Add distance expression support (#642)

* Initial commit to distance calculations

* Add changelog item

* Added polygon tests

* Fix lint

* Fix algorithm, imporve tests readablility

* Add classify rings tests from the maplibre repo

* Add wrap type

* Make the threshold symetrical.

* Allow using classify rings with a mapbox point type, remove circular dependencies.

.gitignore

@@ -5,8 +5,9 @@ dist
 .DS_Store
 */**/*.g.ts
 .cache
-docs/*
+coverage/
 site/
+docs/*
 !docs/assets/extra.css
 !docs/assets/logo.svg
 !docs/README.md

CHANGELOG.md

@@ -1,6 +1,8 @@
 ## main
 
 ### ✨ Features and improvements
+
+- Support `distance` expression in web style spec - [#642](https://github.com/maplibre/maplibre-style-spec/pull/642)
 - _...Add new stuff here..._
 
 ### 🐞 Bug fixes

build/generate-style-spec.ts

@@ -199,6 +199,7 @@ export type ExpressionSpecification =
         ...(ExpressionInputType | ExpressionInputType[] | ExpressionSpecification)[], // repeated as above
         ExpressionInputType | ExpressionSpecification]
     | ['within', unknown | ExpressionSpecification]
+    | ['distance', unknown | ExpressionSpecification]
     // Ramps, scales, curves
     | ['interpolate', InterpolationSpecification, number | ExpressionSpecification,
         ...(number | number[] | ColorSpecification | ExpressionSpecification)[]] // alternating number and number | number[] | ColorSpecification

package.json

@@ -52,8 +52,10 @@
     "@mapbox/unitbezier": "^0.0.1",
     "json-stringify-pretty-compact": "^4.0.0",
     "minimist": "^1.2.8",
+    "quickselect": "^2.0.0",
     "rw": "^1.3.3",
-    "sort-object": "^3.0.3"
+    "sort-object": "^3.0.3",
+    "tinyqueue": "^2.0.3"
   },
   "sideEffects": false,
   "devDependencies": {

src/expression/compound_expression.ts

@@ -21,10 +21,10 @@ import Literal from './definitions/literal';
 import Assertion from './definitions/assertion';
 import Coercion from './definitions/coercion';
 import Var from './definitions/var';
+import Distance from './definitions/distance';
 
 import type {Expression, ExpressionRegistry} from './expression';
 import type {Value} from './values';
-
 import type {Type} from './types';
 
 import {typeOf, Color, validateRGBA, toString as valueToString} from './values';
@@ -664,6 +664,8 @@ function isExpressionConstant(expression: Expression) {
         return false;
     } else if (expression instanceof Within) {
         return false;
+    } else if (expression instanceof Distance) {
+        return false;
     }
 
     const isTypeAnnotation = expression instanceof Coercion ||
@@ -715,6 +717,9 @@ function isFeatureConstant(e: Expression) {
     if (e instanceof Within) {
         return false;
     }
+    if (e instanceof Distance) {
+        return false;
+    }
 
     let result = true;
     e.eachChild(arg => {