[vtkusers] new vtkImagePlaneWidget ENH in VTK

[Dean Inglis]

Hi all,

for those of you with CVS access to the latest VTK, 
this week I added some enhancements to vtkImagePlaneWidget:

1) cross-hair cursoring on left mouse button.  Cross-hair cursor
'snaps' to the center of pixels on a slice.  The cross-hair cursor
is not a global cross-hair: it is internal to a given 
vtkImagePlaneWidget: i.e. it won't jump continuously from slice
to slice in a multi widget pipeline.

2) text annotation which can be controlled via Set/GetTextActor
to access the internal vtkTextActor's vtkTextProperty.  The 
annotation gives the current voxel (integer) coordinates along
with the underlying data value.  During window-level (right mouse)
the window level values are displayed.

3) You can also retrieve:
a) the cursor coords and value into a float array of length 4:
 x,y,z,value (single component image data or first value in 
multi-component images).
b) the current window-level values.

Check out the updated tcl example: 
/Examples/GUI/Tcl/ImagePlaneWidget.tcl

enjoy and your feedback is always welcome,
Dean

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Dean Inglis, Ph.D.
Clinical Research Unit
25 Charlton Avenue East, Unit 610
Hamilton, ONT, L8N 1Y2
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~