(1) 添加曲线条数属性（在一个坐标轴上，一次可画多条曲线，1～MAX_CURVECOUNT 条可设置。）
注意：设置条数后，每条曲线都会画（即使没有用 AddValue 添加值！添加 blnShouldDrawCurve 变量决定是否要画出），
不过，建议想画出多少就设置多少，不要有多余的。
(2) 曲线颜色 属性改动，支持多条曲线不同颜色((1) add the property of the number of curves (on one axis, one can draw a number of curves at a time, and 1 to MAX_CURVECOUNT can be set.)
Note: after setting the number, each curve will be painted (even if no value is added to the AddValue! Add the blnShouldDrawCurve variable to decide whether to draw,
'however, suggest how much you want to set up, don't have any extra.)