VTK 显示大量点云数据及交互（点云拾取、着色、测量等）功能

        VTK (Visualization Toolkit) 是一个强大的开源可视化库，非常适合处理点云数据。下面将介绍如何使用 VTK 显示大量点云数据，并实现点云拾取、着色、测量等功能。

基本点云显示

创建一个基本的点云显示程序：

cpp

#include <vtkSmartPointer.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkVertexGlyphFilter.h>int main() {// 创建点云数据vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();// 添加大量点（这里示例添加100万个随机点）for (int i = 0; i < 1000000; ++i) {points->InsertNextPoint((double)rand() / RAND_MAX * 100.0,(double)rand() / RAND_MAX * 100.0,(double)rand() / RAND_MAX * 100.0);}// 创建PolyData对象并设置点vtkSmartPointer<vtkPolyData> polydata = vtkSmartPointer<vtkPolyData>::New();polydata->SetPoints(points);// 使用VertexGlyphFilter将点转换为可渲染的顶点vtkSmartPointer<vtkVertexGlyphFilter> glyphFilter = vtkSmartPointer<vtkVertexGlyphFilter>::New();glyphFilter->SetInputData(polydata);glyphFilter->Update();// 创建mapper和actorvtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();mapper->SetInputConnection(glyphFilter->GetOutputPort());vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();actor->SetMapper(mapper);actor->GetProperty()->SetPointSize(2); // 设置点大小// 创建渲染器、渲染窗口和交互器vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();renderWindow->AddRenderer(renderer);vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New();renderWindowInteractor->SetRenderWindow(renderWindow);// 添加actor到渲染器renderer->AddActor(actor);renderer->SetBackground(0.1, 0.2, 0.4); // 设置背景颜色// 开始渲染renderWindow->Render();renderWindowInteractor->Start();return 0;
}

点云拾取功能

要实现点云拾取，可以使用 VTK 的点拾取器 (vtkPointPicker):

cpp

#include <vtkPointPicker.h>// 在main函数中创建交互器后添加以下代码// 创建点拾取器
vtkSmartPointer<vtkPointPicker> pointPicker = vtkSmartPointer<vtkPointPicker>::New();
renderWindowInteractor->SetPicker(pointPicker);// 添加观察者处理拾取事件
vtkSmartPointer<vtkCallbackCommand> pickCallback = vtkSmartPointer<vtkCallbackCommand>::New();
pickCallback->SetCallback([](vtkObject* caller, unsigned long eventId, void* clientData, void* callData) {vtkRenderWindowInteractor* interactor = static_cast<vtkRenderWindowInteractor*>(caller);vtkPointPicker* picker = static_cast<vtkPointPicker*>(interactor->GetPicker());int x = interactor->GetEventPosition()[0];int y = interactor->GetEventPosition()[1];picker->Pick(x, y, 0, interactor->GetRenderWindow()->GetRenderers()->GetFirstRenderer());vtkIdType pointId = picker->GetPointId();if (pointId != -1) {double* pos = picker->GetPickPosition();std::cout << "Picked point ID: " << pointId << std::endl;std::cout << "Position: (" << pos[0] << ", " << pos[1] << ", " << pos[2] << ")" << std::endl;}
});renderWindowInteractor->AddObserver(vtkCommand::LeftButtonPressEvent, pickCallback);

点云着色功能

可以为点云添加颜色属性，实现着色效果：

cpp

#include <vtkUnsignedCharArray.h>// 在创建点数据后添加颜色数组
vtkSmartPointer<vtkUnsignedCharArray> colors = vtkSmartPointer<vtkUnsignedCharArray>::New();
colors->SetNumberOfComponents(3); // RGB
colors->SetName("Colors");// 为每个点添加随机颜色
for (int i = 0; i < points->GetNumberOfPoints(); ++i) {unsigned char color[3] = {static_cast<unsigned char>(rand() % 256),static_cast<unsigned char>(rand() % 256),static_cast<unsigned char>(rand() % 256)};colors->InsertNextTypedTuple(color);
}polydata->GetPointData()->SetScalars(colors);// 然后修改mapper以使用这些颜色
mapper->SetScalarVisibility(1); // 启用标量颜色
mapper->SetScalarModeToUsePointData(); // 使用点数据中的标量

