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Re: [svgwg] Radial gradients: "fully overlapping" vs "focal point on the edge" - which takes precedence? (#648)

From: Fredrik Söderqvist via GitHub <sysbot+gh@w3.org>
Date: Mon, 11 Mar 2019 18:58:49 +0000
To: public-svg-issues@w3.org
Message-ID: <issue_comment.created-471675970-1552330728-sysbot+gh@w3.org>
@dirkschulze this is what I'm aware of ATM. I know that other degenerate cases have been considered in SVG and other spec contexts before, but it may be reasonable to revisit (and make sure there are tests).

@AmeliaBR I too suspected that "implementation inertia" could explain part of it, but I don't know to what degree that is true. It is probably more about having a zero-length gradient vector than about the initial value of `fr` (which should match the behavior of SVG 1.1). Gradient rendering tend to suffer from numerical issues, so the exact formulation used by the "solver" can have an effect [1].

[1] I.e a renderer that supports `fr` may use a different formulation than one that doesn't (i.e only supports it as 0). I suspect this is why the "... on the edge" rule was there in the first place (for certain formulations you'll hit infinity on the edge, and probably have numerical instability close to the edge).

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Received on Monday, 11 March 2019 18:58:50 UTC

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