VTK可交互三维坐标轴

因为实习工作需要制作一个如下图所示的可交互的三维坐标轴，制作这个坐标轴，首先需要创建一些三维图形，接着需要熟悉交互模块和鼠标进行交互，最后将它们封装成一个vtkWidget类

VTK中一些基础类介绍

下面是VTK中经常会使用到的类的描述。

vtkProp

渲染场景中数据的可视表达（Visible Depictions）是由vtkProp的子类负责。三维空间中渲染对象最常用的vtkProp子类是vtkActor和vtkVolume，其中vtkActor用于表示场景中的几何数据（Geometry Data），vtkVolume表示场景中的体数据（Volumetric Data）。vtkActor2D常用来表示二维空间中的数据。vtkProp的子类负责确定场景中对象的位置、大小和方向信息。控制Prop位置信息的参数依赖于对象是否在渲染场景中，比如一个三维物体或者二维注释，它们的位置信息控制方式是有所区别的。三维的Prop如vtkActor和vtkVolume（vtkActor和vtkVolume都是vtkProp3D的子类，而vtkProp3D继承自vtkProp）,既可以直接控制对象的位置、方向和放缩信息，也可以通过一个4×4的变换矩阵来实现。而对于二维注释功能的Props如vtkScalarBarActor，其大小和位置有许多的定义方式，其中包括指定相对于视口的位置、宽度和高度。Prop除了提供对象的位置信息控制之外，Prop内部通常还有两个对象，一个是Mapper对象，负责存放数据和渲染信息，另一个是Property（属性）对象，负责控制颜色、不透明度等参数。

VTK中定义了大量的功能细化的Prop（超过50个），如vtkImageActor（负责图像显示）和vtkPieChartActor（用于创建数组数据的饼图可视表示）。其中的有些Props内部直接包括了控制显示的参数和待渲染数据的索引，因此并不需要额外的Property和Mapper对象。vtkActor的子类vtkFollower可以自动的更新方向信息保持自身始终面向一个特定的相机，这样无论如何旋转渲染场景中的对象，vtkFellower对象都是可见的，适用于三维场景中的广告板（Billboards）或者是文本。vtkActor的子类vtkLodActor可以自动改变自身的几何表示来实现所要求的交互帧率，vtkProp3D的子类vtkLODProp3D则是通过从许多Mapper中进行选择来实现不同的交互性（可以是Volumetric Mapper和GeometricMapper的集合）。vtkAssembly建立了Actor的等级结构以便在整个结构平移、旋转或者放缩时能够更合理的控制变换。

vtkAbstractMapper

许多Props如vtkActor和vtkVolume利用vtkAbstractMapper的子类来保存输入数据的引用以及提供真正的渲染功能。vtkPolyDataMapper是渲染多边形几何数据主要的Mapper类。而对于体数据，VTK提供了多种渲染技术。例如，vtkFixedPointVolumeRayCastMapper用来渲染vtkImageData类型的数据，vtkProjectedTetrahedraMapper则是用来渲染vtkUnstructuredGrid类型的数据。

vtkProperty和vtkVolumeProperty

某些Props采用单独的属性对象来存储控制数据外观显示的参数，这样不同的对象可以轻松的实现外观参数的共享。vtkActor利用vtkProperty对象存储外观（属性）参数，如颜色、不透明度、材质的环境光（Ambient）系数、散射光（Diffuse）系数和反射光（Specular）系数等。而vtkVolume则是采用vtkVolumeProperty对象来获取体对象的绘制参数，如将标量值映射为颜色和不透明度的传输函数（Transfer Function）【译者：也有译成“传递函数”】。另外，一些vtkMapper提供相应的函数设置裁剪面以便显示对象的内部结构。

vtkCamera

vtkCamera存储了场景中的摄像机参数，换言之，如何来“看”渲染场景里的对象，主要参数是摄像机的位置、焦点、和场景中的上方向向量。其他参数可以控制视图变换，如平行投影或者透视投影，图像的尺度或者视角，以及视景体的远近裁剪平面等。

vtkRenderer

组成场景的对象包括Prop，Camara和Light都被集中在一个vtkRenderer对象中。vtkRenderer负责管理场景的渲染过程。一个vtkRenderWindow中可以有多个vtkRenderer对象，而这些vtkRenderer可以渲染在窗口中不同的矩形区域中（视口），甚至可以是覆盖的区域。

vtkRendererWindow

vtkRendererWindow将操作系统与VTK渲染引擎连接到一起。不同平台下的vtkRendererWindow子类负责本地计算机系统中窗口创建和渲染过程的管理。当使用VTK开发应用程序时，只需要使用平台无关的vtkRendererWindow类，程序运行时，系统会自动替换为平台相关的vtkRendererWindow子类。vtkRendererWindow中包含了vtkRenderer的集合，以及控制渲染的参数，如立体显示（Stereo）、反走样、运动模糊（Motion Blur）和焦点深度（FocalDepth）

vtkRenderWindowInteractor

vtkRenderWindowInteractor负责监听鼠标、键盘和时钟消息，并通过VTK中的Command/Observer设计模式进行相应的处理。vtkInteractorStyle监听这些消息并进行处理以完成旋转、拉伸和放缩等运动控制。vtkRenderWindowInteractor自动建立一个默认的3D场景交互器样式（InteractorStyle），当然你也可以选择一个二维图像浏览的交互器样式，或者是创建自定义的交互器样式。

vtkTransform

场景中的许多对象，如Prop、光源Light、照相机Camera等都需要在场景中合理的放置，它们通过vtkTransform参数可以方便的控制对象的位置和方向。vtkTransform能够描述三维空间中的线性坐标变换，其内部表示为一个4×4的齐次变换矩阵。vtkTransform对象初始化为一个单位矩阵，你可以通过管线连接的方式将变换进行组合来完成复杂的变换。管线方式能够确保当其中任一个变换被修改时，其后续的变换都会相应的进行更新

