This document is intentionally short. It’s a map to the internal modules that implement ChartGPU behavior, plus a few contracts that are easy to break.

• Render orchestration: createRenderCoordinator.ts
• Options resolution: OptionResolver.ts
• Public wrapper: ChartGPU.ts

• Data store + GPU uploads: createDataStore.ts
• Streaming GPU buffers (double-buffered): createStreamBuffer.ts
• CPU downsampling (LTTB helper): lttbSample.ts

Interaction code lives under src/interaction/.

• Event normalization: createEventManager.ts
  • payload.x/y: canvas-local CSS px
  • payload.gridX/gridY: plot/grid-local CSS px
• Zoom state + inside gestures: createZoomState.ts, createInsideZoom.ts
• Hit-testing: findNearestPoint.ts, findPointsAtX.ts, findPieSlice.ts

Contracts worth keeping in mind:

• Visibility: most helpers ignore series.visible === false.
• Index mapping: if you filter series, preserve original indices in results.
• Sorted-x (cartesian): several fast paths assume increasing x.
• Units must match: if a helper expects range-space inputs, your scales must output the same space.

• Text overlay: createTextOverlay.ts
• Legend: createLegend.ts
• Tooltip: createTooltip.ts
  • Tooltip content is assigned via innerHTML (only pass trusted/sanitized strings).
• DataZoom slider: createDataZoomSlider.ts

• Factory: createRenderCoordinator.ts
• Decomposed modules: src/core/renderCoordinator/

The coordinator computes layout/scales, prepares renderers, uploads data, and emits DOM overlays.

Renderer factories live under src/renderers/.

Notes:

• Grid lines: driven by resolved options (ResolvedChartGPUOptions.gridLines) and wired in renderOverlays.ts.
• WGSL imports: renderers may import WGSL via Vite ?raw (types in wgsl-raw.d.ts).

• queue.writeBuffer(...) offsets/sizes must be 4-byte aligned.
• Uniform buffers are typically 16-byte aligned.
• Pipeline target formats must match the render pass attachment format.