This page tests various features of saveSvgAsPng.
You can test your own SVG code in the Sandbox. If something doesn't work as expected, you can file an issue on GitHub.
Paste you SVG below to see how it renders.
Custom fonts are supported but in a very rudimentary way. Note: if you don't see the demo working, click "Save as PNG" - it should work.
Make sure that the custom font is applied to a non-svg element first. This will help browser to rasterize SVG correctly onto canvas.
@font-face declaration has to be inside document stylesheets (not in the external `link` tag)
Only first `url()` is inlined into svg (don't have multiple urls in the font-face).