[sane-devel] what' mean SANE_FIX ?

[zhu]

Hi,

When I read some backends,I often see SANE_FIX and SANE_UNFIX macro,they are defined in sane.h:

#define SANE_FIXED_SCALE_SHIFT 16
#define SANE_FIX(v) ((SANE_Word) ((v) * (1 << SANE_FIXED_SCALE_SHIFT)))
#define SANE_UNFIX(v) ((double)(v) / (1 << SANE_FIXED_SCALE_SHIFT))

Is SANE_FIX(v)=v*32768 and SANE_UNFIX(v)=v/32768 ?

in many backend, when we initialize some value,we SANE_FIX it,when we need to use these value,we SANE_UNFIX it ,Why we shoud do SANE_FIX and SANE_UNFIX ,what SANE_FIX mean ?

Thank you!

Good Luck!

Sincerely
Jason 
2002-7-24

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