Intent to Ship: Filters in 2D Canvas

[Ali Juma]

Contact emails

aj...@chromium.org, ju...@chromium.org

Spec

https://html.spec.whatwg.org/multipage/scripting.html#filters

Summary

A string attribute 'filter' on CanvasRenderingContext2D to apply effects to primitives drawn to the canvas. The attribute is parsed the same way as CSS filters.

Link to “Intent to Implement” blink-dev discussion

https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/hx5g-yHS45I

Is this feature supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?

Yes

Debuggability

No special debugging support is needed.

Interoperability and Compatibility Risk

Firefox has implemented this feature behind a flag. There are no public signals from Internet Explorer or Safari.

Compatibility risk is low. This is a new API, so doesn’t affect web content that doesn’t use it.

OWP launch tracking bug

https://crbug.com/501642

Entry on the feature dashboard

https://www.chromestatus.com/features/6701649301078016

[Chris Harrelson]

LGTM to ship in M52, to give the spec time for late-breaking feedback. But I am recusing myself since it's a person on my team who is shipping. :)

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[Rick Byers]

Since we're the first to ship (behind a flag doesn't count), I feel compelled to apply a little extra rigor and ask: what's the status of the Mozilla implementation?  Are they happy with the state of the spec?  Has anyone attempted to test the interoperability between the blink and Gecko implementations?

[Ali Juma]

On Wed, Apr 6, 2016 at 7:36 PM Rick Byers <rby...@chromium.org> wrote:

Since we're the first to ship (behind a flag doesn't count), I feel compelled to apply a little extra rigor and ask: what's the status of the Mozilla implementation? Are they happy with the state of the spec?  Has anyone attempted to test the interoperability between the blink and Gecko implementations?

Mozilla has a few bugs left to fix before enabling the feature (tracked in [1]). They seem to be happy with the spec (e.g., see mstange's comment [2]), and indeed the spec wording is mostly derived from Mozilla's original proposal [3]. In my testing of the two implementations, I found one significant difference [4] which I'll make sure gets fixed before we ship.

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1173545

[2] https://github.com/whatwg/html/pull/978#issuecomment-206009581 

[3] https://wiki.mozilla.org/CanvasFilters 

[4] https://crbug.com/601877 

[Rick Byers]

Thanks LGTM1 to ship.

Please just let the Mozilla folks working on this know that we're planning on shipping now and they should speak up here if they have any concerns.

[PhistucK]

​While not entirely related, it feels a bit awkward to have an officially supported API for canvas filters while CSS ​filters (which use the same syntax and give a similar effect, only on all of the elements) are still unofficially supported (prefixed). Is shipping unprefixed CSS filters on the short term table?

And perhaps related - are there CSS filter issues that prevent Blink from unprefixing that also affect canvas filters?

☆PhistucK

[Stephen White]

On Fri, Apr 8, 2016 at 4:57 PM, PhistucK <phis...@gmail.com> wrote:

​While not entirely related, it feels a bit awkward to have an officially supported API for canvas filters while CSS ​filters (which use the same syntax and give a similar effect, only on all of the elements) are still unofficially supported (prefixed). Is shipping unprefixed CSS filters on the short term table?

Unfortunately, since the CSS "filter" property is already in use by SVG filters (on SVG elements), unprefixing "-webkit-filter" is blocked on switching the legacy SVG filters implementation over to using the (HTML) Filter Effects implementation, which sadly is not as simple as it sounds. See https://bugs.chromium.org/p/chromium/issues/detail?id=244295 for some details.

 

And perhaps related - are there CSS filter issues that prevent Blink from unprefixing that also affect canvas filters?

AFAIK, no. This should not affect canvas filters.

Stephen

[TAMURA, Kent]

LGTM3.

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TAMURA Kent
Software Engineer, Google

[Ali Juma]

On Tue, Apr 12, 2016 at 1:39 AM TAMURA, Kent <tk...@chromium.org> wrote:

LGTM3.

Thanks. This still needs one more lgtm (not counting chrishtr's lgtm since he also recused himself).

[Dimitri Glazkov]

LGTM4.

:DG<