Qt&Vtk-031-PickPixel2

Posted 2022-02-03 DreamLife.

​ 最近在开发我的的二维插件的时候，遇到了问题，就是像素点获取问题，所以就百度了一下，准备开搞。

1 官方示例展示

​ 官方链接如下：

官方链接：https://kitware.github.io/vtk-examples/site/Cxx/Images/PickPixel2/

​ 官方给的效果图如下：

2 代码搬运

2.1 PickPixel2.h

#ifndef PICKPIXEL2_H
#define PICKPIXEL2_H

#include <QWidget>
#include "QVTKOpenGLNativeWidget.h"               //新版本，旧版QVTKWidget
#include "vtkAssemblyPath.h"
#include "vtkCell.h"
#include "vtkCommand.h"
#include "vtkCornerAnnotation.h"
#include "vtkImageActor.h"
#include "vtkImageCast.h"
#include "vtkImageData.h"
#include "vtkImageNoiseSource.h"
#include "vtkImageViewer2.h"
#include "vtkInteractorStyleImage.h"
#include "vtkMath.h"
#include "vtkNamedColors.h"
#include "vtkNew.h"
#include "vtkPointData.h"
#include "vtkPropPicker.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkRenderer.h"
#include "vtkSmartPointer.h"
#include "vtkTIFFReader.h"
#include "vtkTextProperty.h"

class vtkImageInteractionCallback;

namespace Ui 
class PickPixel2;


class PickPixel2 : public QWidget

    Q_OBJECT

public:
    explicit PickPixel2(QWidget *parent = nullptr);
    ~PickPixel2();

private:
    Ui::PickPixel2 *ui;
    vtkNew<vtkNamedColors> colors;
    vtkNew<vtkImageViewer2> imageViewer;
    vtkNew<vtkImageNoiseSource> noiseSource;
    vtkNew<vtkImageCast> imageCast;
    vtkNew<vtkPropPicker> propPicker;
    vtkImageActor* imageActor = nullptr;
    vtkRenderer* renderer = nullptr;
    vtkNew<vtkCornerAnnotation> cornerAnnotation;

    vtkNew<vtkImageInteractionCallback> callback;
    vtkInteractorStyleImage* imageStyle;
;

#endif // PICKPIXEL2_H

2.2 PickPixel2.cpp

#include "pickpixel2.h"
#include "ui_pickpixel2.h"
#include <QDebug>

template <typename T>
void vtkValueMessageTemplate(vtkImageData* image, int* position,
                             std::string& message)

    T* tuple = ((T*)image->GetScalarPointer(position));
    int components = image->GetNumberOfScalarComponents();
    for (int c = 0; c < components; ++c)
    
        message += vtkVariant(tuple[c]).ToString();
        if (c != (components - 1))
        
            message += ", ";
        
    
    message += " )";



class vtkImageInteractionCallback : public vtkCommand

public:
    static vtkImageInteractionCallback* New()
    



        return new vtkImageInteractionCallback;
    

    vtkImageInteractionCallback()
    
        this->Viewer = NULL;
        this->Picker = NULL;
        this->Annotation = NULL;
    

    ~vtkImageInteractionCallback()
    
        this->Viewer = NULL;
        this->Picker = NULL;
        this->Annotation = NULL;
    

    void SetPicker(vtkPropPicker* picker)
    
        this->Picker = picker;
    

    void SetAnnotation(vtkCornerAnnotation* annotation)
    
        this->Annotation = annotation;
    

    void SetViewer(vtkImageViewer2* viewer)
    
        this->Viewer = viewer;
    

    virtual void Execute(vtkObject*, unsigned long vtkNotUsed(event), void*)
    

        qDebug() << "asd";

        vtkRenderWindowInteractor* interactor =
                this->Viewer->GetRenderWindow()->GetInteractor();
        vtkRenderer* renderer = this->Viewer->GetRenderer();
        vtkImageActor* actor = this->Viewer->GetImageActor();
        vtkImageData* image = this->Viewer->GetInput();
        vtkInteractorStyle* style =
                dynamic_cast<vtkInteractorStyle*>(interactor->GetInteractorStyle());

        // Pick at the mouse location provided by the interactor
        this->Picker->Pick(interactor->GetEventPosition()[0],
                interactor->GetEventPosition()[1], 0.0, renderer);

        // There could be other props assigned to this picker, so
        // make sure we picked the image actor
        vtkAssemblyPath* path = this->Picker->GetPath();
        bool validPick = false;

        if (path)
        
            vtkCollectionSimpleIterator sit;
            path->InitTraversal(sit);
            for (int i = 0; i < path->GetNumberOfItems() && !validPick; ++i)
            
                auto node = path->GetNextNode(sit);
                if (actor == dynamic_cast<vtkImageActor*>(node->GetViewProp()))
                
                    validPick = true;
                
