1231355 - SVG with only width OR height does not apply img srcset 2x descriptor

Status: RESOLVED DUPLICATE of bug 1149357

(Core :: Layout: Images, Video, and HTML Frames, defect)

Description

[Simon Pieters [:zcorpan]]

See https://github.com/w3c/web-platform-tests/pull/2418

<img srcset="data:image/svg+xml,<svg%20xmlns='http://www.w3.org/2000/svg'%20viewBox='-1%20-1%202%202'%20width='20'><circle%20r='1'/></svg> 2x" data-expect="10">

<img srcset="data:image/svg+xml,<svg%20xmlns='http://www.w3.org/2000/svg'%20viewBox='-1%20-1%202%202'%20height='20'><circle%20r='1'/></svg> 2x" data-expect="10">

Gecko renders these as 20x20 instead of 10x10. Works OK if the SVG specifies both width and height attributes.

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: testcase 1

(Here's a testcase built from test code in comment 0.

Chrome 48 DevEdition renders all 3 img elements the same size. Firefox 45 Nightly renders the first 2 images larger than the 3rd.)

Comment 2

[Daniel Holbert [:dholbert]]

For the first two images in testcase 1, either imgIContainer::GetWidth or GetHeight will fail, and I think imgIContainer::GetIntrinsicSize will fail as well (since we only have one intrinsic dimension).

imgIContainer::GetIntrinsicRatio will succeed, though (since we have a viewBox attribute, which gives us an intrinsic ratio).  That, combined with the attribute that is present, can be used to infer the other dimension if desired, at whatever callsite matters for this bug.

Comment 3

[Josh Matthews [:jdm]]

If layout code is where the problem lies, I'm not a good candidate to look at this.

Comment 4

[Daosheng Mu[:daoshengmu]]

I use this sample to describe my finding
http://daoshengmu.github.io/layout-sample/svg/bug1231355/

At ResponsiveImageSelector::SetCandidatesFromSourceSet, the parse and select src candidate are correct to 4x.
HTMLImageElement::BindToTree also check the responsive context correctly.

I think the issue is happened at VectorImage. I list some stats in my experiment:
 wxh 		Instrinsic size  ratio  width height
 20x? 		1200 -1	         2 2    30     31
 ? x 20		-1  1200         30 31  30     31
 20x20 		1200 1200        20 20  20     20

Hope that would be help.

Comment 5

[Robert Longson [:longsonr]]

All the images are the same size now.

Comment 6

[Daniel Holbert [:dholbert]]

Yup! Fix range:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=ff8505d177b9fcba44b040ccd9b6bb709e238e84&tochange=94d7f0e1c4d0390450028972cfeb65e0550b9892

Looks like this was fixed by (and essentially a dupe of) bug 1149357.