ITK/Tutorials/DOs and DONTs
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- Do call Update() before using the pipeline output
- Do call UpdateLargestPossibleRegion() when reusing a reader.
When reusing a reader you must call: reader->UpdateLargestPossibleRegion() instead of the usual: reader->Update() Otherwise the extent of the previous image is kept, and in some cases lead to Exceptions being thrown if the second image is smaller than the first one.
- Do not assume InputImage->SetRequestedRegion(smallregion) will make the filter faster! The filter will run on the entire InputImage regardless.
- To make it run on a smaller block:
- get a new itkRegionOfInterestImageFilter, say ROIfilter
- CCfilter->SetInput (ROIfilter->GetOutput());
- On a newly-manually-created image, do initialize the pixel values if you expect them to be so!
- Example: image->FillBuffer(0); // initialize it to all dark
- ITK doesn't initialize the image buffer when you call Allocate(). It is your responsibility to initialize the pixel values.
- Do not declare constants using
- #define CONST_VALUE_NAME 3
- Use instead
- const unsigned int CONST_VALUE_NAME = 3,
- ITK doesn't define constants with #defines in header files
- Do not call Delete() in an ITK smart pointer.
- If you want to destroy a smart pointer object itksmartp, do:
itksmartp = NULL; the ITK smart pointer will determine whether the object should be "deleted".
Calling Delete() in ITK smart pointers is a common mistake when combining VTK code (that requires the use of Delete() ) and ITK code, (that forbids the use of Delete() ). Using the new vtkSmartPointer class will help in a more consistent mindset when combining ITK and VTK code. Instead of: vtkclass * ptr = vtkclass::New(); do: vtkSmartPointer< vtkclass > ptr = vtkSmartPointer< vtkclass >::New() and then you won't need to call Delete() in VTK classes either.