[vtkusers] Drawing objects interactively in VTK..??

[Darshan Pai]

Did you multiply z with the near clipping plane . because I could reproduce
what you want to do without the actor . Anyway if that is not working for
you then I don't have any other explanations at this time :)

Regards

Darshan

On Wed, Apr 7, 2010 at 9:58 PM, Rakesh Patil <rakeshthp at in.com> wrote:

>
>
> Yes..
>
> I did try that at the very beginning... Not only this but i tried out the
> various combination of the coordinates.. none of
> them matched for me... :-)
>
> vtkImageTracerWidget is performing the task what i want.. but it needs a
> prop beneath it.... and for me, it is with or without prop object.. wither
> ways it should be possible for me to draw...
>
> Any suggestions..??
>
>
> Thanks
>
> Regards
> Rakesh Patil
> ---------- Original message ----------
> From:Darshan Pai< darshanpai at gmail.com >
> Date: 08 Apr 10 04:55:02
> Subject: Re: [vtkusers] Drawing objects interactively in VTK..??
> To: Rakesh Patil
>
> replied too fast . The displaytoview() and viewToWorld does not take points
> as input.
>
> But you can use the vtkCoordinate . Try this particular snippet of code.
>
> vtkCamera *camera = renderer->GetActiveCamera();
> double *n = new double[2];
> n = camera->GetClippingRange();
>
>
> vtkSmartPointer<vtkCoordinate> coordinate =
> vtkSmartPointer<vtkCoordinate>::New();
> coordinate->SetCoordinateSystemToDisplay();
> coordinate->SetValue(x,y); // display coordinates
> double *pt = new double[3];
> pt = coordinate->GetComputedWorldValue(renderer);
> cout << pt[0] << " " <<pt[1] << " " << pt[2] << endl;
> vtkSmartPointer<vtkSphereSource> sphereSource =
> vtkSmartPointer<vtkSphereSource>::New();
> sphereSource->SetCenter(pt[0],pt[1],pt[2]*-1*n[0]);
> sphereSource->SetRadius(1.0);
> sphereSource->Update();
>
> depth is assumed to be 1 and n[0] is the near clip..
>
>
> On Wed, Apr 7, 2010 at 6:26 PM, Darshan Pai <darshanpai at gmail.com> wrote:
>
>> I don't know how to get the matrices defined . Maybe someone can help .
>> But vtkRenderer has some functions like DisplayToView() and ViewToWorld()
>> which can get you the world coordinate for that point.
>> The default camera has the clipping information . You provide the depth of
>> the point
>> The world point will be <x*depth, y*depth, depth*-1*nearclipplane>
>>
>> See if it works .
>>
>> Regards
>> Darshan
>>
>> On Wed, Apr 7, 2010 at 4:37 AM, Rakesh Patil <rakeshthp at in.com> wrote:
>>
>>>
>>> Hi David,
>>>
>>> That is exactly what i want.. But how can i get the points or lines which
>>> are traced..?? And also it should work without any actor..
>>> I mean this class works only for some actors. But i need for with actor
>>> and without actor..
>>>
>>> Thanks
>>>
>>> Regards
>>> Rakesh Patil
>>>
>>>
>>> ---------- Original message ----------
>>> From:David Doria< daviddoria+vtk at gmail.com <daviddoria%2Bvtk at gmail.com>>
>>> Date: 06 Apr 10 17:59:52
>>> Subject: Re: [vtkusers] Drawing objects interactively in VTK..??
>>> To: Rakesh Patil
>>>
>>> On Tue, Apr 6, 2010 at 5:13 AM, Rakesh Patil wrote:
>>> > Hello,
>>> >
>>> > I am trying to draw a polyline interactively (with help of mouse). What
>>> i'm
>>> > doing is at every left button down event, i get the mouse position and
>>> store
>>> > it is a vector list. Later using this points am displaying on the
>>> rendering
>>> > window.
>>> >
>>> > But when i do this, i noticed the following:
>>> >
>>> > The mouse position values are totally different from the the points
>>> which
>>> > are displayed.. I mean, i click at one location, and it is displayed at
>>> far
>>> > end another location..
>>> >
>>> > I tried changing the coordinate system also.. Still the result is
>>> > unchanged..
>>> >
>>> > Any suggestions how it is to be done..??
>>> >
>>> > Thanks
>>> > Rakesh Patil
>>> >
>>>
>>> Sounds like you may need a coordinate system conversion in there
>>> somewhere, check out:
>>> http://vtk.org/Wiki/VTK/Examples/Coordinate
>>>
>>> It also sounds like you are trying to duplicate already working code in:
>>> http://vtk.org/Wiki/VTK/Examples/Widgets/ImageTracerWidget
>>>
>>> Thanks,
>>>
>>> David
>>>
>>>
>>>
>>> Get Yourself a cool, short *@in.com* Email ID now!<http://mail.in.com/mails/new_reg.php?utm_source=invite&utm_medium=outgoing>
>>>
>>> _______________________________________________
>>> Powered by www.kitware.com
>>>
>>> Visit other Kitware open-source projects at
>>> http://www.kitware.com/opensource/opensource.html
>>>
>>> Please keep messages on-topic and check the VTK FAQ at:
>>> http://www.vtk.org/Wiki/VTK_FAQ
>>>
>>> Follow this link to subscribe/unsubscribe:
>>> http://www.vtk.org/mailman/listinfo/vtkusers
>>>
>>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.vtk.org/pipermail/vtkusers/attachments/20100407/2483e40c/attachment.htm>