Cannot return copy

[none]

In the below code the call:

DisplayImage(job.GetResultImage());

just shows a black image even though it looks fine when its created.



int main() {

typedef MyImg MyImgType;
typedef Job<MyImgType> JobType;

MyImageApp<MyImgType> app;
JobType job;
app.Run(job);

// This only shows a black image!
DisplayImage(job.GetResultImage());
return 0;

}




// ============== MyImageApp ======================

template<typename F>
class MyImageApp {
public:


void Run(JobType & job) {

// The 'processor' instance will die when this function returns.
Processor<F> processor;
processor.Process();

// Not possble to copy the image from the processor into the job!?
job.SetResultImage(processor.GetWarpedImage());
}

};



// ============== Processor =======================

template <typename FI>
class Processor {
public:
typedef FI FixedImageType;
typedef itk::ResampleImageFilter< FixedImageType, FixedImageType > ResampleFilterType;

WarpProcessor ();
virtual ~WarpProcessor ();
void Process();

// Returning a copy not a reference!
typename FixedImageType:ointer GetImage(){return this->imageW;}

private:
typename FixedImageType:ointer imageW;

};

template <typename FI>
void
Processor<FI>:rocess() {
// Computing stuff

// ...

// Copying the result into the imageW instance
CopyImageToImage<typename FixedImageType:ointer, FixedImageType>(
resampler->GetOutput(),
imageW);

// image looks fine when viewed here!
DisplayImage(imageW)

}




// ================== Job =======================

template<typename F>
class Job {
public:
typedef F FixedImageType;

// Return copy!
typename FixedImageType:ointer GetResultImage() {return this->imageR;}
void SetResultImage(typename FixedImageType:ointer image) {this->imageR = image;}

private:
typename FixedImageType:ointer imageR;

};




Any ideas on why the image looks fine when calling:

DisplayImage(imageW)

in Processor:rocess() and pitch black when calling:

DisplayImage(job.GetResultImage());

in main?

 

[Jonathan Lee]

   // Return copy!

   typename FixedImageType:ointer GetResultImage() {return this->imageR;}

From this I would guess that you're not actually returning
a copy, you're returning a pointer. If the destructor is called
for the image that is being pointed to, the data is lost.
(Or, at least practice it should be.)

So, giving that you're passing things around by pointer instead
of by value, I expect that the thing pointed to doesn't exist
anymore. That's just a guess, though.

--Jonathan