I'm posting this message in the name of Rod McGuire, who got his message
rejected apparently.

---

[ I apologize for knowing nothing of current Servo internals ]

For precise layout of things like math equations or SVG diagrams a
Javascrpt application may need to know the width and height extent of
component elements.

Currently in browsers the only way to find this information is with
.getBoundingClientRect() which only works after an element has been
rendered and also returns x and y position information.

The current way to kludge around this is by rendering each element
twice - on the first pass width and height information is collected
to determine the layout in the final render pass.

[ MathJax does this though I think they are moving towards an
external font table approach ]

I've heard that to just get width and height information without
rendering would require a major rewrite of the work flow for most
current browsers.

Has there been any effort in Servo to make available this information
for non-rendered elements?

I think most developers affected by this would be somewhat happy with
width and height just for textual elements. They also might like some
exposure of the actual selected font so that font table information can
be used in layout.

I haven't been able to find any discussion of this issue though there
seems to be some on performance of the full blown
.getBoundingClientRect().

[1]: 
https://developer.mozilla.org/en-US/docs/Web/API/Element/getBoundingClientRect
[2]: Recent Improvements to Functions like getClientBoundingRect - 
https://groups.google.com/forum/#!searchin/mozilla.dev.servo/getBoundingClientRect/mozilla.dev.servo/fpY49KCQ_64/0Mq7fnn4OMIJ

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