.. _event_handling-pipong:
event_handling example code: pipong.py
======================================
[`source code <pipong.py>`_]
::
# A matplotlib based game of Pong illustrating one way to write interactive
# animation which are easily ported to multiple backends
# pipong.py was written by Paul Ivanov <http://pirsquared.org>
from __future__ import print_function
import numpy as np
import matplotlib.pyplot as plt
from numpy.random import randn, randint
instructions = """
Player A: Player B:
'e' up 'i'
'd' down 'k'
press 't' -- close these instructions
(animation will be much faster)
press 'a' -- add a puck
press 'A' -- remove a puck
press '1' -- slow down all pucks
press '2' -- speed up all pucks
press '3' -- slow down distractors
press '4' -- speed up distractors
press ' ' -- reset the first puck
press 'n' -- toggle distractors on/off
press 'g' -- toggle the game on/off
"""
class Pad(object):
def __init__(self, disp, x, y, type='l'):
self.disp = disp
self.x = x
self.y = y
self.w = .3
self.score = 0
self.xoffset = 0.3
self.yoffset = 0.1
if type == 'r':
self.xoffset *= -1.0
if type == 'l' or type == 'r':
self.signx = -1.0
self.signy = 1.0
else:
self.signx = 1.0
self.signy = -1.0
def contains(self, loc):
return self.disp.get_bbox().contains(loc.x, loc.y)
class Puck(object):
def __init__(self, disp, pad, field):
self.vmax = .2
self.disp = disp
self.field = field
self._reset(pad)
def _reset(self, pad):
self.x = pad.x + pad.xoffset
if pad.y < 0:
self.y = pad.y + pad.yoffset
else:
self.y = pad.y - pad.yoffset
self.vx = pad.x - self.x
self.vy = pad.y + pad.w/2 - self.y
self._speedlimit()
self._slower()
self._slower()
def update(self, pads):
self.x += self.vx
self.y += self.vy
for pad in pads:
if pad.contains(self):
self.vx *= 1.2 * pad.signx
self.vy *= 1.2 * pad.signy
fudge = .001
# probably cleaner with something like...
#if not self.field.contains(self.x, self.y):
if self.x < fudge:
#print("player A loses")
pads[1].score += 1
self._reset(pads[0])
return True
if self.x > 7 - fudge:
#print("player B loses")
pads[0].score += 1
self._reset(pads[1])
return True
if self.y < -1 + fudge or self.y > 1 - fudge:
self.vy *= -1.0
# add some randomness, just to make it interesting
self.vy -= (randn()/300.0 + 1/300.0) * np.sign(self.vy)
self._speedlimit()
return False
def _slower(self):
self.vx /= 5.0
self.vy /= 5.0
def _faster(self):
self.vx *= 5.0
self.vy *= 5.0
def _speedlimit(self):
if self.vx > self.vmax:
self.vx = self.vmax
if self.vx < -self.vmax:
self.vx = -self.vmax
if self.vy > self.vmax:
self.vy = self.vmax
if self.vy < -self.vmax:
self.vy = -self.vmax
class Game(object):
def __init__(self, ax):
# create the initial line
self.ax = ax
padAx = padBx = .50
padAy = padBy = .30
padBx += 6.3
pA, = self.ax.barh(padAy, .2, height=.3, color='k', alpha=.5, edgecolor='b', lw=2, label="Player B", animated=True)
pB, = self.ax.barh(padBy, .2, height=.3, left=padBx, color='k', alpha=.5, edgecolor='r', lw=2, label="Player A", animated=True)
# distractors
self.x = np.arange(0, 2.22*np.pi, 0.01)
self.line, = self.ax.plot(self.x, np.sin(self.x), "r", animated=True, lw=4)
self.line2, = self.ax.plot(self.x, np.cos(self.x), "g", animated=True, lw=4)
self.line3, = self.ax.plot(self.x, np.cos(self.x), "g", animated=True, lw=4)
self.line4, = self.ax.plot(self.x, np.cos(self.x), "r", animated=True, lw=4)
self.centerline, = self.ax.plot([3.5, 3.5], [1, -1], 'k', alpha=.5, animated=True, lw=8)
