Python vtk学习(1)

Vtk，（visualization toolkit）是一个开源的免费软件系统，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。以下介绍VTK对于STL图像的基本操作

基础概念

数据源 resource: cone = vtk.vtkConeSource()
映射器 mapper：coneMapper = vtk.vtkPolyDataMapper()
映射器添加数据源： coneMapper.SetInput( cone.GetOutput() )
演员 actor: coneActor = vtk.vtkActor()
演员添加映射器：coneActor.SetMapper( coneMapper )
绘制器 renderer: vtk.vtkRenderer()
绘制器添加演员：renderer.AddActor( coneActor )
绘制窗口 win：vtk.vtkRenderWindow()
绘制窗口添加绘制器：renWin.AddRenderer( renderer )
窗口读取绘制器生成的图形： renWin.Render()

极简示例

import vtk

# 箭头源
arrow_source = vtk.vtkArrowSource()
# 映射器
mapper = vtk.vtkPolyDataMapper()
# 映射器添加数据源
mapper.SetInputConnection(arrow_source.GetOutputPort())
# 演员
actor = vtk.vtkActor()
# 演员添加映射器
actor.SetMapper(mapper)
# 绘制器
ren = vtk.vtkRenderer()
# 绘制器添加演员
ren.AddActor(actor)
# 绘制窗口
renWin = vtk.vtkRenderWindow()
# 绘制窗口添加绘制器
renWin.AddRenderer(ren)
# 创建窗口交互器
iren = vtk.vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)
iren.Initialize()
# 窗口读取绘制器生成的图形
renWin.Render()
iren.Start()

结果

读取文件

文件类型	读取方法
STL	vtkSTLReader()
SLC	vtkSLCReader()
VTP	vtkXMLPolyDataReader()
UnstructuredGrid	vtkNamedColors()
ExodusData	vtkExodusIIReader()

示例

def read_data(file_name):
    reader = vtk.vtkSTLReader()
    reader.SetFileName(file_name)
    return reader

图像旋转

绕()轴旋转	方法
X	actor.RotateX(angle)
Y	actor.RotateY(angle)
Z	actor.RotateZ(angle)

整体旋转
transform.RotateWXYZ(angle, x, y, z)
x,y,z旋转(0,1)表示是否旋转

import vtk


arrow_source = vtk.vtkArrowSource()
mapper = vtk.vtkPolyDataMapper()

transform = vtk.vtkTransform()
transform.RotateWXYZ(90, 0, 0, 1)
transformFilter = vtk.vtkTransformPolyDataFilter()
transformFilter.SetTransform(transform)
transformFilter.SetInputConnection(arrow_source.GetOutputPort())
transformFilter.Update()
mapper.SetInputConnection(transformFilter.GetOutputPort())

actor = vtk.vtkActor()
actor.SetMapper(mapper)
ren = vtk.vtkRenderer()
ren.AddActor(actor)
renWin = vtk.vtkRenderWindow()
renWin.AddRenderer(ren)
renWin.Render()
iren = vtk.vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)
iren.Initialize()
renWin.Render()
iren.Start()

结果

设置演员初始方向

def set_origin(actor, x, y, z):
    actor.SetOrientation(x, y, z)

缩放

def set_scale(x, y, z):
    actor.SetScale(x, y, z)

平移

def add_position(x, y, z):
    actor.AddPosition(x, y, z)

平面切割

def cut(file_name):
    reader = read_data(file_name)

    # 定义切割平面
    clipPlane = vtk.vtkPlane()
    clipPlane.SetNormal(1.0, -1.0, -1.0)
    clipPlane.SetOrigin(0.0, 0.0, 0.0)

    # 平面切割三维数据
    clipper = vtk.vtkClipPolyData()
    clipper.SetInputConnection(reader.GetOutputPort())
    clipper.SetClipFunction(clipPlane)
    clipper.InsideOutOn()  # ?

    # 定义mapper和actor
    superMapper = vtk.vtkPolyDataMapper()
    superMapper.SetInputConnection(clipper.GetOutputPort())
    superActor = vtk.vtkActor()
    # 设置偏转角度
    set_origin(superActor, -50, -75, 120)
    superActor.SetMapper(superMapper)
    superActor.GetProperty().SetColor(colors.GetColor3d("Cyan"))
    only_show(superActor)

原始图片

平面切割后图片

鼠标事件监听

# 监听事件
class MyEvent(vtk.vtkInteractorStyleTrackballCamera):

    def __init__(self, parent=None):
        self.AddObserver("MiddleButtonPressEvent", self.middle_button_press_event)
        self.AddObserver("MiddleButtonReleaseEvent", self.middle_button_release_event)
        self.AddObserver("LeftButtonPressEvent", self.left_button_press_event)
        self.AddObserver("LeftButtonReleaseEvent", self.left_button_release_event)
        self.AddObserver("RightButtonPressEvent", self.right_button_press_event)
        self.AddObserver("RightButtonReleaseEvent", self.right_button_release_event)

    def middle_button_press_event(self, obj, event):
        print("Middle Button pressed")
        self.OnMiddleButtonDown()
        return

    def middle_button_release_event(self, obj, event):
        print("Middle Button released")
        self.OnMiddleButtonUp()
        return

    def left_button_press_event(self, obj, event):
        print("Left Button pressed")
        self.OnLeftButtonDown()
        return

    def left_button_release_event(self, obj, event):
        print("Left Button released")
        self.OnLeftButtonUp()
        return

    def right_button_press_event(self, obj, event):
        print("right Button pressed")
        self.OnRightButtonDown()
        return

    def right_button_release_event(self, obj, event):
        print("right Button released")
        self.OnLeftButtonUp()
        return

# 引入上一段代码调用
iren.SetInteractorStyle(MyEvent())

结果

参考文档

Python VTK Example
计算机图形学-vtk-python学习笔记(初级篇)
VTK笔记——模型的空间变换(Transform).平移、旋转和缩放