使用DirectDraw画线。表面是一个按线性排列的内存块，它可以用一个char数组来描述。通过调用IDirectDrawSurface::Lock()方法，就可以访问与每个表面相关的内存。-using DirectDraw line drawing. The surface is a linear arrangement on the block of memory, it can use a char array to describe. By calling IDirectDrawSurf

// Descr iption: This sample demonstrates how to optimize performance by // using indexed geometry. As a demonstration, the sample // reduces the vertex count of a simple cube from 24 to 8 by // redefining the cube’s geometry using an indice

在矩阵中使用的数据类型是double。因此可以通过语句I2=im2double(I1) 把图像数组I1转换成double精度类型；如果不转换，在对uint8进行加减时会产生溢出，可能提示的错误为：Function * is not defined for values of class uint8 -The data used in the matrix type is double. So you can statement I2 = im2double (I1) converting th