更多基础类的内容可以参考

VTK图像图像开发进阶第二章的内容

第03章-VTK系统概述（1）_DolingStudio的博客-CSDN博客

VTKUsersGuide 第三章的内容

可视化管线

第03章-VTK系统概述（2）_DolingStudio的博客-CSDN博客

使用预定义的Source对象创建三维图形的数据(或通过Reader对象从文件中读取数据)，一个或多个数据对象传入Filter后，经过处理产生新的数据对象，使用Mapper接收数据，并将其装换为可被渲染引擎绘制的可视化表达，再将Mapper绑定到Actor对象上。

一个例子

#include "vtkSmartPointer.h"
#include "vtkSphereSource.h"
#include "vtkPolyDataMapper.h"
#include "vtkActor.h"
#include "vtkRenderer.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"#include "vtkAutoInit.h"
VTK_MODULE_INIT(vtkRenderingOpenGL2);
VTK_MODULE_INIT(vtkInteractionStyle);
VTK_MODULE_INIT(vtkRenderingFreeType);
VTK_MODULE_INIT(vtkRenderingVolumeOpenGL2);int main()
{// 实例化一个球体的数据源对象vtkSmartPointer<vtkSphereSource> sphereSource = vtkSmartPointer<vtkSphereSource>::New();// 实例化一个MappervtkSmartPointer<vtkPolyDataMapper> sphereMapper = vtkSmartPointer<vtkPolyDataMapper>::New();// 实例化一个ActorvtkSmartPointer<vtkActor> sphereActor = vtkSmartPointer<vtkActor>::New();sphereSource->SetRadius(0.2); // 设置球体的Source图像源半径sphereMapper->SetInputConnection(sphereSource->GetOutputPort());  // 关联Source的输出与Mapper的输入口sphereActor->SetMapper(sphereMapper);   // 将Mapper绑定到Actor上// 实例化一个Renderer对象vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();// 实例化一个窗口对象vtkSmartPointer<vtkRenderWindow> renWin = vtkSmartPointer<vtkRenderWindow>::New();// 实例化一个窗口的交互器对象vtkSmartPointer<vtkRenderWindowInteractor> iren = vtkSmartPointer<vtkRenderWindowInteractor>::New();renderer->AddActor(sphereActor);   // 一个Renderer包含多个ActorrenWin->AddRenderer(renderer); // 一个RenderWindow包含多个Renderer，可以为不同Renderer设置视口iren->SetRenderWindow(renWin);     // 关联窗口和交互器renWin->Render();             // RenderWindow 开始渲染iren->Initialize();          // vtkRenderWindowInteractor 初始化事件监听iren->Start();           // vtkRenderWindowInteractor开启事件监听循环return 0;
}

创建坐标轴三维图形

创建XYZ坐标轴

本文封装了一个Arrow类通过指定起点和终点来创建一个箭头，并可以设置箭头上椎体的数量，设置颜色，线宽参数

#include "vtkSmartPointer.h"
#include "vtkActor.h"
#include "vtkLineSource.h"
#include "vtkConeSource.h"namespace myvtk {class Arrow{public:Arrow() :m_line(nullptr), m_cone1(nullptr), m_cone2(nullptr) {}Arrow(double origin[3], double target[3], int coneCount = 1, double color[3] = nullptr, float lineWidth = AXISWIDTH) { CreateArrow(origin, target, coneCount, color, lineWidth); }/*函数名： CreateArrow* @param origin[3]  起点坐标* @param target[3]  终点坐标* @param coneCount  椎体数量* @param color      颜色* @param lineWidth  线宽*/void CreateArrow(double origin[3], double target[3], int coneCount = 1, double color[3] = nullptr, float lineWidth = AXISWIDTH){{// 直线部分m_lineSource = vtkSmartPointer<vtkLineSource>::New();vtkNew<vtkPolyDataMapper> lineMapper;m_line = vtkSmartPointer<vtkActor>::New();lineMapper->SetInputConnection(m_lineSource->GetOutputPort());m_line->SetMapper(lineMapper);m_lineSource->SetPoint1(origin);m_lineSource->SetPoint2(target);m_line->GetProperty()->SetLineWidth(lineWidth);if (color != nullptr) m_line->GetProperty()->SetColor(color);// 箭头部分double directVec[3] = { 0 };vtkMath::Subtract(target, origin, directVec);// 箭头1m_coneCount = coneCount;if (coneCount >= 1){m_coneSource1 = vtkSmartPointer<vtkConeSource>::New();vtkNew<vtkPolyDataMapper> coneMapper1;m_cone1 = vtkSmartPointer<vtkActor>::New();m_coneSource1->SetCenter(target);m_coneSource1->SetHeight(0.5);m_coneSource1->SetRadius(0.08);m_coneSource1->SetResolution(10);m_coneSource1->SetDirection(directVec);coneMapper1->SetInputConnection(m_coneSource1->GetOutputPort());m_cone1->SetMapper(coneMapper1);if (color != nullptr) m_cone1->GetProperty()->SetColor(color);}// 箭头2if (coneCount >= 2){m_coneSource2 = vtkSmartPointer<vtkConeSource>::New();vtkNew<vtkPolyDataMapper> coneMapper2;m_cone2 = vtkSmartPointer<vtkActor>::New();vtkMath::Subtract(origin, target, directVec);m_coneSource2->SetCenter(origin);m_coneSource2->SetHeight(0.5);m_coneSource2->SetRadius(0.08);m_coneSource2->SetResolution(10);m_coneSource2->SetDirection(directVec);coneMapper2->SetInputConnection(m_coneSource2->GetOutputPort());m_cone2->SetMapper(coneMapper2);if (color != nullptr) m_cone2->GetProperty()->SetColor(color);}}}int m_coneCount = 0;vtkSmartPointer<vtkActor> m_line = nullptr;vtkSmartPointer<vtkActor> m_cone1 = nullptr;vtkSmartPointer<vtkActor> m_cone2 = nullptr;vtkSmartPointer<vtkLineSource> m_lineSource = nullptr;vtkSmartPointer<vtkConeSource> m_coneSource1 = nullptr;vtkSmartPointer<vtkConeSource> m_coneSource2 = nullptr;};
}

