我正在尝试生成具有不同分辨率的png。但是，如果我使用动态数组，它只会生成灰色区域。这是我的代码（C++ 16 bit grayscale gradient image from 2D array）的源代码

void generate_horizontal_gradient(char fileName[],int width,int height,int offset,bool direction)
{
    unsigned short** buffer = new unsigned short* [height];
    for (int i = 0; i < height; i++)
    {
    buffer[i] = new unsigned short[width];
    }

    for (int i = 0; i < height; i++)
    {
        unsigned short temp_data = 65535;
        if (direction == true) {
            for (int j = width; j > 0; j--)
            {
                buffer[i][j] = temp_data;
                if (j < width - offset)
                {
                    temp_data -= 65535 / (width - offset);
                }
            }
        }
        else
        {
            for (int j = 0; j < width; j++)
            {
                buffer[i][j] = temp_data;
                if (j > offset)
                {
                    temp_data -= 65535 / (width - offset);
                }
            }
        }
    }
    auto hold_arr = (unsigned short*) &buffer[0][0];
    cimg_library::CImg<unsigned short> img(hold_arr,width,height);
    img.save_png(fileName);
}