fix(mermaid): defer rendering until web fonts are ready#2754
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Mermaid measures label widths at initialization time. When web fonts are still loading at that moment, the measurement uses a narrower fallback font; once the web font arrives the text is wider and gets clipped by the SVG foreignObject default overflow:hidden. Fix by setting startOnLoad:false and deferring mermaid.run() until document.fonts.ready, with a 2.5 s timeout so a slow or blocked font source never stalls diagram rendering.
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Type of change
Description
Mermaid measures label widths at initialization time. When
loadMermaid()callsmermaid.initialize()(defaultstartOnLoad: true), Mermaid renders immediately — before the page's web font has finished loading. Width is measured with the narrower fallback font; once the web font arrives the glyphs are wider and overflow the already-sizedforeignObjectbox, clipping the text (defaultoverflow: hidden).Fix:
startOnLoad: falsesomermaid.initialize()no longer auto-renders.mermaid.run()untildocument.fonts.ready, so label widths are always measured with the final font.Only
_javascript/modules/components/mermaid.jsis changed. Lint (npm run lint:js) and build (npm run build) both pass locally.Additional context
Fixes #2753