1575016 - Revisit the 1px minimum column block-size for column-boxes

Status: RESOLVED FIXED

(Core :: Layout: Columns, task, P5)

Description

[Ting-Yu Lin [:TYLin] (PST, UTC-8)]

In nsColumnSetFrame::ChooseColumnStrategy(), we made the choice of minimun column-box block-size of 1px on non-balancing columns by

    // XXX_jwir3: If a page's height is set to 0, we could continually
    //            create continuations, resulting in an infinite loop, since
    //            no progress is ever made. This is an issue with the spec
    //            (css3-multicol, css3-page, and css3-break) that is
    //            unresolved as of 27 Feb 2013. For the time being, we set this
    //            to have a minimum of 1 css px. Once a resolution is made
    //            on what minimum to have for a page height, we may need to
    //            change this value to match the appropriate spec(s).
    colBSize = std::max(colBSize, nsPresContext::CSSPixelsToAppUnits(1));

I find that the fragmentation spec says,

To guarantee progress, fragmentainers are assumed to have a minimum block size of 1px regardless of their used size.

That is, we can update the comments, and maybe investigate whether we should also apply the 1px minimum block-size when doing column-balancing. (I feel we should.)

Comment 1

[Ting-Yu Lin [:TYLin] (PST, UTC-8)]

Attachment: Bug 1575016 - Update a comment that describes minimum 1px block-size for column-content blocks. r=dbaron

Fragmentation spec already has a paragraph describing this behavior.

DONTBUILD because this is a comment only change.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/88f20e24fa39
Update a comment that describes minimum 1px block-size for column-content blocks. r=dbaron

Comment 3

[Alexandru Michis [:malexandru]]

https://hg.mozilla.org/mozilla-central/rev/88f20e24fa39