Mark Channel Types

A v3 mark's options are not all alike. A channel is classified by its aggregation semantics — size, position, color, or raw — and that classification, not naming convenience, determines how the channel behaves under operators. This essay will document the channel taxonomy.

Planned contents

• The four channel kinds: size, pos, color, raw — and what each means.
• Why a channel is chosen by aggregation semantics rather than by what feels natural.
• How operators treat each channel kind differently.
• Worked examples of picking the right channel type for a new mark option.

Source

Likely covers:: the mark factory and channel code under packages/gofish-graphics/src/ast/marks/. See also The Mark Factory. Add the covers: frontmatter when writing this up, then run pnpm --filter docs sync-backlinks.