如何用C++，QT结合vtk绘制二维的矢量箭头

以下是一个使用C++和QT结合vtk绘制二维矢量箭头的例子：

#include <vtkSmartPointer.h>
#include <vtkVectorText.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkArrowSource.h>
#include <vtkGlyph3D.h>
#include <vtkPolyData.h>
#include <vtkIntArray.h>
#include <vtkCellArray.h>
#include <vtkPoints.h>

#include <QApplication>
#include <QWidget>
#include <QVBoxLayout>
#include <QPushButton>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QWidget widget;
    QVBoxLayout *layout = new QVBoxLayout(&widget);
    QPushButton *button = new QPushButton("Draw", &widget);
    layout->addWidget(button);

    vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
    vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
    renderWindow->AddRenderer(renderer);

    widget.resize(400, 400);
    widget.show();

    vtkSmartPointer<vtkArrowSource> arrowSource = vtkSmartPointer<vtkArrowSource>::New();
    arrowSource->SetTipLength(0.3);
    arrowSource->SetTipRadius(0.1);
    arrowSource->SetShaftRadius(0.03);

    vtkSmartPointer<vtkGlyph3D> glyph3D = vtkSmartPointer<vtkGlyph3D>::New();
    glyph3D->SetInputData(arrowSource->GetOutput());

    vtkSmartPointer<vtkPolyData> polyData = vtkSmartPointer<vtkPolyData>::New();
    vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
    vtkSmartPointer<vtkIntArray> vectors = vtkSmartPointer<vtkIntArray>::New();
    vectors->SetNumberOfComponents(3);

    // 添加矢量和点
    for (int i = 0; i < 5; ++i) {
        for (int j = 0; j < 5; ++j) {
            double x = i * 0.2;
            double y = j * 0.2;
            double z = 0.0;
            points->InsertNextPoint(x, y, z);
            int v[3] = {i, j, 0};
            vectors->InsertNextTupleValue(v);
        }
    }

    polyData->SetPoints(points);
    polyData->GetPointData()->SetVectors(vectors);

    glyph3D->SetSourceConnection(arrowSource->GetOutputPort());
    glyph3D->SetInputData(polyData);
    glyph3D->Update();

    vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
    mapper->SetInputConnection(glyph3D->GetOutputPort());

    vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
    actor->SetMapper(mapper);

    // 添加actor到renderer中
    renderer->AddActor(actor);

    vtkSmartPointer<vtkRenderWindowInteractor> interactor = vtkSmartPointer<vtkRenderWindowInteractor>::New();
    interactor->SetRenderWindow(renderWindow);

    button->connect(button, &QPushButton::clicked, [&](){
        renderer->ResetCamera();
        renderWindow->Render();
    });

    interactor->Initialize();
    app.exec();
    return 0;
}

这个程序首先创建了一个QT窗口，并在窗口中添加了一个按钮。当点击按钮时，程序会显示矢量箭头。

程序使用vtkArrowSource创建了一个箭头，然后使用vtkGlyph3D将箭头放置在二维平面上的多个点上。这些点由vtkPoints对象存储，并使用vtkPolyData对象将它们组合在一起。这些点的矢量由vtkIntArray对象存储，并使用vtkPolyData的SetPointData()函数将它们附加到vtkPolyData对象上。

最后，程序使用vtkPolyDataMapper和vtkActor将箭头可视化，然后将actor添加到vtkRenderer中。当点击按钮时，程序会重置渲染器的相机并更新窗口。