Re-range text opacity from [-128, 127] to [0, 255]

[sovdeeth]

Problem

Text display opacity is very confusing and hard to work with, since it goes from fully transparent at 4, to half opaque at 127, to half opaque at -128, to fully opaque at -1. Re-ranging this to be a simple 4-255 scale would be much easier for users to use and understand (it's what snbt does, too!)

Really, this should have been done from the start.

Solution

Returns opacities from 0 to 255 now, adding 256 to any value < 0. This is a breaking change.
Setting opacity still supports -127 to -1, but adding/subtracting will limit the values to 0 to 255.

The alternative is to allow as much wrapping as desired (eg, subtracting 300 will loop all the way around and be equal to subtracting 44, and users can set the opacity to any value they want and it will be modulo-ed to 0-255). This is versatile but very counter-intuitive for new users. Setting opacity to 300 and getting a result of 44 doesn't make much sense. It's still a minor issue in the current impl, where you can set to -10 and get 246, but that's for backwards compat and can be forgiven imo.

Testing Completed

ExprTextDisplayOpacity.sk

Supporting Information

Created after 2 users reported significant issues trying to deal with text opacity in skunity help channels.

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Completes: none
Related: none
AI assistance: none

[miberss]

It goes fully transparent at 25 for me?

[sovdeeth]

It goes fully transparent at 25 for me?

Yes, it should be fully transparent at 25

Values from 4 to 26 are fully transparent, and opacity increases linearly from there up to 255.

[miberss]

It goes fully transparent at 25 for me?

Yes, it should be fully transparent at 25

Values from 4 to 26 are fully transparent, and opacity increases linearly from there up to 255.

Whoops, missed.

Why specifically 4 to 26 and not 1 to 26?

[sovdeeth]

It goes fully transparent at 25 for me?

Yes, it should be fully transparent at 25

Values from 4 to 26 are fully transparent, and opacity increases linearly from there up to 255.

Whoops, missed.

Why specifically 4 to 26 and not 1 to 26?

idk mate ask mojang, baffles me too

text_opacity: Alpha value of rendered text. Value ranges from 0 to 255. Values up to 3 are treated as fully opaque (255). Similar to the background, the text rendering is discarded for values between 4 and 26. NBT stores the value as signed byte, -128 to 127. Defaults to -1, which represents 255 and is completely opaque. SNBT to NBT handles conversion from unsigned to signed, but if needed, replace values greater than 127 with alpha-256 or alphaUB. Interpolated.

[miberss]

It goes fully transparent at 25 for me?

Yes, it should be fully transparent at 25

Values from 4 to 26 are fully transparent, and opacity increases linearly from there up to 255.

Whoops, missed.
Why specifically 4 to 26 and not 1 to 26?

idk mate ask mojang, baffles me too

text_opacity: Alpha value of rendered text. Value ranges from 0 to 255. Values up to 3 are treated as fully opaque (255). Similar to the background, the text rendering is discarded for values between 4 and 26. NBT stores the value as signed byte, -128 to 127. Defaults to -1, which represents 255 and is completely opaque. SNBT to NBT handles conversion from unsigned to signed, but if needed, replace values greater than 127 with alpha-256 or alphaUB. Interpolated.

I swear I read it, super sorry lol.