VTK_Learning_交互部件_标注类Widget的应用

1.标注类Widget

在可视化程序中，经常会对某个对象做一些标注说明，比如，在医学图像诊断中，常常会手动标注出被诊断为肿瘤的区域或者其他病变区域，并用文字进行标注。

VTK中，与标注相关的Widget如下表所示：

•  vtkTextWidget:在渲染场景中生成一串标识文本，可以随意调整该文本在渲染场景中的位置，缩放其大小等。
• vtkScalarBarWidget:根据输入的数据在渲染场景中生成一个标量条，通过设置颜色查找表，可以用标量条上的颜色来指示输入的数据。渲染场景中的标量条可以随意移动、改变大小、设置不同的方向等。
• vtkCaptionWidget:用一个带线框及箭头的文本信息来标注某一对象。
• vtkOrientationMarkerWidget:渲染场景中所渲染数据的方向指示标志。在医学图像领域有广泛的应用，比如，通过CT/MR等扫描的数据，当将其导入可视化应用程序时需要标识其上、下、左、右、前、后等方位。
• vtkBalloonWidget:当鼠标停留在渲染场景中的某个Actor一段时间后，会弹出提示信息。所提示的信息，除了可以用文本表示，也可以用图像表示。
   

 2.标注类Widget应用程序

#include <vtkAutoInit.h>
VTK_MODULE_INIT(vtkRenderingOpenGL)
VTK_MODULE_INIT(vtkInteractionStyle)
VTK_MODULE_INIT(vtkRenderingFreeType)
 
#include <vtkSmartPointer.h>
#include <vtkUnstructuredGridReader.h>
#include <vtkUnstructuredGrid.h>
#include <vtkLookupTable.h>
#include <vtkDataSetMapper.h>
#include <vtkActor.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
 
#include <vtkScalarBarActor.h>
#include <vtkScalarBarWidget.h>
#include <vtkTextActor.h>
#include <vtkTextWidget.h>
#include <vtkTextProperty.h>
#include <vtkTextRepresentation.h>
#include <vtkAxesActor.h>
#include <vtkOrientationMarkerWidget.h>
#include <vtkCaptionWidget.h>
#include <vtkCaptionActor2D.h>///
#include <vtkCaptionRepresentation.h>
#include <vtkBalloonWidget.h>
#include <vtkBalloonRepresentation.h>
 
int main()
{
  vtkSmartPointer< vtkUnstructuredGridReader > reader = vtkSmartPointer< vtkUnstructuredGridReader >::New();
  reader->SetFileName("data.vtk");
  reader->Update();
 
  vtkSmartPointer< vtkLookupTable > lut = vtkSmartPointer< vtkLookupTable >::New();
  lut->Build();
 
  vtkSmartPointer< vtkDataSetMapper > mapper = vtkSmartPointer< vtkDataSetMapper >::New();
  mapper->SetInputData(reader->GetOutput());
  mapper->SetScalarRange(reader->GetOutput()->GetScalarRange());
  mapper->SetLookupTable(lut);
 
  vtkSmartPointer< vtkActor > actor = vtkSmartPointer< vtkActor >::New();
  actor->SetMapper(mapper);
 
  vtkSmartPointer< vtkRenderer > renderer = vtkSmartPointer< vtkRenderer >::New();
  renderer->AddActor(actor);
  renderer->SetBackground(1, 1, 1);
 
  vtkSmartPointer< vtkRenderWindow > renderWindow = vtkSmartPointer< vtkRenderWindow >::New();
  renderWindow->AddRenderer(renderer);
  renderWindow->Render();
  renderWindow->SetWindowName("AnnotationWidget");
  renderWindow->SetSize(400, 400);
 
  vtkSmartPointer< vtkRenderWindowInteractor > interactor = 
    vtkSmartPointer< vtkRenderWindowInteractor >::New();
  interactor->SetRenderWindow(renderWindow);
/********************************************************************************************/
  //标注类测试
   vtkScalarBarWidget
  vtkSmartPointer< vtkScalarBarActor > scalarBarActor = vtkSmartPointer< vtkScalarBarActor >::New();
  scalarBarActor->SetOrientationToHorizontal();
  scalarBarActor->SetLookupTable(lut);
 
