怎样用qt和c++将已知坐标的三维点连成曲线并且拉伸成曲面

要将已知坐标的三维点连接成曲线并将其拉伸为曲面，您可以使用 Qt 和 VTK 库。以下是一个简单的代码示例，它演示了如何使用 VTK 创建曲线并将其拉伸为曲面：

#include <vtkSmartPointer.h>
#include <vtkPoints.h>
#include <vtkCellArray.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkParametricSpline.h>
#include <vtkParametricFunctionSource.h>
#include <vtkParametricSurfaceSource.h>

int main(int, char *[])
{
    // Create some points
    vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();
    points->InsertNextPoint(0,0,0);
    points->InsertNextPoint(1,0,0);
    points->InsertNextPoint(2,1,0);
    points->InsertNextPoint(3,2,1);
    points->InsertNextPoint(4,3,2);

    // Create a spline
    vtkSmartPointer<vtkParametricSpline> spline =
        vtkSmartPointer<vtkParametricSpline>::New();
    spline->SetPoints(points);

    // Create a curve
    vtkSmartPointer<vtkParametricFunctionSource> curveSource =
        vtkSmartPointer<vtkParametricFunctionSource>::New();
    curveSource->SetParametricFunction(spline);
    curveSource->Update();

    // Create a surface
    vtkSmartPointer<vtkParametricSurfaceSource> surfaceSource =
        vtkSmartPointer<vtkParametricSurfaceSource>::New();
    surfaceSource->SetParametricFunction(spline);
    surfaceSource->SetUResolution(30);
    surfaceSource->SetVResolution(30);
    surfaceSource->Update();

    // Visualize
    vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
    mapper->SetInputData(curveSource->GetOutput());

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

    vtkSmartPointer<vtkPolyDataMapper> surfaceMapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
    surfaceMapper->SetInputData(surfaceSource->GetOutput());

    vtkSmartPointer<vtkActor> surfaceActor =
        vtkSmartPointer<vtkActor>::New();
    surfaceActor->SetMapper(surfaceMapper);

    vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
    renderer->AddActor(actor);
    renderer->AddActor(surfaceActor);

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

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

    renderWindow->Render();
    renderWindowInteractor->Start();

    return EXIT_SUCCESS;
}

以上代码使用了 `vtkParametricSpline` 类来创建一个样条曲线，然后使用 `vtkParametricFunctionSource` 类将曲线转换为 `vtkPolyData` 对象。接下来，使用 `vtkParametricSurfaceSource` 类将曲线拉伸为曲面。最后，使用 `vtkPolyDataMapper` 类和 `vtkActor` 类将曲线和曲面添加到 `vtkRenderer` 类中，并使用 `vtkRenderWindow` 类将其显示在屏幕上。

您可以根据需要修改代码以适应您的应用程序。