)
return
#init_ball_collision_times will set all of the balls' minimum collision time
#with all other balls and store that time within the ith and jth index of
#PQ.ball_collision_time
def init_ball_collision_times(self):
for i in np.arange(self.num_balls):
bi = self.balls[i]
for j in np.arange(i+1, self.num_balls):
bj = self.balls[j]
tij = bi.ball_collision_time(bj)
self.PQ.insert(i, j, tij + self.time, self.balls[i].count,
self.balls[j].count)
# self.ball_collision_times[i][j] = tij
# self.ball_collision_times[j][i] = tij
return
#walls (horizontal and vertical) and all other balls within the PQ array
def update_collision_times(self, i):
bi = self.balls[i]
tix = bi.horizontal_wall_collision_time(self.min_x, self.max_x)
tiy = bi.vertical_wall_collision_time(self.min_y, self.max_y)
self.PQ.insert(i, -1, tix + self.time,self.balls[i].count, -1)
self.PQ.insert(-1, i, tiy + self.time, -1, self.balls[i].count)
for j in np.arange(self.num_balls):
bj = self.balls[j]
tij = bi.ball_collision_time(bj) + self.time
if i > j:
self.PQ.insert(j, i,
tij,self.balls[j].count,self.balls[i].count)
else:
self.PQ.insert(i, j, tij,self.balls[i].count,
self.balls[j].count)
return
#draw will draw the borders and all balls within self.balls
def draw(self):
#Draw walls
self.canvas.create_line((self.min_x, self.min_y), (self.min_x,
self.max_y), fill = "red")
self.canvas.create_line((self.min_x, self.min_y), (self.max_x,
self.min_y), fill = "red")
self.canvas.create_line((self.min_x, self.max_y), (self.max_x,
self.max_y), fill = "red")
self.canvas.create_line((self.max_x, self.min_y), (self.max_x,
self.max_y), fill = "red")
#Draw balls
for b in self.balls:
obj = self.canvas.create_oval(b.x - b.radius, b.y - b.radius, b.x +
b.radius, b.y + b.radius, outline=b.tk_rgb, fill=b.tk_rgb)
self.ball_handles[b] = obj
self.canvas.update()
#refresh is called to update the state of the simulation
#-each refresh call can be considered one iteration of the simulation
def refresh(self):
#get the next collision
i, j, t, num_collisions_i, num_collision_j = self.PQ.get_next()
#gather the current collisions of the ith and jth ball
current_collisions_i = self.balls[i].count
current_collisions_j = self.balls[j].count
#Check the difference in time between the predicted collision time and
#the current time stamp of the simulation
delta = t - self.time
#If the difference is greater than 1, then just move the balls
if delta > 1.0:
# cap delta to 1.0
for bi in self.balls:
bi.move()
self.canvas.move(self.ball_handles[bi], bi.vx, bi.vy)
self.time += 1.0
#Otherwise a collision has occurred
else:
#Move all balls
for bi in self.balls:
bi.move(delta)
self.canvas.move(self.ball_handles[bi], bi.vx*delta,
bi.vy*delta)
#increment the simulation time stamp
self.time += delta
#Delete the top element within the Priority Queue
self.PQ.delete()
#if i is -1 then this indicates a collision with a vertical wall
#also this if statement checks if the number of collisions recorded
#when the collision returned by PQ.get_next() is equal to the
#number of collisions within the jth ball
#this acts as a test to check if the collision is still valid
if i == -1 and num_collision_j == current_collisions_j:
#compute what happens from the vertical wall collision
self.balls[j].collide_with_vertical_wall()
#update collision times for the jth ball
self.update_collision_times(j)
#if j is -1 then this indicates a collision a horizontal wall
#while also checking if the number of collisions match
#to see if the collision is valid
elif j == -1 and num_collisions_i == current_collisions_i:
#compute what happens from the horizontal wall collision
self.balls[i].collide_with_horizontal_wall()
#update collision times for the ith ball
self.update_collision_times(i)
elif num_collision_j == current_collisions_j and num_collisions_i ==
current_collisions_i:
#Execute collision across the ith and jth ball
self.balls[i].collide_with_ball(self.balls[j])
#update collision times for both the ith and jth ball
self.update_collision_times(i)
self.update_collision_times(j)
#update the canvas to draw the new locations of each ball
self.canvas.update()
self.canvas.after(self.refresh_speed, self.refresh)
def __init__(self, radius, x, y, vx, vy, mass, tk_rgb="#000000"):
self.radius = radius
