说明：  图形编辑器（graphical editor）允许用户改变位图图像，比如大家经常用到的Photoshop。它所采用的改变方法和文本编辑器允许修改文档的方法一样。位图图像由MxN 的像素矩阵来表示，并且每个像素点都有给定的颜色。 我们的任务就是来要编写一个程序来模拟一个简单的交互式图形编辑器，并将生成的图片存储到一个 BMP 格式的文件中。
(Graphics editor (graphical editor) allows the user to change the bitmap image, such as we often used Photoshop. It uses a text editor to change the method and the method allows to modify the same document. Bitmap images from the MxN matrix of pixels to represent, and each pixel has a given color. Our task is to write a program to simulate a simple interactive graphic editor, and the resulting picture is stored in a BMP format file.)