[Gegl-developer] alignment of pixels with coordinates

[Martin Nordholts]

Nicolas Robidoux wrote:
> A side effect of this choice is that if one downsamples with one and
> upsamples with the other, the resulting image will not be aligned with
> the original. (Of course, if one uses the same resampler for both, the
> results will be aligned, unless the calling routine (e.g., scale)
> messes things up, which I think it won't.)
>   

I don't like very much that repeated up-and-down-scaling of the image 
can offset the image, to me this sounds like a rather severe 
instability. On the other hand, for high quality "one-way" resampling it 
might be a price worth paying. And with image processing with GEGL being 
non-destructive this is perhaps not that big of an issue.

Is it a lot of work to change convention in a resampler afterwards? 
Would it be possible to parameterize this so you could even toggle 
pixel-center convention during runtime?

 / Martin