1996.12.13 20:57 "Re: fillorder of decoded strips", by Sam Leffler
According to the documentation of TIFFOpen:
By default the library returns data in MSB2LSB bit order for compatibiltiy with older versions of this library. Returning data in the bit order of the native cpu makes the most sense but also requires applications to check the value of the FillOrder tag; something they probably do not do right now.
But according to the man page of TIFFReadEncodedStrip:
The library attempts to hide bit- and byte-ordering dif- ferences between the image and the native machine by con- verting data to the native machine order. Bit reversal is done if the FillOrder tag is opposite to the native machine bit order.
So now I'm quite confused about how TIFFReadEncodedStrip works. From a few experiments I've done it seems the decoded data I get back from doing a TIFFReadEncodedStrip has a fill order of MSB2LSB. Should I assume it will always be like that as the TIFFOpen documentation implies? Is there someway to know for sure what the fill order is of what TIFFReadEncodedStrip returns?
Data is returned in MSB2LSB bit order unless you explicitly override it at TIFFOpen (when samples are >1 bit). If this doesn't happen please provide an example.