295483 - Implement nsTextFrame chain for line layout

Status: RESOLVED WONTFIX

(Core :: Layout: Text and Fonts, defect)

Description

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

We need to nsTextFrame chain for bug 164700, bug bug 156369, bug 289130 and bug
288439. Because these bug needs the first character of next frame or last
character of previous frame.

Currently, we have mNextInFlow. But it cannot solve to the follwing case.

A<span style="position: absolute; top: 500px;">B</span>C

In this case, the mNextInFlow is null. But, for rendering, we need to get C in A.

Comment 1

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Isn't there already some code in nsTextFrame to find the next frame? (Which
might not be a text frame --- it could be any inline frame.)

Comment 2

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Roc:

Really?
Can we get the next (any) frame from nsTextFrame?

I think that we can get the next frame only after all text frame's reflow.
Therefore, I think that I will create the chain at nsBlockFrame::PlaceLine, like
TrimTrailingWhiteSpace.

Comment 3

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

GetNextSibling()

Comment 4

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

GetNextSibling is not related the line layout. 
e.g., the end of line frame's GetNextSibling returns not null.

Comment 5

[rbs]

nsLineLayout::FindNextText()

we use that for, e.g., <a>x&nbsp;</a><b>y</b>. In this case, "x y" has to be
measured as a single non-breakable unit to see if it fits. (It has sufficently
matured and is robust enough to deal with all sorts of nesting.)

As this kind of information is needed at reflow, it is okay to assume that a
linelayout object will be there. Then, at paint, it is assumed that whatever has
been flagged at reflow can be recovered (like trimming spaces or ignoring parts
of the text).

Comment 6

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

This was filed for old design, so that I close this bug.