创建弯曲箭头

本文封装了一个CurveArrow类通过指定弯曲箭头需要经过的一系列的点来绘制曲线，并可以设置箭头上椎体的数量，设置颜色，线宽参数

其中绘制曲线涉及到了 vtkParametricSpline 及 vtkParametricFunctionSource 类

#include "vtkSmartPointer.h"
#include "vtkPoints.h"
#include "vtkParametricFunctionSource.h"
#include "vtkParametricSpline.h"
#include "vtkPolyDataMapper.h"
#include "vtkActor.h"
#include "vtkProperty.h"
#include "vtkConeSource.h"#define AXISWIDTH 3namespace myvtk {class CurveArrow{public:CurveArrow() :m_curve(nullptr), m_cone1(nullptr), m_cone2(nullptr) {}CurveArrow(vtkSmartPointer<vtkPoints> points, int coneCount = 1, double color[3] = nullptr, float lineWidth = AXISWIDTH) { CreateArrow(points, coneCount, color, lineWidth); }/*函数名： CreateArrow* @param points     曲线经过的一组点* @param coneCount  椎体数量* @param color      颜色* @param lineWidth  线宽*/void CreateArrow(vtkSmartPointer<vtkPoints> points, int coneCount = 1, double color[3] = nullptr, float lineWidth = AXISWIDTH){if (points->GetNumberOfPoints() < 2) throw "input points must have at least two points!";// 曲线部分m_curve = vtkSmartPointer<vtkActor>::New();m_spline = vtkSmartPointer<vtkParametricSpline>::New();m_functionSource = vtkSmartPointer<vtkParametricFunctionSource>::New();m_spline->SetPoints(points);m_functionSource->SetParametricFunction(m_spline);m_functionSource->Update();vtkNew<vtkPolyDataMapper> lineMapper;lineMapper->SetInputConnection(m_functionSource->GetOutputPort());m_curve->SetMapper(lineMapper);m_curve->GetProperty()->SetLineWidth(lineWidth);if (color != nullptr) m_curve->GetProperty()->SetColor(color);// 箭头部分double directVec[3] = { 0 };int pointsNum = points->GetNumberOfPoints();//double* target = points->GetPoint(pointsNum - 1);double target[3]{ 0 }, origin[3]{ 0 };points->GetPoint(pointsNum - 1, target);points->GetPoint(pointsNum - 2, origin);//double* origin = points->GetPoint(pointsNum - 2);vtkMath::Subtract(target, origin, directVec);// 箭头1m_coneCount = coneCount;if (coneCount >= 1){m_coneSource1 = vtkSmartPointer<vtkConeSource>::New();vtkNew<vtkPolyDataMapper> coneMapper1;m_cone1 = vtkSmartPointer<vtkActor>::New();m_coneSource1->SetCenter(target);m_coneSource1->SetHeight(0.5);m_coneSource1->SetRadius(0.08);m_coneSource1->SetResolution(10);m_coneSource1->SetDirection(directVec);coneMapper1->SetInputConnection(m_coneSource1->GetOutputPort());m_cone1->SetMapper(coneMapper1);if (color != nullptr) m_cone1->GetProperty()->SetColor(color);}// 箭头2if (coneCount >= 2){points->GetPoint(0, target);points->GetPoint(0, origin);m_coneSource2 = vtkSmartPointer<vtkConeSource>::New();vtkNew<vtkPolyDataMapper> coneMapper2;m_cone2 = vtkSmartPointer<vtkActor>::New();vtkMath::Subtract(target, origin, directVec);m_coneSource2->SetCenter(origin);m_coneSource2->SetHeight(0.5);m_coneSource2->SetRadius(0.08);m_coneSource2->SetResolution(10);m_coneSource2->SetDirection(directVec);coneMapper2->SetInputConnection(m_coneSource2->GetOutputPort());m_cone2->SetMapper(coneMapper2);if (color != nullptr) m_cone2->GetProperty()->SetColor(color);}}int m_coneCount = 0;vtkSmartPointer<vtkActor> m_curve = nullptr;vtkSmartPointer<vtkActor> m_cone1 = nullptr;vtkSmartPointer<vtkActor> m_cone2 = nullptr;vtkSmartPointer<vtkParametricSpline> m_spline = nullptr;vtkSmartPointer<vtkParametricFunctionSource> m_functionSource = nullptr;vtkSmartPointer<vtkConeSource> m_coneSource1 = nullptr;vtkSmartPointer<vtkConeSource> m_coneSource2 = nullptr;};
};

创建有厚度的平面

VTK笔记-图形相关-平面-vtkPlaneSource_黑山老妖的博客的博客-CSDN博客_vtk平面图

（4）建立一个标准尺寸的平面，并对其进行着色贴图、拉伸一定的厚度_rexinx的博客-CSDN博客

本文封装了一个Plane，首先通过 vtkPlaneSource 数据源获取一个平面的点及拓扑数据，通过设置 origin, point1, point2 设置平面图形的大小