点云测量功能

1. 点对点距离测量

首先实现最基本的点对点距离测量功能：

#include <vtkDistanceWidget.h>
#include <vtkDistanceRepresentation3D.h>
#include <vtkSphereSource.h>// 在main函数中创建交互器后添加以下代码// 创建距离测量工具
vtkSmartPointer<vtkDistanceWidget> distanceWidget = vtkSmartPointer<vtkDistanceWidget>::New();
distanceWidget->SetInteractor(renderWindowInteractor);
distanceWidget->CreateDefaultRepresentation();// 设置距离表示的样式
vtkDistanceRepresentation3D* distanceRep = vtkDistanceRepresentation3D::SafeDownCast(distanceWidget->GetRepresentation());
distanceRep->SetLabelFormat("%-#6.3g mm"); // 设置显示格式
distanceRep->GetAxisProperty()->SetColor(1, 0, 0); // 设置轴线颜色
distanceRep->GetAxisProperty()->SetLineWidth(2); // 设置线宽// 添加标记球体
vtkSmartPointer<vtkSphereSource> sphere1 = vtkSmartPointer<vtkSphereSource>::New();
sphere1->SetRadius(1.0);
vtkSmartPointer<vtkSphereSource> sphere2 = vtkSmartPointer<vtkSphereSource>::New();
sphere2->SetRadius(1.0);distanceRep->SetPoint1Representation(sphere1->GetOutput());
distanceRep->SetPoint2Representation(sphere2->GetOutput());// 启用距离测量工具
distanceWidget->On();

2. 多点距离测量（折线测量）

如果需要测量多点间的累计距离，可以实现折线测量：

#include <vtkContourWidget.h>
#include <vtkOrientedGlyphContourRepresentation.h>
#include <vtkPolygonalSurfacePointPlacer.h>// 创建折线测量工具
vtkSmartPointer<vtkContourWidget> contourWidget = vtkSmartPointer<vtkContourWidget>::New();
contourWidget->SetInteractor(renderWindowInteractor);
contourWidget->ContinuousDrawOn(); // 启用连续绘制// 设置表示方式
vtkOrientedGlyphContourRepresentation* contourRep = vtkOrientedGlyphContourRepresentation::SafeDownCast(contourWidget->GetRepresentation());
contourRep->GetLinesProperty()->SetColor(0, 1, 0); // 设置线颜色
contourRep->GetLinesProperty()->SetLineWidth(2); // 设置线宽// 设置点放置器，使点吸附到点云上
vtkSmartPointer<vtkPolygonalSurfacePointPlacer> pointPlacer = vtkSmartPointer<vtkPolygonalSurfacePointPlacer>::New();
pointPlacer->AddProp(actor);
pointPlacer->GetPolys()->AddItem(polydata);
contourRep->SetPointPlacer(pointPlacer);// 添加回调函数计算总长度
vtkSmartPointer<vtkCallbackCommand> contourCallback = vtkSmartPointer<vtkCallbackCommand>::New();
contourCallback->SetCallback([](vtkObject* caller, unsigned long eventId, void* clientData, void* callData) {vtkContourWidget* widget = static_cast<vtkContourWidget*>(caller);vtkContourRepresentation* rep = widget->GetContourRepresentation();int numPoints = rep->GetNumberOfNodes();if (numPoints > 1) {double totalLength = 0.0;double pos1[3], pos2[3];rep->GetNthNodeWorldPosition(0, pos1);for (int i = 1; i < numPoints; ++i) {rep->GetNthNodeWorldPosition(i, pos2);totalLength += sqrt(vtkMath::Distance2BetweenPoints(pos1, pos2));memcpy(pos1, pos2, 3 * sizeof(double));}std::cout << "Total length: " << totalLength << " mm" << std::endl;}
});contourWidget->AddObserver(vtkCommand::InteractionEvent, contourCallback);
contourWidget->On();

