In horizontal writing mode, the default size of an <iframe> in the absence of any constraints or explicit sizing properties is 300px x 150px, according to the CSS 2.1 sizing rules.[1,2] In vertical writing modes, we reinterpret these rules so that "width" becomes inline-size, and "height" becomes block-size, so the <iframe> ends up at 150px wide x 300px high. I suspect this is wrong, although it's not clear to me from the Writing Modes spec which way it should be handled. I've posted to www-style hoping for clarification. Assuming there's agreement that the <iframe> default size should remain physical (which I think makes sense *unless* we were to also propagate the vertical writing mode to its contents), we'll need to fix our implementation to respect this. The reftest reference files writing-mode/abspos/1183431-orthogonal-modes-5-ref.html and writing-mode/abspos/1183431-orthogonal-modes-6-ref.html will then need to be updated, as they are currently designed to work with our existing behavior where writing-mode *does* affect the default sizing of <iframe>.  http://www.w3.org/TR/CSS2/visudet.html#inline-replaced-width  http://www.w3.org/TR/CSS2/visudet.html#inline-replaced-height  https://drafts.csswg.org/css-writing-modes-3/#abstract-layout  https://lists.w3.org/Archives/Public/www-style/2015Aug/0049.html
Created attachment 8644958 [details] [diff] [review] Make the intrinsic size of <iframe> remain physical 300x150, regardless of writing mode Based on the exchange on www-style, I think we should go ahead and do this to align our behavior to the other browsers, and assume the spec will be clarified accordingly.
Attachment #8644958 - Flags: review?(dholbert)
Assignee: nobody → jfkthame
Status: NEW → ASSIGNED
Comment on attachment 8644958 [details] [diff] [review] Make the intrinsic size of <iframe> remain physical 300x150, regardless of writing mode Review of attachment 8644958 [details] [diff] [review]: ----------------------------------------------------------------- Looks good. Thanks!
Attachment #8644958 - Flags: review?(dholbert) → review+
(This behavior -- sticking to physical 300x150 -- is consistent with other replaced elements, right?)
url: https://hg.mozilla.org/integration/mozilla-inbound/rev/96d67fd3c056d89346bb5760e902a67dbe700b98 changeset: 96d67fd3c056d89346bb5760e902a67dbe700b98 user: Jonathan Kew <email@example.com> date: Wed Aug 12 11:02:02 2015 +0100 description: Bug 1191855 - Make the intrinsic size of <iframe> remain physical 300x150, regardless of writing mode. r=dholbert
(In reply to Daniel Holbert [:dholbert] from comment #4) > (This behavior -- sticking to physical 300x150 -- is consistent with other > replaced elements, right?) Yes; e.g. <video> keeps its landscape-aspect intrinsic size unchanged even in vertical mode.
Status: ASSIGNED → RESOLVED
Last Resolved: 3 years ago
status-firefox43: --- → fixed
Resolution: --- → FIXED
Target Milestone: --- → mozilla43
Component: Layout: HTML Frames → Layout: Images
Product: Core Graveyard → Core
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