vtk中畫矩形

 

class MyRubberBand : public vtkInteractorStyleRubberBand2D
{
public:
    static MyRubberBand* New();
    vtkTypeMacro(MyRubberBand, vtkInteractorStyleRubberBand2D);

    virtual void OnLeftButtonDown()
    {
        vtkInteractorStyleRubberBand2D::OnLeftButtonDown(); //必須有這一句
        startPosition[0] = this->GetInteractor()->GetEventPosition()[0];
        startPosition[1] = this->GetInteractor()->GetEventPosition()[1];
        startPosition[2] = 0;
    }
    virtual void OnLeftButtonUp()
    {
        vtkInteractorStyleRubberBand2D::OnLeftButtonUp(); //必須有這一句
        endPosition[0] = this->GetInteractor()->GetEventPosition()[0];
        endPosition[1] = this->GetInteractor()->GetEventPosition()[1];
        endPosition[2] = 0;
        std::cout<<"Position"<<endPosition[0]<<"  "<<endPosition[1]<<std::endl;

        this->viewer->GetRenderer()->SetDisplayPoint(startPosition);
        this->viewer->GetRenderer()->DisplayToView();
        this->viewer->GetRenderer()->ViewToWorld();

        double start[4];
        this->viewer->GetRenderer()->GetWorldPoint(start);


        this->viewer->GetRenderer()->SetDisplayPoint(endPosition);
        this->viewer->GetRenderer()->DisplayToView();
        this->viewer->GetRenderer()->ViewToWorld();

        double end[4];
        this->viewer->GetRenderer()->GetWorldPoint(end);


        double point1[3];
        double point2[3];
        double point3[3];
        double point4[3];

        double left[2];
        double right[2];

        left[0] = start[0]<=end[0] ? start[0] : end[0];
        left[1] = start[1]<=end[1] ? start[1] : end[1];

        right[0] = start[0]>end[0] ? start[0] : end[0];
        right[1] = start[1]>end[1] ? start[1] : end[1];

        point1[0] = left[0];  point1[1] = left[1];  point1[2] = 0;
        point2[0] = left[0];  point2[1] = right[1]; point2[2] = 0;
        point3[0] = right[0]; point3[1] = right[1]; point3[2] = 0;
        point4[0] = right[0]; point4[1] = left[1];  point4[2] = 0;

        this->SetLine(point1,point2);
        this->SetLine(point2,point3);
        this->SetLine(point3,point4);
        this->SetLine(point4,point1);

    }
    void SetLine(double point1[],double point2[])
    {
        vtkSmartPointer<vtkLineSource> lineSource = vtkSmartPointer<vtkLineSource>::New();
        lineSource->SetPoint1(point1);
        lineSource->SetPoint2(point2);
        lineSource->Update();

        vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
        mapper->SetInputConnection(lineSource->GetOutputPort());
        vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
        actor->SetMapper(mapper);
        actor->GetProperty()->SetLineWidth(2);
        actor->GetProperty()->SetColor(1.0,0.0,0.0);

        this->viewer->GetRenderer()->AddActor(actor);
        this->viewer->Render();
    }
    vtkImageViewer2* viewer;
//
private:
    double startPosition[3];
    double endPosition[3];

};

要點：

1.在從新實現的onLeftButtonDown()函數中，必須調用 vtkInteractorStyleRubberBand2D::OnLeftButtonDown(); 不然沒法交互；onLeftButtonUp()函數同理；

2.經過 this->GetInteractor()->GetEventPosition()獲得的是屏幕座標，必須先將其轉換成世界座標，不然矩形位置並不正確；

3.viewer->SetupInteractor(iren)必須置於iren->SetInteractorStyle(style)以前，否者viewer還使用原來的InteractorStyle。