3. 面积测量（多边形区域）

对于闭合区域的面积测量：

#include <vtkPolygon.h>
#include <vtkCellArray.h>// 修改contourWidget的回调函数以支持面积计算
contourCallback->SetCallback([](vtkObject* caller, unsigned long eventId, void* clientData, void* callData) {vtkContourWidget* widget = static_cast<vtkContourWidget*>(caller);vtkContourRepresentation* rep = widget->GetContourRepresentation();int numPoints = rep->GetNumberOfNodes();if (numPoints > 2) {// 计算周长double totalLength = 0.0;double pos1[3], pos2[3];rep->GetNthNodeWorldPosition(0, pos1);for (int i = 1; i < numPoints; ++i) {rep->GetNthNodeWorldPosition(i, pos2);totalLength += sqrt(vtkMath::Distance2BetweenPoints(pos1, pos2));memcpy(pos1, pos2, 3 * sizeof(double));}// 闭合路径rep->GetNthNodeWorldPosition(0, pos2);totalLength += sqrt(vtkMath::Distance2BetweenPoints(pos1, pos2));// 计算面积vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();for (int i = 0; i < numPoints; ++i) {rep->GetNthNodeWorldPosition(i, pos1);points->InsertNextPoint(pos1);}vtkSmartPointer<vtkPolygon> polygon = vtkSmartPointer<vtkPolygon>::New();polygon->Initialize(numPoints, points->GetPoints(), points->GetBounds());double area = polygon->ComputeArea();std::cout << "Perimeter: " << totalLength << " mm" << std::endl;std::cout << "Area: " << area << " mm²" << std::endl;}
});

4. 点云高度差测量

对于三维点云，可以测量高度差：

// 在点拾取回调中添加高度差计算
pickCallback->SetCallback([](vtkObject* caller, unsigned long eventId, void* clientData, void* callData) {static double lastPos[3] = {0, 0, 0};static bool firstPick = true;vtkRenderWindowInteractor* interactor = static_cast<vtkRenderWindowInteractor*>(caller);vtkPointPicker* picker = static_cast<vtkPointPicker*>(interactor->GetPicker());int x = interactor->GetEventPosition()[0];int y = interactor->GetEventPosition()[1];picker->Pick(x, y, 0, interactor->GetRenderWindow()->GetRenderers()->GetFirstRenderer());vtkIdType pointId = picker->GetPointId();if (pointId != -1) {double* pos = picker->GetPickPosition();std::cout << "Picked point ID: " << pointId << std::endl;std::cout << "Position: (" << pos[0] << ", " << pos[1] << ", " << pos[2] << ")" << std::endl;if (!firstPick) {double distance = sqrt(vtkMath::Distance2BetweenPoints(pos, lastPos));double heightDiff = fabs(pos[2] - lastPos[2]);std::cout << "Distance from last point: " << distance << " mm" << std::endl;std::cout << "Height difference: " << heightDiff << " mm" << std::endl;}memcpy(lastPos, pos, 3 * sizeof(double));firstPick = false;}
});

5. 测量结果显示在3D视图

将测量结果直接显示在3D视图上：

#include <vtkTextActor.h>
#include <vtkTextProperty.h>// 创建文本actor用于显示测量结果
vtkSmartPointer<vtkTextActor> textActor = vtkSmartPointer<vtkTextActor>::New();
textActor->SetPosition(10, 10);
textActor->GetTextProperty()->SetFontSize(18);
textActor->GetTextProperty()->SetColor(1.0, 1.0, 1.0);
renderer->AddActor2D(textActor);// 修改距离测量的回调函数
distanceWidget->AddObserver(vtkCommand::InteractionEvent, [textActor](vtkObject* caller, unsigned long eventId, void* clientData, void* callData) {vtkDistanceWidget* widget = static_cast<vtkDistanceWidget*>(caller);vtkDistanceRepresentation3D* rep = vtkDistanceRepresentation3D::SafeDownCast(widget->GetRepresentation());double distance = rep->GetDistance();std::stringstream ss;ss << "Distance: " << std::fixed << std::setprecision(2) << distance << " mm";textActor->SetInput(ss.str().c_str());
});

