VTK中实现距离测量

    根据http://www.vislab.cn/bbs/viewthread.php?tid=223中提供的代码，实现了其效果。

#include "vtkDistanceWidget.h"
#include "vtkSphereSource.h"
#include "vtkPolyDataMapper.h"
#include "vtkActor.h"
#include "vtkRenderer.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkCommand.h"
#include "vtkInteractorEventRecorder.h"
#include "vtkRegressionTestImage.h"
#include "vtkDebugLeaks.h"
#include "vtkCoordinate.h"
#include "vtkMath.h"
#include "vtkHandleWidget.h"
#include "vtkPointHandleRepresentation2D.h"
#include "vtkAxisActor2D.h"
#include "vtkProperty2D.h"
#include "vtkDistanceRepresentation2D.h"
///////////////////////
#include "vtkTIFFReader.h"
#include "vtkImageDataGeometryFilter.h"

class vtkDistanceCallback : public vtkCommand
{
public:
    static vtkDistanceCallback *New()
    { return new vtkDistanceCallback; }
    virtual void Execute(vtkObject *caller, unsigned long, void*);
    vtkDistanceCallback():Renderer(0),RenderWindow(0),DistanceWidget(0),Distance(0) {}
    vtkRenderer *Renderer;
    vtkRenderWindow *RenderWindow;
    vtkDistanceWidget *DistanceWidget;
    vtkDistanceRepresentation2D *Distance;
};


void vtkDistanceCallback::Execute(vtkObject*, unsigned long eid, void* callData)
{
    if ( eid == vtkCommand::InteractionEvent ||
        eid == vtkCommand::EndInteractionEvent )
    {
        double pos1[3], pos2[3];
        // Modify the measure axis
        this->Distance->GetPoint1WorldPosition(pos1);
        this->Distance->GetPoint2WorldPosition(pos2);
        double dist=sqrt(vtkMath::Distance2BetweenPoints(pos1,pos2));

        char title[256]="asasa";
        this->Distance->GetAxis()->SetRange(0.0,dist);
        this->Distance->GetAxis()->SetRange(0.0,dist);
        sprintf(title,"%-#6.3g",dist);
        this->Distance->GetAxis()->SetTitle(title);
    }
    else
    {
        int pid = *(reinterpret_cast<int*>(callData));

        //From the point id, get the display coordinates
        double pos1[3], pos2[3], *pos;
        this->Distance->GetPoint1DisplayPosition(pos1);
        this->Distance->GetPoint2DisplayPosition(pos2);
        if ( pid == 0 )
        {
            pos = pos1;
        }
        else
        {
            pos = pos2;
        }

        // Okay, render without the widget, and get the color buffer
        int enabled = this->DistanceWidget->GetEnabled();
        if ( enabled )
        {
            this->DistanceWidget->SetEnabled(0); //does a Render() as a side effect
        }

        // Pretend we are doing something serious....just randomly bump the
        // location of the point.
        double p[3];
        p[0] = pos[0] + static_cast<int>(vtkMath::Random(-5.5,5.5));
        p[1] = pos[1] + static_cast<int>(vtkMath::Random(-5.5,5.5));
        p[2] = 0.0;

        // Set the new position
        if ( pid == 0 )
        {
            this->Distance->SetPoint1DisplayPosition(p);
        }
        else
        {
            this->Distance->SetPoint2DisplayPosition(p);
        }

        // Side effect of a render here
        if ( enabled )
        {
            this->DistanceWidget->SetEnabled(1);
        }
    }
}

int main(int argc, char *argv[] )
{// Create the RenderWindow, Renderer and both Actors
    //
    vtkRenderer *ren1 = vtkRenderer::New();
    vtkRenderWindow *renWin = vtkRenderWindow::New();
    renWin->AddRenderer(ren1);

    vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New();
    iren->SetRenderWindow(renWin);

    // Create a test pipeline
    //
    vtkSphereSource *ss = vtkSphereSource::New();
    vtkPolyDataMapper *mapper = vtkPolyDataMapper::New();
    mapper->SetInput(ss->GetOutput());
    vtkActor *actor = vtkActor::New();
    actor->SetMapper(mapper);

    // Create the widget and its representation
    vtkPointHandleRepresentation2D *handle = vtkPointHandleRepresentation2D::New();
    handle->GetProperty()->SetColor(1,0,0);
    vtkDistanceRepresentation2D *rep = vtkDistanceRepresentation2D::New();
    rep->SetHandleRepresentation(handle);

    // rep->GetAxis()->SetNumberOfMinorTicks(4);
    rep->GetAxis()->SetTickLength(9);
    //rep->GetAxis()->SetTitlePosition(0.2);


    vtkDistanceWidget *widget = vtkDistanceWidget::New();
    widget->SetInteractor(iren);

    widget->SetRepresentation(rep);

    vtkDistanceCallback *mcbk = vtkDistanceCallback::New();
    mcbk->Renderer = ren1;
    mcbk->RenderWindow = renWin;
    mcbk->Distance = rep;
    mcbk->DistanceWidget = widget;

    // Add the actors to the renderer, set the background and size
    //
    ren1->AddActor(actor);
    ren1->SetBackground(0.1, 0.2, 0.4);
    renWin->SetSize(300, 300);

    // record events
    ///////////////////////////////////
    vtkInteractorEventRecorder *recorder = vtkInteractorEventRecorder::New();
    recorder->SetInteractor(iren);

    recorder->SetFileName("c:/record.log");
    // render the image
    iren->Initialize();
    widget->On();
    iren->Start();
    widget->On();
    ///std::cout<<"asasas"<<std::endl;
    /// renWin->Render();
    std::cout<<"asasas"<<std::endl;
    //widget->On();

    /////// recorder->Play();

    // Remove the observers so we can go interactive. Without this the "-I"
    // testing option fails.
    ////////////////// recorder->Off();

    int retVal = vtkRegressionTestImage( renWin );
    if ( retVal == vtkRegressionTester::DO_INTERACTOR)
    {
        iren->Start();
    }
    ss->Delete();
    mapper->Delete();
    actor->Delete();
    handle->Delete();
    rep->Delete();
    widget->RemoveObserver(mcbk);
    mcbk->Delete();
}

程序运行截图：