Bug 202791 – SMIL animations of href / xlink:href of <image> have no visual effect

• Component: SVG
• Status: RESOLVED FIXED

[Nikolas Zimmermann]

LayoutTests/svg/W3C-SVG-1.1/animate-elem-39-t.svg shows that SMIL animations of the <image> element href / xlink:href have no effect.

A quick investigation shows that imageSourceURL() is the culprit, since it simply returns getAttribute(SVGNames::hrefAttr, XLinkNames::hrefAttr) -- which is equal to the serialized baseVal of the underlying SVGAnimatedString, never reflecting the animVal.

SVGURIReference::href() returns the right value, and also correctly handles href vs. xlink:href, since the baseVal is either reflecting href, or if xlink:href (if any of them is set).

The only issue is that imageSourceURL() returns a reference to a const AtomString, and thus we cannot simply return href().

A quick hack to fix SMIL animations on the aforementioned testcase is:

const AtomString& SVGImageElement::imageSourceURL() const
{   
    static NeverDestroyed<AtomString> tempAtom("tempAtom", AtomString::ConstructFromLiteral);
    AtomString& mutableAtom = tempAtom;
    mutableAtom = href();
    return tempAtom;
}

We either have to give up the "const AtomString&" return value, or add a new AtomString m_imageSourceURL member to SVGImageElement.
And obviously we need more test coverage!

[Radar WebKit Bug Importer]

<rdar://problem/96316808>

[Ahmad Saleem]

Fixed in Blink by giving up on AtomString& and just returning ("href()").

https://src.chromium.org/viewvc/blink?view=revision&revision=157025

[Ahmad Saleem]

(In reply to Ahmad Saleem from comment #2)
> Fixed in Blink by giving up on AtomString& and just returning ("href()").
> 
> https://src.chromium.org/viewvc/blink?view=revision&revision=157025

SVG link is gone - https://source.chromium.org/chromium/chromium/src/+/93976b6624f40024070bea7dde68e81a3d366173

[Ahmad Saleem]

Pull request: https://github.com/WebKit/WebKit/pull/61066

[EWS]

Committed 310236@main (4a210d1278f1): <https://commits.webkit.org/310236@main>

Reviewed commits have been landed. Closing PR #61066 and removing active labels.

[Brent Fulgham]

This change is present in Safari Technology Preview 242. Please install that revision or newer to confirm the fix.

Release notes: https://webkit.org/blog/17934/release-notes-for-safari-technology-preview-242/

[Brent Fulgham]

This change is present in Safari Technology Preview 241. Please install that revision or newer to confirm the fix.

Release notes: https://webkit.org/blog/17917/release-notes-for-safari-technology-preview-241/