Re: [csswg-drafts] [css-text][css-fonts] Optical bounds of a line (#5466)

Here’s a demo I made on the issue a few years ago, and [referred to the MPEG-OTSPEC list](https://lists.aau.at/pipermail/mpeg-otspec/2020-September/002355.html) earlier this month.

https://www.axis-praxis.org/tests/sidebearings/test-20170316.html

Look at the third example, set in Source Sans with optically zeroed sidebearings and spaced with CSS `letter-spacing`.

My proposal was that fonts can be made with glyph sidebearings aligned to optical left and optical right bounds (just as glyphs are aligned to the font’s baseline and cap-height). In CSS terms it’s like removing horizontal padding. Then, spacing can be applied via one of:
* CSS `letter-spacing`
* the tracking feature in an app
* a variable spacing axis in the font

Back in 2013, Cameron Booth on his Transit Maps blog published a good tutorial on dealing with the issue in Illustrator:
* [Tutorial: Working with Point Type Labels in Adobe Illustrator](https://www.transitmap.net/point-type/)

> you need to be aware that the text you type almost never aligns with the point that you’ve created. Because of the letter spacing that’s baked into each character, there’s a small – but noticeable – gap between the point and the adjacent character 

BTW, making the above tests alerted me to be a bug or an underspecification, such that CSS `letter-spacing` is applied after every glyph _including glyphs at the end of a line of justified text_.

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Received on Sunday, 27 September 2020 20:47:49 UTC