[Webkit-unassigned] [Bug 30949] New: Wrong calculation of the width of empty table cells.

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=30949

           Summary: Wrong calculation of the width of empty table cells.
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: PC
               URL: http://news.xinhuanet.com/video/2007-04/22/content_601
                    0553.htm
        OS/Version: Windows XP
            Status: UNCONFIRMED
          Severity: Normal
          Priority: P2
         Component: CSS
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: hanrui.gao at gmail.com
                CC: johnnyding.webkit at gmail.com


Browsers tested:
     Safari 4: Fail
     Chrome 4: Fail
    Firefox 3: OK
     IE 6/7/8: OK

What steps will reproduce the problem?
1. Launch the URL above
2. Pay attention to bottom area of the page
3. The right column has no black nor gray bar

What is the expected result?
The right column should have a black bar and a gray bar like what IE and
Firefox do.

What happens instead?
The right column has no black nor gray bar.

Please provide any additional information below.
Screenshot attached.
There seems to be something wrong with the width calculation for empty 
cells in Chrome.
The page uses codes below to show the black bar and gray bar:
      <table width="227" border="0" cellspacing="0" cellpadding="0"> 
        <tr> 
          <td bgcolor="#FFFFFF" height="9"></td> 
        </tr> 
        <tr> 
          <td bgcolor="#000000" height="5"></td> 
        </tr> 
        <tr> 
          <td bgcolor="#E5E5E5" height="5"></td> 
        </tr> 
      </table>
This table has three rows with one empty cell in each row.
In Chrome and Safari, it counts the width of the three cells as 0, so there's
no bar in the two browsers.
>From 17.5.2.2 in W3C
standard(http://www.w3.org/TR/CSS21/tables.html#propdef-table-layout), we can
see that "If the 'table' or 'inline-table' element's 'width' property has a
computed value (W) other than 'auto', the property's value as used for layout
is the greater of W and the minimum width required by all the columns plus cell
spacing or borders (MIN). If W is greater than MIN, the extra width should be
distributed over the columns."
In this case, W is greater than MIN, so the extra width(227px) should be
distributed to the only one column.

>From my test-cases attached, we can find that Chrome always treat empty cells
as zero-width. So if the cell has background-color or background-image, you
cannot see the it in Chrome as well as Safari.

This bug will be triggered in Chrome and Safari if all the conditions listed
below are met:
1) The table's style 'table-layout' is 'auto'.
2) The table's width is specified.
3) The table's border width is 0.
4) The table cell is an empty cell.
5) The table cell's width is 'auto'.
6) The table cell's border width is 0.
7) The table cell's padding is 0.
8) In the same column, there is no other table cell which is not affected 
by this bug.

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