[vtkusers] Re : Displaying points on a 2D image

[Prathamesh Kulkarni]

I would be surprised if vtkSeedWidget cannot be used to place pre-defined
points on an image.

You can flip vtkImageData using vtkImageFlip.


Prathamesh

On Tue, Jul 27, 2010 at 2:38 AM, Trystan Louboutin <tanstry at gmail.com>wrote:

> Hi,
>
> Thanks all for replying.
>
> In fact, I don't want to manually place points over the image but just
> displaying some points I obtained by my own contours computation.
>
> I think my problem comes from the image displaying: the references between
> image and contour display are mismatching.
> (the contours points are not superposing well the image)
>
> Image reference origin: upper left
> ---------------> X
> |
> |
> |
> |
> Y
>
> Contours points reference origin: lower left
> Y
> |
> |
> |
> |--------------> X
>
> Is there any parameter to configure to flip my image (vtkImageActor) or my
> contours (vtkActor2D) so that their references match ?
>
> Regards,
> Trystan
>
>
>
> 2010/7/23 Prathamesh Kulkarni <prathameshmkulkarni at gmail.com>
>
> How about using the vtkSeedWidget for placing points?
>>
>> Here is an example:
>> http://www.vtk.org/Wiki/VTK/Examples/Widgets/vtkSeedWidget
>>
>>
>> Prathamesh
>>
>> Message: 3
>> Date: Fri, 23 Jul 2010 04:31:17 -0700 (PDT)
>> From: Malsoaz James <jmalsoaz at yahoo.fr>
>> Subject: [vtkusers] Re :  Displaying points on a 2D image
>> To: vtkusers at vtk.org, Trystan Louboutin <tanstry at gmail.com>
>> Message-ID: <151153.72822.qm at web28312.mail.ukl.yahoo.com>
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>>
>> Hi,
>>
>> I have been facing similar problems few weeks ago.
>> A solution has been to create a vtkImageData for each set of points I had
>> (in my case, it was contours). Then, I have used a vtkTexture to paste the
>> vtkImageData on the image (which was also a texture).
>> To my mind, this isn't ideal at all, but I didn't find any other solutions
>> and I'm still looking for something else.
>>
>> I hope someone could help us with this issue.
>>
>> Best
>> James
>>
>> --- En date de?: Mer 21.7.10, Trystan Louboutin <tanstry at gmail.com> a
>> ?crit?:
>>
>>
>> De: Trystan Louboutin <tanstry at gmail.com>
>> Objet: [vtkusers] Displaying points on a 2D image
>> ?: vtkusers at vtk.org
>> Date: Mercredi 21 juillet 2010, 17h13
>>
>> Hi vtk users,
>>
>> I want to display some points over a 2D-image, it displays fine but the
>> problem is that the points and image are not linked together.
>> In fact, I want the points to be associated with the image so that zoom
>> in/out will affect the image either the points, which is not the case
>> actually.
>>
>> The image is obtained by re-slicing a vtkData volume as vtkImageData and
>> displayed in a QVTKWidget.
>>
>> For displaying the points, I use :
>> vtkPoints : defines the points
>> vtkCellArray : to link points
>>
>> vtkPolyData : setPoints( theVtkPoints ) - setVerts( theCellArray )
>> vtkActor2D
>> vtkPolyData2DMapperAdd the actor to the renderer (same as image)
>>
>> The points (ie, representing a contour) are visible over the image but not
>> superposing it correctly (coordinates are mismatching).
>>
>>
>> I would like to know how to display some points (displayed in different
>> colors) on a vtkImageActor ?
>> Is the vtkImageActorPointPlacer suitable for this kind of thing ? I can't
>> find any satisfactory example on how using it in such a case...
>>
>>
>> Thanks in advance for any help,
>>
>> Regards,
>> Trystan
>>
>>
>>
>>
>>
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