Open Bug 455986 Opened 16 years ago Updated 2 years ago

SVG filters feImage with xlink:href doesn't work with fragments

Categories

(Core :: SVG, defect)

Product:
Core
Component:
SVG
Type:
defect

Tracking

()

Tracking Flags:
Tracking Status
status2.0 --- wanted

People

(Reporter: hansschmucker, Unassigned)

References

(Blocks 2 open bugs,
URL
)

Details

(Keywords: dev-doc-needed)

Attachments

(2 files)

Testcase for feImage xlink:href document fragment bug.
(deleted), image/svg+xml
Details
WIP: Bug 455986 - WIP - Support local feImage.
(deleted), text/x-phabricator-request
Details
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b1pre) Gecko/20080916043910 Minefield/3.1b1pre Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b1pre) Gecko/20080916043910 Minefield/3.1b1pre The feImage filter is supposed to support document fragments (see http://www.w3.org/TR/SVG/filters.html#feImage ), including but not limited to fragments of the current document, in practice emulating the "use" element and rendering the output to the current buffer. Basically, this deprives SVG filters of any way to work with dynamic data, like canvas and instead forces webdevelopers to instead use very slow JS implementations of those filters. For example, to recreate the old Java "waves" demo, the canvas could be fed into an feDisplacement filter. Reproducible: Always Steps to Reproduce: 1. Open the attached testcase in Firefox 2. Open it again in Inkscape Actual Results: Firefox doesn't display the green rectangle inserted into the rendering chain through an feImage. Output of Inkscape and Firefox differ. Expected Results: The green rectangle should be added to the rendering via the feImage filter, overlaying the red background-
Blocks: 410761, 311029
Depends on: 390379
Version: unspecified → Trunk
I can confirm this bug in Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.5; en-US; rv:1.9.0.1) Gecko/2008070206 Firefox/3.0.1
This is really just another example of bug 272288.
Depends on: 272288
Confirming, although this is likely to simply be marked as a a duplicate of bug 272288 eventually.
Status: UNCONFIRMED → NEW
Ever confirmed: true
Blocks: svg11tests
To get this to work (for <feImage xlink:href="#idOfSomeElement">), I think we actually need to import the <use> behavior for into <feImage>, right? (to clone a subtree, or at least generate the document with that subtree if the targeted ID is in a different document) We could almost fall back on moz-element here, except that the targeted element could be in a completely different document from the one we're displaying (e.g. xlink:href="foo.svg#SomeNodeID"), and IIUC, -moz-element only works for elements in the same document. Still, we might be able to take advantage of some of moz-element's underlying mechanics.
(In reply to comment #3) > This is really just another example of bug 272288. I think this is actually distinct from bug 272288 (which is about <image>) -- this bug is about using fragment IDs, and the <image> tag doesn't accept those... > Unlike ‘use’, the ‘image’ element cannot reference elements within an SVG file. http://www.w3.org/TR/SVG/struct.html#ImageElement ...whereas the <feImage> tag does accept fragment IDs (as noted in comment 0).
It might be time for someone to work on this. Safari and Chrome(Canary) as well as IE now support importing document fragments correctly into filter streams. aka http://codepen.io/mullany/pen/rKLdJ Now displays correctly except in Firefox.
There will be increasing interest in blending modes since they are heavily used in the iOS7 visual style. Because of the lack of support for enable-background in every browser except IE10, the only way to achieve these effects in SVG is to use document fragments via feImage. And Firefox is now the only browser that doesn't support these.
Do the other browsers handle dynamic changes to the referenced content updating the filter? What do they do if the referenced content itself uses the filter? Do they handle <foreignObject> content inside the referenced content subtree?
I think I would implement this in a way similar to the way -moz-element is implemented. nsImageRenderer in nsCSSRendering implements that.
Other use cases for feImage fragments: If you want to do a linear focus blur on text then you need to be able to get a gradient into your filter chain in some way. If you want to do distortion effects on text then it's handy to import linear and radial gradients as displacement inputs. Other browsers update the in-filter feImage when the referenced object is updated. Erik Dahlstrom's ripple distortion effect is a good demo: http://svg-wow.org/filterEffects/ripple.svg
No longer blocks: 410761

I'm adding the note to the BCD for feImage to the xlink:href variable to cover this case.

""notes": "Document fragments (including references to fragments in current document) are not supported (see <a href='https://bugzil.la/455986 '>bug 455986</a>).""

  1. Does the bug also apply to href (or just xlink:href)?
  2. Would this also impact SVGFEImageElement and if so, how? (i.e. can't see an href or xlink:href variable).
  3. Is there a better way to describe the above note?
Flags: needinfo?(jwatt)
  1. yes, both.
  2. That page says that SVGFEImageElement implements the properties of SVGURIReference so we do document that already.
  3. sure that seems fine.
Flags: needinfo?(jwatt)

I gave this a shot, but it is a bit harder than it seems...

Apart of the hard-coded intrinsic sizes and such (which obviously would
need to be fixed), the main issue is that we query filter bounds from
layout, to compute overflow rects, but:

  • SVGFEImageElement::GetPrimitiveDescription works by querying the
    filter surfaces, which need painting, and we shouldn't start painting
    from layout. So we'd need a way to query filter bounds without a
    full-fledged GetPrimitiveDescription, which I don't know how hard is
    it.

  • The target element might not be reflowed yet, so we might not know
    its bounds (we might get away with only supporting some SVG frames we
    know the intrinsic dimensions of).

With that fixed, something like this ought to do, but that's not quite
easy to fix...

Severity: normal → S3

The severity field for this bug is relatively low, S3. However, the bug has 5 duplicates and 24 votes.
:jwatt, could you consider increasing the bug severity?

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Flags: needinfo?(jwatt)

The last needinfo from me was triggered in error by recent activity on the bug. I'm clearing the needinfo since this is a very old bug and I don't know if it's still relevant.

Flags: needinfo?(jwatt)
Duplicate of this bug: 1800391
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