Bug 58006 – Images with percentage based height/max-height are missing when they are inside blocks inside tables

• Component: Tables
• Status: RESOLVED FIXED

[Adele Peterson]

Created attachment 88557 [details]
test

Images with max-height:100% are missing when they are inside blocks inside tables

See attached test case.  It works fine in Firefox and IE.

I think this has something to do with this code in RenderBox::availableLogicalHeightUsing

    if (isTableCell() && (h.isAuto() || h.isPercent()))
        return overrideSize() - borderAndPaddingLogicalWidth();

In this case, if you check hasOverrideSize() you get false, and overrideSize just returns -1.  So I think we need some kind of overrideLogical… method that's like the overrideHeight and overrideWidth methods that will check hasOverrideSize for you.

<rdar://problem/7972529>

[Adele Peterson]

As a test, I just added a check of hasOverrideSize() to that condition, and it gets the image to the right size.  That is probably overly simplistic though.

[Adele Peterson]

That experiment breaks tables/mozilla/bugs/bug137388-1.html  so I'll use that test to understand how this code is supposed to work.

[Adele Peterson]

One thing that puzzles me is that the inner paragraph element is getting the right height.  If I set the exact same height on the paragraph explicitly, then the image also gets the right size.

[Adele Peterson]

Sounds a bit similar to this old bug:

JPEG image not shown when height is specified as percentage inside a table
https://bugs.webkit.org/show_bug.cgi?id=15359

Fixed with:
http://trac.webkit.org/changeset/29039

[Adele Peterson]

This also occurs with percentage-based height.  Attaching a new test case.

[Adele Peterson]

Created attachment 89338 [details]
New test

[Adele Peterson]

Now I'm thinking that the reason RenderTableSection's cell children flex code doesn't run is that percentHeightDescendants doesn't ever include this image element.

In http://trac.webkit.org/changeset/36513, Dan wrote this comment about code in RenderBox that adds to that list:

(WebCore::RenderBox::calcReplacedHeightUsing): Changed to skip over
anonymous containing blocks, if any, and when that happens, use
addPercentHeightDescendant() to ensure that the non-anonymous block
is aware of the dependent percent-height box.

In this case, because the containing block is never an anonymous block, we never add the image element to any RenderBox's list.  I tried an experiment in RenderBox::computeReplacedLogicalHeightUsing to change that loop to a do while loop so the first containing block calls addPercentHeightDescendant even if its not an anonymous block.  Again, this experiment fixed the original problem -- and broke the last test case in my attachment horribly.  So maybe I'm off in the weeds here.

[Adele Peterson]

That experiment was a bust.  Adding to percentHeightDescendant had no effect, but screwing up the concept of what is the containing block did.

Created attachment 91945 [details]
Extend the fix for bug 15359 to cover the nested case

Fixed in r85499. <http://trac.webkit.org/changeset/85499>