[ios, macos] Integrated MGLHeatmapStyleLayer into SDK (#11075)

Made MGLHeatmapStyleLayer.h public and added it to the umbrella header. Customized MGLHeatmapStyleLayer documentation to describe heatmaps in more detail and give an example. Added MGLHeatmapStyleLayer to the jazzy table of contents.

10 files changed, 59 insertions, 10 deletions

diff --git a/platform/darwin/scripts/style-spec-overrides-v8.json b/platform/darwin/scripts/style-spec-overrides-v8.json
index 12cfa31575..07ab7e330b 100644
--- a/platform/darwin/scripts/style-spec-overrides-v8.json
+++ b/platform/darwin/scripts/style-spec-overrides-v8.json
@@ -23,6 +23,9 @@
         "circle": {
           "doc": "An `MGLCircleStyleLayer` is a style layer that renders one or more filled circles on the map.\n\nUse a circle style layer to configure the visual appearance of point or point collection features in vector tiles loaded by an `MGLVectorSource` object or `MGLPointAnnotation`, `MGLPointFeature`, `MGLPointCollection`, or `MGLPointCollectionFeature` instances in an `MGLShapeSource` object.\n\nA circle style layer renders circles whose radii are measured in screen units. To display circles on the map whose radii correspond to real-world distances, use many-sided regular polygons and configure their appearance using an `MGLFillStyleLayer` object."
         },
+        "heatmap": {
+          "doc": "An `MGLHeatmapStyleLayer` is a style layer that renders a <a href=\"https://en.wikipedia.org/wiki/Heat_map\">heatmap</a>.\n\nA heatmap visualizes the spatial distribution of a large, dense set of point data, using color to avoid cluttering the map with individual points at low zoom levels. The points are weighted by an attribute you specify. Use a heatmap style layer in conjunction with point or point collection features in vector tiles loaded by an `MGLVectorSource` object or `MGLPointAnnotation`, `MGLPointFeature`, `MGLPointCollection`, or `MGLPointCollectionFeature` instances in an `MGLShapeSource` object.\n\nConsider accompanying a heatmap style layer with an `MGLCircleStyleLayer` or `MGLSymbolStyleLayer` at high zoom levels. If you are unsure whether the point data in an `MGLShapeSource` is dense enough to warrant a heatmap, you can alternatively cluster the source using the `MGLShapeSourceOptionClustered` option and render the data using an `MGLCircleStyleLayer` or `MGLSymbolStyleLayer`."
+        },
         "raster": {
           "doc": "An `MGLRasterStyleLayer` is a style layer that renders georeferenced raster imagery on the map, especially raster tiles.\n\nUse a raster style layer to configure the color parameters of raster tiles loaded by an `MGLRasterSource` object or raster images loaded by an `MGLImageSource` object. For example, you could use a raster style layer to render <a href=\"https://www.mapbox.com/satellite/\">Mapbox Satellite</a> imagery, a <a href=\"https://www.mapbox.com/help/define-tileset/#raster-tilesets\">raster tile set</a> uploaded to Mapbox Studio, or a raster map authored in <a href=\"https://tilemill-project.github.io/tilemill/\">TileMill</a>, the classic Mapbox Editor, or Mapbox Studio Classic.\n\nRaster images may also be used as icons or patterns in a style layer. To register an image for use as an icon or pattern, use the `-[MGLStyle setImage:forName:]` method. To configure a point annotation’s image, use the `MGLAnnotationImage` class."
         },
diff --git a/platform/darwin/src/MGLHeatmapStyleLayer.h b/platform/darwin/src/MGLHeatmapStyleLayer.h
index aa6224a5a0..1cecc30441 100644
--- a/platform/darwin/src/MGLHeatmapStyleLayer.h
+++ b/platform/darwin/src/MGLHeatmapStyleLayer.h
@@ -7,7 +7,23 @@
 NS_ASSUME_NONNULL_BEGIN
 