接着使用 vtkLinearExtrusionFilter 通过SetVector()及SetScaleFactor()方法设置平面的厚度

#include "vtkSmartPointer.h"
#include "vtkActor.h"
#include "vtkPlaneSource.h"
#include "vtkLinearExtrusionFilter.h"
#include "vtkTriangleFilter.h"
#include "vtkPolyDataMapper.h"
#include "vtkProperty.h"namespace myvtk {class Plane{public:Plane() :m_plane(nullptr), m_planeSource(nullptr), m_planeLinearExtrusionFilter(nullptr), m_planeTriangleFilter(nullptr) {}Plane(double origin[3], double point1[3], double point2[3], double width, double color[3]) { CreatePlane(origin, point1, point2, width, color); };/*函数名： CreatePlane* @param origin     平面矩形的一个顶点* @param point1     平面矩形的一个与origin相邻的顶点* @param point2     平面矩形的一个与origin相邻的顶点* @param width      平面厚度* @param color      颜色*/void CreatePlane(double origin[3], double point1[3], double point2[3], double width, double color[3]){m_planeSource = vtkSmartPointer<vtkPlaneSource>::New();vtkNew<vtkPolyDataMapper> PlaneMapper;m_plane = vtkSmartPointer<vtkActor>::New();m_planeSource->SetOrigin(origin);m_planeSource->SetPoint1(point1);m_planeSource->SetPoint2(point2);m_planeSource->Update();// Apply linear extrusionm_planeLinearExtrusionFilter = vtkSmartPointer<vtkLinearExtrusionFilter>::New();m_planeLinearExtrusionFilter->SetInputConnection(m_planeSource->GetOutputPort());m_planeLinearExtrusionFilter->SetExtrusionTypeToNormalExtrusion();double vec[3]{ 1,0,0 };m_planeLinearExtrusionFilter->SetVector(vec);m_planeLinearExtrusionFilter->SetScaleFactor(width);m_planeTriangleFilter = vtkSmartPointer<vtkTriangleFilter>::New();m_planeTriangleFilter->SetInputConnection(m_planeLinearExtrusionFilter->GetOutputPort());PlaneMapper->SetInputConnection(m_planeTriangleFilter->GetOutputPort());m_plane->SetMapper(PlaneMapper);m_plane->GetProperty()->SetColor(color);}public:vtkSmartPointer<vtkActor> m_plane;vtkSmartPointer<vtkPlaneSource> m_planeSource;vtkSmartPointer<vtkLinearExtrusionFilter> m_planeLinearExtrusionFilter;vtkSmartPointer<vtkTriangleFilter> m_planeTriangleFilter;};
};

创建始终跟随镜头的坐标轴文本

第04章-VTK基础（5）_DolingStudio的博客-CSDN博客

使用 vtkVectorText 作为数据源，vtkFollower是vtkActor的子类，通过SetCamera()方法设置后，可以始终朝向指定的镜头

auto textsSource = vtkSmartPointer<vtkVectorText>::New();
auto textMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
auto texts = vtkSmartPointer<vtkFollower>::New();textsSource->SetText("x");
textMapper->SetInputConnection(textsSource->GetOutputPort());
texts->SetMapper(textMapper);
texts->SetScale(0.1, 0.1, 0.1);vtkMath::MultiplyScalar(point2, 1.05);
texts->SetPosition(point2);
texts->GetProperty()->SetColor(color);
texts->SetCamera(renderer->GetActiveCamera());

创建中心圆球

// 绘制中心圆球
m_centerSphereSource = vtkSmartPointer<vtkSphereSource>::New();
vtkNew<vtkPolyDataMapper> sphereMapper;
m_centerSphere = vtkSmartPointer<vtkActor>::New();m_centerSphereSource->SetRadius(0.2);
m_centerSphereSource->SetCenter(0, 0, 0);
sphereMapper->SetInputConnection(m_centerSphereSource->GetOutputPort());
m_centerSphere->SetMapper(sphereMapper);m_centerSphere->GetProperty()->SetColor(0.8,0.8,0.8);  // 初始设置较暗的颜色
m_centerSphere->GetProperty()->SetDiffuse(1.0);
m_centerSphere->SetPosition(0, 0, 0);

Picker通过鼠标拾取三维图形

第04章-VTK基础（4）_DolingStudio的博客-CSDN博客

拾取操作是可视化应用程序中常见的一种功能。拾取主要是用于选择数据和Actor或者获取底层的数据值。在显示位置(以像素为坐标值)中拾取时，就会调用vtkAbstractPicker的Pick()方法。

本文中使用的是 vtkPropPicker

初始化Picker

// 初始化 vtkPropPicker
this->m_picker = vtkPropPicker::New();
// 将所有的三维坐标系中的Actor使用 AddPickList() 方法添加到 picker 的列表中
TravelAllActors([this](vtkActor* actor) {this->m_picker->AddPickList(actor);
});
// 限定picker只拾取列表中的Actor
this->m_picker->PickFromListOn();

使用Picker获取鼠标位置的Actor

vtkActor* GetPickedActor(double x, double y) {m_picker->Pick(x, y, 0, this->Renderer);return m_picker->GetActor();
}

其中 x, y 对应的是鼠标在屏幕上的位置，当鼠标触发事件时，可以通过 RenderWindowInteractor的GetEventPosition()方法获取鼠标当前的位置

double X = self->Interactor->GetEventPosition()[0];
double Y = self->Interactor->GetEventPosition()[1];

