vtkImage problem

[Wilfrid Lefer]

Hi,
could anybody tell me why the following code works on a true colors
display but raises an X error on a false colors one?
Here is the piece of code:

source $env(VTKDIR)/imaging/examplesTcl/vtkImageInclude.tcl
wm withdraw .
vtkImageCanvasSource2D canvas
  canvas SetScalarType $VTK_UNSIGNED_CHAR
  canvas SetNumberOfScalarComponents 3
  canvas SetExtent 0 299 0 299 0 0
  canvas SetDrawColor 255 0 0
  canvas FillBox 50 150 50 150
vtkImageMapper mapper
  mapper SetInput [canvas GetOutput]
vtkActor2D actor
  actor SetMapper mapper
vtkImager imager
  imager AddActor2D actor
vtkImageWindow win
  win AddImager imager
win Render      

and here is the X error message:

X Error of failed request:  BadValue (integer parameter out of range for
operation)
  Major opcode of failed request:  86 (X_AllocColorCells)
  Value in failed request:  0x0
  Serial number of failed request:  6
  Current serial number in output stream:  6

-- 

_____________________________________________________________________________
|                                       
|                                    |
| Wilfrid LEFER                          | phone: (+33)
3.21.97.00.46         |
| Laboratoire d'Informatique du Littoral
|                                    |
| B.P. 719                               | fax: (+33)
3.21.19.06.61           |
| 62 228 CALAIS Cedex                   
|                                    |
| FRANCE                                 | e-mail:
lefer at lil.univ-littoral.fr |
|________________________________________|____________________________________|


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