specialized widgets for vtk - wright state...

3-1 Department of Computer Science and Engineering

3 Specialized Widgets for VTK

Specialized Widgets for VTK



Thanks • National Library of Medicine / NIH

– Dr. Terry Yoo: A2D2 awards (Algorithms, Adaptors, and Data Distribution)

• National Science Foundation

– Visual Journal project

• NIH National Center for Biomedical Computing

– NAMIC

• DOE National Labs

– Sandia

– Livermore

• Contributors

– Will Schroeder

– Karthik Krishnan

– Lisa Avila

– Brad King

– Sebastien Barre

– Dave Cole



Goals

• Directly interact with data

• Provide complex, potentially 3D interaction techniques

– Probing

– Annotation

– Measurements



4

Interactor styles • Everybody has their favorite way of interacting with

Data.

RenderWindow

User Events

Interactor Interactor Style

Events

vtkCamera

Actions

Render()

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Object Relationships

vtkInteractorObserver

vtkInteractorStyle vtkAbstractWidget

vtkRenderWindowInteractor


3 Specialized Widgets for VTK Interactor Styles (contd..)

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Interactor styles (usage)

• Set the interactor style on the Render Window Interactor

vtkInteractorStyleTrackballCamera *style =

vtkInteractorStyleTrackballCamera::New();

renderWindowInteractor -> SetInteractorStyle( style );



VTK Widgets



VTK - Widgets • Widgets are simply Interactive Props

• VTK currently has widgets to perform

– Measurements

– Annotation and Labeling

– Segmentation

– Registration

– Data interaction

– Scene parameter manipulation: Light, camera, etc.

– Probing underlying data

• Timer support

• Multiple geometrical representations for the same widget

• Reconfigurable key/mouse bindings

• Grouping widgets



Visualization pipeline



vtkRenderWindow

Widget

User Interaction

Events

vtkRenderWindowInteractor

Widgets are interactive props

vtkRenderer Render()

Manipulate one

or more props

Widget Representation



Widgets – Design goals

• Separate representation from event processing

– Support distributed processing (client-server)

• Reconfigurable bindings

• Support hierarchical use of widgets

• Grouping widgets

• Timer, Hover support



RenderWindow

vtkAbstractWidget

vtkWidgetRepresentation

(type of vtkProp)

Events

Renderer

Render()

Widgets Architecture

Behavior Geometry



One widget, multiple geometries

vtkHandleWidget vtkPointHandleRepresentation2D

vtkPointHandleRepresentation3D

vtkSphereHandleRepresentation

vtkPolygonalHandleRepresentation

Behavior Geometry



15

Configurable bindings: Event Translation



Event Translation

• Re-configurable keyboard/mouse bindings

• Example:

vtkWidgetEventTranslator *eventTranslator = widget->GetEventTranslator();

eventTranslator->SetTranslation( vtkCommand::MiddleButtonPressEvent, vtkWidgetEvent::Select ); eventTranslator->SetTranslation( vtkCommand::MiddleButtonReleaseEvent, vtkWidgetEvent::EndSelect );



Widget Assemblies • Create composite widgets from several individual widgets

• Children listen to events from Parent. Hence parent can alter

behavior of child

Parent

Child Child

RenderWindow Events

Events Events



Widget Assemblies

• Code reuse

• Component framework:

– Change behaviour / geometry of Line widget by changing the

handle widgets.

HandleWidget HandleWidget

Line Widget



Timer support

• Widgets may respond to timers

– Hover widget

– Balloon widget

– Timer based hover annotations, Popups (text, thumbnails etc).



Handle Framework • Handles are often fundamental building blocks of other widgets

– vtkLineWidget2

– vtkDistanceWidget

– vtkAngleWidget

– vtkBiDimensionalWidget

– vtkSeedWidget

– vtkParallelopipedWidget

• Need multiple representations for handles

• Need a framework for constraints on handles

• To plane

• To surface

• To a terrain

• To a region.


