- From: Gérard Talbot <css21testsuite@gtalbot.org>
- Date: Mon, 15 Oct 2012 17:54:07 -0400
- To: "Zhang, Zhiqiang" <zhiqiang.zhang@intel.com>
- Cc: "Public CSS testsuite mailing list" <public-css-testsuite@w3.org>, "Christensen, Kenneth" <kenneth.christensen@intel.com>, "Zhang, Haili" <haili.zhang@intel.com>, "Yu, Ling L" <ling.l.yu@intel.com>, "Yang, Lei A" <lei.a.yang@intel.com>
Le Dim 14 octobre 2012 23:04, Zhang, Zhiqiang a écrit : > Gérard, > > Thank you very much on your feedbacks. I really appreciate your review > of my tests. > >> >> Zhiqiang, >> >> Here's a preliminary review of 1 test. >> >> http://test.csswg.org/source/contributors/intel/submitted/css3- >> background/background-334.html >> >> 1- >> a) >> The test is obviously about background shorthand: so the title element >> should say so. > > Updated @ https://hg.csswg.org/test/rev/4a42bfba3b60 > Zhiqiang, I wonder why you unite, you join all the words in the last part of the title with underscore characters. Eg. background_shorthand_specified_color_image eg. background_specified_box_two >> >> b) >> " >> For specifications other than CSS 2.1, you can include the module name >> somewhere before the colon, like "CSS Selectors Test:" or "CSS Test >> (Selectors):". Do not include the module version number, since the >> test >> might get reused for the next version. >> " >> http://wiki.csswg.org/test/format#title-element >> >> So, >> <title>CSS Test (Backgrounds and Borders): (...)</title> >> or >> <title>CSS Backgrounds and Borders Test: (...)</title> > > Updated @ https://hg.csswg.org/test/rev/b3381a9594e0 > >> >> are okay. >> >> 2- >> The test design and assert text suggest that background-size '100% >> auto' >> will imply a rescale of the background-image to fill the background >> area. >> >> 3- >> top: 1px; >> left: 1px; >> >> I wondered why top and left 1px. >> >> width: 158px; >> height: 158px; >> background: red; >> } >> #test { >> position: absolute; >> top: 0px; >> left: 0px; >> width: 100px; >> height: 100px; >> padding: 25px; >> border: 5px dotted #000000; >> >> The overlapping #test generates a 160px wide and 160px tall CSS box >> while the red-overlapped #ref generates a 158px by 158px box; the only >> possible reason I can imagine would be to counter/take into account >> anti-aliasing. > > Yes. This is referred to > http://test.csswg.org/source/contributors/ttwf/samples/ttwf-reftest-tutorial-001.html, > and I think it's a good practice. > Well,... hmm... I think there is an issue here. The test allocates a margin for error of 2px which is for anti-aliasing. We discussed before about anti-aliasing: thread started with http://lists.w3.org/Archives/Public/public-css-testsuite/2012Mar/0020.html although we did not discuss about allocating a 1px or 2px of margin of error in the tests. As far as I know and understand this, anti-aliasing will mostly occur with oblique lines, not for straight vertical lines and not for straight horizontal lines. Anti-aliasing may occur with glyphs, in particular oblique ones like "V" or "W", "Y", etc. and curvy glyphs. In the relativity, 2px may be a lot. Let me give you an example of where such 2px may not be a good thing: http://www.gtalbot.org/BrowserBugsSection/review/background-size-xyz.html Firefox 16.0.1, Chrome 22.0.1229.94 and Konqueror 4.9.2: displays no red Opera 12.02: there is a 1px vertical line of red on the right and a 1px horizontal line of red at the bottom. Most likely because of rounding effects: the scaling from 60px to 100px is not accurate. My initial thought was that this should be considered as a bug. For practical reasons, I would also believe this is a bug. Users or developers would eventually report this to Opera BTS as a bug and complaint that browserX, browserY and browserZ don't display red. Now, to make things furthermore complicated, let's add 'background-color: #CCC' (which is the background-color originally included in background-334) to that test. We have: http://www.gtalbot.org/BrowserBugsSection/review/background-size-xyz-with-gray-color.html and now, it *appears* that Opera 12.02 passes the test but in reality it does not... and the test would probably be reported as failed when/with automated-comparing to its reftest. Gérard -- Contributions to the CSS 2.1 test suite: http://www.gtalbot.org/BrowserBugsSection/css21testsuite/ CSS 2.1 Test suite RC6, March 23rd 2011: http://test.csswg.org/suites/css2.1/20110323/html4/toc.html CSS 2.1 test suite harness: http://test.csswg.org/harness/ Contributing to to CSS 2.1 test suite: http://www.gtalbot.org/BrowserBugsSection/css21testsuite/web-authors-contributions-css21-testsuite.html
Received on Monday, 15 October 2012 21:54:40 UTC