John J. Barton wrote:
However, the rules are found if we "inspect" the element and the
mouse is over the element. It is as if the result of
getCSSStyleRules(element) depends on content state.
It does, indeed. It also depends on the attributes the element has,
its position in the tree, and so forth. These are all no different
from each other, really.
Well from the developer's viewpoint attributes and position are quite
different from 'hover'. We need the mouse to run the debugger so we
can't be hovering all day...
That's not that different from dealing with a page that is performing
animation by setting a class attribute, say. That's a rarer case, but
fundamentally the same.
Doing that would sorta work if you only twiddle the ESM-managed bits,
but it would actually change the ESM's state (for example, you can't
remove hover state by unsetting the hover bit this way, as far as I
can tell). In general, the content state stuff in inspector utils is
pretty broken and could use some serious work, imo.
What is an ESM?
EventStateManager. The class that keeps track of things like hover state.
I guess Firebug needs to present 'what if' options to the user, at least
for mouse-dependent rules. So imagine the element rules that are active
followed grey-ed rules that would apply to the element if certain
conditions are met, eg "hovered". The user can move the debugger mouse
over the grey-ed rules and they will be activated temporarily so the
developer can take a look. And if the mouse does hover, then the rules
are activated.
That would require a getAllCSSStyleRules(element) as well as temporary
get/set bits working.
Ok. Bugs filed? This would need new APIs into the selector-matching
engine, and it's not obvious what the right APIs would look like. For
example, what should happen with rules like "div:hover > p" when looking
at paragraphs?
Is there anything like an 'onHover'? onContentStateChange? Firebug could
at least reflect the hover change in its UI if it got an event.
onMouseOver, no?
There is no generic notification for content state changes (or even just
event state changes; content state includes things like :default that
are not managed by the ESM).
-Boris
_______________________________________________
dev-tech-layout mailing list
dev-tech-layout@lists.mozilla.org
https://lists.mozilla.org/listinfo/dev-tech-layout
