Re: Double hires mode color artifacts

[Dirk Thierbach <dthierbach@usenet.arcornews.de>]

Linards Ticmanis <ticmanis@gmx.de> wrote:
> Dirk Thierbach wrote:
> 
>> I've tried to do the Fourier projection myself, but I arrive at different
>> values. Do you assume any phase shift between the square waves of the
>> bit pattern and the sine/cosine base functions?

> Maybe it's the most simple solution if I just post my code. I wrote this
> a good while ago so I'm a bit foggy about the details.

[code snipped]

Ok, you don't do the Fourier projection directly, but instead have
precalculated the angles. Then, taking the square bit pattern waves as
reference, the corresponding sine and cosine have 45 degrees phase offset.

Just for fun, I changed the transformation to YIQ instead of YCrCb.
Then you get the same colors (as far as I can judge with naked eye),
but for 0 degrees phase offset. So it looks like you really to YIQ,
but have disguised it as YCrCb :-)

But neither gives a "brown" color for number 8. You can make it
into brown by shifting for 40 degrees or so, but that will distort all
the other colors. Shifting for 10 degrees or so will leave the other
colors mostly intact and will give you a sort of greenish-brown, but
that's all.

No idea what's going on here. Maybe the saturation is wrong, and it
will get better at a slightly different saturation? Or maybe my 
monitor/graphic card isn't just correctly color adjusted. Or maybe
today's phosphors are different?

- Dirk