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event_handling example code: pipong.pyΒΆ

[source code]

#!/usr/bin/env python
# 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 < 0+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 Search examples)