psFits ImageCube functions; Image and Table functions

[Paul Price]

It's kind of annoying to have to get NAXIS3 and do multiple calls to
psFitsReadImage, etc, so I propose a new set of functions: psFitsReadImageCube,
psFitsWriteImageCube, psFitsUpdateImageCube, psFitsInsertImageCube. Instead of
working on a single 2D image, these functions will work on a psArray of images.

psArray *psFitsReadImageCube(const psFits *fits, psRegion region);
bool psFitsUpdateImageCube(psFits *fits, const psArray *input, int x0, int y0);
bool psFitsWriteImageCube(psFits *fits, psMetadata *header, const psArray
*input, const char *extname);
bool psFitsInsertImageCube(psFits *fits, psMetadata *header, const psArray
*input, const char *extname, bool after);

In the process of putting these together, I noticed differences between the
Image (or the ImageCube) functions and the Table functions, specifically in the
use of the extname.

bool psFitsWriteImageCube(psFits *fits, psMetadata *header, const psArray
*input, const char *extname);
bool psFitsWriteTable(psFits* fits, const psMetadata *header, const psArray*
table);

bool psFitsInsertImageCube(psFits *fits, psMetadata *header, const psArray
*input, const char *extname, bool after);
bool psFitsInsertTable(psFits *fits, const psMetadata *header, const psArray*
table, bool after);

I propose adding the extname to the Table functions, following the Image
functions. This would mean that it is the responsibility of pslib to update the
header with the EXTNAME.

[Paul Price]

Some code that might be helpful for psFitsWriteImageCube follows. It checks
that NAXIS3 is in the header and then makes repeated calls to psFitsWriteImage.

XXX Not sure I should have to do this check (push into psLib?)
if (hdu->header) {

bool mdok = true; Result of MD lookup
bool naxis3 = psMetadataLookupS32(&mdok, hdu->header, "NAXIS3");

Number of image planes

if ((!mdok && hdu->images->n > 1)

(mdok && naxis3 !=

hdu->images->n)) {

psMetadataItem *naxis3item = psMetadataLookup(hdu->header,

"NAXIS3"); Item with NAXIS3

naxis3item->data.S32 = hdu->images->n;

}

} else if (hdu->images->n > 1) {

hdu->header = psMetadataAlloc();
psMetadataAddS32(hdu->header, PS_LIST_HEAD, "NAXIS3",

PS_META_REPLACE, "Number of image planes",

hdu->images->n);

}
Now we can safely write the images out
for (int i = 0; i < hdu->images->n; i++) {

if (! psFitsWriteImage(fits, hdu->header, hdu->images->data[i], i,

hdu->extname)) {

psError(PS_ERR_IO, false, "Error writing image plane %d\n", i);
return false;

}

}

[Paul Price]

Gene accepts these proposals; I am to write the code. I will work in the
rel10_ifa branch.

[eugene]

these were finished a long time ago.