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Re: [css-values] Rounding a real number to an integer

From: Gérard Talbot <www-style@gtalbot.org>
Date: Tue, 18 Dec 2018 21:15:31 -0500
To: fantasai <fantasai.lists@inkedblade.net>
Cc: W3C www-style mailing list <www-style@w3.org>
Message-ID: <7091988d1286792d10c20c69a4d1f85b@gtalbot.org>
Le 2018-12-18 19:58, fantasai a écrit :
> On 12/15/18 6:46 PM, Gérard Talbot wrote:
>> Le 2018-12-15 19:46, Gérard Talbot a écrit :
>>> Hello,
>>> 
>>> "
>>> (...) interpolation happens in the real number space as for 
>>> <number>s,
>>> and the result is converted to an <integer> by rounding to the 
>>> nearest
>>> integer, with *_values halfway between adjacent integers rounded
>>> towards positive infinity_*.
>>> "
>>> CSS4 Values, section 5.1.1. Combination of <integer>
>>> https://www.w3.org/TR/css-values-4/#combine-integers
>>> 
>>> So
>>> 
>>> 'z-index: -1.5'
>>> should be converted to 'z-index: -1' and not to 'z-index: -2'
>>> while
>>> 'z-index: 1.5'
>>> should be converted to 'z-index: 2'.
>> 
>> Oops.. I meant
>> 
>> 'z-index: calc(-1.5)'
>> should compute to 'z-index: -1' and not to 'z-index: -2'
>> while
>> 'z-index: calc(1.5)'
>> should compute to 'z-index: 2'.
>> 
>>> 
>>> Is my interpretation of the spec correct?
> 
> Afaict it is correct. If that's not what implementations do,
> though, let us know as we may need to adjust the spec. :)
> 
> ~fantasai

Firefox 66 buildID=20181218191030 resolves 'z-index: calc(-3 / 2)' to 
'z-index: -2' not as 'z-index: -1' in:
http://www.gtalbot.org/BrowserBugsSection/CSS3Values/calc-negative-fraction-001.html

Chromium 73.0.3645.0 passes (false positive)
http://www.gtalbot.org/BrowserBugsSection/CSS3Values/calc-negative-fraction-001.html
but that is because 'z-index: calc(-3 / 2)' is not resolved, is not 
handled at all.

- - - - -

Chromium 71, Chromium 73.0.3645.0 and Epiphany 3.31.3-3-g64a3330ce 
(WebKitGTK+ 2.23.1) fail
http://www.gtalbot.org/BrowserBugsSection/CSS3Values/calc-positive-fraction-001.html

Firefox 66 buildID=20181218191030 passes
http://www.gtalbot.org/BrowserBugsSection/CSS3Values/calc-positive-fraction-001.html

Gérard
Received on Wednesday, 19 December 2018 02:16:00 UTC

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