self.x = x
self.y = y
self.vx = vx
self.vy = vy
self.mass = mass
self.tk_rgb = tk_rgb
#since this ball was just initialized, it hasn't had any collisions yet
self.count = 0
return
#move changes the displacement of the ball by the velocity
def move(self, dt=1.0):
self.x += self.vx*dt
self.y += self.vy*dt
return
#check_overlap checks if this ball is overlapping with any other
#ball, it is used to see if a collision has occurred
def check_overlap(self, others):
for b in others:
min_dist = b.radius + self.radius
center_dist = math.sqrt((b.x - self.x)*(b.x - self.x) + \
(b.y - self.y)*(b.y - self.y))
if center_dist < min_dist:
return True
return False
#collide_with_ball computes collision, changing the Ball's velocity
#as well as the other ball's velocity
def collide_with_ball(self, other):
dv_x = other.vx - self.vx
dv_y = other.vy - self.vy
dr_x = other.x - self.x
dr_y = other.y - self.y
sigma = self.radius + other.radius
dv_dr = dv_x * dr_x + dv_y * dr_y
J = 2.0 * self.mass * other.mass * dv_dr/((self.mass +
other.mass)*sigma)
Jx = J * dr_x/sigma
Jy = J * dr_y/sigma
self.vx += Jx/self.mass
self.vy += Jy/self.mass
other.vx -= Jx/other.mass
other.vy -= Jy/other.mass
#Increment the collision count for both balls
self.count += 1
other.count += 1
return
# Compute when an instance of Ball collides with the given Ball other
# Return the timestamp that this will occur
def ball_collision_time(self, other):
dr_x = other.x - self.x
dr_y = other.y - self.y
if dr_x == 0 and dr_y == 0:
return float('inf')
dv_x = other.vx - self.vx
dv_y = other.vy - self.vy
dv_dr = dv_x * dr_x + dv_y * dr_y
if dv_dr > 0:
return float('inf')
dv_dv = dv_x * dv_x + dv_y * dv_y
dr_dr = dr_x * dr_x + dr_y * dr_y
sigma = self.radius + other.radius
d = dv_dr * dv_dr - dv_dv * (dr_dr - sigma * sigma)
# No solution
if d < 0 or dv_dv == 0:
return float('inf')
return - (dv_dr + np.sqrt(d))/dv_dv
#collide_with_horizontal_wall executes the change in the Ball's
#velocity when colliding with a horizontal wall
def collide_with_horizontal_wall(self):
self.vx = -self.vx
self.count += 1
return
#collide_with_vertical_wall executes the change in the Ball's
#velocity when colliding with a vertical wall
def collide_with_vertical_wall(self):
self.vy = -self.vy
self.count += 1
return
# Compute when the instance of Ball collides with a horizontal wall
# Return the time stamp that this will occur
def horizontal_wall_collision_time(self, min_x, max_x):
if self.vx < 0:
# x + delta_t * vx = min_x + radius
return (min_x + self.radius - self.x)/(1.0*self.vx)
if self.vx > 0:
# x + delta_t * vx = max_x - radius
return (max_x - self.radius - self.x)/(1.0*self.vx)
return float('inf')
# Compute when the instance of Ball collides with a vertical wall
# Return the time stamp that this will occur
# Inputs of min_y and max_y
def vertical_wall_collision_time(self, min_y, max_y):
if self.vy < 0:
# y + delta_t * vy = min_y + radius
return (min_y + self.radius - self.y)/(1.0*self.vy)
if self.vy > 0:
# y + delta_t * vy = max_y - radius
return (max_y - self.radius - self.y)/(1.0*self.vy)
return float('inf')
#show_stats will print out the Ball's data
#specifically the radius, position, velocity, mass, and color
def show_stats(self):
print("radius: %f"%self.radius)
print("position: %f, %f"%(self.x, self.y))
print("velocity: %f, %f"%(self.vx, self.vy))
print("mass: %f"%self.mass)
print("rgb: %s"%self.tk_rgb)
return
#Main script
if __name__ == "__main__":
#Set the parameters for the graphics window and simulation
scale = 800
border = 5
#Set radius range for all balls
max_radius = 20
min_radius = 5
#set number of balls
num_balls = 10
#set refresh rate
refresh_speed = 5
rand.seed(12394)
#create the graphics object
root = Tk()
#Create the painter object
p = Painter(root, scale, border, refresh_speed, None, min_radius,max_radius,
num_balls)
#If you have the commented out files in your directory then
#uncomment them to see what they do
#p = Painter(root, scale, border, refresh_speed, 'wallbouncing.txt')
#p = Painter(root, scale, border, refresh_speed, 'p10.txt')
#p = Painter(root, scale, border, refresh_speed, 'billiards4.txt')
#p = Painter(root, scale, border, refresh_speed, 'squeeze.txt')
#run the Painter main loop function (calls refresh many times)
root.mainloop()