Fonts and Text Rendering

ggaction stores a CSS-style fontFamily string in concrete text graphics and passes it to the selected rendering backend. The default family is sans-serif. ggaction does not bundle a font or expose a font-loading or registration API, so the browser, operating system, and native renderer decide which installed face satisfies that family.

Cross-platform contract

SVG markup referencing a family is not proof that the font is embedded. Likewise, PDF metadata is not a font-embedding control. Qualify the final file in the deployment environment when exact typography is a product requirement.

Set text styles explicitly

Chart titles expose separate title and subtitle style objects:

const titled = program.createTitle({
  text: "Quarterly revenue",
  subtitle: "USD millions",
  titleStyle: {
    fontFamily: "Inter, Helvetica, Arial, sans-serif",
    fontSize: 22,
    fontWeight: 600
  },
  subtitleStyle: {
    fontFamily: "Inter, Helvetica, Arial, sans-serif",
    fontSize: 14,
    fontWeight: 400
  }
});

Text marks and guide-specific label/title options expose their documented font properties separately. Setting a chart title style does not create a global theme or rewrite every axis and legend.

Loading in browsers

Load required web fonts before building and rendering charts whose layout depends on them. A common host pattern is to wait for document.fonts.ready, then create or rebuild the program. If the first render uses a fallback and the font arrives later, ggaction does not automatically remeasure or rerender that immutable snapshot.

await document.fonts.ready;
const program = buildChart(rows);
render(program, context);

Reproducibility checklist

• Use a complete fallback stack, not one unqualified family name.
• Install or load the approved fonts in every renderer environment.
• Build the program only after those fonts are ready when text bounds affect layout.
• Compare text wrapping, axis labels, legends, and title bounds in browser and Node artifacts.
• Avoid depending on an intermediate numeric weight such as 650 remaining distinct; renderer normalization rounds it to a supported hundred.

Related

Accessibility · Titles · Text marks · Rendering