1236386 - CSS transformed (scaled down) element causes unexpected overflow scroll bar in parent element

Status: NEW

(Core :: Layout, defect)

Description

[Duan Yao]

Attachment: transform-overflow.html

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:45.0) Gecko/20100101 Firefox/45.0
Build ID: 20151230004007

Steps to reproduce:

Load the attachment or https://jsbin.com/damanujosu/edit?html,css,output .





Actual results:

The red box is big one (600*600) scaled down to 150*150, and it causes vertical overflow scroll bar in its ancestor (the black box, 300*300).


Expected results:

The ancestor box (black) should have no scroll bar, because there is nothing can be revealed by the scrolling.

Even if there have to be scroll bars, I think both horizontal and vertical scroll bars should be shown, not just the vertical one.

MS Edge shows both horizontal and vertical scroll bars. Chrome shows vertical scroll bar if there is no intermediate sized box.

Comment 1

[Alice0775 White]

Attachment: Bug 1236386-transform-overflow_setTimeout_version.html

It behaves same as Edge if used setTimeout.

Comment 2

[Boris Zbarsky [:bzbarsky]]

It's not clear to me from the transforms spec what the right behavior is here...

Comment 3

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

Me neither. I think Edge's behavior is reasonable. Our appears to be a bug since Alice is quite right, dynamic changes shouldn't lead to a different result. Chrome's behavior also looks buggy; the green box shouldn't matter.  Guess I'll email www-style.

Comment 4

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

https://lists.w3.org/Archives/Public/www-style/2016Jan/0045.html

Comment 5

[keith]

The fix for bug 1236386 (planned for 51) deals with a similar issue, but for scaled-up content.

Comment 6

[keith]

Sorry, that should be bug 1300611 — not 1236386 — which is this issue

Comment 7

[Jonathan Watt [:jwatt]]

Mass bug change to replace various 'parity' whiteboard flags with the new canonical keywords. (See bug 1443764 comment 13.)