利用vtkwidget 实现剪裁

想利用vtkBoxWidget和vtkExtractVOI实现剪裁。之前介绍过vtkBoxWidget，主要是说基本功能和接口，没有贴出完整实例。
Study-VTK：vtkWidget 分割/配准类之正交六面体3D小部件 vtkBoxWidget
干脆直接介绍如何利用vtkwidget 实现剪裁。本文代码基本就是 cp 一遍vtk相关接口。

利用vtkwidget 实现剪裁

1 利用vtkwidget 剪裁步骤
2 利用vtkwidget 剪裁模型展示
3 利用vtkwidget 剪裁模型代码
4 利用vtkwidget 剪裁影像展示
5 利用vtkwidget 剪裁影像代码

1 利用vtkwidget 剪裁步骤

实现剪裁需要三步：

输入被剪裁模型；
被剪裁数据一般有：
影像（vti/vtr格式 dcm/图片/矩阵等数据）、
模型（vtp/vtu格式 stl/obj/体网格等数据）、
场景
剪切区域选择（交互）；
vtk提供大量现成的交互vtkWidget。可以自己开发交互，我只搞过一个，很麻烦。现成的虽然丑点但是是很多前辈积累的，比较实用。一般不建议自己开发。跟剪切相关的，遵循kiss原则，大家直接想到的无非就是：
平面上任意点两个点，模型分成两个部分
平面上任意点多个点，练成闭合样条曲线，分成曲线内、曲线外
空间放置一个球，分成球内求外
空间放置一个立方体，截取立方体内外
剪切算法实现。
模型的基本上是自己搞一个无限长的平面，利用在利用现成的与或非
影像的话vtkExtractVOI可以实现任意剪裁

2 利用vtkwidget 剪裁模型展示

临时搞一个demo，可以先看下效果。

被剪裁模型：

本地stl文件

剪切区域选择：

球、
box、
平面任意两点、
平面任意多点

剪切算法：

vtkClipPolyData实现两个模型取并、
vtkClipPolyData实现两个模型取异、
vtkCutter实现两个模型去交线、
vtkBoxClipDataSet生成无限平面后去并

stl、box、取交集

stl、box、取外部

stl、box、取交线

stl、ball、取交集

stl、ball、取外部

stl、平面直线、取最大连通域（直线设置比较细，录屏压缩后看不到了）

stl、平面多点、取最大连通域（顺时针内、逆时针外）

3 利用vtkwidget 剪裁模型代码

vtkWidget 大部分使用方法基本一样，vtkBoxWidget举例

1 初始化

 if (widget_type_ == BOX) {if (clip_box_widget_ == nullptr) {clip_box_widget_ = vtkSmartPointer<vtkBoxWidget>::New();clip_box_widget_->GetFaceProperty()->SetColor(0.6, 0.6, 0.2);clip_box_widget_->GetFaceProperty()->SetOpacity(0.25);clip_box_widget_->SetInteractor(vmtk_renderer_->GetRenderWindowInteractor());}}

1 设置rans

  clip_box_widget_->GetTransform(transform_);

2 开启交互

    if (widget_type_ == BOX) {clip_box_widget_->SetInputData(surface_);clip_box_widget_->PlaceWidget();} else if (widget_type_ == SPHERE) {} else if (widget_type_ == LINE) {}if (transform_ && widget_type_ == BOX) {clip_box_widget_->SetTransform(transform_);clip_box_widget_->On();}

