在单文档框中进行绘图，自由画图，画直线，画圆与设置线的各种属性-Single document box drawing, free drawing, draw a straight line, circle and set the various properties of the line

在单文档里通过菜单调取字体对话框设置文档字体。程序简单，一看就懂。-In a single document retrieval via the menu in the Font dialog box to set the document font. Simple procedures, one can understand.