SVGDom

[Jonas M.]

Hello Skia team,

I am currently working on a light simulation with SVG, which is rendered using Skia's SVGDOM module. I have noticed a few issues that I couldn't find clear answers to in the documentation:

1. Which SVG standard does Skia's SVGDOM target?
I found a post from a few years ago that says the target is SVG 1.1 up to and including section 15 (filter effects), with interactivity, scripting and animation explicitly excluded. Is that still correct? Is there any official, up-to-date documentation listing the supported and unsupported features?

2. Are `matrix3d(...)` / 3D CSS transformations supported?
The SVG attribute `transform` supports `matrix(a b c d e f)` for 2D affine transformations. Is there support for 3D transformations (e.g. `matrix3d(...)` or `perspective(...)`) in the SVG module, or is the transformation system strictly 2D?

3. Is additive colour mixing from an SVG string possible in Skia?
I need to combine light contributions additively. CSS `mix-blend-mode: plus-lighter` is not available without CSS support.
For example, via a non-standard extension `mode=‘plus’` or via `feComposite operator="lighter"`?

Many thanks

Kind regards,
Jonas