 /**
- A heatmap.
+ An `MGLHeatmapStyleLayer` is a style layer that renders a <a
+ href="https://en.wikipedia.org/wiki/Heat_map">heatmap</a>.
+ 
+ A heatmap visualizes the spatial distribution of a large, dense set of point
+ data, using color to avoid cluttering the map with individual points at low
+ zoom levels. The points are weighted by an attribute you specify. Use a heatmap
+ style layer in conjunction with point or point collection features in vector
+ tiles loaded by an `MGLVectorSource` object or `MGLPointAnnotation`,
+ `MGLPointFeature`, `MGLPointCollection`, or `MGLPointCollectionFeature`
+ instances in an `MGLShapeSource` object.
+ 
+ Consider accompanying a heatmap style layer with an `MGLCircleStyleLayer` or
+ `MGLSymbolStyleLayer` at high zoom levels. If you are unsure whether the point
+ data in an `MGLShapeSource` is dense enough to warrant a heatmap, you can
+ alternatively cluster the source using the `MGLShapeSourceOptionClustered`
+ option and render the data using an `MGLCircleStyleLayer` or
+ `MGLSymbolStyleLayer`.
 
  You can access an existing heatmap style layer using the
  `-[MGLStyle layerWithIdentifier:]` method if you know its identifier;
@@ -18,6 +34,14 @@ NS_ASSUME_NONNULL_BEGIN
  ### Example
 
  ```swift
+ let layer = MGLHeatmapStyleLayer(identifier: "earthquake-heat", source: earthquakes)
+ layer.heatmapWeight = NSExpression(format: "FUNCTION(magnitude, 'mgl_interpolateWithCurveType:parameters:stops:', 'linear', nil, %@)",
+                                    [0: 0,
+                                     6: 1])
+ layer.heatmapIntensity = NSExpression(format: "FUNCTION($zoomLevel, 'mgl_interpolateWithCurveType:parameters:stops:', 'linear', nil, %@)",
+                                       [0: 1,
+                                        9: 3])
+ mapView.style?.addLayer(layer)
  ```
  */
 MGL_EXPORT
diff --git a/platform/darwin/src/MGLVectorStyleLayer.h b/platform/darwin/src/MGLVectorStyleLayer.h
index 7780a34c7f..177b1b70f0 100644
--- a/platform/darwin/src/MGLVectorStyleLayer.h
+++ b/platform/darwin/src/MGLVectorStyleLayer.h
@@ -10,10 +10,10 @@ NS_ASSUME_NONNULL_BEGIN
  is defined by an `MGLShapeSource` or `MGLVectorSource` object.
 
  Create instances of `MGLCircleStyleLayer`, `MGLFillStyleLayer`,
- `MGLFillExtrusionStyleLayer`, `MGLLineStyleLayer`, and `MGLSymbolStyleLayer` in
- order to use `MGLVectorStyleLayer`'s properties and methods. Do not create
- instances of `MGLVectorStyleLayer` directly, and do not create your own
- subclasses of this class.
+ `MGLFillExtrusionStyleLayer`, `MGLHeatmapStyleLayer`, `MGLLineStyleLayer`, and
+ `MGLSymbolStyleLayer` in order to use `MGLVectorStyleLayer`'s properties and
+ methods. Do not create instances of `MGLVectorStyleLayer` directly, and do not
+ create your own subclasses of this class.
  */
 MGL_EXPORT
 @interface MGLVectorStyleLayer : MGLForegroundStyleLayer
diff --git a/platform/darwin/test/MGLDocumentationExampleTests.swift b/platform/darwin/test/MGLDocumentationExampleTests.swift
index 9bf9924869..5a6e00bc4e 100644
--- a/platform/darwin/test/MGLDocumentationExampleTests.swift
+++ b/platform/darwin/test/MGLDocumentationExampleTests.swift
@@ -230,6 +230,24 @@ class MGLDocumentationExampleTests: XCTestCase, MGLMapViewDelegate {
         
         XCTAssertNotNil(mapView.style?.layer(withIdentifier: "buildings"))
     }
+    
+    func testMGLHeatmapStyleLayer() {
+        let earthquakes = MGLShapeSource(identifier: "earthquakes", url: URL(string: "https://example.com/earthquakes.json")!, options: [:])
+        mapView.style?.addSource(earthquakes)
+        
+        //#-example-code
+        let layer = MGLHeatmapStyleLayer(identifier: "earthquake-heat", source: earthquakes)
+        layer.heatmapWeight = NSExpression(format: "FUNCTION(magnitude, 'mgl_interpolateWithCurveType:parameters:stops:', 'linear', nil, %@)",
+                                           [0: 0,
+                                            6: 1])
+        layer.heatmapIntensity = NSExpression(format: "FUNCTION($zoomLevel, 'mgl_interpolateWithCurveType:parameters:stops:', 'linear', nil, %@)",
+                                              [0: 1,
+                                               9: 3])
+        mapView.style?.addLayer(layer)
+        //#-end-example-code
+        
+        XCTAssertNotNil(mapView.style?.layer(withIdentifier: "earthquake-heat"))
+    }
 
