Re: [css-backgrounds] [css-images] Interop for sizing gradients with only width

Le 2017-04-13 17:37, Gérard Talbot a écrit :
> Le 2017-04-13 17:24, Gérard Talbot a écrit :
>> Le 2017-04-13 16:38, Tab Atkins Jr. a écrit :
>>> On Thu, Apr 13, 2017 at 5:51 AM, Philippe Wittenbergh
>>> <ph.wittenbergh@l-c-n.com> wrote:
>>>> 
>>>>> On Apr 13, 2017, at 7:30 PM, Henrik Andersson 
>>>>> <henke@henke37.cjb.net> wrote:
>>>>> 
>>>>> This following code acts differently in Chrome and 
>>>>> SeaMonkey(Gecko).
>>>>> Which is correct?
>>>>> 
>>>>> Chrome gives the same result as if the background-size specified 
>>>>> 33% for
>>>>> the height. SeaMonkey thinks it should have a height of 100%.
>>>>> 
>>>>> div {
>>>>>    width: 160px;
>>>>>    background-repeat: repeat-x;
>>>>>    background-size: 33%;
>>>>>    height: 400px;
>>>>>    background-image: linear-gradient(red, red);
>>>>>    border: black solid 1px;
>>>>> }
>>>> 
>>>> Per CSS3 - backgrounds:
>>>> https://drafts.csswg.org/css-backgrounds/#the-background-size
>>>> 
>>>> For background-size:
>>>> 
>>>>> [ <length-percentage> | auto ]{1,2}
>>>>> The first value gives the width of the corresponding image, the 
>>>>> second value its height. If only one value is given the second is 
>>>>> assumed to be ‘auto’.
>>>> 
>>>> further, for auto, the text notes:
>>>> 
>>>>> An ‘auto’ value for one dimension is resolved by using the image's 
>>>>> intrinsic ratio and the size of the other dimension, or failing 
>>>>> that, using the image's intrinsic size, or failing that, treating 
>>>>> it as 100%.
>>>> 
>>>> For a gradient (as in your example), the “image” has no intrinsic 
>>>> size, thus 100% should be used. That is what Firefox / Gecko does. 
>>>> Chrome and Safari are wrong.
>>> 
>>> This is correct. Chrome/Safari are buggy here.  Mind filing bugs?
>>> 
>>> ~TJ
>> 
>> Philippe or Henrik,
>> 
>> If you file a bug report on this, you can include a link to these 2 
>> draft tests:
>> 
>> http://www.gtalbot.org/BrowserBugsSection/CSS3Backgrounds/draft-background-size-one-value-percent-0xx.xht
>> 
>> http://www.gtalbot.org/BrowserBugsSection/CSS3Backgrounds/draft-background-size-one-value-0xx.xht
>> 
>> I will submit eventually those tests (under different filenames) to
>> the CSS3 backgrounds and borders test suite to improve test coverage.
>> Those tests are quick draft for now (many text improvements needed and
>> (not sure) possible test reduction) but they demonstrate clearly and
>> cleanly an implementation failure of Chrome/Safari browsers.
>> 
>> Gérard
> 
> 
> It appears that MS-Edge 13 also fails these 2 tests.
> 
> I checked the background and borders test suite on background-position
> 
> http://test.csswg.org/suites/css-backgrounds-3_dev/nightly-unstable/html4/chapter-3.htm#s3.9
> 
> and none of the 8 tests we have on one single background-position
> value fails in Chrome. So, we definitely can improve the coverage of
> the test suite here.
> 
> +CC: Thierry Michel
> 
> Gérard


I filed this bug report:

Issue 711489: background-position with only one [ <length | <percent> ] 
value with gradient incorrectly rendered
https://bugs.chromium.org/p/chromium/issues/detail?id=711489

Gérard

Received on Thursday, 13 April 2017 23:03:02 UTC