You can view the graphics with drag mouse.
You can zoom in/zoom out the graphics with scroll wheel.
Click button【Full Frame】，graphics will shown in the dialog box for largest.
After get satisfied smoothing effect ， click button 【 Apply 】， curves will processing smooth
according to smoothness settings.
Select “Direct smooth” , you can use another smoothing method.
The choice of smoothing method should be changed with the needs of the actual graphic.
2.13.5 Check Closure
Click menu【Handle】->【Curve auto close】，or click System Bar
appears.
,the following dialog box
Close error: When distance from the starting point to ending point less than close tolerance,
automatic closing of the curve.
Force to close: Mandatory closure of all selected curves.
