Double buffering in Jython - jython

Question

recently I started learning Jython and now I have rather simply problem. I would like to improve quality of my animation. Unfortunately I don't know how to add double buffering to my applet . Could you help me?
Best regards!
from javax.swing import JToolBar
from javax.swing import JButton
from javax.swing import JFrame
import time
from java import awt
from java.awt import BorderLayout
class Canvas(awt.Canvas):
u"Canvas - drawing area"
def __init__(self,winSize = 400):
self.play = False
self.background=awt.Color.black
self.winSize = winSize
self.l = 0
def playSim(self, play):
if play == True:
self.play = True
self.repaint()
else: self.play = False
def paint(self, g):
g.fillRect(50, int(self.winSize/4), self.l, int(self.winSize/2))
if self.l < self.winSize: self.l += 1
else: self.l = 0
time.sleep(0.02)
if self.play == True: self.repaint()
class Example(JFrame):
def __init__(self):
super(Example, self).__init__()
self.initUI()
def initUI(self):
winSize = 600
toolbar = JToolBar()
self.playButton = JButton("Start", actionPerformed=self.playButtonPress )
toolbar.add(self.playButton)
self.add(toolbar, BorderLayout.NORTH)
self.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)
self.setSize(winSize, winSize)
self.setResizable(False)
self.setLocationRelativeTo(None)
self.setVisible(True)
self.canvas = Canvas(winSize)
self.getContentPane().add(self.canvas)
self.setTitle("TEST")
self.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)
def playButtonPress(self, e):
if self.playButton.getLabel() == "Start":
self.canvas.playSim(True)
self.playButton.setLabel("Stop")
else:
self.playButton.setLabel("Start")
self.canvas.playSim(False)
if __name__ == '__main__':
Example()

Answer 1

I solved my recent problem:
from javax.swing import JToolBar
from javax.swing import JButton
from javax.swing import JFrame
import time
from java import awt
from java.awt import BorderLayout
class Canvas(awt.Canvas):
u"Canvas - drawing area"
def __init__(self,winSize = 400):
self.play = False
self.background=awt.Color.black
self.winSize = winSize
self.l = 0
self.bi = BufferedImage(winSize, winSize, BufferedImage.TYPE_INT_RGB)
self.offScreenGraphics = self.bi.getGraphics()
def playSim(self, play):
if play == True:
self.play = True
self.repaint()
else: self.play = False
def paint(self, g):
self.offScreenGraphics.fillRect(50, int(self.winSize/4), self.l, int(self.winSize/2))
if self.l < self.winSize: self.l += 1
else: self.l = 0
g.drawImage(self.bi, 0, 0, None)
time.sleep(0.02)
if self.play == True: self.repaint()
class Example(JFrame):
def __init__(self):
super(Example, self).__init__()
self.initUI()
def initUI(self):
winSize = 600
toolbar = JToolBar()
self.playButton = JButton("Start", actionPerformed=self.playButtonPress )
toolbar.add(self.playButton)
self.add(toolbar, BorderLayout.NORTH)
self.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)
self.setSize(winSize, winSize)
self.setResizable(False)
self.setLocationRelativeTo(None)
self.setVisible(True)
self.canvas = Canvas(winSize)
self.getContentPane().add(self.canvas)
self.setTitle("TEST")
self.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)
def playButtonPress(self, e):
if self.playButton.getLabel() == "Start":
self.canvas.playSim(True)
self.playButton.setLabel("Stop")
else:
self.playButton.setLabel("Start")
self.canvas.playSim(False)
if __name__ == '__main__':
Example()
Now I've another(rather trivial) problem:
How can I make from this python file *the class file* which would be ready to publish it on website as an applet?