I see it everywhere there is a "Break" row, but not "lunch" row, on both days. Also on canary 68.0.3399.0

Able to reproduce this issue on reported version 65.0.3325.181, on latest stable 66.0.3359.117 and on latest canary 68.0.3400.0 using Mac 10.13.3, Windows 10 and Ubuntu 14.04.

Good Build: 61.0.3137.0
Bad Build: 61.0.3138.0

You are probably looking for a change made after 481330 (known good), but no later than 481331 (first known bad).
CHANGELOG URL:
 https://chromium.googlesource.com/chromium/src/+log/08a57486698031c8dc183e77503d8a54f8987ec8..0c1f73a50ab7c31c987decaba4abb5e3cbe8e286

Reviewed-on: https://chromium-review.googlesource.com/528561

@ wangxianzhu: Please confirm the bug and help in re-assigning if this is not related to your change.

Thanks!

In the row, the 3 cells have different heights:
 the first: 14.688px
 the second: 14.688px
 the third: 14.344px

In firefox, they are all 14.866px. In Safari (high DPI), they are all 31px (which seems multiplied by the device scale and rounded).

I tried 61.0.3137.0 with the page and it also shows the different heights. So I guess this is a layout issue exposed by the collapsed-border-painting CL. Will look into more details to verify.

(BTW, what's the relationship between the M-XX and Target-XX labels? I didn't find documentation about this.)

I think this is a table layout issue that cells in the same row get different heights. Reduced test case attached. Bisected and found that the issue had existed before r340000.

The current paint code correctly snaps the cell borders to whole pixels, but because of the different heights, the bottom borders of the cells are snapped to different pixels. The layout issue was hidden by the old paint code before my CL.

dgrogan@ can you take a look?

Deleted: table-misalign.html 669 bytes

table-misalign.html 669 bytes View Download

Can we have a fix during M68 time frame?

I will first try to mimic the old painting behavior we used before r481331.

Filed bug 838401 for the different height issue. Changing this issue to Blink>Paint for the workaround.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ebe018ff6c1d4240331a2be96fe5ed8256a6b0fc

commit ebe018ff6c1d4240331a2be96fe5ed8256a6b0fc
Author: Xianzhu Wang <wangxianzhu@chromium.org>
Date: Tue May 01 20:32:25 2018

[PE] When painting collapsed borders, snap size to whole pixels

For now we don't fully support subpixel layout in tables, but may
produce subpixel layout results and different heights for cells in
the same row (crbug.com/838401).

Now use the traditional method to snap size to pixels before
applying paint offset for collapsed borders.

Bug:  834648 
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: Ic8866e1a9d52bb6b60ea96dfda692040af8ecea8
Reviewed-on: https://chromium-review.googlesource.com/1036305
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555171}
[add] https://crrev.com/ebe018ff6c1d4240331a2be96fe5ed8256a6b0fc/third_party/WebKit/LayoutTests/paint/tables/align-subpixel-td-expected.html
[add] https://crrev.com/ebe018ff6c1d4240331a2be96fe5ed8256a6b0fc/third_party/WebKit/LayoutTests/paint/tables/align-subpixel-td.html
[modify] https://crrev.com/ebe018ff6c1d4240331a2be96fe5ed8256a6b0fc/third_party/blink/renderer/core/paint/collapsed_border_painter.cc
[modify] https://crrev.com/ebe018ff6c1d4240331a2be96fe5ed8256a6b0fc/third_party/blink/renderer/core/paint/table_cell_painter.cc
[modify] https://crrev.com/ebe018ff6c1d4240331a2be96fe5ed8256a6b0fc/third_party/blink/renderer/core/paint/table_cell_painter.h

Will you merge the fix to 67?

 Issue 846628  has been merged into this issue.

Re #c12: Sorry, the fix won't be merged into M67.

Able to reproduce the issue on build without fix, hence verifying the fix on latest canary 69.0.3443.0 using Windows 10, Ubuntu 14.04 and Mac 10.13.3.

Now observing equal heights in table, tested with html file given in comment#5.

Attaching screenshot for reference. As fix is working as intended, adding verified labels.

Thanks!

Deleted: 834648_M69.png 126 KB

	834648_M69.png 126 KB View Download