QVTKWidget控件显示三维图片

QVTKWidget控件一般显示二维图片，如果要显示三维图片，并通过鼠标滚轮切换单张图片，则需要加入监听机制，可以自定义一个类来实现所需要的交互方式，该类可以继承于vtkCommand类。

（1）定义鼠标滚轮交互方式，用于显示下一张切片

class vtkNextSliceCallbk : public vtkCommand
{
private:
    vtkRenderWindowInteractor *Interactor;
    vtkImageViewer2* viewer;
    vtkInteractorStyleImage* style;

public:
    static vtkNextSliceCallbk *New()
    {
        return new vtkNextSliceCallbk;
    }

    vtkNextSliceCallbk()//构造函数
    {
        this->Interactor = 0;
    }

    void SetInteractorStyle(vtkInteractorStyleImage* style)
    {
        this->style = style;
    }

    void SetInteractor(vtkRenderWindowInteractor *interactor)
    {
        this->Interactor = interactor;
    }

    vtkRenderWindowInteractor *GetInteractor()
    {
        return this->Interactor;
    }

    void SetViewer(vtkImageViewer2* viewer)
    {
        this->viewer = viewer;
    }

    virtual void Execute(vtkObject *caller, unsigned long eventId, void *callData)
    {
        int max = viewer->GetSliceMax();//获得最大切片数目，避免翻页超出范围//63，从0开始
        int cur = viewer->GetSlice();//获得当前切片
        if (eventId == vtkCommand::MouseWheelForwardEvent && cur >= 0)//向前翻页
        {
            if(cur == 0)//切换到第一张，滚轮继续向前，保持显示第一张切片
                viewer->SetSlice(0);
            else
                viewer->SetSlice(--cur);
            viewer->SetSliceOrientationToXY();
            Interactor->SetInteractorStyle((vtkInteractorObserver *)style);
        } 
        if (eventId == vtkCommand::MouseWheelBackwardEvent &&  cur  <= max)//向后翻页
        {
            if(cur == max)//切换到最后一张，滚轮继续向后，保持显示最后一张切片
                viewer->SetSlice(max);
            else
                viewer->SetSlice(++cur);
            viewer->SetSliceOrientationToXY();
            Interactor->SetInteractorStyle((vtkInteractorObserver *)style);
        }
    }
};

(2) 读入MHD三维医学图片，通过滚轮切换单张图片，源码如下：

    mhdReader = vtkMetaImageReader::New();
    mhdReader->SetFileName(inputFileName);
    mhdReader->Update();
    //统计最大最小灰度值 （或者数据类型），自适应设置窗宽&窗位
    //当灰度值高于该范围的最大值时，均以白影显示；而低于该范围时均显示为黑色
    dataType =  mhdReader->GetDataScalarType();//获得数据类型
    imgSize = mhdReader->GetOutput()->GetExtent();//显示图像尺寸
    rotate = vtkImageFlip::New();//图像反转
    rotate->SetInputConnection(mhdReader->GetOutputPort());
    rotate->SetFilteredAxis(1);//y轴反转
    originalVtkViewer->SetInputConnection(rotate->GetOutputPort());
    //交互
    renWinInteractor = vtkRenderWindowInteractor::New();
    originalVtkViewer->SetRenderer(originalRenderder);//设置为同一个渲染场景
    originalVtkViewer->SetRenderWindow(ui->originalQVTKViewer->GetRenderWindow());
    pCall = vtkNextSliceCallbk::New();//实例化自定义类
    style = vtkInteractorStyleImage::New();
    style->AddObserver(vtkCommand::MouseWheelBackwardEvent, pCall); 
    style->AddObserver(vtkCommand::MouseWheelForwardEvent, pCall);
    renWinInteractor->SetInteractorStyle(style);
    renWinInteractor->AddObserver(vtkCommand::MouseWheelBackwardEvent, pCall);//通过交互窗口去监听
    renWinInteractor->AddObserver(vtkCommand::MouseWheelForwardEvent, pCall);
    pCall->SetInteractorStyle(style);
    pCall->SetViewer(originalVtkViewer);
    pCall->SetInteractor(renWinInteractor);
    ui->originalQVTKViewer->GetRenderWindow()->SetInteractor(renWinInteractor);
    originalVtkViewer->SetupInteractor(ui->originalQVTKViewer->GetRenderWindow()->GetInteractor());//设置交互方式
    originalVtkViewer->SetSliceOrientationToXY();//设置切片方向
    originalVtkViewer->SetColorLevel(128);//窗位
    originalVtkViewer->SetColorWindow(256);//窗宽

QVTKWidget控件显示三维图片效果如下：