Framebuffer中画点，画线，画多边形，画圆，画抛物线的实现函数

使用OLED显示器作为显示设备。有效果显示区域为128X48点阵，调用函数接口，实现了画点、画线、画圆、多边形、窗体等等功能。-As a display device using the OLED display. Be effective for the 128X48 dot matrix display area, call the function interface, implements the drawing point, drawing a line, circle, polygo

实现计算多边形面积的功能。第一行输入多边形的顶点数。第二行以后按照次序依次输入坐标点（如“2 3”,代表X 坐标和Y 坐标，中间加入空格区分）-To achieve the function of calculating the polygon area. Enter the first line of the polygon vertices. After the second line followed in the order of the input coordinates of poi