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Diffstat (limited to 'platform/darwin/src/MGLShapeSource.h')
| -rw-r--r-- | platform/darwin/src/MGLShapeSource.h | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/platform/darwin/src/MGLShapeSource.h b/platform/darwin/src/MGLShapeSource.h index f11e45722b..73171dfe17 100644 --- a/platform/darwin/src/MGLShapeSource.h +++ b/platform/darwin/src/MGLShapeSource.h @@ -45,19 +45,27 @@ FOUNDATION_EXTERN MGL_EXPORT const MGLShapeSourceOption MGLShapeSourceOptionClus An `NSDictionary` object where the key is an `NSString`. The dictionary key will be the feature attribute key. The resulting attribute value is aggregated from the clustered points. The dictionary value is an `NSArray` - consisting of two objects. + consisting of two `NSExpression` objects. The first object determines how the attribute values are accumulated from the - cluster points. The resulting value is assigned to the specified attribute key. - You can use one of the following: - - * An `[NSExpression expressionForConstantValue:]` containing a single function string, such as `sum` or `max`, which takes at least two operands. - * An `NSExpression` that takes two expression arguments: `featureAccumulated` and - another valid expression. + cluster points. It is an `NSExpression` with an expression function that accepts + two or more arguments (such as `sum` or `max`). The arguments should be + `featureAccumulated` and the previously defined feature attribute key. The + resulting value is assigned to the specified attribute key. The second `NSExpression` in the array determines which attribute values are accessed from individual features within a cluster. + ```swift + let key = "sumValue" + let firstExpression = NSExpression(format: "sum({ $featureAccumulated, %@ })", key) + let secondExpression = NSExpression(forKeyPath: "magnitude") + let clusterPropertiesDictionary = [key : [firstExpression, secondExpression]] + + let options : [MGLShapeSourceOption : Any] = [.clustered : true, + .clusterProperties: clusterPropertiesDictionary] + ``` + This option corresponds to the <a href="https://www.mapbox.com/mapbox-gl-style-spec/#sources-geojson-clusterProperties"><code>clusterProperties</code></a> source property in the Mapbox Style Specification. |