[whatwg] CSS Filter Effects for Canvas 2D Context

Robert O'Callahan robert at ocallahan.org
Wed Jul 25 22:18:09 PDT 2012

On Tue, Jul 17, 2012 at 4:34 PM, Rik Cabanier <cabanier at gmail.com> wrote:

> I agree that it would be great to have filter effects in Canvas. It should
> be fairly efficient if you have a GPU backend since the effects can all be
> done with shaders so it should take up too much memory.
> This workflow could even support our CSS shaders proposal. Also since CORS
> is no longer an issue with Canvas, we could remove all the limitations we
> had to build in to ensure security.

CORS is still an issue. You would have to apply the same limitations when
using non-origin-clean source images.

Something like canvas.filter = <CSS-filter-value> would probably be good,
but you'd have to define what the object bounding box for SVG filters is.
This would be useful for Shumway.

“You have heard that it was said, ‘Love your neighbor and hate your enemy.’
But I tell you, love your enemies and pray for those who persecute you,
that you may be children of your Father in heaven. ... If you love those
who love you, what reward will you get? Are not even the tax collectors
doing that? And if you greet only your own people, what are you doing more
than others?" [Matthew 5:43-47]

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