二维数组旋转90度、180度、270度

图像处理中，很多时候要使用到二维数组的旋转。本质上二维数组的旋转其实就是坐标的变换，即旋转后的坐标(x,y)需要对应到原有二维数组的坐标点上，取到正确的值即可完成正确的旋转。

  规则很好找。见如下的代码中的3个转换公式即可。

void Rotate90()
{
    int b[2][3] = {{1,2,3},{4,5,6}};
    int a[3][2] = {0};

    for(int i=0;i<3;i++)
    {
        for(int j=0;j<2;j++)
        {
            //a[i][j] = b[h-1-j][i]; here h = 2
            a[i][j] = b[2-1-j][i];
        }
    }

    //使用一维数组模拟二维数组
    int w = 3;
    int h = 2;
    int *p = (int *)new int[w*h];
    int *p2 = (int *)new int[w*h];
    for(int i=0;i<w*h;i++)
    {
        p[i] = i+1;
    }
    int newH = w;
    int newW = h;
    for(int i=0;i<newH;i++)
    {
        for(int j=0;j<newW;j++)
        {
            //a[i][j] = b[h-1-j][i]
            p2[i*newW+j] = p[(h-1-j)*w+i];
        }
    }

    delete []p;
    delete []p2;
}

void Rotate180()
{
    int b[2][3] = {{1,2,3},{4,5,6}};
    int a[2][3] = {0};

    for(int i=0;i<2;i++)
    {
        for(int j=0;j<3;j++)
        {
            //a[i][j] = b[h-1-i][w-1-j]; here h = 2
            a[i][j] = b[2-1-i][3-1-j];
        }
    }

    //使用一维数组模拟二维数组
    int w = 3;
    int h = 2;
    int *p = (int *)new int[w*h];
    int *p2 = (int *)new int[w*h];
    for(int i=0;i<w*h;i++)
    {
        p[i] = i+1;
    }
    int newH = h;
    int newW = w;
    for(int i=0;i<newH;i++)
    {
        for(int j=0;j<newW;j++)
        {
            //a[i][j] = b[h-1-i][w-1-j];
            p2[i*newW+j] = p[(h-1-i)*w+w-1-j];
        }
    }

    delete []p;
    delete []p2;
}

void Rotate270()
{
    int b[2][3] = {{1,2,3},{4,5,6}};
    int a[3][2] = {0};

    for(int i=0;i<3;i++)
    {
        for(int j=0;j<2;j++)
        {
            //a[i][j] = b[j][w-1-i]; here w = 3
            a[i][j] = b[j][3-1-i];
        }
    }

    //使用一维数组模拟二维数组
    int w = 3;
    int h = 2;
    int *p = (int *)new int[w*h];
    int *p2 = (int *)new int[w*h];
    for(int i=0;i<w*h;i++)
    {
        p[i] = i+1;
    }
    int newH = w;
    int newW = h;
    for(int i=0;i<newH;i++)
    {
        for(int j=0;j<newW;j++)
        {
            //a[i][j] = b[j][w-1-i];
            p2[i*newW+j] = p[j*w+w-1-i];
        }
    }

    delete []p;
    delete []p2;
}

原文:https://blog.csdn.net/faithzzf/article/details/77009777