Gosub embedded media test

<canvas> (drawn via 2D context), <video>/<audio> controls, <iframe> (srcdoc), <object>, and aspect-ratio.

canvas (2D drawing)

shapes, gradient, text via getContext('2d')

paths, arcs, lines

If the canvas API is unsupported, these boxes stay blank.

controls + poster (the source file is intentionally absent — tests poster + missing-media handling)

muted loop, no poster — default control chrome & box sizing

Renders the native audio control bar (the source file is intentionally absent).

Tests nested-document rendering & the iframe's own viewport.

<object> loading an SVG

<embed> loading an SVG

16 / 9

aspect-ratio: 16/9, width 200px

1 / 1

aspect-ratio: 1