实现了图形绘制功能和文字处理功能，图形绘制功能包括绘制直线，绘制矩形，绘制圆形，绘制Bezier曲线。文字处理功能包括保存和加载。-Achieve a graphical rendering capabilities and word processing functions, graphics rendering features include draw lines, draw a rectangle, draw a circle, draw Bezier curves. Word proc