VTK 3D Widgets

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VTK 3D Widgets
Karthik Krishnan Will Schroeder Kitware, Inc.
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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

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Goals

• Directly interact with data
• Provide complex, potentially 3D interaction
  techniques
• Probing
• Annotation
• Measurements

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Interactor styles

• Everybody has their favorite way of interacting
  with Data.

User Events
RenderWindow
Interactor
Interactor Style
Events
Actions
vtkCamera
Render()
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Object Relationships
vtkRenderWindowInteractor
vtkInteractorObserver
vtkInteractorStyle
vtkAbstractWidget
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Interactor Styles (contd..)
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Interactor styles (usage)

• Set the interactor style on the Render Window
  Interactor
• vtkInteractorStyleTrackballCamera style
• vtkInteractorStyleTrackballCameraNew()
• renderWindowInteractor -gt SetInteractorStyle(
  style )

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• VTK Widgets

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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

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Visualization pipeline
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Widgets are interactive props
vtkRenderWindow
vtkRenderWindowInteractor
User Interaction Events
Widget
Manipulate one or more props
vtkRenderer
Render()
Widget Representation
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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

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Widgets Architecture
Behavior
Geometry
RenderWindow
Renderer
Events
Render()
vtkAbstractWidget
vtkWidgetRepresentation(type of vtkProp)
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One widget, multiple geometries
Behavior
Geometry
vtkPointHandleRepresentation2D
vtkHandleWidget
vtkPointHandleRepresentation3D
vtkSphereHandleRepresentation
vtkPolygonalHandleRepresentation
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Configurable bindings Event Translation
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Event Translation

• Re-configurable keyboard/mouse bindings
• Example
• vtkWidgetEventTranslator eventTranslator
  widget-gtGetEventTranslator()
• eventTranslator-gtSetTranslation(
• vtkCommandMiddleButtonPressEvent,
  
• vtkWidgetEventSelect )
• eventTranslator-gtSetTranslation(
• vtkCommandMiddleButtonReleaseEvent,
  
• vtkWidgetEventEndSelect )

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Widget Assemblies

• Create composite widgets from several individual
  widgets
• Children listen to events from Parent. Hence
  parent can alter behavior of child

RenderWindow
Events
Parent
Events
Events
Child
Child
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Widget Assemblies

• Code reuse
• Component framework
• Change behaviour / geometry of Line widget by
  changing the handle widgets.

Line Widget
HandleWidget
HandleWidget
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Timer support

• Widgets may respond to timers
• Hover widget
• Balloon widget
• Timer based hover annotations, Popups (text,
  thumbnails etc).

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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.

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Various handle representations (geometries)
vtkPointHandleRepresentation2D
vtkHandleWidget
vtkPointHandleRepresentation3D
vtkSphereHandleRepresentation
vtkPolygonalHandleRepresentation
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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.

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Widgets

• Handles

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Widgets (cont.)

• vtkSliderWidget
• 2D
• 3D
• vtkBorderWidget
• Widgets with rectangular borders
• vtkTextWidget
• Position size text

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Widgets (cont.)

• BalloonWidget
• Text and/or image in rectangular popup

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Widgets (cont.)

• vtkCameraWidget
• Keyframe playback camera
• vtkCaptionWidget
• Text with leader

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Widgets (cont.)

• vtkCheckerboardWidget
• Interleave two images
• vtkRectilinearWipeWidget
• Window pane(2x2 checkerboard)with movable focus

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Widgets (cont.)

• vtkContourWidget
• 2D (on plane)
• 3D (move contours through slices in a volume)

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Widgets (cont.)

• vtkDistanceWidget
• Measure distance between points

• vtkAngleWidget
• Measure angles

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Widgets (cont.)

• vtkSeedWidget
• Add one or more seeds / markers
• vtkAffineWidget
• Translate
• Scale
• Rotate
• Shear images

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Widgets (cont.)

• vtkBiDimensionalWidget
• Tumor response (RECIST vs WHO)

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Widgets (cont.)

• Box

• Implicit Plane

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Widgets (cont.)

• Finite Plane

• Line

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Widgets (cont.)

• vtkSphereWidget

• vtkScalarBarWidget

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Slider Widget Example

• vtkSliderRepresentation2D sliderRep
  vtkSliderRepresentation2DNew()
• sliderRep-gtSetValue(0.25)
• sliderRep-gtSetTitleText("Spike Size")
• sliderRep-gtGetPoint1Coordinate()-gtSetCoordinateS
  ystemToNormalizedDisplay()
• sliderRep-gtGetPoint1Coordinate()-gtSetValue(0.2,0
  .15)
• sliderRep-gtGetPoint2Coordinate()-gtSetCoordinateS
  ystemToNormalizedDisplay()
• sliderRep-gtGetPoint2Coordinate()-gtSetValue(0.8,0
  .15)
• sliderRep-gtSetSliderLength(0.02)
• sliderRep-gtSetSliderWidth(0.03)
• sliderRep-gtSetEndCapLength(0.01)
• sliderRep-gtSetEndCapWidth(0.03)
• sliderRep-gtSetTubeWidth(0.005)
• vtkSliderWidget sliderWidget
  vtkSliderWidgetNew()
• sliderWidget-gtSetInteractor(iren)
• sliderWidget-gtSetRepresentation(sliderRep)
• sliderWidget-gtSetAnimationModeToAnimate()
• vtkSlider2DCallback callback
  vtkSlider2DCallbackNew()

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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_castltvtkSliderWidgetgt(caller)
  
• this-gtGlyph-gtSetScaleFactor(static_castltvtkS
  liderRepresentation gt(sliderWidget-gtGetRepresenta
  tion())-gtGetValue())
• vtkSlider2DCallback()Glyph(0)
• vtkGlyph3D Glyph

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vtkPointPlacer
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Widget Sets

• Grouping widgets on multiple render windows,
  relieving the application of the responsibility
  of doing so.

Event
RenderWindow
Widget
Event
Event
Event
RenderWindow
WidgetSet
Widget
Event
RenderWindow
Event
Widget