模拟windows画图

总的来说是一个画图程序，能够画出"直线","矩开","椭圆","圆角矩形","贝氏曲线","扇型","多边形"等一系列规则图形,还有工具"铅笔","橡皮擦","文字","选取"，功能有新建(N)|78","打开(O)|79","保存(S)|83","另存为(A)","退出(X)|88","撤消(U)|90","重复(R)|89