Optional WebGL geometry rendering

Set chartOptions.rendererPolicy: 'webgl' to opt in. Standalone Charts and Pivot use the same owner and appearance control. Omission remains SVG; no size threshold silently enables a GPU. Existing category/series/data-point limits still apply; GPU selection does not raise them. The stress fixtures explicitly set limits: { maxCategories: count, maxSeries: 2000, maxDataPoints: count * 3 } for their known input shape. ChartRendererPolicy / PivotChartRendererPolicy include this value; the existing ChartSvgRendererPolicy aliases remain SVG-only.

await chart.update({ chartOptions: { rendererPolicy: 'webgl' } });
// Explicitly return to the compatible default:
await chart.update({ chartOptions: { rendererPolicy: 'svg' } });

Native family	Accepted policies	CPU fallback after GPU failure
groupedColumn, groupedBar, scatter	svg, batched-svg, webgl	Batched SVG
heatmap	svg, webgl	Existing SVG heatmap buckets
Other families, including combination, line, polar and geographic	Existing policies; webgl rejects atomically	No GPU port

This policy belongs to the native renderer. ECharts and custom adapters retain their own rendering contracts; this option does not enable WebGL in them.

Canonical CPU data, domains, navigation, clipping and inspection remain authoritative. Bars/scatter retain the batched geometry index and a bounded number of SVG paths, with no individual DOM node per observation. Arrow/Home/End inspection and Enter/Space activation resolve canonical raw data. Heatmaps retain existing bounded row/column bucket reduction: an aggregate bucket is inspection-only, while a single-source cell retains raw activation. A million input matrix cells does not mean a million GPU rectangles. Existing category/bar navigation, scatter numeric X/Y windows and heatmap row/column windows retain their semantics.

Styling and interaction limits

The following requests deterministically use individual SVG: authored datum or segment encodings (including an empty encoding), runtime datumStyle, elements or onRender, saved member/measure/value-map colors, color-channel binding, authored bar stack groups, derived series, synthetic aggregate categories, and selection or peer-highlight appearance. WebGL previews/sparklines and authored markOpacity other than 1 also use SVG. Clearing incompatible saved options restores eligibility; runtime options require recreating the renderer.

GPU geometry supports the existing basic rectangular/rounded bar and circular scatter marks, theme/palette fills, heatmap intensity/grid strokes and clipping. Named/custom CSS colors outside supported hex and numeric RGB/RGBA paint forms fall back to CPU paint. Per-item DOM selectors/listeners/classes and external per-datum CSS are unsupported. Select SVG when relying on them. Hover CSS/filter paint effects are not mirrored by GPU geometry. CPU tooltips, crosshair, keyboard focus and activation remain available; selection updates can trigger an SVG fallback and a full CPU repaint. Transitions remain immediate on this backend. GPU float precision, edge antialiasing and scatter alpha compositing can differ from SVG; pixel-identical output and SVG feature equivalence are not promised.

Availability, resize and recovery

One WebGL2 context belongs to each active chart surface. The backing canvas follows actual size and device pixel ratio; plot clipping uses the same CPU bounds. GPU size limits, resource allocation, shader/draw errors and unavailable WebGL2/SSR use CPU SVG. A surface whose initial GPU probe fails stays on CPU through data updates; recreate it, or switch to SVG and back, to retry availability. Subpixel grouped bars use a floating-point coverage buffer to avoid rounding tiny marks to transparent. This additionally requires EXT_color_buffer_float and EXT_float_blend; unavailable extensions produce CPU fallback.

Context loss shows CPU geometry immediately. After webglcontextrestored, shaders, buffers and dense-bar coverage resources are recreated from the latest committed scene, including windows updated while the context was lost. Recovery follows the WEBGL_lose_context lifecycle. Resize reuses the context; switching backend or destroying the chart removes listeners, releases GPU resources and loses the old context. The model stores only the requested policy and existing data/windows, never a GPU context, canvas or callback. Hydration rechecks host GPU availability.

The SVG surface reports the effective data-chart-renderer-policy and optional data-chart-renderer-fallback. These diagnostics do not change the saved policy. Failures use reasons such as webgl-unavailable, webgl-context-lost, webgl-initialization, webgl-size-limit, webgl-float-coverage, webgl-draw, webgl-paint or webgl-empty-frame. Customization fallbacks report their existing reason (for example datum-style, runtime-customization or selection-style).

Export and performance policy

SVG, PNG and PDF exports reconstruct CPU SVG from the committed geometry and exclude GPU canvases, controls and transient focus. They never screenshot the GPU framebuffer. Bars/scatter export batched SVG; heatmaps export native SVG buckets. Raw data views and CSV retain their existing source/window semantics. SVG and raster exports can therefore differ at edges or overlapping translucent marks from the interactive GPU view; authored data and domains remain the same.

See performance protocol and results and verification. CPU preparation and semantic-index costs remain; selecting WebGL alone does not establish frame-rate, native GPU memory or million-observation performance parity.