1432341 - Drawing of the column-rule is incorrect for the fragments of an inner multicol in nested multicols.

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[Neerja Pancholi[:neerja]]

Attachment: ColumnRuleDrawingBroken.html

Open the attached test case ColumnRuleDrawingBroken.html in Nightly. You will see that the column-rules for the inner multicol fragments are extended beyond the size of the multicol.

Comment 1

[Neerja Pancholi[:neerja]]

Attachment: NightlyColumnRuleDrawing.jpg

Comment 2

[Neerja Pancholi[:neerja]]

These column-rules are not drawn at all on Firefox 57.

Comment 3

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=4d91092a0c8fa18b3eec42669777482073891b07&group_state=expanded

Comment 4

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Attachment: Bug 1432341 - Simplify by using GetContentRectRelativeToSelf.

This is just cleanup in advance of the patch to fix this bug.

Review commit: https://reviewboard.mozilla.org/r/216094/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/216094/

Comment 5

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Attachment: Bug 1432341 - Rename functions that relate to column rules to have clearer names.

This is followup to bug 1361668, and is just cleanup in advance of the
patch to fix this bug.

Review commit: https://reviewboard.mozilla.org/r/216096/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/216096/

Comment 6

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Attachment: Bug 1432341 - Draw column-rules with border-code in box-decoration-break: clone mode, rather than slice.

This fixes the bug.  The underlying problem was that we were hitting the
case where ConstructBorderRenderer sets aNeedsClip to true, but nothing
in the column-rule drawing path was honoring that.

(Choosing clone rather than slice may make a difference for dotted and
dashed column-rules, but I think the clone behavior is preferable.)

Review commit: https://reviewboard.mozilla.org/r/216098/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/216098/

Comment 7

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Attachment: Bug 1432341 - Add reftest for column-rule broken across columns.

I tested locally that the reftest fails without the previous patch, and
passes with it.  The failure is because the column rules overflow (as
though they're drawn in each column for the entire extent of the inner
columnset rather than just the piece visible in that column, i.e.,
overflowing only below in the first column, above and below in the
second column, and only above in the third column).

Review commit: https://reviewboard.mozilla.org/r/216100/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/216100/

Comment 8

[Matt Woodrow (:mattwoodrow)]

Comment on attachment 8946062 [details]
Bug 1432341 - Simplify by using GetContentRectRelativeToSelf.

https://reviewboard.mozilla.org/r/216094/#review222120

Comment 9

[Matt Woodrow (:mattwoodrow)]

Comment on attachment 8946063 [details]
Bug 1432341 - Rename functions that relate to column rules to have clearer names.

https://reviewboard.mozilla.org/r/216096/#review222122

Comment 10

[Matt Woodrow (:mattwoodrow)]

Comment on attachment 8946064 [details]
Bug 1432341 - Draw column-rules with border-code in box-decoration-break: clone mode, rather than slice.

https://reviewboard.mozilla.org/r/216098/#review222124

I agree that the clone behaviour is preferable here!

Comment 11

[Matt Woodrow (:mattwoodrow)]

Comment on attachment 8946065 [details]
Bug 1432341 - Add reftest for column-rule broken across columns.

https://reviewboard.mozilla.org/r/216100/#review222128

Comment 12

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/6fe40d8edcf64beeac5573c00e1b33e88e838578
Bug 1432341 - Simplify by using GetContentRectRelativeToSelf.  r=mattwoodrow

https://hg.mozilla.org/integration/mozilla-inbound/rev/45d0f06fb923eabd1520754de60b0a29d7941dc1
Bug 1432341 - Rename functions that relate to column rules to have clearer names.  r=mattwoodrow

https://hg.mozilla.org/integration/mozilla-inbound/rev/8d8a093e718c460c9252666a5e4d949a244483bf
Bug 1432341 - Draw column-rules with border-code in box-decoration-break: clone mode, rather than slice.  r=mattwoodrow

https://hg.mozilla.org/integration/mozilla-inbound/rev/ded3e23e2442aedea6392ceb02fe4b76b4b47f8c
Bug 1432341 - Add reftest for column-rule broken across columns.  r=mattwoodrow

Comment 13

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/mozilla-central/rev/6fe40d8edcf6
https://hg.mozilla.org/mozilla-central/rev/45d0f06fb923
https://hg.mozilla.org/mozilla-central/rev/8d8a093e718c
https://hg.mozilla.org/mozilla-central/rev/ded3e23e2442