planning

node_modules/@mapbox/mapbox-gl-style-spec/expression/evaluation_context.js

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+// @flow
+
+import {Color} from './values.js';
+
+import type Point from '@mapbox/point-geometry';
+import type {FormattedSection} from './types/formatted.js';
+import type {GlobalProperties, Feature, FeatureState} from './index.js';
+import type {CanonicalTileID} from '../../source/tile_id.js';
+import type {FeatureDistanceData} from '../feature_filter/index.js';
+
+const geometryTypes = ['Unknown', 'Point', 'LineString', 'Polygon'];
+
+class EvaluationContext {
+    globals: GlobalProperties;
+    feature: ?Feature;
+    featureState: ?FeatureState;
+    formattedSection: ?FormattedSection;
+    availableImages: ?Array<string>;
+    canonical: null | CanonicalTileID;
+    featureTileCoord: ?Point;
+    featureDistanceData: ?FeatureDistanceData;
+
+    _parseColorCache: {[_: string]: ?Color};
+
+    constructor() {
+        this.globals = (null: any);
+        this.feature = null;
+        this.featureState = null;
+        this.formattedSection = null;
+        this._parseColorCache = {};
+        this.availableImages = null;
+        this.canonical = null;
+        this.featureTileCoord = null;
+        this.featureDistanceData = null;
+    }
+
+    id(): number | null {
+        return this.feature && this.feature.id !== undefined ? this.feature.id : null;
+    }
+
+    geometryType(): null | string {
+        return this.feature ? typeof this.feature.type === 'number' ? geometryTypes[this.feature.type] : this.feature.type : null;
+    }
+
+    geometry(): ?Array<Array<Point>> {
+        return this.feature && 'geometry' in this.feature ? this.feature.geometry : null;
+    }
+
+    canonicalID(): null | CanonicalTileID {
+        return this.canonical;
+    }
+
+    properties(): {[string]: any} {
+        return (this.feature && this.feature.properties) || {};
+    }
+
+    distanceFromCenter(): number {
+        if (this.featureTileCoord && this.featureDistanceData) {
+
+            const c = this.featureDistanceData.center;
+            const scale = this.featureDistanceData.scale;
+            const {x, y} = this.featureTileCoord;
+
+            // Calculate the distance vector `d` (left handed)
+            const dX = x * scale - c[0];
+            const dY = y * scale - c[1];
+
+            // The bearing vector `b` (left handed)
+            const bX = this.featureDistanceData.bearing[0];
+            const bY = this.featureDistanceData.bearing[1];
+
+            // Distance is calculated as `dot(d, v)`
+            const dist = (bX * dX + bY * dY);
+            return dist;
+        }
+
+        return 0;
+    }
+
+    parseColor(input: string): ?Color {
+        let cached = this._parseColorCache[input];
+        if (!cached) {
+            cached = this._parseColorCache[input] = Color.parse(input);
+        }
+        return cached;
+    }
+}
+
+export default EvaluationContext;