NA-MIC
National Alliance for Medical Image Computing
http://na-mic.org
VTK Widgets
William J. Schroeder
Kitware, Inc.
June 2006
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
National Alliance for Medical Image Computing
http://na-mic.org
Overview
• Goals
• Architecture
• Widgets
• Implementation
National Alliance for Medical Image Computing
http://na-mic.org
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
National Alliance for Medical Image Computing
http://na-mic.org
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
National Alliance for Medical Image Computing
http://na-mic.org
Architecture
• Decoupling representation from
event processing
RenderWindow
Events
vtkAbstractWidget
National Alliance for Medical Image Computing
http://na-mic.org
Renderer
Render()
vtkWidgetRepresentation
(type of vtkProp)
One widget, multiple geometries
Geometry
Behavior
vtkHandleWidget
vtkPointHandleRepresentation2D
2D Cross hair
vtkPointHandleRepresentation3D
3D Cross hair
vtkSphereHandleRepresentation
Spherical handle
vtkPolygonalHandleRepresentation
User defined polygonal shape
National Alliance for Medical Image Computing
http://na-mic.org
7
Event Translation
National Alliance for Medical Image Computing
http://na-mic.org
Widget Assemblies
• Create composite widgets from several individual widgets
• Children listen to events from Parent. Hence parent can alter
behavior of child
Parent
Events
Events
Events
Child
Child
National Alliance for Medical Image Computing
http://na-mic.org
RenderWindow
9
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
National Alliance for Medical Image Computing
http://na-mic.org
Handle Framework
• Types of handles
– 2D (display space)
– 3D (world space)
– Constrained
• To plane
• To surface
• Etc?
National Alliance for Medical Image Computing
http://na-mic.org
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.
National Alliance for Medical Image Computing
http://na-mic.org
12
vtkPointPlacer
National Alliance for Medical Image Computing
http://na-mic.org
13
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
National Alliance for Medical Image Computing
http://na-mic.org
14
Widgets
• Handles
National Alliance for Medical Image Computing
http://na-mic.org
Widgets (cont.)
• vtkSliderWidget
– 2D
– 3D
• vtkBorderWidget
– Widgets with
rectangular borders
• vtkTextWidget
– Position & size text
National Alliance for Medical Image Computing
http://na-mic.org
Widgets (cont.)
• BalloonWidget
– Text and/or image in rectangular popup
National Alliance for Medical Image Computing
http://na-mic.org
Widgets (cont.)
• vtkCameraWidget
– Keyframe &
playback camera
• vtkCaptionWidget
– Text with leader
National Alliance for Medical Image Computing
http://na-mic.org
Widgets (cont.)
• vtkCheckerboardWidget
– Interleave two images
• vtkRectilinearWipeWidget
– Window pane
(2x2 checkerboard)
with movable focus
National Alliance for Medical Image Computing
http://na-mic.org
Widgets (cont.)
• vtkContourWidget
– 2D (on plane) : vtkBoundedPlanePointPlacer
– 3D move through slices in volume : vtkImageActorPointPlacer
National Alliance for Medical Image Computing
http://na-mic.org
Widgets (cont.)
– Livewire (shortest path, set
arbitrary cost functions, for
instance gradient of image)
– Dijkstra trace paths on
polygonal data
National Alliance for Medical Image Computing
http://na-mic.org
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
National Alliance for Medical Image Computing
http://na-mic.org
Widgets (cont.)
• vtkDistanceWidget
– Measure distance
between points
National Alliance for Medical Image Computing
http://na-mic.org
• vtkAngleWidget
– Measure angles
Widgets (cont.)
• vtkSeedWidget
– Add one or more
seeds / markers
• vtkAffineWidget
– Translate
– Scale
– Rotate
– Shear images
National Alliance for Medical Image Computing
http://na-mic.org
Widgets (cont.)
• vtkBiDimensionalWidget
– Tumor response (RECIST vs WHO)
National Alliance for Medical Image Computing
http://na-mic.org
Widgets (cont.)
• Box
National Alliance for Medical Image Computing
http://na-mic.org
• Implicit Plane
Widgets (cont.)
• Finite Plane
National Alliance for Medical Image Computing
http://na-mic.org
• Line
Widgets (cont.)
• vtkScalarBarWidget
National Alliance for Medical Image Computing
http://na-mic.org
• vtkSphereWidget
Widgets (cont.)
• vtkImagePlaneWidget
National Alliance for Medical Image Computing
http://na-mic.org
Widgets (cont.)
• vtkParallelopipedWidget
(3D Affine)
National Alliance for Medical Image Computing
http://na-mic.org
• vtkTensorProbeWidget
Probe tensors along a tract
Widgets (cont.)
• vtkSplineWidget
National Alliance for Medical Image Computing
http://na-mic.org
Widget Sets
• Grouping widgets on multiple render windows, relieving the
application of the responsibility of doing so.
RenderWindow
RenderWindow
RenderWindow
Event
Event
Event
National Alliance for Medical Image Computing
http://na-mic.org
Widget
Widget
Widget
Event
Event
WidgetSet
Event
32