6. 测量工具切换

添加键盘控制来切换不同的测量工具：

// 添加键盘回调
vtkSmartPointer<vtkCallbackCommand> keyCallback = vtkSmartPointer<vtkCallbackCommand>::New();
keyCallback->SetCallback([](vtkObject* caller, unsigned long eventId, void* clientData, void* callData) {vtkRenderWindowInteractor* interactor = static_cast<vtkRenderWindowInteractor*>(caller);std::string key = interactor->GetKeySym();static vtkDistanceWidget* distanceWidget = static_cast<vtkDistanceWidget*>(clientData);static vtkContourWidget* contourWidget = static_cast<vtkContourWidget*>(clientData);if (key == "d") {// 切换距离测量distanceWidget->SetEnabled(!distanceWidget->GetEnabled());contourWidget->SetEnabled(false);} else if (key == "c") {// 切换轮廓测量contourWidget->SetEnabled(!contourWidget->GetEnabled());distanceWidget->SetEnabled(false);} else if (key == "a") {// 切换面积测量bool enabled = contourWidget->GetEnabled();contourWidget->SetEnabled(!enabled);distanceWidget->SetEnabled(false);if (enabled) {contourWidget->CloseLoop();}}
});renderWindowInteractor->AddObserver(vtkCommand::KeyPressEvent, keyCallback);

性能优化

对于大量点云数据，可以考虑以下优化措施：

1、使用vtkOctreePointLocator 加速点查找

#include <vtkOctreePointLocator.h>vtkSmartPointer<vtkOctreePointLocator> pointLocator = vtkSmartPointer<vtkOctreePointLocator>::New();
pointLocator->SetDataSet(polydata);
pointLocator->BuildLocator();// 拾取时使用locator查找最近点
double searchPoint[3] = {x, y, z};
vtkIdType pointId = pointLocator->FindClosestPoint(searchPoint);

2、使用点云简化 减少显示点数

#include <vtkQuadricClustering.h>vtkSmartPointer<vtkQuadricClustering> decimate = vtkSmartPointer<vtkQuadricClustering>::New();
decimate->SetInputData(polydata);
decimate->SetNumberOfDivisions(50, 50, 50); // 调整简化程度
decimate->Update();

3、使用GPU加速

#include <vtkGPUInfo.h>
#include <vtkGPUInfoList.h>// 检查GPU信息
vtkSmartPointer<vtkGPUInfoList> infoList = vtkSmartPointer<vtkGPUInfoList>::New();
infoList->Probe();if (infoList->GetNumberOfGPUs() > 0) {mapper->SetUseHardwareShading(true);
}

