Render a live preview under every code block written in a diagram language.
The preview is chrome, not content: a non-editable widget element appended
inside the block's <pre> after its <code>, which the renderer's inline
rebuilds leave alone and the position mapper skips, so the document model
and its serialized HTML never see it. Results are cached by language and
code, so caret moves and edits elsewhere cost nothing, and a stale
asynchronous result can never overwrite a newer one. A result is only ever
shown by blocks whose code still matches it. Returns a no-op controller for
a headless editor.
Render a live preview under every code block written in a diagram language.
The preview is chrome, not content: a non-editable widget element appended inside the block's
<pre>after its<code>, which the renderer's inline rebuilds leave alone and the position mapper skips, so the document model and its serialized HTML never see it. Results are cached by language and code, so caret moves and edits elsewhere cost nothing, and a stale asynchronous result can never overwrite a newer one. A result is only ever shown by blocks whose code still matches it. Returns a no-op controller for a headless editor.