3 交互完成后获取数据

vtkSmartPointer<vtkClipPolyData> clipper = vtkSmartPointer<vtkClipPolyData>::New();vtkSmartPointer<vtkPlanes> clip_planes_function;vtkSmartPointer<vtkSphere> clip_sphere_function;clipper->SetInputData(surface_);clipper->GenerateClippedOutputOn();clipper->SetInsideOut(inside_out_);if (widget_type_ == BOX) {clip_planes_function = vtkSmartPointer<vtkPlanes>::New();clipper->SetClipFunction(clip_planes_function);} else if (widget_type_ == SPHERE) {clip_sphere_function = vtkSmartPointer<vtkSphere>::New();clipper->SetClipFunction(clip_sphere_function);}vtkSmartPointer<vtkCutter> cutter = vtkSmartPointer<vtkCutter>::New();cutter->SetInputData(surface_);if (widget_type_ == BOX) {cutter->SetCutFunction(clip_planes_function);} else if (widget_type_ == SPHERE) {cutter->SetCutFunction(clip_sphere_function);}clipped_surface_ = vtkSmartPointer<vtkPolyData>::New();cut_lines_ = vtkSmartPointer<vtkPolyData>::New();if (widget_type_ == BOX) {clip_box_widget_->GetPlanes(clip_planes_function);} else if (widget_type_ == SPHERE) {clip_sphere_widget_->GetSphere(clip_sphere_function);}clipper->Update();if (widget_type_ == BOX) {clip_box_widget_->Off();} else if (widget_type_ == SPHERE) {clip_sphere_widget_->Off();}cutter->Update();

4 关闭交互

    if (widget_type_ == BOX) {clip_box_widget_->Off();} else if (widget_type_ == SPHERE) {clip_sphere_widget_->Off();}

完整代码

我这里把vtkSeedWidget、vtkBoxWidget、vtkSphereWidget封装在一起。

#ifndef VMTKSURFACECLIPPER_H
#define VMTKSURFACECLIPPER_H#include <QObject>
#include <QPointer>
#include "vmtkrenderer.h"#include <vtkPolyData.h>
#include <vtkTransform.h>
#include <vtkBoxWidget.h>
#include <vtkSeedWidget.h>
#include <vtkSmartPointer.h>
#include <vtkSphereWidget.h>class SurfaceClipper : public QObject {Q_OBJECTpublic:enum WidgetType {// 切割方式BOX,SPHERE,LINE};public:explicit SurfaceClipper(QObject *parent = nullptr);virtual ~SurfaceClipper() override;void Execute();void SetEnable(const bool value);void SetSurface(const vtkSmartPointer<vtkPolyData> value);void SetWidgetType(const WidgetType value);void SetTransform(const vtkSmartPointer<vtkTransform> value);void SetInsideOut(const bool value);void SetVmtkRenderer(const QPointer<VmtkRenderer> value);vtkSmartPointer<vtkPolyData> GetSurface() const;vtkSmartPointer<vtkPolyData> GetClippedSurface() const;vtkSmartPointer<vtkPolyData> GetCutLines() const;vtkSmartPointer<vtkTransform> GetTransForm() const;Q_SIGNALS:void SignalClippedFinish();private:void Initial();void Display();void ClipCallback();private Q_SLOTS:void SlotKeyPressed(const QString &key);void SlotSeedChanged(vtkObject *caller, unsigned long vtk_event,void *client_data, void *call_data);private:bool first_connect_;bool own_renderer_;bool inside_out_;QPointer<VmtkRenderer> vmtk_renderer_;vtkSmartPointer<vtkPolyData> surface_;vtkSmartPointer<vtkPolyData> clipped_surface_;vtkSmartPointer<vtkPolyData> cut_lines_;vtkSmartPointer<vtkEventQtSlotConnect> vtk_connections_;vtkSmartPointer<vtkSeedWidget> seed_widget_;vtkSmartPointer<vtkBoxWidget> clip_box_widget_;vtkSmartPointer<vtkSphereWidget> clip_sphere_widget_;vtkSmartPointer<vtkTransform> transform_;WidgetType widget_type_;
};#endif // VMTKSURFACECLIPPER_H

