vtk中如何保存当前视角并读取当前视角，用vb语言实现

在 VTK 中，可以使用 `vtkCamera` 类来保存和读取当前视角。以下是使用 VB 语言实现的示例代码：

保存当前视角：

Dim renderer As vtkRenderer = vtkRenderer.New()
Dim camera As vtkCamera = renderer.GetActiveCamera()

' 获取当前视角参数
Dim position As Double() = camera.GetPosition()
Dim focalPoint As Double() = camera.GetFocalPoint()
Dim viewUp As Double() = camera.GetViewUp()

' 创建一个文本文件用于保存视角参数
Dim fileWriter As StreamWriter = File.CreateText("camera_position.txt")

' 将视角参数写入文件
fileWriter.WriteLine(position(0) & " " & position(1) & " " & position(2))
fileWriter.WriteLine(focalPoint(0) & " " & focalPoint(1) & " " & focalPoint(2))
fileWriter.WriteLine(viewUp(0) & " " & viewUp(1) & " " & viewUp(2))

fileWriter.Close()
renderer.Dispose()
camera.Dispose()

读取当前视角：

Dim renderer As vtkRenderer = vtkRenderer.New()
Dim camera As vtkCamera = renderer.GetActiveCamera()

' 读取保存的视角参数
Dim fileReader As StreamReader = File.OpenText("camera_position.txt")

Dim position As New Double() {0, 0, 0}
Dim focalPoint As New Double() {0, 0, 0}
Dim viewUp As New Double() {0, 0, 0}

' 解析文件中的视角参数
Dim line As String = fileReader.ReadLine()
Dim values As String() = line.Split(" ")
position(0) = Convert.ToDouble(values(0))
position(1) = Convert.ToDouble(values(1))
position(2) = Convert.ToDouble(values(2))

line = fileReader.ReadLine()
values = line.Split(" ")
focalPoint(0) = Convert.ToDouble(values(0))
focalPoint(1) = Convert.ToDouble(values(1))
focalPoint(2) = Convert.ToDouble(values(2))

line = fileReader.ReadLine()
values = line.Split(" ")
viewUp(0) = Convert.ToDouble(values(0))
viewUp(1) = Convert.ToDouble(values(1))
viewUp(2) = Convert.ToDouble(values(2))

fileReader.Close()

' 设置读取到的视角参数
camera.SetPosition(position)
camera.SetFocalPoint(focalPoint)
camera.SetViewUp(viewUp)

renderer.ResetCamera()
renderer.Dispose()
camera.Dispose()

在保存当前视角时，将当前视角的位置、焦点和视线向上方向写入一个文本文件。然后在读取当前视角时，从文件中读取这些参数，并将它们应用于相机对象。注意，在读取视角参数后，还需要调用 `renderer.ResetCamera()` 方法来更新渲染器的相机设置。