鼠标监听事件模拟，在一个目标区域画出标准矩形框，分别展现鼠标双击，单击，移动时生的事件。-Mouse listener event simulation, the target area to draw in a standard rectangular box, respectively, show the mouse double click, click, moving raw events.

画板程序，可以画矩形椭圆曲线，可以填充，有橡皮清除功能，支持文本框输入。-Sketchpad program, you can draw a rectangle elliptic curve can be filled with rubber clearance, support for text input box.