完整示例

完整示例1（点云显示+点云拾取+点云着色）

#include <vtkSmartPointer.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkVertexGlyphFilter.h>
#include <vtkUnsignedCharArray.h>
#include <vtkPointPicker.h>
#include <vtkCallbackCommand.h>
#include <vtkOctreePointLocator.h>
#include <iostream>int main() {// 创建点云数据vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();// 添加10万个随机点for (int i = 0; i < 100000; ++i) {points->InsertNextPoint((double)rand() / RAND_MAX * 100.0,(double)rand() / RAND_MAX * 100.0,(double)rand() / RAND_MAX * 100.0);}// 创建颜色数组vtkSmartPointer<vtkUnsignedCharArray> colors = vtkSmartPointer<vtkUnsignedCharArray>::New();colors->SetNumberOfComponents(3);colors->SetName("Colors");for (int i = 0; i < points->GetNumberOfPoints(); ++i) {unsigned char color[3] = {static_cast<unsigned char>(rand() % 256),static_cast<unsigned char>(rand() % 256),static_cast<unsigned char>(rand() % 256)};colors->InsertNextTypedTuple(color);}// 创建PolyData对象vtkSmartPointer<vtkPolyData> polydata = vtkSmartPointer<vtkPolyData>::New();polydata->SetPoints(points);polydata->GetPointData()->SetScalars(colors);// 创建点定位器（用于加速拾取）vtkSmartPointer<vtkOctreePointLocator> pointLocator = vtkSmartPointer<vtkOctreePointLocator>::New();pointLocator->SetDataSet(polydata);pointLocator->BuildLocator();// 将点转换为可渲染的顶点vtkSmartPointer<vtkVertexGlyphFilter> glyphFilter = vtkSmartPointer<vtkVertexGlyphFilter>::New();glyphFilter->SetInputData(polydata);glyphFilter->Update();// 创建mapper和actorvtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();mapper->SetInputConnection(glyphFilter->GetOutputPort());mapper->SetScalarVisibility(1);mapper->SetScalarModeToUsePointData();vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();actor->SetMapper(mapper);actor->GetProperty()->SetPointSize(3);// 创建渲染器和窗口vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();renderWindow->AddRenderer(renderer);renderWindow->SetSize(800, 600);vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New();renderWindowInteractor->SetRenderWindow(renderWindow);// 设置点拾取器vtkSmartPointer<vtkPointPicker> pointPicker = vtkSmartPointer<vtkPointPicker>::New();renderWindowInteractor->SetPicker(pointPicker);// 添加拾取回调vtkSmartPointer<vtkCallbackCommand> pickCallback = vtkSmartPointer<vtkCallbackCommand>::New();pickCallback->SetCallback([](vtkObject* caller, unsigned long eventId, void* clientData, void* callData) {vtkRenderWindowInteractor* interactor = static_cast<vtkRenderWindowInteractor*>(caller);int x = interactor->GetEventPosition()[0];int y = interactor->GetEventPosition()[1];interactor->GetPicker()->Pick(x, y, 0, interactor->GetRenderWindow()->GetRenderers()->GetFirstRenderer());vtkPointPicker* picker = static_cast<vtkPointPicker*>(interactor->GetPicker());vtkIdType pointId = picker->GetPointId();if (pointId != -1) {double* pos = picker->GetPickPosition();std::cout << "Picked point ID: " << pointId << std::endl;std::cout << "Position: (" << pos[0] << ", " << pos[1] << ", " << pos[2] << ")" << std::endl;// 高亮显示选中的点（例如改变颜色）// 这里可以添加代码修改选中点的颜色}});renderWindowInteractor->AddObserver(vtkCommand::LeftButtonPressEvent, pickCallback);// 添加actor到渲染器renderer->AddActor(actor);renderer->SetBackground(0.1, 0.2, 0.4);// 开始渲染renderWindow->Render();renderWindowInteractor->Start();return 0;
}

