fixed palette FX to more closely match original 1D version

[DedeHai]

• rotation scale is now exactly 180° (divide slider input by 255 instead of 256)
• removed shift offset: offset is now zero at slider 0, to hit 128 on touch input devices is really hard
• added a 90° shift to input rotation, enabling to rotate from 0 to 180° instead of +90 to -90 (which is not useful in 1D)
• changed default settings values to more closely match the old 1D effect

We frequently get confused beta users because rotation is enabled by default and sliders need to be fiddled with to arbitrary but exact positions to get an approximate match of the original 1D palette effect. Also it was not possible to make it match exactly: the moving direction was inverted. The shifted rotation angle now makes it possible to choose the direction. This does not fix everything but tries to match it as closely as possible, an exact match is not possible unfortunately. Existing presets will match worse with this update, but at least it is possible to make them match again. It is basically a question of which version will annoy more users: having an approximate match on old presets but being unable to match it exactly or have a complete missmatch but the possibility to set it the same again. Another downside: presets made in any 0.15 beta will also not match anymore...

with the new default values, selecting the palette effect will give a close match to the original in 1D but will be different than the 2D beta version up to this point.

If this PR is to be merged it better be done so before 0.15 release. The minimum that should be changed are the default check settings.

[DedeHai]

There was some initial discussion about this in the original PR: https://github.com/Aircoookie/WLED/pull/3683

[softhack007]

If this PR is to be merged it better be done so before 0.15 release. The minimum that should be changed are the default check settings.

I agree with your reasoning 👍 should be for 0.15.0, to avoid breaking previous behaviour.

[DedeHai]

@TripleWhy @dosipod can you please check if this looks ok to you and if its the desired improvement?