创建图像

    vtkSmartPointer<vtkImageData> img = vtkSmartPointer<vtkImageData>::New();
	vtkSmartPointer<vtkInformation> info = vtkSmartPointer<vtkInformation>::New();
	img->SetDimensions(225, 225, 336);
	img->SetScalarType(VTK_UNSIGNED_CHAR, info);  //VTK_UNSIGNED_CHAR表示图像的类型
	img->SetNumberOfScalarComponents(1, info);//每个像素需要表示的组份 =1是指标量图  一般是填1
	img->AllocateScalars(info);//给图像分配内存

修改图像像素

    int dims[3];
    //获取图片的位数
    img->GetDimensions(dims);


    for (int k = 0; k < dims[2]; k++)
     {
         for (int j = 0; j < dims[1]; j++)
         {
             for (int i = 0; i < dims[0]; i++)
             {
                 //i < 400 && i > 0 && j > 0 && j < 400表示要改修的范围
                 if (i < 400 && i > 0 && j > 0 && j < 400)
                 {
                 //如果是要修改彩色图片RGB的值 记得要转换成(unsigned char *)类型
                 unsigned char *pixel = (unsigned char *)(img->GetScalarPointer(i, j, k));
                 //修改R
                 *pixel = 255 - *pixel;
                 //修改G
                 *(pixel + 1) = 255 - *(pixel + 1);
                 //修改B
                 *(pixel + 2) = 255 - *(pixel + 2);
                 }
             }
         }
     }