I haven't seen border images in the wild since CSS added them, I think (apart from examples). Perhaps that was solving a 1998 use-case in 2008. Nevertheless, CSS is still based on styling runs of text and boxes of content. Boxes usually aren't triangular.
As for HTML in SVG, there is foreignObject [4.72], but browser support is spotty in places. And wrapping text in arbitrary shapes is on the roadmap for SVG 2, if I remember correctly. But we'll be a bit older when that's universally implemented ;-)
As for HTML in SVG, there is foreignObject [4.72], but browser support is spotty in places. And wrapping text in arbitrary shapes is on the roadmap for SVG 2, if I remember correctly. But we'll be a bit older when that's universally implemented ;-)
[4.72] https://developer.mozilla.org/en-US/docs/Web/SVG/Element/for...