现在我们已经完成了拾取鼠标位置的Actor操作，但由于三维坐标系由许多的 Actor 组合而成，为了知道我们拾取的Actor是什么，当我们按下鼠标左键开始拾取的时候是点击了X轴，还是Y轴，还是Z轴，或者是点击了平面，又或者是点击了拖动旋转的箭头，我们需要对拾取的Actor在对象组中进行识别。

int GetSelectedState(vtkActor* actor)
{int offset = 0;// X Y Z 轴for (int i = 0; i < m_axesArrow.size(); i++){if ((unsigned long)(m_axesArrow[i]->m_line.GetPointer()) == (unsigned long)actor ||(m_axesArrow[i]->m_cone1 != nullptr && (unsigned long)(m_axesArrow[i]->m_cone1.GetPointer()) == (unsigned long)actor)){return SelAxis(i);}}offset += m_axesArrow.size();// 中心圆球if ((unsigned long)(m_centerSphere.GetPointer()) == (unsigned long)actor){return SelAxis(offset);}offset += 1;// planefor (int i = 0; i < m_planes.size(); i++){if ((unsigned long)(m_planes[i]->m_plane.GetPointer()) == (unsigned long)actor){return SelAxis(i + offset);}}offset += m_planes.size();// rotatefor (int i = 0; i < m_rotateArrow.size(); i++){if ((unsigned long)(m_rotateArrow[i]->m_curve.GetPointer()) == (unsigned long)actor ||(m_rotateArrow[i]->m_cone1 != nullptr && (unsigned long)(m_rotateArrow[i]->m_cone1.GetPointer()) == (unsigned long)actor) ||(m_rotateArrow[i]->m_cone2 != nullptr && (unsigned long)(m_rotateArrow[i]->m_cone2.GetPointer()) == (unsigned long)actor)){return SelAxis(i + offset);}}return noAxis;
}

依次将拾取的 Actor 地址与X Y Z 轴、中心圆球、平面、旋转箭头对象组中各个成员进行比较，确定当前选中了哪个对象组，使用一个int类型的变量InteractionState配合SelAxis枚举类型进行指示。

坐标变换

齐次坐标

当知道了拾取的对象组之后就可以配合相关变量对操作进行响应

对坐标轴的平移，旋转，缩放操作，都可以通过操作Actor对象的齐次变换矩阵（UserMatrix）来完成，假设当前的坐标点 A(x1, y1, z1) 与移动后的坐标B(x2, y2, z2)
{x2=k1x1+b1y2=k2y1+b2z2=k3z1+b3\begin{cases} x_2 = k_{1}x_1 + b_{1} \\ y_2 = k_{2}y_1 + b_{2} \\ z_2 = k_{3}z_1 + b_{3} \end{cases} ⎩⎨⎧x2=k1x1+b1y2=k2y1+b2z2=k3z1+b3
转换为矩阵形式
(x2y2z21)=[k100b10k20b200k3b30001](x1y1z11)\left( \begin{matrix} x_2 \\ y_2 \\ z_2 \\ 1 \end{matrix} \right) = \left[ \begin{matrix} k_{1}&0&0&b_{1} \\ 0&k_{2}&0&b_{2} \\ 0&0&k_{3}&b_{3} \\ 0&0&0&1 \end{matrix} \right] \left( \begin{matrix} x_1 \\ y_1 \\ z_1 \\ 1 \end{matrix} \right) ⎝⎛x2y2z21⎠⎞=⎣⎡k10000k20000k30b1b2b31⎦⎤⎝⎛x1y1z11⎠⎞
A点对应的齐次变换矩阵为
[1000010000100001]\left[ \begin{matrix} 1&0&0&0 \\ 0&1&0&0 \\ 0&0&1&0 \\ 0&0&0&1 \end{matrix} \right] ⎣⎡1000010000100001⎦⎤
移动到B点对应的齐次变换矩阵为
[k100b10k20b200k3b30001]\left[ \begin{matrix} k_{1}&0&0&b_{1} \\ 0&k_{2}&0&b_{2} \\ 0&0&k_{3}&b_{3} \\ 0&0&0&1 \end{matrix} \right] ⎣⎡k10000k20000k30b1b2b31⎦⎤

vtk中对矩阵的变换可以通过vtkTransform类方便的进行

【VTK学习】空间几何变换_JinSu_的博客-CSDN博客_vtk 矩阵乘法

vtkNew<vtkTransform> transform;
transform->PostMultiply(); //M=A*M
transform->RotateZ(30);      // 绕Z轴旋转30度
transform->Translate(1, 0, 0);   // 平移一个 (1,0,0) 向量transform->GetMatrix();    // 获取一系列操作合成出的齐次变换矩阵

沿指定轴(X,Y,Z)移动

motion_vector 为坐标轴移动到鼠标位置的向量，m_moveByVec为指定移动的轴方向，m_userMatrix4x4为预定义的vtkMatrix4x4矩阵

double length = vtkMath::Dot(motion_vector, m_moveByVec);double vec[3] = { 0 };
vec[InteractionState] = length;vtkNew<vtkTransform> transform;
transform->SetMatrix(m_userMatrix4x4);
transform->Translate(vec);
transform->GetMatrix(m_userMatrix4x4);actor->GetUserMatrix()->DeepCopy(m_userMatrix4x4);

沿xyz所有方向移动

double vec[3] = { 0 };
vec[0] = motion_vector[0];
vec[1] = motion_vector[1];
vec[2] = motion_vector[2];
printf("move vec (%f, %f, %f)\n", vec[0], vec[1], vec[2]);vtkNew<vtkTransform> transform;
transform->SetMatrix(m_userMatrix4x4);
transform->Translate(vec);
transform->GetMatrix(m_userMatrix4x4);actor->GetUserMatrix()->DeepCopy(m_userMatrix4x4);

沿指定平面移动

double vec[3];
vec[0] = m_moveByVec[0] * motion_vector[0];
vec[1] = m_moveByVec[1] * motion_vector[1];
vec[2] = m_moveByVec[2] * motion_vector[2];
printf("move vec (%f, %f, %f)\n", vec[0], vec[1], vec[2]);vtkNew<vtkTransform> transform;
transform->SetMatrix(m_userMatrix4x4);
transform->Translate(vec);
transform->GetMatrix(m_userMatrix4x4);actor->GetUserMatrix()->DeepCopy(m_userMatrix4x4);

