[whatwg] Outline style to use for drawSystemFocusRing

Ian Hickson ian at hixie.ch
Wed Jul 24 16:14:02 PDT 2013

On Wed, 24 Jul 2013, Dominic Mazzoni wrote:
> I'm looking into implementing
> drawSystemFocusRing<http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#dom-context-2d-drawsystemfocusring>in
> Blink, but it's unclear what style to use when drawing the focus ring
> -
> i.e. the color, thickness, etc., assuming that the user hasn't overridden
> it for accessibility. Here are some possible interpretations:
> 1. Hard-code default values. I don't think this would be ideal, since it
> wouldn't necessarily match the focus color of other elements that get the
> focus color from the system.
> 2. Get them from the default style of a generic element (which may match
> the system focus style). This could work, but I think this is less flexible
> for developers - if they picked a custom outline color for every other
> element in their site but would have no way to override it for canvas
> (other than using drawCustomFocusRing).
> 3. Get them from the outline style of the canvas element. This means every
> focus ring within the canvas would be the same, but otherwise I have no
> objection.
> 4. Get them from the outline style ofelement passed to drawSystemFocusRing.
> This is my preference.

The idea is it's supposed to be the system style (hence the name of the 
method, draw _system_ focus ring), and that if the authors wants a special 
style, they use drawCustomFocusRing() and if it returns true they draw it 
themselves (using strokeStyle and stroke(), or whatever).

There's an example in the spec -- search for "couple of checkboxes".

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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