Re: Dithering using windows palette (16 colors)

4N wrote:
"bugbear" <bugbear@xxxxxxxxxxxxxxxxxxxxxxxxx> ha scritto nel messaggio news:zamdnQU7iIBHHXHVnZ2dnUVZ8t7inZ2d@xxxxxxxxxxxxxxxxx
4N wrote:
"bugbear" <bugbear@xxxxxxxxxxxxxxxxxxxxxxxxx> ha scritto nel messaggio news:cJ6dnfnyCc0Vt3bVnZ2dnUVZ8s3inZ2d@xxxxxxxxxxxxxxxxx
I suggested:
case (A) dither a large image, sub sample by (e.g.) 8
case (B) subsample the same large image by (e.g.) 8
compare the result of (A) and (B).

well, obviously there is some desaturated area...
but my code is organized so that only the generator of the palette changes, so actually the code of the dithering is the same and only the content of the palette is changed (its colors).
When I use median cut everything is fine, the problems arise only when I fill the palette with the colors of the windows palette.

Over a sufficiently large area (the point of my subsampling in the check
I propose) any accurate implementation of error diffusion dithering should work,
as long as the pallette has examples of the color space extremes.

Obviously (?) if the pallette doesn't contain (e.g.) a fully saturated
blue, a fully saturated blue input cannot be handled.

BugBear
.

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