绕指定轴旋转

oldPoint为鼠标上次触发事件时的位置，newPoint为鼠标当前触发事件时的位置

// 将鼠标位置移动到自身坐标系下，求两次鼠标位置向量在投影平面的夹角
vtkNew<vtkTransform> trans;
trans->SetMatrix(m_userMatrix4x4);double pos_t1[4]{ oldPoint[0], oldPoint[1], oldPoint[2], 1 };
double pos_t2[4]{ newPoint[0], newPoint[1], newPoint[2], 1 };
vtkNew<vtkMatrix4x4> posture_inv;
vtkMatrix4x4::Invert(m_userMatrix4x4, posture_inv);
auto pos_t = posture_inv->MultiplyDoublePoint(pos_t1);
double v1[3] = { pos_t[0], pos_t[1], pos_t[2] };
pos_t = posture_inv->MultiplyDoublePoint(pos_t2);
double v2[3] = { pos_t[0], pos_t[1], pos_t[2] };double projection1[3], projection2[3];
GetPlaneProjection(m_moveByVec, v1, projection1);
GetPlaneProjection(m_moveByVec, v2, projection2);
vtkMath::Normalize(projection1);
vtkMath::Normalize(projection2);
double axis[3];
vtkMath::Cross(projection1, projection2, axis);
double radians = acos(vtkMath::Dot(projection1, projection2));
double degrees = vtkMath::DegreesFromRadians(radians);
trans->RotateWXYZ(degrees, axis);
trans->Update();m_userMatrix4x4->DeepCopy(trans->GetMatrix());

vtkWidget类

参考VTK图形图像开发进阶 8.3 VTK Widget

vtkInteractorObserver.h

vtkInteractorObserver.cxx

vtkAbstractWidget.h

vtkAbstractWidget.cxx

vtkWidgetRepresentation.h

vtkWidgetRepresentation.cxx

VTK中Widget的设计是从VTK 5.0版本开始引入的，最初的Widget是从vtk3DWidget派生出来的，从VTK5.1版本开始，VTK Widget从新进行设计，主要的设计理念是将Widget的消息处理与几何表达实体分离，但还是保留了 vtk3DWidget及其子类。vtkAbstractWidget作为基类，只定义一些公共的API以及实现了“交互/表达实体”分离的设计机制，其中，把从vtkRenderWindowInteractor路由过来的消息（事件）交给vtkAbstractWidget的“交互”部分处理，而Widget的“表达实体”则对应一个vtkProp对象（或者是vtkWidgetRepresentation的子类）。这样做的好处是：事件的处理与Widget的表达实体互不干扰，而且可以实现同类Widget使用不同的表达形式，每个VTKAbstractWidget子类内部包含一个vtkWidgetEventTranslate对象和一个vtkWidgetCallbackMapper对象，vtkWidgetEventTranslate的作用是将外部的VTK事件映射为Widget事件(定义于 vtkWidgetEvenet.h文件中)， vtkWidgetCallbackMapper将相应的Widget事件与各个受保护的静态操作函数关联起来。

可以使用vtkWidgetCallbackMapper的SetCallbackMethod函数设置 VTK Event, Widget Event, Method Invocation之间的关联

void vtkWidgetCallbackMapper::SetCallbackMethod(unsigned long VTKEvent, unsigned long widgetEvent, vtkAbstractWidget* w, CallbackType f)
{this->EventTranslator->SetTranslation(VTKEvent, widgetEvent);this->SetCallbackMethod(widgetEvent, w, f);
}

示例：

this->CallbackMapper->SetCallbackMethod(vtkCommand::LeftButtonReleaseEvent,vtkWidgetEvent::EndSelect,this, vtkDistanceWidget::EndSelectAction);

本文将可拖动的三维坐标轴封装为 vtkAbstractWidget 的子类，作为交互与表达实体相分离的部件，还需要一个继承vtkWidgetRepresentation的子类对象，

继承vtkAbstractWidget类

继承vtkAbstractWidget类只需实现 vtkAbstractWidget 的纯虚函数 virtual void CreateDefaultRepresentation() = 0;即可

void vtkMoveableAxesWidget::CreateDefaultRepresentation()
{if (!this->WidgetRep){auto rep = vtkMoveableAxesRepresentation::New();this->SetWidgetRepresentation(rep);}
}

此外 vtkWidget 类还应该实现事件到方法的映射，通过在构造函数执行时调用 vtkWidgetCallbackMapper 对象的 SetCallbackMethod 方法关联 VTK Event, Widget Event, Method Invocation

vtkMoveableAxesWidget::vtkMoveableAxesWidget(): m_cursorActor(nullptr),WidgetState(vtkMoveableAxesWidget::Start)
{this->CallbackMapper->SetCallbackMethod(vtkCommand::LeftButtonPressEvent, vtkWidgetEvent::Select, this, vtkMoveableAxesWidget::SelectAction);this->CallbackMapper->SetCallbackMethod(vtkCommand::MouseMoveEvent, vtkWidgetEvent::Move, this, vtkMoveableAxesWidget::MoveAction);this->CallbackMapper->SetCallbackMethod(vtkCommand::LeftButtonReleaseEvent, vtkWidgetEvent::EndSelect, this, vtkMoveableAxesWidget::EndSelectAction);}