#include "vmtksurfaceclipper.h"
#include <QDebug>
#include <vtkPoints.h>
#include <vtkCamera.h>
#include <vtkCutter.h>
#include <vtkPlanes.h>
#include <vtkSphere.h>#include <vtkStripper.h>
#include <vtkProperty.h>
#include <vtkPointData.h>
#include <vtkProperty2D.h>
#include <vtkClipPolyData.h>
#include <vtkContourFilter.h>
#include <vtkCleanPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkBoxClipDataSet.h>
#include <vtkSeedRepresentation.h>
#include <vtkDataSetSurfaceFilter.h>
#include <vtkPolyDataConnectivityFilter.h>
#include <vtkPointHandleRepresentation2D.h>SurfaceClipper::SurfaceClipper(QObject *parent) : QObject(parent) {Initial();
}SurfaceClipper::~SurfaceClipper() {if (own_renderer_) {vmtk_renderer_->deleteLater();}
}/*** @brief SurfaceClipper::Execute* ui交互开启*/
void SurfaceClipper::Execute() {qDebug();if (surface_ == nullptr) {qWarning() << "no Surface";return ;}if (vmtk_renderer_ == nullptr) {vmtk_renderer_ = new VmtkRenderer();vmtk_renderer_->Initialize();own_renderer_ = true;}if (widget_type_ == BOX) {if (clip_box_widget_ == nullptr) {clip_box_widget_ = vtkSmartPointer<vtkBoxWidget>::New();clip_box_widget_->GetFaceProperty()->SetColor(0.6, 0.6, 0.2);clip_box_widget_->GetFaceProperty()->SetOpacity(0.25);clip_box_widget_->SetInteractor(vmtk_renderer_->GetRenderWindowInteractor());}} else if (widget_type_ == SPHERE) {if (clip_sphere_widget_ == nullptr) {clip_sphere_widget_ = vtkSmartPointer<vtkSphereWidget>::New();clip_sphere_widget_->GetSphereProperty()->SetColor(0.6, 0.6, 0.2);clip_sphere_widget_->GetSphereProperty()->SetOpacity(0.25);clip_sphere_widget_->GetSelectedSphereProperty()->SetColor(0.6, 0.0, 0.0);clip_sphere_widget_->GetSelectedSphereProperty()->SetOpacity(0.75);clip_sphere_widget_->SetRepresentationToSurface();clip_sphere_widget_->SetPhiResolution(20);clip_sphere_widget_->SetThetaResolution(20);clip_sphere_widget_->SetInteractor(vmtk_renderer_->GetRenderWindowInteractor());}} else if (widget_type_ == LINE) {if (this->seed_widget_ == nullptr) {this->seed_widget_ = vtkSmartPointer<vtkSeedWidget>::New();vtkNew<vtkPointHandleRepresentation2D> handle_rep;handle_rep->GetProperty()->SetColor(1, 0, 0);vtkNew<vtkSeedRepresentation> widget_rep;widget_rep->SetHandleRepresentation(handle_rep);this->seed_widget_->SetInteractor(this->vmtk_renderer_->GetRenderWindowInteractor());this->seed_widget_->SetRepresentation(widget_rep);}qint32 num_seeds =this->seed_widget_->GetSeedRepresentation()->GetNumberOfSeeds();for (qint32 i = 0; i < num_seeds; ++i) {this->seed_widget_->GetSeedRepresentation()->RemoveLastHandle();this->seed_widget_->DeleteSeed(this->seed_widget_->GetSeedRepresentation()->GetNumberOfSeeds());}}if (first_connect_) {connect(vmtk_renderer_, &VmtkRenderer::SignalKeyPressed,this, &SurfaceClipper::SlotKeyPressed);this->vtk_connections_ = vtkSmartPointer<vtkEventQtSlotConnect>::New();vtk_connections_->Connect(seed_widget_, vtkCommand::PlacePointEvent,this, SLOT(SlotSeedChanged(vtkObject *, unsigned long,void *, void *)));first_connect_ = false;}transform_ = vtkSmartPointer<vtkTransform>::New();if (widget_type_ == BOX) {clip_box_widget_->GetTransform(transform_);}Display();if (own_renderer_) {vmtk_renderer_->Deallocate();}
