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#!/usr/bin/python
# events-example3.py
# Demos timer, mouse, and keyboard events
from tkinter import *
import math
import random
class Vector(object):
"""N-dimensional vector class."""
def __init__(self, *components):
"""Create a vector from its components."""
self.components = components
def __add__(self, other):
"""Add two vectors."""
return self.__class__(
*map(lambda xy: xy[0] + xy[1], zip(self.components, other.components))
)
def __sub__(self, other):
"""Subtract two vectors."""
return self.__class__(
*map(lambda xy: xy[0] - xy[1], zip(self.components, other.components))
)
def __mul__(self, other):
"""Multiply a vector by a constant."""
return self.__class__(*map(lambda x: x * other, self.components))
def __rmul__(self, other):
"""Multiply a constant by a vector."""
return self * other
def __abs__(self):
"""Return the 2-norm of the vector."""
return math.sqrt(sum(map(lambda x: x * x, self.components)))
def __truediv__(self, scalar):
"""Return self * 1 / scalar."""
return self * (1 / scalar)
def __eq__(self, other):
return self.components == other.components
def init(data):
data.squareLeft = 50
data.squareTop = 0
data.squareFill = "red"
data.squareSize = 25
data.circleCenters = [ ]
data.counter = 0
data.headingRight = True
data.headingDown = True
data.isPaused = False
data.timerDelay = 50
data.speed = Vector(10, 0)
data.drag = -1
data.tailAcceleration = Vector(5, 0)
data.tailDuration = 2
data.tailMoving = False
data.tailThreshold = 5
data.tailMoveCount = 0
def mousePressed(event, data):
newCircleCenter = (event.x, event.y)
data.circleCenters.append(newCircleCenter)
def keyPressed(event, data):
if (event.char == "d"):
if (len(data.circleCenters) > 0):
data.circleCenters.pop(0)
else:
print("No more circles to delete!")
elif (event.char == "p"):
data.isPaused = not data.isPaused
elif (event.char == "s"):
doStep(data)
if (event.keysym == "Left"):
moveLeft(data)
elif (event.keysym == "Right"):
moveRight(data)
def moveLeft(data):
data.squareLeft -= 20
def moveRight(data):
data.squareLeft += 20
def moveUp(data):
data.squareTop -= 20
def moveDown(data):
data.squareTop += 20
def timerFired(data):
if (not data.isPaused): doStep(data)
def fixDirection(data, theta=None):
if theta is None:
theta = random.random() * 2 * math.pi
costheta = math.cos(theta)
sintheta = math.sin(theta)
speedx = data.tailAcceleration.components[0]
speedy = data.tailAcceleration.components[1]
# From en.wikipedia.org/wiki/Rotation_matrix
data.tailAcceleration = Vector(
speedx * costheta - speedy * sintheta,
speedx * sintheta + speedy * costheta
)
def doStep(data):
data.counter += 1
if random.random() < 1 / 50:
fixDirection(data)
#print(abs(data.tailAcceleration))
data.speed += data.drag * data.speed / abs(data.speed)
if abs(data.speed) < data.tailThreshold:
data.tailMoving = True
if data.tailMoveCount > data.tailDuration:
data.tailMoveCount = 0
data.tailMoving = False
if data.tailMoving:
data.speed += data.tailAcceleration
data.tailMoveCount += 1
data.squareLeft += data.speed.components[0]
data.squareTop += data.speed.components[1]
if data.squareLeft + data.squareSize > data.width:
data.squareLeft = 0
if data.squareLeft < 0:
data.squareLeft = data.width - data.squareSize
if data.squareTop < 0:
data.squareTop = data.height - data.squareSize
if data.squareTop + data.squareSize > data.height:
data.squareTop = 0
def redrawAll(canvas, data):
# draw the square
canvas.create_rectangle(data.squareLeft,
data.squareTop,
data.squareLeft + data.squareSize,
data.squareTop + data.squareSize,
fill=data.squareFill)
# draw the circles
for circleCenter in data.circleCenters:
(cx, cy) = circleCenter
r = 20
canvas.create_oval(cx-r, cy-r, cx+r, cy+r, fill="cyan")
# draw the text
canvas.create_text(150,20,text="events-example3.py")
canvas.create_text(150,40,text="Mouse clicks create circles")
canvas.create_text(150,60,text="Pressing 'd' deletes circles")
canvas.create_text(150,80,text="Pressing 'p' pauses/unpauses timer")
canvas.create_text(150,100,text="Pressing 's' steps the timer once")
canvas.create_text(150,120,text="Left arrow moves square left")
canvas.create_text(150,140,text="Right arrow moves square right")
canvas.create_text(150,160,text="Timer changes color of square")
####################################
# use the run function as-is
####################################
def run(width=300, height=300):
def redrawAllWrapper(canvas, data):
canvas.delete(ALL)
redrawAll(canvas, data)
canvas.update()
def mousePressedWrapper(event, canvas, data):
mousePressed(event, data)
redrawAllWrapper(canvas, data)
def keyPressedWrapper(event, canvas, data):
keyPressed(event, data)
redrawAllWrapper(canvas, data)
def timerFiredWrapper(canvas, data):
timerFired(data)
redrawAllWrapper(canvas, data)
# pause, then call timerFired again
canvas.after(data.timerDelay, timerFiredWrapper, canvas, data)
# Set up data and call init
class Struct(object): pass
data = Struct()
data.width = width
data.height = height
data.timerDelay = 100 # milliseconds
init(data)
# create the root and the canvas
root = Tk()
canvas = Canvas(root, width=data.width, height=data.height)
canvas.pack()
# set up events
root.bind("<Button-1>", lambda event:
mousePressedWrapper(event, canvas, data))
root.bind("<Key>", lambda event:
keyPressedWrapper(event, canvas, data))
timerFiredWrapper(canvas, data)
# and launch the app
root.mainloop() # blocks until window is closed
print("bye!")
run(600, 1000)
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