在屏幕上移动一幅图象：

world.gif作为背景,car.gif作为移动物体,且被绘制了两次,造成

一个两辆车比赛的场景。



-Double-buffering technology:

　　　　　　　　Another reducing flicker between frames is to use double buffering, which in many animation applet

　　　　Was used.

　　　　　　　　The main principle is to create a background image, to a painting into the images, then call drawImage ()

　　　　The entire image to the screen a picture up. Advantage is that most of the drawing is off screen. Will move an image on the screen:

　　　　　　　　world.gif as background, car.gif as moving objects, and was drawn twice, resulting in

　　　　A two car race scene.