}/*** @brief SurfaceClipper::SetSurface* 设置输入模型* @param value*/
void SurfaceClipper::SetSurface(const vtkSmartPointer<vtkPolyData> value) {surface_ = value;
}/*** @brief SurfaceClipper::SetWidgetType* 设置切割方式* @param value*/
void SurfaceClipper::SetWidgetType(const SurfaceClipper::WidgetType value) {widget_type_ = value;
}/*** @brief SurfaceClipper::SetTransform* 设置Trans转换* @param value*/
void SurfaceClipper::SetTransform(const vtkSmartPointer<vtkTransform> value) {transform_ = value;
}/*** @brief SurfaceClipper::SetInsideOut* 设置是否取反* @param value*/
void SurfaceClipper::SetInsideOut(const bool value) {inside_out_ = value;
}/*** @brief SurfaceClipper::SetVmtkRenderer* 输入Renderer* @param value*/
void SurfaceClipper::SetVmtkRenderer(const QPointer<VmtkRenderer> value) {vmtk_renderer_ = value;
}/*** @brief SurfaceClipper::GetSurface* 获取剪切后模型（交）* @return*/
vtkSmartPointer<vtkPolyData> SurfaceClipper::GetSurface() const {return surface_;
}/*** @brief SurfaceClipper::GetClippedSurface* 获取剪切后模型（异）* @return*/
vtkSmartPointer<vtkPolyData> SurfaceClipper::GetClippedSurface() const {return clipped_surface_;
}/*** @brief SurfaceClipper::GetCutLines* 获取剪切后交线* @return*/
vtkSmartPointer<vtkPolyData> SurfaceClipper::GetCutLines() const {return cut_lines_;
}/*** @brief SurfaceClipper::GetTransForm* BOX模式剪切转换* @return*/
vtkSmartPointer<vtkTransform> SurfaceClipper::GetTransForm() const {return transform_;
}/*** @brief SurfaceClipper::Initial* 初始化*/
void SurfaceClipper::Initial() {surface_ = nullptr;clipped_surface_ = nullptr;cut_lines_ = nullptr;vmtk_renderer_ = nullptr;clip_box_widget_ = nullptr;clip_sphere_widget_ = nullptr;first_connect_ = true;own_renderer_ = false;transform_ = nullptr;widget_type_ = LINE;inside_out_ = true;setObjectName("vmtksurfaceclipper");
}/*** @brief SurfaceClipper::Display* 开启widget*/
void SurfaceClipper::Display() {if (widget_type_ == BOX) {clip_box_widget_->SetInputData(surface_);clip_box_widget_->PlaceWidget();} else if (widget_type_ == SPHERE) {clip_sphere_widget_->SetInputData(surface_);clip_sphere_widget_->PlaceWidget();clip_sphere_widget_->On();} else if (widget_type_ == LINE) {this->seed_widget_->On();}if (transform_ && widget_type_ == BOX) {clip_box_widget_->SetTransform(transform_);clip_box_widget_->On();}vmtk_renderer_->Render();
}/*** @brief SurfaceClipper::ClipCallback* 剪裁函数*/
void SurfaceClipper::ClipCallback() {qDebug();if ((widget_type_ == BOX &&clip_box_widget_->GetEnabled() != 1) ||(widget_type_ == SPHERE &&clip_sphere_widget_->GetEnabled() != 1)) {return ;}if(widget_type_ == LINE) {if (this->seed_widget_->GetSeedRepresentation()->GetNumberOfSeeds() != 2|| this->surface_ == nullptr) {return ;}double pos1[3], pos2[3];this->seed_widget_->GetSeedRepresentation()->GetSeedWorldPosition(0, pos1);this->seed_widget_->GetSeedRepresentation()->GetSeedWorldPosition(1, pos2);this->seed_widget_->Off();QList<QList<double>> pts = {{0, 0, 0},{1, 0, 0},{1, 1, 0},{0, 1, 0},{0, 0, 1},{1, 0, 1},{1, 1, 1},{0, 1, 1}};vtkNew<vtkPoints> points;for (qint32 i = 0; i < pts.size(); ++i) {points->InsertPoint(i, pts[i][0], pts[i][1], pts[i][2]);}double direction[3];this->vmtk_renderer_->GetRenderer()->GetActiveCamera()->GetDirectionOfProjection(direction);points->SetPoint(0,pos1[0] - direction[0] * 1000,pos1[1] - direction[1] * 1000,pos1[2] - direction[2] * 1000);points->SetPoint(3,pos1[0] + direction[0] * 1000,pos1[1] + direction[1] * 1000,pos1[2] + direction[2] * 1000);points->SetPoint(1,pos2[0] - direction[0] * 1000,pos2[1] - direction[1] * 1000,pos2[2] - direction[2] * 1000);points->SetPoint(2,pos2[0] + direction[0] * 1000,pos2[1] + direction[1] * 1000,pos2[2] + direction[2] * 1000);double direction2[3], direction_offset[3];direction2[0] = pos1[0] - pos2[0];direction2[1] = pos1[1] - pos2[1];direction2[2] = pos1[2] - pos2[2];vtkMath::Cross(direction, direction2, direction_offset);points->SetPoint(4,pos1[0] - direction[0] * 1000 + direction_offset[0] * 0.01,pos1[1] - direction[1] * 1000 + direction_offset[1] * 0.01,pos1[2] - direction[2] * 1000 + direction_offset[2] * 0.01);points->SetPoint(7,pos1[0] + direction[0] * 1000 + direction_offset[0] * 0.01,pos1[1] + direction[1] * 1000 + direction_offset[1] * 0.01,pos1[2] + direction[2] * 1000 + direction_offset[2] * 0.01);points->SetPoint(5,pos2[0] - direction[0] * 1000 + direction_offset[0] * 0.01,pos2[1] - direction[1] * 1000 + direction_offset[1] * 0.01,pos2[2] - direction[2] * 1000 + direction_offset[2] * 0.01);points->SetPoint(6,pos2[0] + direction[0] * 1000 + direction_offset[0] * 0.01,pos2[1] + direction[1] * 1000 + direction_offset[1] * 0.01,pos2[2] + direction[2] * 1000 + direction_offset[2] * 0.01);vtkNew<vtkBoxClipDataSet> box_clip;box_clip->SetInputData(this->surface_);box_clip->GenerateClippedOutputOn();double n0[3], n1[3], n2[3], n3[3], n4[3], n5[3];double p0[3], p1[3], p2[3], p3[3], p4[3], p5[3];double pt0[3], pt1[3], pt2[3], pt3[3], pt4[3], pt5[3], pt6[3], pt7[3];points->GetPoint(0, pt0);points->GetPoint(1, pt1);points->GetPoint(2, pt2);points->GetPoint(3, pt3);points->GetPoint(4, pt4);points->GetPoint(5, pt5);points->GetPoint(6, pt6);points->GetPoint(7, pt7);for (qint32 i = 0; i < 3; ++i) {p0[i] = (pt1[i] + pt3[i]) / 2;n0[i] = (pt1[i] - pt5[i]);p1[i] = (pt5[i] + pt7[i]) / 2;n1[i] = (pt5[i] - pt1[i]);p2[i] = (pt2[i] + pt5[i]) / 2;n2[i] = (pt5[i] - pt4[i]);p3[i] = (pt3[i] + pt4[i]) / 2;n3[i] = (pt4[i] - pt5[i]);p4[i] = (pt0[i] + pt5[i]) / 2;n4[i] = (pt5[i] - pt6[i]);p5[i] = (pt2[i] + pt7[i]) / 2;n5[i] = (pt6[i] - pt5[i]);}box_clip->SetBoxClip(n0, p0,n1, p1,n2, p2,n3, p3,n4, p4,n5, p5);vtkNew<vtkDataSetSurfaceFilter> surface_in;surface_in->SetInputConnection(box_clip->GetOutputPort(0));vtkNew<vtkDataSetSurfaceFilter> surface_out;surface_out->SetInputConnection(box_clip->GetOutputPort(1));vtkNew<vtkPolyDataConnectivityFilter> connectivity_filter;connectivity_filter->SetInputConnection(surface_out->GetOutputPort());connectivity_filter->SetExtractionModeToLargestRegion();connectivity_filter->Update();this->surface_ = connectivity_filter->GetOutput();return;}vtkSmartPointer<vtkClipPolyData> clipper = vtkSmartPointer<vtkClipPolyData>::New();vtkSmartPointer<vtkPlanes> clip_planes_function;vtkSmartPointer<vtkSphere> clip_sphere_function;clipper->SetInputData(surface_);clipper->GenerateClippedOutputOn();clipper->SetInsideOut(inside_out_);if (widget_type_ == BOX) {clip_planes_function = vtkSmartPointer<vtkPlanes>::New();clipper->SetClipFunction(clip_planes_function);} else if (widget_type_ == SPHERE) {clip_sphere_function = vtkSmartPointer<vtkSphere>::New();clipper->SetClipFunction(clip_sphere_function);}vtkSmartPointer<vtkCutter> cutter = vtkSmartPointer<vtkCutter>::New();cutter->SetInputData(surface_);if (widget_type_ == BOX) {cutter->SetCutFunction(clip_planes_function);} else if (widget_type_ == SPHERE) {cutter->SetCutFunction(clip_sphere_function);}clipped_surface_ = vtkSmartPointer<vtkPolyData>::New();cut_lines_ = vtkSmartPointer<vtkPolyData>::New();if (widget_type_ == BOX) {clip_box_widget_->GetPlanes(clip_planes_function);} else if (widget_type_ == SPHERE) {clip_sphere_widget_->GetSphere(clip_sphere_function);}clipper->Update();if (widget_type_ == BOX) {clip_box_widget_->Off();} else if (widget_type_ == SPHERE) {clip_sphere_widget_->Off();}cutter->Update();cut_lines_->DeepCopy(cutter->GetOutput());surface_->DeepCopy(clipper->GetOutput());clipped_surface_->DeepCopy(clipper->GetClippedOutput());
}/*** @brief SurfaceClipper::SlotKeyPressed* 键盘回调函数* @param key*/
void SurfaceClipper::SlotKeyPressed(const QString &key) {if (key == "space") {ClipCallback();emit SignalClippedFinish();} else if (key == "Escape") {if (widget_type_ == BOX) {clip_box_widget_->Off();} else if (widget_type_ == SPHERE) {clip_sphere_widget_->Off();} else if (widget_type_ == SPHERE) {seed_widget_->Off();}emit SignalClippedFinish();}
}/*** @brief SurfaceClipper::SetEnable* 设置是否启动* @param value*/
void SurfaceClipper::SetEnable(const bool value) {if (widget_type_ == BOX) {clip_box_widget_->SetEnabled(value);} else if (widget_type_ == SPHERE) {clip_sphere_widget_->SetEnabled(value);}
}/*** @brief SurfaceClipper::SlotSeedChanged* 点选取后槽函数* @param caller* @param vtk_event* @param client_data* @param call_data*/
void SurfaceClipper::SlotSeedChanged(vtkObject *caller, unsigned long vtk_event,void *client_data, void *call_data) {Q_UNUSED(client_data)if (vtk_event == vtkCommand::PlacePointEvent) {qint32 n = *static_cast<int *>(call_data);vtkSmartPointer<vtkSeedWidget> widget = dynamic_cast<vtkSeedWidget *>(caller);if (n >= 0 && widget) {qint32 num_seeds = widget->GetSeedRepresentation()->GetNumberOfSeeds();if (num_seeds > 2) {this->seed_widget_->DeleteSeed(0);}}}
}

4 利用vtkwidget 剪裁影像展示

影像剪裁一般在平面选择切割方向让后利用vtkExtractVOI重新切割影像，网友问vtkExtractVOI + vtkBoxWidget应该是在空间剪裁。方法跟上边模型切割一样，周末不上边了补上。

5 利用vtkwidget 剪裁影像代码

Study-VTK：三维影像实现任意方向、大小的切割