            
        

        if (!validPick)
        
            this->Annotation->SetText(0, "Off Image");
            interactor->Render();
            // Pass the event further on
            style->OnMouseMove();
            return;
        

        // Get the world coordinates of the pick
        double pos[3];
        this->Picker->GetPickPosition(pos);

        int image_coordinate[3];

        int axis = this->Viewer->GetSliceOrientation();
        switch (axis)
        
        case vtkImageViewer2::SLICE_ORIENTATION_XZ:
            image_coordinate[0] = vtkMath::Round(pos[0]);
            image_coordinate[1] = this->Viewer->GetSlice();
            image_coordinate[2] = vtkMath::Round(pos[2]);
            break;
        case vtkImageViewer2::SLICE_ORIENTATION_YZ:
            image_coordinate[0] = this->Viewer->GetSlice();
            image_coordinate[1] = vtkMath::Round(pos[0]);
            image_coordinate[2] = vtkMath::Round(pos[1]);
            break;
        default: // vtkImageViewer2::SLICE_ORIENTATION_XY
            image_coordinate[0] = vtkMath::Round(pos[0]);
            image_coordinate[1] = vtkMath::Round(pos[1]);
            image_coordinate[2] = this->Viewer->GetSlice();
            break;
        

        std::string message = "Location: ( ";
        message += vtkVariant(image_coordinate[0]).ToString();
        message += ", ";
        message += vtkVariant(image_coordinate[1]).ToString();
        message += ", ";
        message += vtkVariant(image_coordinate[2]).ToString();
        message += " )\\nValue: ( ";

        switch (image->GetScalarType())
        
        vtkTemplateMacro(
                    (vtkValueMessageTemplate<VTK_TT>(image, image_coordinate, message)));

        default:
            return;
        

        this->Annotation->SetText(0, message.c_str());
        interactor->Render();
        style->OnMouseMove();
    

private:
    vtkImageViewer2* Viewer;         // Pointer to the viewer
    vtkPropPicker* Picker;           // Pointer to the picker
    vtkCornerAnnotation* Annotation; // Pointer to the annotation
;




PickPixel2::PickPixel2(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::PickPixel2)

    ui->setupUi(this);


    noiseSource->SetWholeExtent(0, 512, 0, 512, 0, 512);
    noiseSource->SetMinimum(0.0);
    noiseSource->SetMaximum(255.0);

    imageCast->SetInputConnection(noiseSource->GetOutputPort());
    imageCast->SetOutputScalarTypeToUnsignedChar();
    imageCast->Update();
    imageViewer->SetInputConnection(imageCast->GetOutputPort());
    propPicker->PickFromListOn();

    imageActor = vtkSmartPointer<vtkImageActor>::New();
    imageActor = imageViewer->GetImageActor();
    propPicker->AddPickList(imageActor);
    imageActor->InterpolateOff();

    vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
      imageViewer->SetupInteractor(renderWindowInteractor);


    cornerAnnotation->SetLinearFontScaleFactor(2);
    cornerAnnotation->SetNonlinearFontScaleFactor(1);
    cornerAnnotation->SetMaximumFontSize(20);
    cornerAnnotation->SetText(0, "Off Image");
    cornerAnnotation->SetText(3, "<window>\\n<level>");
    cornerAnnotation->GetTextProperty()->SetColor(
                colors->GetColor3d("LightGoldenrodYellow").GetData());
    imageViewer->GetRenderer()->AddViewProp(cornerAnnotation);

    renderer = imageViewer->GetRenderer();
    renderer->ResetCamera();
    renderer->GradientBackgroundOn();
    renderer->SetBackground(colors->GetColor3d("DarkSlateGray").GetData());
    renderer->SetBackground2(colors->GetColor3d("LightSlateGray").GetData());

    callback->SetViewer(imageViewer);
    callback->SetAnnotation(cornerAnnotation);
    callback->SetPicker(propPicker);


    imageStyle = imageViewer->GetInteractorStyle();
    if(imageStyle)
        imageStyle->AddObserver(vtkCommand::MouseMoveEvent, callback);
    renderWindowInteractor->Initialize();
    renderWindowInteractor->Start();
    imageViewer->SetRenderWindow(ui->openGLWidget->renderWindow());




PickPixel2::~PickPixel2()

    delete ui;

​ 这里有点小问题，就是这个程序运行起来的时候是一个独立的窗口，没有在我们的大程序里面，不过这个目前没有时间修饰，我们重点是看懂怎么搞屏幕坐标和世界坐标的。

3 运行效果

★ 源码 ★

​ 源码分享一时爽，一直分享一直爽， 链接如下：

自取：https://github.com/DreamLife-Jianwei/Qt-Vtk

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