Writing a custom trace

This tutorial will walk through building a new trace type from scratch, using the same public contract the built-in traces use.

Planned topics:

• Declaring the trace's attribute schema
• supplyDefaults and calc: turning input into computed data
• Rendering with the GPU primitives (markers, lines, rects, fills, text)
• Hover, selection, and the legend glyph
• Registering the trace and publishing it as a package
• Testing: unit tests for calc and visual tests for rendering

See the trace module contract for the interface itself.