gPdf
Release · minor

v2026.08 August 2026: native vector charts

JSON Render adds native bar, line, area, combo, pie, and donut charts with presets, dual value axes, stacking, gradients, patterns, and explicit opacity controls.

by gPdf Engineering
Highlights
  • Add native bar, line, area, combo, pie, and donut elements to JSON Render.
  • Support Combo charts with primary and secondary value axes in one stable contract.
  • Provide dashboard_light, business_light, executive_dark, and print_mono presets.
  • Expose solid, gradient, and pattern fills with independent outer and gradient-stop opacity.

All changes

  • added The chart element renders bar, line, area, combo, pie, and donut charts as native PDF vectors.
  • added Combo series can select bar, line, or area rendering and bind to primary or secondary value axes.
  • added Normal and percent stacking, value formatting, legends, data labels, category-label overflow controls, and zero alignment are available in the public JSON contract.
  • added ChartFillStyle supports solid colors, linear gradients, reusable patterns, and explicit outer opacity; gradient stop opacity remains independently configurable.
  • improved The Playground and public examples include small-input presets plus advanced JSON examples for richer chart styling.

What’s new

JSON Render can now place native vector charts alongside text, tables, images, containers, headers, footers, and layers. The first release includes bar, line, area, combo, pie, and donut chart kinds.

Simple requests can select one of four presets and provide only categories and series values. Advanced requests can configure Combo series kinds, two value axes, stacking, label overflow, legends, data labels, markers, gradients, patterns, and number formats.

Combo and dual axes

Combo charts use series[].kind for bar, line, or area rendering and series[].value_axis for the fixed primary or secondary axis slots. This keeps common single-axis requests compact while supporting revenue-plus-margin and similar business reporting layouts without a separate chart type.

Opacity and print output

Chart fills can use a solid color, linear gradient, or pattern. Outer fill.opacity is applied independently from each gradient stop’s opacity, so the effective stop alpha is their product. Line series use stroke opacity. The print_mono preset remains opaque and uses pattern, dash, and marker differences so series do not depend on color alone.

See the JSON Render API reference and the chart examples in the Playground for the complete contract.