[vtkusers] How to change pixel color?

[yenanqu at scs.fsu.edu]

How do you make it work, what is the problem before. all my pixel data  
is three componen. I just can not retieve it from the id(vtkImageData).

Yenan

Quoting Romuald BERTRAND <beromuald at wanadoo.fr>:

> Ok, pPix = (unsigned char*)id->GetScalarPointer(); works for me.
>
> But I have a problem : I display a grey image (1 component) and I   
> want to change few pixels in green (for example), I don't know how   
> can I do this.
> The grey image has 1 scalar component, and I need to transform its   
> to 3 components, and it takes a lot of time, and it's not very   
> interactiv.
>
> Someone know can I do my task?
>
> Thanks a lot for answers,
>
> Romu
>
> PS : yenan, make sure you change just one component if you have a   
> grey image, and change 3 components if you have a rgb image.
>
>
>
>
>> Message du 19/05/08 20:54
>> De : yenanqu at scs.fsu.edu
>> A : "Romuald BERTRAND"
>> Copie à : "Mark Wyszomierski" , vtkusers at vtk.org
>> Objet : Re: [vtkusers] How to change pixel color?
>>
>> No, I am still trying it. if you have other way to or could make it
>> work, please, please let me know.
>>
>> Yenan
>>
>> Quoting Romuald BERTRAND :
>>
>> > Hi,
>> >
>> > Thanks for your answers.
>> >
>> > I have tried but pPix = (unsigned char*)id->GetScalarPointer();
>> > doesn't work for me.
>> >
>> > when I change the components, nothing change, and after I have
>> > display the array and I have seen it is null.
>> > Know you why?
>> >
>> > Yenan: Have you arrived to manipulate it correctly?
>> >
>> > Thanks
>> >
>> >
>> >
>> >> Message du 16/05/08 21:35
>> >> De : "Mark Wyszomierski"
>> >> A : yenanqu at scs.fsu.edu
>> >> Copie à : "Romuald BERTRAND" , vtkusers at vtk.org
>> >> Objet : Re: [vtkusers] How to change pixel color?
>> >>
>> >> >>  pPix = (unsigned char*)id->GetScalarPointer();
>> >>
>> >> That should work, I've used it many times for instance in this project:
>> >>
>> >>
>> >>   
>> http://devsample.org/index.php?option=com_content&task=view&id=48&Itemid=27
>> >>
>> >> I show the value of the pixel that the mouse is over. Maybe there's
>> >> something else going on in your pipeline?
>> >>
>> >> Mark
>> >>
>> >>
>> >>
>> >> On 5/16/08, yenanqu at scs.fsu.edu  wrote:
>> >> >   How to get pointer from vtkImageData is the hardest thing,which I
>> >> > still can not make it.
>> >> >
>> >> > //id is vtkImageData
>> >> > int *uExtent = id->GetUpdateExtent();
>> >> > pPix = (unsigned char*)id->GetScalarPointer(uExtent[0], uExtent[2],
>> >> > uExtent[4]);
>> >> >
>> >> >   or
>> >> >
>> >> >   pPix = (unsigned char*)id->GetScalarPointer();
>> >> >
>> >> > the only method I could find out. It didn't work for me. try it to see
>> >> > if it works for you.
>> >> >
>> >> > Yenan
>> >> >
>> >> > Quoting Mark Wyszomierski :
>> >> >
>> >> >> Yeah once you get a pointer to the pixel data in vtkImageData you can
>> >> >> manipulate it however you want. It's just an array of values.
>> >> >>
>> >> >> Mark
>> >> >>
>> >> >> On 5/16/08, yenanqu at scs.fsu.edu  wrote:
>> >> >>> Did you retrieve pixel data from vtkImageData seccessfully?
>> >> >>>
>> >> >>>
>> >> >>> Yenan
>> >> >>> Quoting Romuald BERTRAND :
>> >> >>>
>> >> >>>> Hi all,
>> >> >>>>
>> >> >>>> I have to display an image for my work. After, I have to change the
>> >> >>>> color of several pixels, I don't know why. I have a vtkImageData,
>> >> >>>> and I have search some methods to set the scalars of the pixels
>> >> >>>> which are stored in, but I don't arrived.
>> >> >>>>
>> >> >>>> Someone could help me?
>> >> >>>>
>> >> >>>> Thanks for answers.
>> >> >>>>
>> >> >>>> Romuald
>> >> >>>>
>> >> >>>> --
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