[vtkusers] Fwd: non-square image "cropped" after rotate 90º

[David Gobbi]

Hi Marcos,

Changing to SetResliceAxes is simple.  Just do this:

    reslicer->SetResliceAxes(transform->GetMatrix());

Then remove the call to SetOutputExtent().

The output extent should not be the same as the input extent when
you rotate a rectangular image.

Also, do not set the Extent with the Bounds.  The Bounds and the Extent
are not the same thing (here the Bounds is measured in millimetres, but
the Extent is measured in voxels).  It might have worked for you if your
voxel size was 1mm x 1mm x 1mm, but in general this is not the case.

 - David



On Wed, Sep 16, 2015 at 4:24 PM, Marcos <fotosentido at gmail.com> wrote:

>
> Hi,
>
> I tried before woth SetResliceAxes, but I didn't get how to use a
> vtkMatrix4x4 as I said in another post.
>
> It was working with SetResliceTransform, until I saw that.
>
>
> I tried to do this:
>
> void ViewerWidget::rotateCalculate(int angle, double axis[])
>
> {
>
>     double bounds[6];
>
>     con->GetOutput()->GetBounds(bounds);
>
>     double center[3];
>
>     center[0] = (bounds[1] + bounds[0]) / 2.0;
>
>     center[1] = (bounds[3] + bounds[2]) / 2.0;
>
>     center[2] = (bounds[5] + bounds[4]) / 2.0;
>
>     transform->Translate(center[0], center[1], center[2]);
>
>     transform->RotateWXYZ(angle, axis);
>
>     transform->Translate(-center[0], -center[1], -center[2]);
>
>     reslicer->SetResliceTransform(transform);
>
>
>     // added this line,
>
>     reslicer->SetOutputExtent(bounds[2], bounds[3], bounds[0], bounds[1],
>
>             bounds[4], bounds[5]);
>
>
>     reslicer->Update();
>
> }
>
>
> I got an exception : read access violation on
> vtkImageMapToWindowLevelColors::ThreadedRequestData
> even with square images.
>
> The bound values for a non square-image (multiframe):
> 299.5, 898.5, 214.5, 643.5, 4.5, 13.5
>
> The bound values for the square image (multiframe):
> 127.5, 382.5, 127.5, 382.5, 521.024, 1563.0749
>
>
> 2015-09-16 22:49 GMT+02:00 David Gobbi <david.gobbi at gmail.com>:
>
>> On Wed, Sep 16, 2015 at 1:46 PM, Siavash Khallaghi <siavashk at ece.ubc.ca>
>> wrote:
>>
>>> Hi Marcos,
>>>
>>> Can you compare the extent of the output of vtkImageReslice against its
>>> input? My gut feeling is that they are not equal.
>>>
>>
>> I suggest to use SetResliceAxes() (using transform->GetMatrix()) instead
>> of
>> SetResliceTransform.  Here is why:
>>
>> When you use SetResliceAxes(), vtkImageReslice will transform the input
>> sampling (i.e. the extent and spacing) so that the output extent is
>> rotated as
>> compared to the input extent.
>>
>> Another option is to manually set the output extent, with
>> reslice->SetOutputExtent().
>>
>>
>>
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