接着定义响应事件的回调函数 SelectAction, MoveAction, EndSelectAction 这些回调函数必须定义为静态成员，并且设置一个形参vtkAbstractWidget *w

void vtkMoveableAxesWidget::SelectAction(vtkAbstractWidget *w)
{vtkMoveableAxesWidget* self = reinterpret_cast<vtkMoveableAxesWidget*>(w);// Get the event positionint X = self->Interactor->GetEventPosition()[0];int Y = self->Interactor->GetEventPosition()[1];if (!self->CurrentRenderer || !self->CurrentRenderer->IsInViewport(X, Y)){self->WidgetState = vtkMoveableAxesWidget::Start;return;}double e[2];e[0] = static_cast<double>(X);e[1] = static_cast<double>(Y);// 调用 vtkWidgetRepresentation 子类中定义的交互接口函数self->WidgetRep->StartWidgetInteraction(e);int interactionState = self->WidgetRep->GetInteractionState();if (interactionState < 0){return;}// 更新鼠标指针self->UpdateCursorShape(interactionState);// 设置组件状态为 激活self->WidgetState = vtkMoveableAxesWidget::Active;// 阻断事件传递，发送StartInteractionEvent事件，渲染self->GrabFocus(self->EventCallbackCommand);self->StartInteraction();self->EventCallbackCommand->SetAbortFlag(1);self->InvokeEvent(vtkCommand::StartInteractionEvent, nullptr);self->Render();
}void vtkMoveableAxesWidget::MoveAction(vtkAbstractWidget* w)
{vtkMoveableAxesWidget* self = reinterpret_cast<vtkMoveableAxesWidget*>(w);double X = self->Interactor->GetEventPosition()[0];double Y = self->Interactor->GetEventPosition()[1];// 鼠标移动时高亮功能self->MoveHighLight(X, Y);// 判断组件是否激活if (self->WidgetState == vtkMoveableAxesWidget::Start){return;}// 开始交互，调用 vtkWidgetRepresentation 子类中定义的交互接口函数double e[2];e[0] = static_cast<double>(X);e[1] = static_cast<double>(Y);self->WidgetRep->WidgetInteraction(e);// 阻断事件传递，发送InteractionEvent事件，渲染self->EventCallbackCommand->SetAbortFlag(1);self->InvokeEvent(vtkCommand::InteractionEvent, nullptr);self->Render();
}void vtkMoveableAxesWidget::EndSelectAction(vtkAbstractWidget* w)
{vtkMoveableAxesWidget* self = reinterpret_cast<vtkMoveableAxesWidget*>(w);self->WidgetState = vtkMoveableAxesWidget::Start;// 调用 vtkWidgetRepresentation 子类中定义的交互接口函数self->WidgetRep->EndWidgetInteraction(nullptr);// 更新鼠标指针self->UpdateCursorShape(-1);// 阻断事件传递，发送InteractionEvent事件，渲染self->ReleaseFocus();self->EventCallbackCommand->SetAbortFlag(1);self->EndInteraction();self->InvokeEvent(vtkCommand::EndInteractionEvent, nullptr);self->Render();
}

继承vtkWidgetRepresentation类

继承vtkWidgetRepresentation首先要实现它的纯虚函数virtual void BuildRepresentation() = 0;

void vtkMoveableAxesRepresentation::BuildRepresentation()
{// 刷新Repif (!this->Renderer || !this->Renderer->GetRenderWindow()) {return;}// actor、source重新计算if (this->GetMTime() > this->BuildTime|| this->Renderer->GetRenderWindow()->GetMTime() > this->BuildTime) {}// 重建和renderwindow更改时调整控制柄的大小if (this->GetMTime() > this->BuildTime|| this->Renderer->GetRenderWindow()->GetMTime() > this->BuildTime) {this->SizeHandles();this->BuildTime.Modified();}
}

根据 vtkWidgetRepresentation.h中所述
为了让 vtkWidgetRepresentation 子类表现得像个 vtkProp对象子类需要实现以下方法

  /*** Methods to make this class behave as a vtkProp. They are repeated here (from the* vtkProp superclass) as a reminder to the widget implementor. Failure to implement* these methods properly may result in the representation not appearing in the scene* (i.e., not implementing the Render() methods properly) or leaking graphics resources* (i.e., not implementing ReleaseGraphicsResources() properly).*/double *GetBounds() override {return nullptr;}void ShallowCopy(vtkProp *prop) override;void GetActors(vtkPropCollection *) override {}void GetActors2D(vtkPropCollection *) override {}void GetVolumes(vtkPropCollection *) override {}void ReleaseGraphicsResources(vtkWindow *) override {}int RenderOverlay(vtkViewport *vtkNotUsed(viewport)) override {return 0;}int RenderOpaqueGeometry(vtkViewport *vtkNotUsed(viewport)) override {return 0;}int RenderTranslucentPolygonalGeometry(vtkViewport *vtkNotUsed(viewport)) override {return 0;}int RenderVolumetricGeometry(vtkViewport *vtkNotUsed(viewport)) override {return 0;}int HasTranslucentPolygonalGeometry() override { return 0; }

本文由于只使用到了Actor对象，根据需要实现了如下方法

    double* GetBounds() VTK_SIZEHINT(6) override;void GetActors(vtkPropCollection* pc) override;void ReleaseGraphicsResources(vtkWindow*) override;int RenderOpaqueGeometry(vtkViewport*) override;int RenderTranslucentPolygonalGeometry(vtkViewport*) override;vtkTypeBool HasTranslucentPolygonalGeometry() override;

具体实现可以查阅VTK提供的完整的源码，部分示例如下

void vtkMoveableAxesRepresentation::GetActors(vtkPropCollection* pc)
{pc = vtkPropCollection::New();TravelAllActors([&pc](vtkActor* actor) {pc->AddItem(actor);});
}

