Zx spectrum dark mode

[robin-raymond]

The current Zx spectrum implementation only dithers "bright" mode colors. I think it's possible with a few tweaks to enable proper usage of the 'i' color attribute and expand the color palette as a result.

[robin-raymond]

BEFORE:

AFTER:

[sehugg]

That's dark mode? Cool :)

[robin-raymond]

The user can now select, default (both light and dark in the same picture), a dark mode palette, a bright mode palette, a dark selection forced bright, or a bright selection forced dark.

[sehugg]

ZX looks good! The modes all have different personalities. I think ZX looks best with the Hue-Based color function. I also started on some unit tests to see if these differences can be quantified. Thanks!

[robin-raymond]

Agreed. I've been creating a good base class for both, and adding intellivision support.