[Insight-developers] backward compatibility issue with new streaming support

[M.Staring at lumc.nl]

Hi Brad, 

We upgraded from ITK 3.10 to the latest release 3.16.

With MetaImageIO we got an IORegion of size zero.
We just tested TiffImageIO, and that did not give a zero-sized region,
but it unfortunately did return a different image than we put into it.

Do you want us to test other IO's?

If we add the lines

itk::ImageIORegion ioRequestedRegion(nrOfDimensions);
itk::ImageIORegion actualIORegion =
m_itkImageIO->GenerateStreamableReadRegionFromRequestedRegion(ioRequeste
dRegion);
m_itkImageIO->SetIORegion(actualIORegion);

to our code, it seems to work again. Does that give you any ideas of
what's wrong?

Marius


> -----Original Message-----
> From: Bradley Lowekamp [mailto:blowekamp at mail.nih.gov] 
> Sent: vrijdag 11 december 2009 16:19
> To: Staring, M. (LKEB)
> Cc: insight-developers at itk.org
> Subject: Re: [Insight-developers] backward compatibility 
> issue with new streaming support
> 
> What version were you upgrading from and to?
> 
> Is it all readers that broke for you or just MetaImageIO?
> 
> I am sorry that these changes broke your code, I tried very 
> hard to ensure that the interface was backwards compatible.
> 
> Brad
> 
> On Dec 11, 2009, at 10:00 AM, M.Staring at lumc.nl wrote:
> 
> > Dear developers,
> > 
> > In our institute (LKEB) we sometimes use the ITK image IO classes
> > without using the itk::ImageFileReader. (This way we can 
> e.g. directly
> > read in the data buffer into our own image type: lkebImage.)
> > 
> > We recently updated the underlying ITK to a more recent version, and
> > found out that it did not work anymore. The reason it does 
> not work are
> > the changes that were made to support streaming. A new 
> member m_IORegion
> > was added to the class ImageIOBase; it's constructor 
> initializes that
> > member to a 2D region of size [0 0]. The framework now 
> expects that this
> > m_IORegion is set externally, which in the ITK is done in the
> > ImageFileReader (line 389 of the txx). However, we do not use the
> > ImageFileReader and therefore our code breaks.
> > 
> > To fix this issue I would expect that the m_IORegion is by 
> default set
> > to the largest possible region (or the requested region) 
> and not to size
> > 0. I'm not sure if it is the best place to fix this, but 
> this could be
> > fixed by adapting the Read() or 
> ReadImageInformation()-functions of all
> > ImageIO's that support streaming. For example 
> MetaImageIO::Read() could
> > check if m_IORegion was manually set, and if not set it to 
> the requested
> > region. Something like:
> > 
> > if ( !m_IORegionManuallySet ) // or: if ( 
> m_IORegion.GetSize() == 0 )
> > {
> > m_IORegion = m_RequestedRegion; // or: m_IORegion =
> > m_LargestPossibleRegion;
> > }
> > 
> > and then proceed ...
> > 
> > What do you think ?
> > 
> > Regards,
> > 
> > Marius
> > 
> > 
> > Marius Staring, PhD
> > Division of Image Processing (LKEB)
> > Department of Radiology
> > Leiden University Medical Center
> > PO Box 9600, 2300 RC Leiden, The Netherlands
> > phone: +31 (0)71 526 1106, fax: +31 (0)71 526 6801
> > m.staring at lumc.nl
> > 
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