[css3-multicol] Problems with multicol-fill-002

Hello,

[src]
http://test.csswg.org/source/contributors/opera/submitted/multicol/multicol-fill-002.xht

[reftest]
http://test.csswg.org/source/contributors/opera/submitted/multicol/multicol-fill-ref.xht

1-
The filename should be renamed to multicol-fill-balance-001.xht . That
way, a set of tests testing 'column-fill: balance' would be easier to
find/get.

2-
The test in its current version passes in UAs which do not support
multi-column.

3-
Computed font-size of multi-column element should be dividable by 5px
without remainer in order to be accurate and reliable across platform.

4-
The most important problem with the test is that the test is not truly
creating the appropriate, suitable conditions where 'column-fill:
balance' would create a rendering different from 'column-fill: auto'. If
the test was good, then the test, in my opinion, should fail and fail in
a predictable manner if an UA does not support 'column-fill: balance'
and only support 'column-fill: auto'. Here, the test passes if
'column-fill: balance' is removed!

If all the inline content is expected to fill each line and to fill each
column box, then there is no predictable difference to be expected when
setting 'column-fill: balance' or when setting 'column-fill: auto'.

So, ideally, a test testing 'column-fill: balance' versus 'column-fill:
auto' needs to create not too much inline content so that it can and
will only fill half of all column boxes and then verify that all inline
content fills all column boxes but only half of them (column-fill:
balance) as compared to filling half of all column boxes (column-fill:
auto).

Imagine something like:

div
{
column-count: 2;
column-gap: 1em;
height: 6em;
width: 21em;
}

where digits represents single characters

<div>1234567890 12 4567 90 123 56 890 123 56789 1 34567 90 12 4567 90
123 56 890 123 56</div>

with 'column-fill: balance':
------------  ------------
|1234567890|  |1 34567 90|
|12 4567 90|  |12 4567 90|
|123 56 890|  |123 56 890|
|123 56789 |  |123 56    |
|          |  |          |
|          |  |          |
------------  ------------

Same inline content with 'colum-fill: auto':
------------  ------------
|1234567890|  |123 56 890|
|12 4567 90|  |123 56    |
|123 56 890|  |          |
|123 56789 |  |          |
|1 34567 90|  |          |
|12 4567 90|  |          |
------------  ------------

In conclusion, testing 'column-fill: balance' versus 'column-fill: auto'
requires less content to fill the column boxes, shorter words (versus)
large column boxes. That way, the test provides a leeway where both
column-fill values can "express" their characteristics.

Gérard
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Received on Friday, 2 August 2013 01:30:09 UTC