Andrew Fedoniouk <news@terrainformatica.com> wrote:
> "The transition must be contained within the segment of the border
> where the tangent of the inner curve either not defined or is not
> parallel with the sides of the box."
>
> It is not clear what does "tangent of the inner curve not defined"
> mean exactly. Is it an attempt to define case #9 here? :
>
> http://www.terrainformatica.com/w3/round-corners-sciter.png
> (case: width of borders is larger than border radius)
That's how I read it. The tangent is undefined at a sharp corner.
Thus, in your case #9, the gradients can extend to the points where the
outer and inner edges become parallel lines again.
Perhaps that's better wording? Something like
The transition may not include any region of the border which is
visually "side" rather than "corner": formally, the transition may
not include any region where the inner and outer edges are parallel
straight lines.
I'm having trouble coming up with words that are both unambiguous and
plain, so I think a diagram would be helpful; maybe something like the
attached SVG file.
> I believe that the only reasonable type of gradient here is so called
> conic gradient. Probably it makes sense to define just that?
I'd call that out of scope for Level 3. There are several shipping
implementations that do sharp transitions.
zw
