drawSystemFocusRing in Canvas

I am working with Google on their implementing support for this feature.
One of the things we did not specify with greater clarity is how the focus
ring style is determined for the standard focus ring associated with a
fallback element.

Default Focus styling by default should be determined from the outline
style of the fallback element associated with the element drawn on the


>From CSS2:
"Graphical user interfaces may use outlines around elements to tell the
user which element on the page has the focus. These outlines are in
addition to any borders, and switching outlines on and off should not cause
the document to reflow. The focus is the subject of user interaction in a
document (e.g., for entering text, selecting a button, etc.). User agents
supporting the interactive media group must keep track of where the focus
lies and must also represent the focus. This may be done by using dynamic
outlines in conjunction with the :focus pseudo-class.

For example, to draw a thick black line around an element when it has the
focus, and a thick red line when it is active, the following rules can be

:focus  { outline: thick solid black }
:active { outline: thick solid red }"

This would of course mean that should the author decide to change the
default focus style for the outline of that element that that style could
change on the physical canvas.

I would like to add informative text to the Canvas 2D API document that
states something on the order of (and this could be placed in a note):


The agents may use the <a href="
http://www.w3.org/TR/CSS2/ui.html#dynamic-outlines">CSS outlines around
focused elements</a> in determining the system focus style on fallback
elements to determine the standard system focus ring style drawn on the
canvas. This would mean that if an author were to override this style that
the appearance of the standard focus ring drawn on the canvas could reflect
this change in style.

Since this is non-normative text and would not require us to go back to
Last Call and because Google requested that we add informative text I would
like to propose adding this or similar to text to the current Canvas 2D API
CR document.


Received on Thursday, 25 July 2013 15:03:25 UTC