可以使用TravelAllActors传入一个匿名函数的方式遍历所有Actor对象

#include <functional>
class vtkActor;using travelActorsCallback = std::function<void(vtkActor*)>;
void TravelAllActors(travelActorsCallback);void vtkMoveableAxesRepresentation::TravelAllActors(travelActorsCallback callback)
{vtkActor* actor;// x,y,z轴for (int i = 0; i < m_axesArrow.size(); i++){actor = m_axesArrow[i]->m_line.GetPointer();callback(actor);actor = m_axesArrow[i]->m_cone1.GetPointer();callback(actor);}// 坐标轴文本for (int i = 0; i < this->m_texts.size(); i++){actor = this->m_texts[i];callback(actor);}// 拓展部分m_extendActors->InitTraversal();while ((actor = m_extendActors->GetNextActor()) != nullptr){callback(actor);}
}

以下是推荐的vtkWidgetRepresentation 子类与 vtkWidget交互的接口函数

  /*** The following is a suggested API for widget representations. These methods* define the communication between the widget and its representation. These* methods are only suggestions because widgets take on so many different* forms that a universal API is not deemed practical. However, these methods* should be implemented when possible to insure that the VTK widget hierarchy* remains self-consistent.* <pre>* PlaceWidget() - given a bounding box (xmin,xmax,ymin,ymax,zmin,zmax), place* the widget inside of it. The current orientation of the widget* is preserved, only scaling and translation is performed.* StartWidgetInteraction() - generally corresponds to a initial event (e.g.,* mouse down) that starts the interaction process* with the widget.* WidgetInteraction() - invoked when an event causes the widget to change* appearance.* EndWidgetInteraction() - generally corresponds to a final event (e.g., mouse up)* and completes the interaction sequence.* ComputeInteractionState() - given (X,Y) display coordinates in a renderer, with a* possible flag that modifies the computation,* what is the state of the widget?* GetInteractionState() - return the current state of the widget. Note that the* value of "0" typically refers to "outside". The* interaction state is strictly a function of the* representation, and the widget/represent must agree* on what they mean.* Highlight() - turn on or off any highlights associated with the widget.* Highlights are generally turned on when the widget is selected.* </pre>* Note that subclasses may ignore some of these methods and implement their own* depending on the specifics of the widget.*/virtual void PlaceWidget(double* vtkNotUsed(bounds[6])) {}virtual void StartWidgetInteraction(double eventPos[2]) { (void)eventPos; }virtual void WidgetInteraction(double newEventPos[2]) { (void)newEventPos; }virtual void EndWidgetInteraction(double newEventPos[2]) { (void)newEventPos; }virtual int ComputeInteractionState(int X, int Y, int modify=0);virtual int GetInteractionState(){return this->InteractionState;}virtual void Highlight(int vtkNotUsed(highlightOn)) {}

与picker相关的接口函数

  /*** Register internal Pickers in the Picking Manager.* Must be reimplemented by concrete widget representations to register* their pickers.*/virtual void RegisterPickers();/*** Unregister internal pickers from the Picking Manager.*/virtual void UnRegisterPickers();/*** Update the pickers registered in the Picking Manager when pickers are* modified.*/virtual void PickersModified();

明确了满足 vtkAbstractWidget 与 vtkWidgetRepresentation 类需要实现的接口，以及它们之间交互需要的接口，完整代码见源码。

使用

#include "vtkRenderer.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkAutoInit.h"
VTK_MODULE_INIT(vtkRenderingOpenGL2);
VTK_MODULE_INIT(vtkInteractionStyle);
VTK_MODULE_INIT(vtkRenderingFreeType);
VTK_MODULE_INIT(vtkRenderingVolumeOpenGL2);#include "vtkMoveableAxesWidget.h"int main()
{vtkNew<vtkRenderer> renderer;vtkNew<vtkRenderWindow> renWin;vtkNew<vtkRenderWindowInteractor> renWinI;renderer->GetActiveCamera()->SetPosition(8, 8, 8);renWin->AddRenderer(renderer);renWinI->SetRenderWindow(renWin);renWinI->Initialize();// Widget的创建需要在 renWinI->SetRenderWindow(renWin) 和 renWinI->Initialize() 之后// 创建可移动坐标轴vtkMoveableAxesWidget* axes = vtkMoveableAxesWidget::New();axes->SetInteractor(renWinI);axes->On();renWin->Render();renWinI->Start();return EXIT_SUCCESS;
}

其他

Qt VS Tools插件安装

https://blog.51cto.com/u_15707179/5447267

VS配置Qt开发环境

https://www.cnblogs.com/szitcast/p/15733691.html

解决：Qt项目中出现红色波浪线错误提示

解决：vs打开.ui文件出现Qt Designer后闪退

VTK源码编译

https://www.bilibili.com/video/BV1S5411D7uj?spm_id_from=333.1007.top_right_bar_window_history.content.click&vd_source=c9263c84459a6eabff37b3b1b85328e6

Visual Studio C++项目使用第三方库

https://blog.csdn.net/u012611644/article/details/81105539

https://blog.csdn.net/yangfchn/article/details/85162934

控制台显示调试信息

工程属性->链接器->系统->子系统设置为控制台

参考

VTK官方网址
VTK官方文档
VTK源码
VTK可移动三维坐标轴 vtkMovableAxesWidget
【VTK】可拖动的坐标轴MovableAxesWidget
第03章-VTK系统概述（1）_DolingStudio的博客-CSDN博客
VTK笔记-图形相关-平面-vtkPlaneSource_黑山老妖的博客的博客-CSDN博客_vtk平面图
（4）建立一个标准尺寸的平面，并对其进行着色贴图、拉伸一定的厚度_rexinx的博客-CSDN博客
第04章-VTK基础（4）_DolingStudio的博客-CSDN博客
【VTK学习】空间几何变换_JinSu_的博客-CSDN博客_vtk 矩阵乘法
第04章-VTK基础（5）_DolingStudio的博客-CSDN博客
《VTK图形图像开发进阶》
《VTKUsersGuide》