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background-size-[002-024]: reviewed and most of them approved

From: Gérard Talbot <css21testsuite@gtalbot.org>
Date: Sat, 10 Nov 2012 00:55:03 -0500
Message-ID: <c650bdb4026c4dd9fac19a224687bc1a.squirrel@ed-sh-cp3.entirelydigital.com>
To: "Zhang, Zhiqiang" <zhiqiang.zhang@intel.com>
Cc: "Public CSS testsuite mailing list@w3.org" <public-css-testsuite@w3.org>, "Santos, Thiago" <thiago.santos@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 Ven 9 novembre 2012 3:28, Zhang, Zhiqiang a écrit :
>> Zhiqiang, let me know if you have more tests (and which tests) to
>> review, to approve.
>> Gérard
>> --
> Hi Gerard,

> background-size-002 to 034 (except background-size-008 above) need to be
> reviewed again, and to be approved :).

background-size-009, at line 21:
I changed height: 100px to height: 50px;. This way, if width and height
are not matched correctly and respectively to first and second values,
then the green square will be small and testers will see red. By setting
height: 50px, we reduce risks, chances of false positives; we reduce
chances that a faulty implementation does not get caught by the test.

background-size-011, at line 19:
I changed support/60x60-green.png to support/50x50-green.png for reasons
mentioned regarding Opera 12.10 and Linux inaccurate rounding APIs.

background-size-014, at line 22:
I changed width: 200px for width: 50px so that if the UA applies 45% to
50px (and not 200px), then the painted green area will be definitely
smaller than 45px; with width: 200px, it would be 90px which is more
than enough to cover the red square, in which case we wouldn't see a
failure. By setting width: 50%, this restricts chances of false

background-size-017, at line 23:
If 45% is incorrectly applied on width: 50px, then testers will red. If
45% is incorrectly applied on width: 200px, then we will *not* see red
(although we won't see a green square but rather a green 90px by 45px
rectangle). So, I replaced width: 200px with width: 50px to maximize
possibilities to notice failures due to incorrect implementation.

background-size-021: the image should be scaled from 98px wide by 99px
tall to 100px wide and 100px tall. There is a rounding of fractional
pixels: it's actually difficult to figure out what happens with
calculations here. When I set 'background-size: 99% 99%' in that test,
then I should see a 1px wide red vertical line at the right of the cat
with a 1px tall red horizontal line below the cat but this is not
happening in Opera 12.10. So, the failure in Chrome 23.0.1271.64 is most
likely only due to rounding effects of a fraction in the calculation.
The way to work around this difficulty would be to create an image whose
dimensions won't be subject to fraction when being scaled. The cat image
does not have ideal dimensions for scaling: 98px wide by 99px height.

Idea: a 40px wide by 20px tall filled green rectangle in place of the
cat image:

background-size-022 and background-size-023: Here too, there could be
rounding effects of fractions, although I do not see any in Firefox
16.0.2, Opera 12.10, Chrome 23.0.1271.64 under Linux KDE 4.9.3 ... but
there could be under other operating systems and with other browsers.
The image should be scaled from 98px wide by 99px tall to 80px wide and
80px tall and to 75px and 75px. When I try with other values, then I see
differences between browsers. It would be best to use another image with
dimensions as such that there will be more predictable rendering when
scaled down. These 2 tests could still be acceptable, approved since the
pass/fail conditions can still be honored ... I need to think more on
these 2.

background-size-024: I see a small differences between Opera 12.10 and
the other browsers, most likely due to rounding effects of fraction when
scaling up the image. Maybe this test should be acceptable anyway as it

Those background-size-022, 023 and 024 tests, as they are, can not be


Approved tests
background-size-002, 005, 006, 007, 008, 009, 010, 011, 012, 013, 014,
015, 016, 017, 018, 019, 020, 024.

Should be retracted: background-size-003, 004

More later.

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Received on Saturday, 10 November 2012 05:55:34 UTC

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