2、　　转换为灰度图像。

这个算法是依照彩色图转化为灰度图像的方式：

灰度值 = 0.3*R+0.59*G+0.11*B

用两重循环遍历截取的图片，对于每一个象素点，用MFC的函数取得其COLORREF形式的颜色值，从中分解出R、G、B三种颜色的值，计算出对应的灰度值后，赋给R、G、B即可。完成遍历后刷新图片就可以看到转换后的灰度图像。

-2, converted to grayscale images. This algorithm are in accordance with the color map into a gray image of the way: gray value = 0.3* R+0.59* G+0.11* B with double cycle traversal intercepted picture, for each pixel, using MFC function obtained their forms of COLORREF color value, from decomposition of the R, G, B three color values, calculate the corresponding gray-scale value, assigned to R, G, B can be. After the completion of traversal can be seen on the picture to refresh the converted gray image.