3 Specialized Widgets for VTK Various handle representations

(geometries)

vtkHandleWidget vtkPointHandleRepresentation2D

vtkPointHandleRepresentation3D

vtkSphereHandleRepresentation

vtkPolygonalHandleRepresentation



Constraints – Point Placers

• To map 2D display positions to 3D world coordinates.

Does a 2D display position map to:

– Focal Plane ?

– Point on a surface ?

– Point on a plane / image ?

– Out of bounds ?

• Allows a variety of constraints to be placed the

placement of widgets.



Widgets

• Handles



Widgets (cont.) • vtkSliderWidget

– 2D

– 3D

• vtkBorderWidget

– Widgets with rectangular borders

• vtkTextWidget

– Position & size text



Widgets (cont.)

• BalloonWidget

– Text and/or image in rectangular popup



Widgets (cont.)

• vtkCameraWidget

– Keyframe &

playback camera

• vtkCaptionWidget

– Text with leader



Widgets (cont.)

• vtkCheckerboardWidget

– Interleave two images

• vtkRectilinearWipeWidget

– Window pane

(2x2 checkerboard)

with movable focus



Widgets (cont.)

• vtkContourWidget

– 2D (on plane)

– 3D (move contours through slices in a volume)



Widgets (cont.) • vtkDistanceWidget

– Measure distance

between points

• vtkAngleWidget

– Measure angles



Widgets (cont.)

• vtkSeedWidget

– Add one or more seeds / markers

• vtkAffineWidget

– Translate

– Scale

– Rotate

– Shear images



Widgets (cont.)

• vtkBiDimensionalWidget

– Tumor response (RECIST vs WHO)



Widgets (cont.) • Box

• Implicit Plane



Widgets (cont.) • Finite Plane • Line



Widgets (cont.)

• vtkScalarBarWidget

• vtkSphereWidget



Slider Widget Example vtkSliderRepresentation2D *sliderRep = vtkSliderRepresentation2D::New();

sliderRep->SetValue(0.25);

sliderRep->SetTitleText("Spike Size");

sliderRep->GetPoint1Coordinate()->SetCoordinateSystemToNormalizedDisplay();

sliderRep->GetPoint1Coordinate()->SetValue(0.2,0.15);

sliderRep->GetPoint2Coordinate()->SetCoordinateSystemToNormalizedDisplay();

sliderRep->GetPoint2Coordinate()->SetValue(0.8,0.15);

sliderRep->SetSliderLength(0.02);

sliderRep->SetSliderWidth(0.03);

sliderRep->SetEndCapLength(0.01);

sliderRep->SetEndCapWidth(0.03);

sliderRep->SetTubeWidth(0.005);

vtkSliderWidget *sliderWidget = vtkSliderWidget::New();

sliderWidget->SetInteractor(iren);

sliderWidget->SetRepresentation(sliderRep);

sliderWidget->SetAnimationModeToAnimate();

vtkSlider2DCallback *callback = vtkSlider2DCallback::New();

callback->Glyph = glyph;

sliderWidget->AddObserver(vtkCommand::InteractionEvent,callback);



Slider Widget Example (Cont.) class vtkSlider2DCallback : public vtkCommand

{

public:

static vtkSlider2DCallback *New()

{ return new vtkSlider2DCallback; }

virtual void Execute(vtkObject *caller, unsigned long, void*)

{

vtkSliderWidget *sliderWidget =

reinterpret_cast<vtkSliderWidget*>(caller);

this->Glyph->SetScaleFactor(static_cast<vtkSliderRepresentation *>(sliderWidget-

>GetRepresentation())->GetValue());

}

vtkSlider2DCallback():Glyph(0) {}

vtkGlyph3D *Glyph;

};



vtkPointPlacer



Widget Sets

• Grouping widgets on multiple render windows, relieving the

application of the responsibility of doing so.

RenderWindow

Event Widget

RenderWindow Event

Widget

RenderWindow Event

Widget

WidgetSet Event

Event

Event

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