self.puckdisp = self.ax.scatter([1], [1], label='_nolegend_', s=200, c='g', alpha=.9, animated=True)
self.canvas = self.ax.figure.canvas
self.background = None
self.cnt = 0
self.distract = True
self.res = 100.0
self.on = False
self.inst = True # show instructions from the beginning
self.background = None
self.pads = []
self.pads.append(Pad(pA, 0, padAy))
self.pads.append(Pad(pB, padBx, padBy, 'r'))
self.pucks = []
self.i = self.ax.annotate(instructions, (.5, 0.5),
name='monospace',
verticalalignment='center',
horizontalalignment='center',
multialignment='left',
textcoords='axes fraction', animated=True)
self.canvas.mpl_connect('key_press_event', self.key_press)
def draw(self, evt):
draw_artist = self.ax.draw_artist
if self.background is None:
self.background = self.canvas.copy_from_bbox(self.ax.bbox)
# restore the clean slate background
self.canvas.restore_region(self.background)
# show the distractors
if self.distract:
self.line.set_ydata(np.sin(self.x + self.cnt/self.res))
self.line2.set_ydata(np.cos(self.x - self.cnt/self.res))
self.line3.set_ydata(np.tan(self.x + self.cnt/self.res))
self.line4.set_ydata(np.tan(self.x - self.cnt/self.res))
draw_artist(self.line)
draw_artist(self.line2)
draw_artist(self.line3)
draw_artist(self.line4)
# show the instructions - this is very slow
if self.inst:
self.ax.draw_artist(self.i)
# pucks and pads
if self.on:
self.ax.draw_artist(self.centerline)
for pad in self.pads:
pad.disp.set_y(pad.y)
pad.disp.set_x(pad.x)
self.ax.draw_artist(pad.disp)
for puck in self.pucks:
if puck.update(self.pads):
# we only get here if someone scored
self.pads[0].disp.set_label(" " + str(self.pads[0].score))
self.pads[1].disp.set_label(" " + str(self.pads[1].score))
self.ax.legend(loc='center')
self.leg = self.ax.get_legend()
#self.leg.draw_frame(False) #don't draw the legend border
self.leg.get_frame().set_alpha(.2)
plt.setp(self.leg.get_texts(), fontweight='bold', fontsize='xx-large')
self.leg.get_frame().set_facecolor('0.2')
self.background = None
self.ax.figure.canvas.draw()
return True
puck.disp.set_offsets([puck.x, puck.y])
self.ax.draw_artist(puck.disp)
# just redraw the axes rectangle
self.canvas.blit(self.ax.bbox)
if self.cnt == 50000:
# just so we don't get carried away
print("...and you've been playing for too long!!!")
plt.close()
self.cnt += 1
return True
def key_press(self, event):
if event.key == '3':
self.res *= 5.0
if event.key == '4':
self.res /= 5.0
if event.key == 'e':
self.pads[0].y += .1
if self.pads[0].y > 1 - .3:
self.pads[0].y = 1 - .3
if event.key == 'd':
self.pads[0].y -= .1
if self.pads[0].y < -1:
self.pads[0].y = -1
if event.key == 'i':
self.pads[1].y += .1
if self.pads[1].y > 1 - .3:
self.pads[1].y = 1 - .3
if event.key == 'k':
self.pads[1].y -= .1
if self.pads[1].y < -1:
self.pads[1].y = -1
if event.key == 'a':
self.pucks.append(Puck(self.puckdisp, self.pads[randint(2)], self.ax.bbox))
if event.key == 'A' and len(self.pucks):
self.pucks.pop()
if event.key == ' ' and len(self.pucks):
self.pucks[0]._reset(self.pads[randint(2)])
if event.key == '1':
for p in self.pucks:
p._slower()
if event.key == '2':
for p in self.pucks:
p._faster()
if event.key == 'n':
self.distract = not self.distract
if event.key == 'g':
#self.ax.clear()
self.on = not self.on
if event.key == 't':
self.inst = not self.inst
self.i.set_visible(self.i.get_visible())
if event.key == 'q':
plt.close()
Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)