MvtMapboxStyleLoader

Parser for a subset of the Mapbox GL Style Specification, producing an MvtRuleBasedStyle usable with MvtVectorLayer. The intent is "drop in a hand-authored style.json or a downloaded one from Maptiler/Mapbox and have it just work for typical basemap use cases" — not full spec fidelity.

Supported

• Layer types: fill, line, symbol (text-only — no icons).

• Properties: id (display name), source-layer, filter, minzoom, maxzoom, paint, layout.

• Filter expressions (legacy "filter" form only): ["==", k, v], ["!=", k, v], ["in", k, ...], ["!in", k, ...], ["has", k], ["!has", k], ["<", k, n], ["<=", k, n], [">", k, n], [">=", k, n], ["all", ...], ["any", ...], ["!", subFilter]. $type is not supported — set MvtStyleRule.geometryType manually or use a layer-name convention.

• Paint/layout values:

• Constants (number, color hex string #rrggbb/#rrggbbaa).

• Legacy zoom-stop form: { "stops": [[zoom, value], …] }.

• Not supported: modern ["interpolate", …] expressions, ["case", …], ["match", …], ["step", …], arithmetic, ["get", …], ["zoom"], feature-state. Throws MvtStyleParseException when encountered so misrendering doesn't go silent.

• Paint/layout properties (fill / line / symbol):

• fill-color, fill-opacity

• line-color, line-width, line-opacity

• text-field (plain string "{name}" form or top-level property reference)

• text-color, text-size, text-halo-color, text-halo-width, text-font (first entry; weight inferred from "bold"/"italic" suffix)

Not supported (deliberately)

• Modern expression DSL (["interpolate", "linear", ["zoom"], …], ["case", …], ["match", …], arithmetic, string concatenation). Not yet implemented.

• Icons / sprites / images / patterns. Symbol layers without text-field are silently dropped.

• Layer types other than fill/line/symbol (heatmap, hillshade, raster, background).

• Layout properties beyond text-field/text-size/text-font.

• Source / sprite / glyphs / metadata blocks at the top of the document — parsed and ignored.

• Visibility = "none" on layout — handled, layer skipped.

If your style relies on something unsupported, MvtStyleParseException surfaces a specific error pointing at the offending node.