Dear All,

Since we arre discussing possible reorganization, can I recommend not using pixdim[0] as qfac. It causes confusion at every step and I think we can spare 8 bytes for qfac to have its own special field.

Why it causes confusion? Normal people does not expect pixdim[0] to be used this way. I have to tell new programmers to watch out for it. If I use nifti_tool -mod_hdr to fix pixdim I have to be aware not to upset pixdim[0]. When using nifticlib I have to take care not to change nim->pixdim[0].

Can I propose that it is used to indicate how many pixdim element is valid, i.e. pixdim[0]=4 means pixdim[1..4] is valid. This give us the ability to say the pixels does not have any physical dimension by setting pixdim[0] to 0.

Thanks
Cinly