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| author | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2008-12-28 16:24:42 +0000 |
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| committer | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2008-12-28 16:24:42 +0000 |
| commit | 9d558114b4dc863311ca9005be231cb809455bc5 (patch) | |
| tree | 23e11e4281b40336e45544f35c8d02867797d53d | |
| parent | 588ca3671e258b8381e0404d81668b0d828b362d (diff) | |
| download | netpbm-mirror-9d558114b4dc863311ca9005be231cb809455bc5.tar.gz netpbm-mirror-9d558114b4dc863311ca9005be231cb809455bc5.tar.xz netpbm-mirror-9d558114b4dc863311ca9005be231cb809455bc5.zip | |
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git-svn-id: http://svn.code.sf.net/p/netpbm/code/trunk@795 9d0c8265-081b-0410-96cb-a4ca84ce46f8
| -rw-r--r-- | converter/other/fitstopnm.c | 13 | ||||
| -rw-r--r-- | converter/other/pamtofits.c | 14 |
2 files changed, 27 insertions, 0 deletions
diff --git a/converter/other/fitstopnm.c b/converter/other/fitstopnm.c index 86bdfbb8..9df47be3 100644 --- a/converter/other/fitstopnm.c +++ b/converter/other/fitstopnm.c @@ -30,6 +30,12 @@ ** disabled min max scanning when reading from stdin. */ +/* + The official specification of FITS format (which is for more than + just visual images) is at + ftp://legacy.gsfc.nasa.gov/fits_info/fits_office/fits_standard.pdf +*/ + #include <string.h> #include <float.h> @@ -507,6 +513,13 @@ convertPgmRaster(FILE * const ifP, double const datamin, xel ** const xels) { + /* Note: the FITS specification does not give the association between + file position and image position (i.e. is the first pixel in the + file the top left, bottom left, etc.). We use the common sense, + popular order of row major, top to bottom, left to right. This + has been the case and accepted since 1989, but in 2008, we discovered + that Gimp and ImageMagick do bottom to top. + */ unsigned int image; pm_message("writing PGM file"); diff --git a/converter/other/pamtofits.c b/converter/other/pamtofits.c index 04b43c35..7a71ff56 100644 --- a/converter/other/pamtofits.c +++ b/converter/other/pamtofits.c @@ -20,6 +20,12 @@ ** in the FITS header, but do not cause the data to be rescaled. */ +/* + The official specification of FITS format (which is for more than + just visual images) is at + ftp://legacy.gsfc.nasa.gov/fits_info/fits_office/fits_standard.pdf +*/ + #include <assert.h> #include <string.h> #include <stdio.h> @@ -201,6 +207,14 @@ writeRaster(struct pam * const pamP, unsigned int const bitpix, int const offset) { + /* Note: the FITS specification does not give the association between + file position and image position (i.e. is the first pixel in the + file the top left, bottom left, etc.). We use the common sense, + popular order of row major, top to bottom, left to right. This + has been the case and accepted since 1989, but in 2008, we discovered + that Gimp and ImageMagick do bottom to top. + */ + unsigned int plane; for (plane = 0; plane < pamP->depth; ++plane) { |