如何使用Python VTK高亮显示actor-编程学习网

前言：

VTK，（visualizationtoolkit）是一个开放资源的免费软件系统，主要用于三维计算机图形学、图像处理和可视化。Vtk是在面向对象原理的基础上设计和实现的，它的内核是用C++构建的，包含有大约250,000行代码，2000多个类，还包含有几个转换界面，因此也可以自由的通过Java，Tcl/Tk和Python各种语言使用vtk。

主要函数介绍：

NewPickedActor.GetProperty()： 通过该函数，可以设置actor的性质，如颜色、表面样式等。

vtk.vtkSphereSource()： 创建球体的函数，文中通过一个for循环创建了10个球体。

vtk.vtkMinimalStandardRandomSequence()： VTK的随机数生成器，用于代码中的十个球体，随机生成球体的大小和位置。

MouseInteractorHighLightActor： 定义actor操作方法，这个是一个鼠标操作控件的控制方法。

leftButtonPressEvent(self, obj, event)： 这是一个事件触发函数，当鼠标左键点击对应的actor时，会触发函数，对点的actor高亮显示。

主要代码如下：

#!/usr/bin/env python

# noinspection PyUnresolvedReferences
import vtk

colors = vtk.vtkNamedColors()
NUMBER_OF_SPHERES = 10


class MouseInteractorHighLightActor(vtk.vtkInteractorStyleTrackballCamera):

    def __init__(self, parent=None):
        self.AddObserver("LeftButtonPressEvent", self.leftButtonPressEvent)

        self.LastPickedActor = None
        self.LastPickedProperty = vtk.vtkProperty()

    def leftButtonPressEvent(self, obj, event):
        clickPos = self.GetInteractor().GetEventPosition()

        picker = vtk.vtkPropPicker()
        picker.Pick(clickPos[0], clickPos[1], 0, self.GetDefaultRenderer())

        # 创建一个新的actor
        self.NewPickedActor = picker.GetActor()

        # If something was selected
        if self.NewPickedActor:
            # If we picked something before, reset its property
            if self.LastPickedActor:
                self.LastPickedActor.GetProperty().DeepCopy(self.LastPickedProperty)

            # Save the property of the picked actor so that we can
            # restore it next time
            self.LastPickedProperty.DeepCopy(self.NewPickedActor.GetProperty())
            # 高亮选中球体，并显示边缘
            self.NewPickedActor.GetProperty().SetColor(colors.GetColor3d('Red'))
            self.NewPickedActor.GetProperty().SetDiffuse(1.0)
            self.NewPickedActor.GetProperty().SetSpecular(0.0)
            self.NewPickedActor.GetProperty().EdgeVisibilityOn()

            # 保存最后一个选中的actor
            self.LastPickedActor = self.NewPickedActor

        self.OnLeftButtonDown()
        return


def main():
    # 创建render和window
    renderer = vtk.vtkRenderer()
    renderer.SetBackground(colors.GetColor3d('SteelBlue'))

    renwin = vtk.vtkRenderWindow()
    renwin.AddRenderer(renderer)
    renwin.SetSize(640, 480)
    renwin.SetWindowName('HighlightPickedActor')

    # 建立interactor(交互操作)
    interactor = vtk.vtkRenderWindowInteractor()
    interactor.SetRenderWindow(renwin)

    # 交互操作方法
    style = MouseInteractorHighLightActor()
    style.SetDefaultRenderer(renderer)
    interactor.SetInteractorStyle(style)

    randomSequence = vtk.vtkMinimalStandardRandomSequence()
    # randomSequence.SetSeed(1043618065)
    # randomSequence.SetSeed(5170)
    randomSequence.SetSeed(8775070)
    # 添加球体
    for i in range(NUMBER_OF_SPHERES):
        source = vtk.vtkSphereSource()

        # random position and radius
        x = randomSequence.GetRangeValue(-5.0, 5.0)
        randomSequence.Next()
        y = randomSequence.GetRangeValue(-5.0, 5.0)
        randomSequence.Next()
        z = randomSequence.GetRangeValue(-5.0, 5.0)
        randomSequence.Next()
        radius = randomSequence.GetRangeValue(0.5, 1.0)
        randomSequence.Next()

        source.SetRadius(radius)
        source.SetCenter(x, y, z)
        source.SetPhiResolution(11)
        source.SetThetaResolution(21)

        mapper = vtk.vtkPolyDataMapper()
        mapper.SetInputConnection(source.GetOutputPort())
        actor = vtk.vtkActor()
        actor.SetMapper(mapper)

        r = randomSequence.GetRangeValue(0.4, 1.0)
        randomSequence.Next()
        g = randomSequence.GetRangeValue(0.4, 1.0)
        randomSequence.Next()
        b = randomSequence.GetRangeValue(0.4, 1.0)
        randomSequence.Next()

        actor.GetProperty().SetDiffuseColor(r, g, b)
        actor.GetProperty().SetDiffuse(.8)
        actor.GetProperty().SetSpecular(.5)
        actor.GetProperty().SetSpecularColor(colors.GetColor3d('White'))
        actor.GetProperty().SetSpecularPower(30.0)

        renderer.AddActor(actor)

    # 运行
    interactor.Initialize()
    renwin.Render()
    interactor.Start()


if __name__ == '__main__':
    main()

显示结果如下：未选择球体：