完整示例2（点云测量）

#include <vtkSmartPointer.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkVertexGlyphFilter.h>
#include <vtkUnsignedCharArray.h>
#include <vtkPointPicker.h>
#include <vtkCallbackCommand.h>
#include <vtkDistanceWidget.h>
#include <vtkDistanceRepresentation3D.h>
#include <vtkSphereSource.h>
#include <vtkContourWidget.h>
#include <vtkOrientedGlyphContourRepresentation.h>
#include <vtkPolygonalSurfacePointPlacer.h>
#include <vtkTextActor.h>
#include <vtkTextProperty.h>
#include <vtkMath.h>
#include <iostream>
#include <sstream>
#include <iomanip>int main() {// 创建点云数据vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();// 添加随机点for (int i = 0; i < 50000; ++i) {points->InsertNextPoint((double)rand() / RAND_MAX * 100.0,(double)rand() / RAND_MAX * 100.0,(double)rand() / RAND_MAX * 20.0); // Z轴范围小一些，便于观察高度差}// 创建颜色数组vtkSmartPointer<vtkUnsignedCharArray> colors = vtkSmartPointer<vtkUnsignedCharArray>::New();colors->SetNumberOfComponents(3);colors->SetName("Colors");for (int i = 0; i < points->GetNumberOfPoints(); ++i) {unsigned char color[3] = {static_cast<unsigned char>(rand() % 256),static_cast<unsigned char>(rand() % 256),static_cast<unsigned char>(rand() % 256)};colors->InsertNextTypedTuple(color);}// 创建PolyData对象vtkSmartPointer<vtkPolyData> polydata = vtkSmartPointer<vtkPolyData>::New();polydata->SetPoints(points);polydata->GetPointData()->SetScalars(colors);// 将点转换为可渲染的顶点vtkSmartPointer<vtkVertexGlyphFilter> glyphFilter = vtkSmartPointer<vtkVertexGlyphFilter>::New();glyphFilter->SetInputData(polydata);glyphFilter->Update();// 创建mapper和actorvtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();mapper->SetInputConnection(glyphFilter->GetOutputPort());mapper->SetScalarVisibility(1);mapper->SetScalarModeToUsePointData();vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();actor->SetMapper(mapper);actor->GetProperty()->SetPointSize(3);// 创建渲染器和窗口vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();renderWindow->AddRenderer(renderer);renderWindow->SetSize(800, 600);vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = vtkSmartPointer<vtkRenderWindowInteractor>::New();renderWindowInteractor->SetRenderWindow(renderWindow);// 设置点拾取器vtkSmartPointer<vtkPointPicker> pointPicker = vtkSmartPointer<vtkPointPicker>::New();renderWindowInteractor->SetPicker(pointPicker);// 创建文本actor用于显示测量结果vtkSmartPointer<vtkTextActor> textActor = vtkSmartPointer<vtkTextActor>::New();textActor->SetPosition(10, 10);textActor->GetTextProperty()->SetFontSize(18);textActor->GetTextProperty()->SetColor(1.0, 1.0, 1.0);renderer->AddActor2D(textActor);// 创建距离测量工具vtkSmartPointer<vtkDistanceWidget> distanceWidget = vtkSmartPointer<vtkDistanceWidget>::New();distanceWidget->SetInteractor(renderWindowInteractor);distanceWidget->CreateDefaultRepresentation();vtkDistanceRepresentation3D* distanceRep = vtkDistanceRepresentation3D::SafeDownCast(distanceWidget->GetRepresentation());distanceRep->SetLabelFormat("%-#6.3g mm");distanceRep->GetAxisProperty()->SetColor(1, 0, 0);distanceRep->GetAxisProperty()->SetLineWidth(2);vtkSmartPointer<vtkSphereSource> sphere1 = vtkSmartPointer<vtkSphereSource>::New();sphere1->SetRadius(1.0);vtkSmartPointer<vtkSphereSource> sphere2 = vtkSmartPointer<vtkSphereSource>::New();sphere2->SetRadius(1.0);distanceRep->SetPoint1Representation(sphere1->GetOutput());distanceRep->SetPoint2Representation(sphere2->GetOutput());distanceWidget->AddObserver(vtkCommand::InteractionEvent, [textActor](vtkObject* caller, unsigned long eventId, void* clientData, void* callData) {vtkDistanceWidget* widget = static_cast<vtkDistanceWidget*>(caller);vtkDistanceRepresentation3D* rep = vtkDistanceRepresentation3D::SafeDownCast(widget->GetRepresentation());double distance = rep->GetDistance();std::stringstream ss;ss << "Distance: " << std::fixed << std::setprecision(2) << distance << " mm";textActor->SetInput(ss.str().c_str());});// 创建轮廓测量工具vtkSmartPointer<vtkContourWidget> contourWidget = vtkSmartPointer<vtkContourWidget>::New();contourWidget->SetInteractor(renderWindowInteractor);contourWidget->ContinuousDrawOn();vtkOrientedGlyphContourRepresentation* contourRep = vtkOrientedGlyphContourRepresentation::SafeDownCast(contourWidget->GetRepresentation());contourRep->GetLinesProperty()->SetColor(0, 1, 0);contourRep->GetLinesProperty()->SetLineWidth(2);vtkSmartPointer<vtkPolygonalSurfacePointPlacer> pointPlacer = vtkSmartPointer<vtkPolygonalSurfacePointPlacer>::New();pointPlacer->AddProp(actor);pointPlacer->GetPolys()->AddItem(polydata);contourRep->SetPointPlacer(pointPlacer);contourWidget->AddObserver(vtkCommand::InteractionEvent, [textActor](vtkObject* caller, unsigned long eventId, void* clientData, void* callData) {vtkContourWidget* widget = static_cast<vtkContourWidget*>(caller);vtkContourRepresentation* rep = widget->GetContourRepresentation();int numPoints = rep->GetNumberOfNodes();if (numPoints > 1) {// 计算周长double totalLength = 0.0;double pos1[3], pos2[3];rep->GetNthNodeWorldPosition(0, pos1);for (int i = 1; i < numPoints; ++i) {rep->GetNthNodeWorldPosition(i, pos2);totalLength += sqrt(vtkMath::Distance2BetweenPoints(pos1, pos2));memcpy(pos1, pos2, 3 * sizeof(double));}std::stringstream ss;ss << "Perimeter: " << std::fixed << std::setprecision(2) << totalLength << " mm";// 如果闭合，计算面积if (numPoints > 2 && rep->IsClosed()) {vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();for (int i = 0; i < numPoints; ++i) {rep->GetNthNodeWorldPosition(i, pos1);points->InsertNextPoint(pos1);}vtkSmartPointer<vtkPolygon> polygon = vtkSmartPointer<vtkPolygon>::New();polygon->Initialize(numPoints, points->GetPoints(), points->GetBounds());double area = polygon->ComputeArea();ss << "\nArea: " << std::fixed << std::setprecision(2) << area << " mm²";}textActor->SetInput(ss.str().c_str());}});// 添加键盘控制vtkSmartPointer<vtkCallbackCommand> keyCallback = vtkSmartPointer<vtkCallbackCommand>::New();keyCallback->SetCallback([distanceWidget, contourWidget, textActor](vtkObject* caller, unsigned long eventId, void* clientData, void* callData) {vtkRenderWindowInteractor* interactor = static_cast<vtkRenderWindowInteractor*>(caller);std::string key = interactor->GetKeySym();if (key == "d" || key == "D") {// 切换距离测量distanceWidget->SetEnabled(!distanceWidget->GetEnabled());contourWidget->SetEnabled(false);textActor->SetInput("Distance measurement mode (click two points)");} else if (key == "c" || key == "C") {// 切换轮廓测量contourWidget->SetEnabled(!contourWidget->GetEnabled());distanceWidget->SetEnabled(false);textActor->SetInput("Contour measurement mode (click multiple points)");} else if (key == "a" || key == "A") {// 切换面积测量bool enabled = !contourWidget->GetEnabled();contourWidget->SetEnabled(enabled);distanceWidget->SetEnabled(false);if (enabled) {textActor->SetInput("Area measurement mode (click points to close loop)");contourWidget->CloseLoop();}} else if (key == "Escape") {// 退出所有测量模式distanceWidget->SetEnabled(false);contourWidget->SetEnabled(false);textActor->SetInput("");}});renderWindowInteractor->AddObserver(vtkCommand::KeyPressEvent, keyCallback);// 添加actor到渲染器renderer->AddActor(actor);renderer->SetBackground(0.1, 0.2, 0.4);// 开始渲染renderWindow->Render();// 显示操作提示std::cout << "Measurement Controls:" << std::endl;std::cout << "  D - Toggle distance measurement" << std::endl;std::cout << "  C - Toggle contour measurement" << std::endl;std::cout << "  A - Toggle area measurement" << std::endl;std::cout << "  ESC - Exit measurement mode" << std::endl;renderWindowInteractor->Start();return 0;
}

功能说明

  1. 距离测量：按 'D' 键激活，点击两个点测量它们之间的距离

  2. 轮廓测量：按 'C' 键激活，点击多个点测量折线总长度

  3. 面积测量：按 'A' 键激活，点击多个点后闭合区域测量面积

  4. 结果显示：测量结果实时显示在3D视图左上角

  5. 退出测量：按 ESC 键退出所有测量模式

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