Standard <svg> markup, authored inline as normal. The library rasterizes each one onto a shared art-pixel grid into its shadow DOM, while the original <svg> stays untouched in the light DOM.
This icon lives in a container Idiomorph can morph, the same engine Datastar uses for server-driven DOM patches. The buttons below simulate the server re-sending HTML for this fragment: once identical, once with a different icon. The raster survives both without flashing back to raw SVG, because the morph only ever touches the light-dom <svg>, never the shadow-dom canvas.
With a debug delay set on the render pipeline, the raw <svg> (via the shadow-root <slot>) stays visible the whole time rasterization is genuinely in flight, then the canvas swaps in when it's ready. No JS, or a slow one, degrades to a plain icon rather than nothing.