Add persistence of unicodes for glyphs between builds

[mondeja]

Resolves #221

Is not really a breaking change, as we don't have persistence now. But I prefer to push it with the next v15 major change.

[LitoMore]

This might not be a good solution for persisting unicodes. Some of them used a preserved code of emoji. Here is the preview:

For example the "gofundme": 128207 (0x1f4cf) is for the 📏 emoji.

I think it's fine to keep our current solution due to the special nature of our icon library. The unicode that will be changed can be understood as a feature rather than a bug.

What do you think?

[mondeja]

Good catch. I think that we must not use these reserved symbols, like the emoji ones. Not sure about what you're referring to the "special nature of the library". I'll expect that the font would behave like whatever another icons font.

I don't know how could be a feature something that breaks the usage of the font directly, even with minor version changes. You only need to remove the remove the unicode.json file and set the maximum unicode value to 59905 + 3282 (previous start plus current number of icons) to revert to the previous behaviour. The generated unicode values are not hashed to an absolute, are hashed + mapped inside a range.

I'll tweak the range to not use emojis.

[mondeja]

Should be good now 👍🏼

[LitoMore]

I’m a bit busy these days. I will take a deeper review later this week.

[LitoMore]

@mondeja Can we move it to v16? I just noticed some projects are using both simple-icons-font and simple-icons and assuming the unicode follows the index in the data JSON file.

https://github.com/jlnrrg/simple_icons/blob/8355761040946e84410314efce9622fe7daed2ac/tool/build.sh#L25-L31

https://github.com/jlnrrg/simple_icons/blob/8355761040946e84410314efce9622fe7daed2ac/lib/src/icon_data.dart