[vtkusers] fill vtkImageData with RGB data?

[Dov Grobgeld]

Hi Mark,

One way of doing it is by first quantizing your image into 
a small set of colors (e.g. 1024) and then using a color lookup
table to define the mapping between the color index and the
actual RGB color, as well as an optional alpha channel. 

Using RGB directly (if it is all possible) would make it much
more difficult to control transparency through the various
lookup tables. 

Hope this helps.

Regards,
Dov

On Mon, Apr 11, 2005 at 12:48:05PM -0400, Mark Wyszomierski wrote:
> Hi,
> 
> I have an RGB image, I would like to load it into an instance of
> vtkImageData. I use the following:
> 
> image_data->SetDimensions(cx, cy, 1);
> image_data->SetScalarType(VTK_UNSIGNED_CHAR);
> image_data->SetNumberOfScalarComponents(3);
> image_data->AllocateScalars();
> unsigned char *p = (unsigned char*)image_data->GetScalarPointer();
> 
> // Now here I will fill image_data with my RGB components in
> RGB..RGB..RGB order.
> 
> When I go to display my image using vtkImageViewer2, they always come
> out grey. Is there a way to make it recognize there are really 3 color
> channels to create the actual colors?
> 
> Thanks.
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