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Re: [csswg-drafts] [css-values] Trigonometric functions (#2331)

From: Amelia Bellamy-Royds via GitHub <sysbot+gh@w3.org>
Date: Fri, 01 Mar 2019 16:16:31 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-468719629-1551456990-sysbot+gh@w3.org>
> disturbs me from a mathematical point of view

Not only you!

I brought this up at the end of the face-to-face discusssion, but maybe it didn't get clearly reflected in the minutes.  All mathematical operations will need to apply to dimensions in a proper way, following the [CSS Typed OM rules](https://drafts.css-houdini.org/css-typed-om/#numeric-typing) (which treat `%` as a unit which may have a separate meaning from its numeric equivalent, so `pow(2%, 4)` would return a value with % to the power of 4).

Powers and roots will need to cancel out to get regular CSS values. This is why numeric precision may become an issue.  It is slightly annoying if powers and roots don't neatly cancel out on the value. But it is a big problem if they don't neatly cancel out on the unit!  One suggestion at the end of the call was to limit `pow()` and `sqrt` to plain numbers without units for now. (`hypot` would still be available for the most common case of manipulating lengths, since it cancels out units internally.)

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Received on Friday, 1 March 2019 16:16:37 UTC

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