实现动态画线的功能。在客户屏幕上建立一个曲线绘制区域并创建一个与设备描述表pDC兼容的位图，用来保存需要移动的曲线图。曲线每隔200毫秒前进5单元水平距离 -Dynamic drawing a line function. The client to establish a curve on the screen and create a regional map and the device compatible bitmap pDC to preserve curve needs to