  vtkSmartPointer< vtkScalarBarWidget > scalarBarWidget = vtkSmartPointer< vtkScalarBarWidget >::New();
  scalarBarWidget->SetInteractor(interactor);
  scalarBarWidget->SetScalarBarActor(scalarBarActor);
  scalarBarWidget->On();
 
  vtkTextWidget
  vtkSmartPointer<vtkTextActor> textActor = vtkSmartPointer<vtkTextActor>::New();
  textActor->SetInput("VTK Widgets");
  textActor->GetTextProperty()->SetColor(1, 0, 0);
 
  vtkSmartPointer<vtkTextWidget> textWidget = vtkSmartPointer<vtkTextWidget>::New();
  textWidget->SetInteractor(interactor);
  textWidget->SetTextActor(textActor);
 
  vtkSmartPointer<vtkTextRepresentation>  textRepresentation =
    vtkSmartPointer<vtkTextRepresentation>::New();
  textRepresentation->GetPositionCoordinate()->SetValue(0.15, 0.15);
  textRepresentation->GetPosition2Coordinate()->SetValue(0.7, 0.2);
 
  textWidget->SetRepresentation(textRepresentation);
  textWidget->SelectableOff();
  textWidget->On();
 
  / vtkOrientationMarkerWidget
  vtkSmartPointer<vtkAxesActor> iconActor = vtkSmartPointer<vtkAxesActor>::New();
  vtkSmartPointer<vtkOrientationMarkerWidget> orientationWidget =
    vtkSmartPointer<vtkOrientationMarkerWidget>::New();
  orientationWidget->SetOutlineColor(0.9300, 0.5700, 0.1300);
  orientationWidget->SetInteractor(interactor);
  orientationWidget->SetOrientationMarker(iconActor);
  orientationWidget->SetViewport(0.0, 0.0, 0.2, 0.2);
  orientationWidget->SetEnabled(1);
  orientationWidget->InteractiveOn();
 
   vtkCaptionWidget
  //vtkSmartPointer<vtkCaptionWidget> captionWidget = 
  //  vtkSmartPointer<vtkCaptionWidget>::New();
  //captionWidget->SetInteractor(interactor);
 
  //vtkSmartPointer<vtkCaptionRepresentation> captionRepresentation =
  //  vtkSmartPointer<vtkCaptionRepresentation>::New();
  //captionRepresentation->GetCaptionActor2D()->SetCaption("Caption Widget");
  //captionRepresentation->GetCaptionActor2D()->GetTextActor()->GetTextProperty()->SetFontSize(20);
  //
  //double pos[3] = { .5, 0, 0 };
  //captionRepresentation->SetAnchorPosition(pos);
  //captionWidget->SetRepresentation(captionRepresentation);
  //captionWidget->On();
 
  / vtkBalloonWidget
  vtkSmartPointer<vtkBalloonWidget> balloonWidget =
    vtkSmartPointer<vtkBalloonWidget>::New();
  balloonWidget->SetInteractor(interactor);
 
  vtkSmartPointer<vtkBalloonRepresentation> balloonRep =
    vtkSmartPointer<vtkBalloonRepresentation>::New();
  balloonRep->SetBalloonLayoutToImageRight();
 
  balloonWidget->SetRepresentation(balloonRep);
  balloonWidget->AddBalloon(actor, "This is a widget example", NULL);
  balloonWidget->On();
 
  renderWindow->Render();
  interactor->Initialize();
  interactor->Start();
  return 0;
}

输出结果如下：

 使用标注类Widget需要注意的是，除了指定的Widget表达实体之外，某些Widget还需要与其他Actor协同使用；如上例中的vtkScalarBarWidget要与vtkScalarBarActor协同工作；vtkTextWidget要与vtkTextActor协同工作。