VTK Widgets

1
VTK Widgets

• William J. Schroeder
• Kitware, Inc.
• June 2006

2
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
• Contributors
• Will Schroeder
• Lisa Avila
• Karthik Krishnan
• Brad King
• Sebastien Barre
• Dave Cole

3
Overview

• Goals
• Architecture
• Widgets
• Implementation

4
Goals

• Improve human-data interaction
• Provide palette of widgets supporting
• Segmentation
• Registration
• Data interaction
• Text and annotation
• Light, camera, etc. manipulation
• Support client-server (distributed) computing
• Rework initial design

5
Design Goals

• Separate representation from event processing
• Support distributed processing (client-server)
• Introduce translation mechanism between events
  and widget behavior
• Support hierarchical use of widgets
• Create general handle framework for positioning
  points

6
Architecture

• Decoupling representation from event processing

7
One widget, multiple geometries
Geometry
Behavior
vtkPointHandleRepresentation2D
vtkHandleWidget
2D Cross hair
vtkPointHandleRepresentation3D
3D Cross hair
vtkSphereHandleRepresentation
Spherical handle
vtkPolygonalHandleRepresentation
User defined polygonal shape
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Event Translation
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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 Hierarchies

• Example vtkDistanceWidget
• Uses two instances of vtkHandleWidget
• Responds to events from its handles
• Notion of parent
• Reduce number of events
• Reduce number of Render() invocations
• Can change behavior of widget by using different
  types of handles

HandleWidget
HandleWidget
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Handle Framework

• Types of handles
• 2D (display space)
• 3D (world space)
• Constrained
• To plane
• To surface
• Etc?

12
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.

13
vtkPointPlacer
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Widgets

• 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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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) vtkBoundedPlanePointPlacer
• 3D move through slices in volume
  vtkImageActorPointPlacer

21
Widgets (cont.)

• Livewire (shortest path, set arbitrary cost
  functions, for instance gradient of image)
• Dijkstra trace paths on polygonal data

22
Widgets (cont.)
Bezier contours
Live wire
Polygon tracing
Trace on meshes
Trace on Digital elevation map data
vtkContourWidget Users can plug in their own
interpolators
23
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

25
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.)

• vtkScalarBarWidget

• vtkSphereWidget

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Widgets (cont.)

• vtkImagePlaneWidget

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Widgets (cont.)

• vtkParallelopipedWidget
• (3D Affine)

• vtkTensorProbeWidget
• Probe tensors along a tract

31
Widgets (cont.)

• vtkSplineWidget

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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
Widget
Event