Bug 117436 – Correctly calculate auto margins for column flows

• Status: NEW
• Component: Layout and Rendering

[Ryosuke Niwa]

Consider merging https://chromium.googlesource.com/chromium/blink/+/4727602ff32037dede84f2acd9534d6256f3e001

In RenderBox::computeInlineDirectionMargins, we have to pretend that
auto margins are zero so that the line cross size gets calculated
correctly (compare http://dev.w3.org/csswg/css-flexbox/#auto-margins)

That fix exposed a bug in RenderFlexibleBox::updateAutoMarginsInCrossAxis,
which needs to take LTR/RTL-ness into account -- it needs to adjust the
position iff margin-before is auto, which can be margin-right.

This CL also adds a few comments in an attempt to clarify the code a little.

[Ahmad Saleem]

I am able to reproduce this issue kind of based on linked Chromium patch:

Link - https://jsfiddle.net/abgLcdpq/show

*** Safari Technology Preview 152 ***

Shows "only four" - centeredWithAlignSelf

*** Chrome Canary 107 ***

Shows "five" - centeredWithAlignSelf

*** Firefox Nightly 106 ***

Shows "five" - centeredWithAlignSelf

_____________________________

Just wanted to share updated results. Thanks!

[Ahmad Saleem]

This is already added in RenderBox.cpp:

https://github.com/WebKit/WebKit/blob/4385a00da760f9db033925547caa238d3a9f0885/Source/WebCore/rendering/RenderBox.cpp#L3065

RenderFlexibleBox.cpp - Added this already

https://github.com/WebKit/WebKit/blob/4ccdb2ac7f7c989dd9d92ec1c42dccc44ef21b6a/Source/WebCore/rendering/RenderFlexibleBox.cpp#L1288

https://github.com/WebKit/WebKit/blob/4ccdb2ac7f7c989dd9d92ec1c42dccc44ef21b6a/Source/WebCore/rendering/RenderFlexibleBox.cpp#L1302

https://github.com/WebKit/WebKit/blob/4ccdb2ac7f7c989dd9d92ec1c42dccc44ef21b6a/Source/WebCore/rendering/RenderFlexibleBox.cpp#L1315

I think this was added but now we still have different behavior as mentioned in my previous comment. :-?

[Radar WebKit Bug Importer]

<rdar://problem/99344089>