MarkPropDefStringNullTypeForShape

Shape of the mark.

1. For point marks the supported values include: - plotting shapes: "circle", "square", "cross", "diamond", "triangle-up", "triangle-down", "triangle-right", or "triangle-left". - the line symbol "stroke" - centered directional shapes "arrow", "wedge", or "triangle" - a custom SVG path string (For correct sizing, custom shape paths should be defined within a square bounding box with coordinates ranging from -1 to 1 along both the x and y dimensions.)

2. For geoshape marks it should be a field definition of the geojson data

Default value: If undefined, the default shape depends on mark config's shape property. ("circle" if unset.)

A FieldDef with Condition { condition: {value: ...}, field: ..., ... }