[vtkusers] How to change pixel color?

[Romuald BERTRAND]

Hi Yenan,

I have just use this exemple
==> http://devsample.org/index.php?option=com_content&task=view&id=48&Itemid=27

But in this exmple, Mark used the unsigned char type, and make sure your data are in unsigned char, or change the type which is used in the example. (GetScalarTypeAsString()).

I hope this help you,
Bye

Romu
 
 
 

> Message du 22/05/08 18:14
> 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?
> 
> 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 :
> 
> > 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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