[Octave-patch-tracker] [patch #8709] fixes to color conversion functions (mainly rgb2ntsc and ntsc2rgb)

[Hartmut]

Follow-up Comment #11, patch #8709 (project octave):

Alright, there seems to be some reasonable definition of how to save YIQ
colors in integer values. But when I read this for example: 

https://en.wikipedia.org/wiki/YUV#Numerical_approximations

then I see that it is for some funny reasons NOT only about scaling the
possible value range [Y_min, Y_max] to [0, int_max]. But there is some
additionally shifting involved.

The cited Wikipedia article is about the definition and implementation integer
datatypes for YUV images (and NOT the YIQ images used by rgb2ntsc and ntsc2rgb
in Octave). But I would guess there will be similar shiftings involved as
well.

I am in no way against an implementation of integer types for YIQ colors in
Octave. But I personally would not bother to code it. And I think they aren't
too frequently used any more, either. (In contrast I have heard of integer
valued Lab colors before.)

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