在vtk 中有时我们需要监听 键盘或鼠标做一些事；

1. 创建 Actor；

Sphere = vtk.vtkSphereSource()
Sphere.SetRadius(10)

mapper = vtk.vtkPolyDataMapper()
mapper.SetInputConnection(Sphere.GetOutputPort())
actor = vtk.vtkActor()
actor.SetMapper(mapper)
actor.GetProperty().SetColor(0.0, 1.0, 0.0)

2.创建 vtkRenderer vtkRenderWindow  vtkRenderWindowInteractor

ren = vtk.vtkRenderer()
renWin = vtk.vtkRenderWindow()
renWin.AddRenderer(ren)
iren = vtk.vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)

3.重写交互器 Style

class KeyPressInteractorStyle(vtk.vtkInteractorStyleTrackballCamera):

    def __init__(self, parent=None):
        self.parent = vtk.vtkRenderWindowInteractor()
        if (parent is not None):
            self.parent = parent

        self.AddObserver("KeyReleaseEvent", self.keyRelease)

    def keyRelease(self, obj, event):
        key = self.parent.GetKeySym()
        if key == 'Up':
           pt =  actor.GetPosition()
           actor.SetPosition(pt[0],pt[1]+5,pt[2])
        elif key == 'Down':
           pt =  actor.GetPosition()
           actor.SetPosition(pt[0],pt[1]-5,pt[2])
        if key == 'Left':
           pt =  actor.GetPosition()
           actor.SetPosition(pt[0]-5,pt[1],pt[2])
        elif key == 'Right':
           pt =  actor.GetPosition()
           actor.SetPosition(pt[0]+5,pt[1],pt[2])

        elif key== 'c':
            # 产生随机颜色
            r = vtk.vtkMath.Random()
            g = vtk.vtkMath.Random()
            b = vtk.vtkMath.Random()
            actor.GetProperty().SetColor(r, g, b)
        renWin.Render()

 4.添加交互器：

iren.SetInteractorStyle(KeyPressInteractorStyle(parent=iren))

ren.AddActor(actor)