一个绘制图形的为库。包含各种小控件，可绘制时实曲线。6.0.0版本的的跟之前的安装后的处理方式不一样。记得把qwt安装目录下的插件库文件考到Designer的plugin文件夹下。-Draw a graph for the library. Contains a variety of small controls can be drawn when the real curve. 6.0.0 version of the pre-installed with the approach is di