[vtkusers] How to use vtkTransform with vtkImagePlaneWidget

[Uril Yakubov]

Hi Dean,

I have fixed the problem. It was the center of the image for x, y and z.

eval $transform Translate -99.609375 -99.609375 -85.5
eval $transform RotateX  1  # Rotation around X 
eval $transform Translate 99.609375  99.609375 85.5

Thank a lot.

Uril.


On Wed, 2008-10-29 at 10:46 -0400, Uril Yakubov wrote:
> Hi Dean,
> 
> Thank you for help.
> 
> I have question. I executed code that you sent me and came to the
> conclusion that rotation centered by origin and I need centered at the
> center of the image. Using GetWholeExtent of the Image data I got xMin,
> xMax, yMin, yMax, zMin, zMax. I have for example xMin = 0 xMax = 255
> yMin = 0 yMax = 255 zMin = 0 zMax = 57   so I calculated center of the
> image 127, 127, 28.
> 
>     set pt1 [planeWidgetZ GetPoint1 ]
>     set pt2 [planeWidgetZ GetPoint2 ]
>     set wo [planeWidgetZ GetOrigin ] 
>     set normal [planeWidgetZ GetNormal ]
> 
>     set transform [vtkTransform New]
>     $transform PostMultiply
> 
>     eval $transform Translate -127.0 -127.0 -28.0
>     eval $transform RotateX  1  # Rotation around X 
>     eval $transform Translate 127.0 127.0 28.0
> 
> 
>     set points [vtkPoints New ]
>     eval $points InsertNextPoint $pt1
>     eval $points InsertNextPoint $pt2
>     eval $points InsertNextPoint $wo
> 
>     set newpoints [vtkPoints New ]
>     eval $transform TransformPoints $points $newpoints
> 
>     eval planeWidgetZ SetPoint1 [$newpoints GetPoint 0  ]
>     eval planeWidgetZ SetPoint2 [$newpoints GetPoint 1  ]
>     eval planeWidgetZ SetOrigin [$newpoints GetPoint 2  ]
>     eval planeWidgetZ UpdatePlacement 
>    
>     set pt11 [$newpoints GetPoint 0  ]
>     set pt12 [$newpoints GetPoint 1  ]
>     set pt13 [$newpoints GetPoint 2  ]
> 
> Now it is better but still it is not exactly  centered at the center of
> the image. Do you now what could be the problem?
> 
> 
> 
> Thank you,
> 
> Uril.
> 
> 
> 
> 
> On Thu, 2008-08-07 at 08:12 -0400, Dean Inglis wrote:
> > Hi Uril,
> > 
> >  
> > 
> > If you look at the doxygen documentation for this class,
> > 
> > you will see that you can recover the center and normal of the plane,
> > 
> > GetCenter GetNormal, as well as the three points defining a pair of 
> > 
> > orthonormal axes corresponding to its bottom and left side edges:
> > 
> > GetOrigin, GetPoint1, GetPoint2.  vtkTransform can be used
> > 
> > to rotate those points around the plane normal, 
> > 
> > as long as you know the origin of the image data that it slices
> > through:
> > 
> >  
> > 
> > vtkImagePlaneWidget widget  
> > 
> > widget->GetPoint1(pt1);
> > 
> > widget->GetPoint2(pt2);
> > 
> > widget->GetOrigin(wo);
> > 
> > widget->GetNormal(n);
> > 
> >  
> > 
> > vtkImageData image
> > 
> > image->GetOrigin(io);
> > 
> >  
> > 
> > vtkTransform transform
> > 
> > // may have to be transform->PreMultiply() or
> > transform->PostMultiply() here … I always forget
> > 
> > transform->Translate(io);
> > 
> > transform->RotateWXYZ(angle,n[0], n[1], n[2]);
> > 
> > transform->Translate(-io[0], -io[1], -io[2]);
> > 
> >  
> > 
> >  
> > 
> > vtkPoints points
> > 
> > points->InsertNextPoint(pt1);
> > 
> > points->InsertNextPoint(pt2);
> > 
> > points->InsertNextPoint(wo);
> > 
> >  
> > 
> > vtkPoints newpoints
> > 
> >  
> > 
> > transform->TransformPoints(points,newpoints);
> > 
> >  
> > 
> > widget->SetPoint1(newpoints->GetPoint(0));
> > 
> > widget->SetPoint2(newpoints->GetPoint(1));
> > 
> > widget->SetOrigin(newpoints->GetPoint(2));
> > 
> > widget->UpdatePlacement();
> > 
> >  
> > 
> >  
> > 
> >  
> > 
> > Dean
> > 
> > 
> 
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