379709 - During the initial reflow of SVG we should assume scrollbars won't be needed

Status: RESOLVED FIXED

(Core :: SVG, defect)

Description

[Jonathan Watt [:jwatt]]

In bug 378975 the initial reflow of documents was changed to assume that a scrollbar would be needed, and if not, documents are reflowed a second time. This change is intended to improve performance for long documents in HTML that require scrollbars (the common case in HTML) but in SVG documents don't get longer the more complex they are. Scrollbars are the rare case. It would be good to make this optimization conditional so SVG isn't penalized (maybe even check the SVG root element in advance to _know_ if we need scrollbars).

Comment 1

[Boris Zbarsky [:bzbarsky]]

Sure.  Feel free to tweak nsHTMLScrollFrame::InInitialReflow().  I guess you're want to see whether the scrolled frame is an SVG outer frame when mInner.mIsRoot?

Comment 2

[Jonathan Watt [:jwatt]]

Attachment: patch

Was reminded again while debugging that this is still happening.

Comment 3

[Boris Zbarsky [:bzbarsky]]

Comment on attachment 606752 [details] [diff] [review]
patch

Why is the nsLayoutUtils method needed?  Why not just put that code inline in the scrollframe code?

Comment 4

[Jonathan Watt [:jwatt]]

Because then I need to export nsSVGOuterSVGFrame.h, and all headers that in depends on, and all the headers they depend on, etc.

Comment 5

[Robert Longson [:longsonr]]

We have a state bit for the outer SVG frame. That's better than a GetType call.

Comment 6

[Jonathan Watt [:jwatt]]

To use that I need to check that the frame is an SVG frame first, which just makes the code more verbose for no real win.

Comment 7

[Boris Zbarsky [:bzbarsky]]

> Because then I need to export nsSVGOuterSVGFrame.h

Export in what sense?  You just need to add the relevant directory to LOCAL_INCLUDES in layout/generic, no?  That's why it works in layout/base...

Comment 8

[Jonathan Watt [:jwatt]]

Attachment: patch

Yeah, good point; I should get more sleep.

Comment 9

[Boris Zbarsky [:bzbarsky]]

Comment on attachment 606866 [details] [diff] [review]
patch

r=me

Comment 10

[Matt Brubeck (:mbrubeck)]

https://hg.mozilla.org/mozilla-central/rev/b81ec953e4d6