VTK初入门径--第五只小板凳

这两天有人问我,
前几章的示例都是在窗口中绘制图形,
或对窗口进行放大,旋转等,
我们能对图形进行操作么?如怎样把图形拉大,拉长?

"大家说行么?"
有人嘿嘿一笑,坏坏地说:"例子里就有"
"你答对了"

下面我就把这个例子阐述一下,也增加点我的经验值,

 
这个例子介绍了3D窗口小部件(widgets),3D widgets利用了第二只小板凳中
提到的事件/观察器的设计模式.3D widgets在场景中使用了一个特别的物件,
能够用键盘或鼠标进行交互式选择和操作.当操作widets物件时,它们依次调用
相应的消息事件.

特别提醒:更多的widget相关例子在VTK/Examples/GUI

首先:还是先添加相应的头文件;
其次:加入相互作用的回调类,这个类将会在oberser中由程序自动加载调用;
然后:像前几章一样添加相应的函数

 

#include "vtkConeSource.h"#include "vtkPolyDataMapper.h"#include "vtkRenderWindow.h"#include "vtkRenderWindowInteractor.h"#include "vtkCamera.h"#include "vtkActor.h"#include "vtkRenderer.h"#include "vtkCommand.h"#include "vtkBoxWidget.h"#include "vtkTransform.h"#include "vtkInteractorStyleTrackballCamera.h"class vtkWidgetsCallback : public vtkCommand{public: static vtkWidgetsCallback *New() { return new vtkWidgetsCallback; } virtual void Execute(vtkObject *caller, unsigned long, void*) { vtkTransform *t = vtkTransform::New(); vtkBoxWidget *widget = reinterpret_cast<vtkBoxWidget*>(caller); widget->GetTransform(t); widget->GetProp3D()->SetUserTransform(t); t->Delete(); }};int UseWidgets(){ //创建数据源 vtkConeSource *cone = vtkConeSource::New(); cone->SetHeight( 3.0 ); cone->SetRadius( 1.0 ); cone->SetResolution( 10 ); vtkPolyDataMapper *coneMapper = vtkPolyDataMapper::New(); coneMapper->SetInputConnection( cone->GetOutputPort() ); vtkActor *coneActor = vtkActor::New(); coneActor->SetMapper( coneMapper ); vtkRenderer *ren1= vtkRenderer::New(); ren1->AddActor( coneActor ); ren1->SetBackground( 0.1, 0.2, 0.4 ); vtkRenderWindow *renWin = vtkRenderWindow::New(); renWin->AddRenderer( ren1 ); renWin->SetSize( 300, 300 ); vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New(); iren->SetRenderWindow(renWin); /* 在这里vtkRenderWindowInteractor示范了一个vtkInteractorStyle实例,vtkInteractorStyle 旨在翻译消息事件为相应的操作,这些操作与vtkRenderWinodwInteractor密切相关. */ vtkInteractorStyleTrackballCamera *style = vtkInteractorStyleTrackballCamera::New(); iren->SetInteractorStyle(style); /* 在这里我们用了一个vtkBoxWidget对象来对actor进行相应的转换变形,更多类型的widget 可参考相应的文档 vtk3DWidget的SetInteractor方法是vtk3DWidget与vtkRenderWindowInteractor的桥梁和纽带, */ vtkBoxWidget *boxWidget = vtkBoxWidget::New(); boxWidget->SetInteractor(iren); boxWidget->SetPlaceFactor(1.25); boxWidget->SetProp3D(coneActor); boxWidget->PlaceWidget(); vtkWidgetsCallback *callback = vtkWidgetsCallback::New(); boxWidget->AddObserver(vtkCommand::InteractionEvent, callback); boxWidget->On(); iren->Initialize(); iren->Start(); // // 对象的释放 cone->Delete(); coneMapper->Delete(); coneActor->Delete(); callback->Delete(); boxWidget->Delete(); ren1->Delete(); renWin->Delete(); iren->Delete(); style->Delete(); return 0;}

 

 

效果图: