Adding support of Center-X/Y/Z for VolReader/Writer

[jlevallois]

Overview

Actually, VolReader & VolWriter don't care about Center-X params set in vol files.
It can be problematic if you write a .vol from a centered object and read it after: a shift appears

Before Writing: [HyperRectDomain] = [[PointVector] {-20, -20, -20}]x[[PointVector] {20, 20, 20}]
After Reading: [HyperRectDomain] = [[PointVector] {0, 0, 0}]x[[PointVector] {40, 40, 40}]

In this PR, Center-X/Y/Z params are parsed if they are into the vol file and took into consideration.:

Before Writing: [HyperRectDomain] = [[PointVector] {-20, -20, -20}]x[[PointVector] {20, 20, 20}]
After Reading: [HyperRectDomain] = [[PointVector] {-20, -20, -20}]x[[PointVector] {20, 20, 20}]

If no Center-X/Y/Z params are into the vol file, the previous behavior is used:

[HyperRectDomain] = [[PointVector] {0, 0, 0}]x[[PointVector] {40, 40, 40}]

Same for LongvolReader & LongvolWriter

Minor changes

VolReader.getHeaderValueAsInt() returns always a value greater than zero (aka failure). This bug is fixed (also in LongvolReader.getHeaderValueAsInt()).

[jlevallois]

One test fail with this PR : testSliceImageFromFunctor. I've look at it but don't know exactly where is the issue. Any idea @kerautret ?

It seems when PGMWriter::exportPGM is called, it check the value for [PointVector] {20, -20, 19} when the domain is only [HyperRectDomain] = [[PointVector] {-20, -20, -20}]x[[PointVector] {19, 19, 19}]

[jlevallois]

Ok, got it!
The 20 value passed in Projector constructor is the coordinate of center of object. Since cat10.vol has Center-X/Y/Z params to 0, the (new) center isn't longer {20,20,20} but {0,0,0}.

So this PR is ready to be reviewed 😎

[dcoeurjo]

would you have a small test (write/read a vol with translated domains and making sure that domains are identical) ?
Otherwise, nice PR

[jlevallois]

Test added ( testVolReader ):
Before this PR :

New Block [Testing VolWriter ...]
[HyperRectDomain] = [[PointVector] {-17, -14, -13}]x[[PointVector] {5, 7, 11}]
EndBlock [Testing VolWriter ...]
New Block [Testing VolReader ...]
[HyperRectDomain] = [[PointVector] {0, 0, 0}]x[[PointVector] {22, 21, 24}]
EndBlock [Testing VolReader ...]
Failed.

After :

New Block [Testing VolWriter ...]
[HyperRectDomain] = [[PointVector] {-17, -14, -13}]x[[PointVector] {5, 7, 11}]
EndBlock [Testing VolWriter ...]
New Block [Testing VolReader ...]
[HyperRectDomain] = [[PointVector] {-17, -14, -13}]x[[PointVector] {5, 7, 11}]
EndBlock [Testing VolReader ...]
Passed.

[dcoeurjo]

nice.. could you please check the travis error ?

[jlevallois]

My bad, an unexpected ctrl+x has been there.

[dcoeurjo]

Thanks..