1566693 - Provide a way for stylesheets to opt out from default native focus ring

Status: NEW

(Core :: Widget: Cocoa, enhancement, P3)

Description

[Tim Nguyen :ntim]

See https://twitter.com/rob_dodson/status/1151284106623254528

Testcase: https://jsbin.com/nogorefevu/1/edit?html,output

It appears Webkit+Blink let you use outline: none; to opt-out, but I don't know if this is standard.

Comment 1

[Tim Nguyen :ntim]

Emilio/Cameron, do you know if there's an existing spec regarding this ?

Comment 2

[Emilio Cobos Álvarez (:emilio)]

data:text/html,<style>::-moz-focus-inner { border: none }</style><button>Foo?

Comment 3

[Emilio Cobos Álvarez (:emilio)]

Ah, you mean the mac outline.

Comment 4

[Tim Nguyen :ntim]

Attachment: screenshot of outline

This doesn't appear to work on macOS, I'm guessing there's some widget code involved here.

Also, is there no actual standard for this ? Chrome/Safari allow you to remove the focus outline using outline: none. Maybe Firefox should do the same ?

Comment 5

[Emilio Cobos Álvarez (:emilio)]

So ok, this is what I learnt:

• This outline seems hardcoded in the mac code, so not tied to outline at all: https://searchfox.org/mozilla-central/rev/22b330ecb3edba1536a54887060cbdd09db21c59/widget/cocoa/nsNativeThemeCocoa.mm#1506
• We indeed not paint any outline for buttons by default for this reason: https://searchfox.org/mozilla-central/rev/22b330ecb3edba1536a54887060cbdd09db21c59/layout/style/res/html.css#718
• We disabled support for outline-style: auto in bug 1034018.

I don't think form controls have any proper spec for this kind of stuff, but it makes sense to do this. It seems it should be feasible to just skip that bit if the button doesn't specify an outline. Probably recording a hasOutline boolean here: https://searchfox.org/mozilla-central/rev/22b330ecb3edba1536a54887060cbdd09db21c59/widget/cocoa/nsNativeThemeCocoa.mm#1291

Like params.hasOutline = aFrame && aFrame->StyleOutline()->ShouldPaintOutline();, probably.

But this is mac-specific code, not style code. I also don't have a mac, so take anything with a grain of salt :)