[cairo] rewriting libpixman
Jeff Muizelaar
jeff at infidigm.net
Mon Apr 2 12:47:56 PDT 2007
On Mon, Apr 02, 2007 at 12:30:48PM -0400, James Cloos wrote:
> And of course, do remember that .99999... == 1.0, and that that works
> for the largest digit of any base. So the sample specified by all 1
> bits is, if you treat samples as the first approximations of infinite
> series, the same as 2^n, given an n-bit sample.
I still don't follow this logic, specifically the last sentence.
> So, given a 5 bit sample, were you to cast it to an int32_t or float,
> multiply it by 256 and then divide by 31 you get (with the right
> rounding, of course) the same as doing the bit shifts.
Why should we prefer:
28*256/31 = 231.225806451
instead of
28*255/31 = 230.322580645
when:
28/31 = .903225806
and
231/255 = .905882352
230/255 = .901960784
-Jeff
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