     func testMGLSymbolStyleLayer() {
         let pois = MGLVectorSource(identifier: "pois", configurationURL: URL(string: "https://example.com/style.json")!)
diff --git a/platform/ios/ios.xcodeproj/project.pbxproj b/platform/ios/ios.xcodeproj/project.pbxproj
index 51258b49b9..166793c68e 100644
--- a/platform/ios/ios.xcodeproj/project.pbxproj
+++ b/platform/ios/ios.xcodeproj/project.pbxproj
@@ -226,8 +226,8 @@
 		55E2AD131E5B125400E8C587 /* MGLOfflineStorageTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 55E2AD121E5B125400E8C587 /* MGLOfflineStorageTests.mm */; };
 		632281DF1E6F855900D75A5D /* MBXEmbeddedMapViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = 632281DE1E6F855900D75A5D /* MBXEmbeddedMapViewController.m */; };
 		6407D6701E0085FD00F6A9C3 /* MGLDocumentationExampleTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6407D66F1E0085FD00F6A9C3 /* MGLDocumentationExampleTests.swift */; };
-		8989B17C201A48EB0081CF59 /* MGLHeatmapStyleLayer.h in Headers */ = {isa = PBXBuildFile; fileRef = 8989B17A201A48EA0081CF59 /* MGLHeatmapStyleLayer.h */; };
-		8989B17D201A48EB0081CF59 /* MGLHeatmapStyleLayer.h in Headers */ = {isa = PBXBuildFile; fileRef = 8989B17A201A48EA0081CF59 /* MGLHeatmapStyleLayer.h */; };
+		8989B17C201A48EB0081CF59 /* MGLHeatmapStyleLayer.h in Headers */ = {isa = PBXBuildFile; fileRef = 8989B17A201A48EA0081CF59 /* MGLHeatmapStyleLayer.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		8989B17D201A48EB0081CF59 /* MGLHeatmapStyleLayer.h in Headers */ = {isa = PBXBuildFile; fileRef = 8989B17A201A48EA0081CF59 /* MGLHeatmapStyleLayer.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		8989B17E201A48EB0081CF59 /* MGLHeatmapStyleLayer.mm in Sources */ = {isa = PBXBuildFile; fileRef = 8989B17B201A48EA0081CF59 /* MGLHeatmapStyleLayer.mm */; };
 		8989B17F201A48EB0081CF59 /* MGLHeatmapStyleLayer.mm in Sources */ = {isa = PBXBuildFile; fileRef = 8989B17B201A48EA0081CF59 /* MGLHeatmapStyleLayer.mm */; };
 		920A3E5D1E6F995200C16EFC /* MGLSourceQueryTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 920A3E5C1E6F995200C16EFC /* MGLSourceQueryTests.m */; };
diff --git a/platform/ios/jazzy.yml b/platform/ios/jazzy.yml
index b3662adc70..61e9ad39e8 100644
--- a/platform/ios/jazzy.yml
+++ b/platform/ios/jazzy.yml
@@ -95,6 +95,7 @@ custom_categories:
       - MGLCircleStyleLayer
       - MGLFillStyleLayer
       - MGLFillExtrusionStyleLayer
+      - MGLHeatmapStyleLayer
       - MGLHillshadeStyleLayer
       - MGLLineStyleLayer
       - MGLSymbolStyleLayer
diff --git a/platform/ios/src/Mapbox.h b/platform/ios/src/Mapbox.h
index d105189bb8..11720ac68e 100644
--- a/platform/ios/src/Mapbox.h
+++ b/platform/ios/src/Mapbox.h
@@ -45,6 +45,7 @@ FOUNDATION_EXPORT MGL_EXPORT const unsigned char MapboxVersionString[];
 #import "MGLSymbolStyleLayer.h"
 #import "MGLRasterStyleLayer.h"
 #import "MGLCircleStyleLayer.h"
+#import "MGLHeatmapStyleLayer.h"
 #import "MGLHillshadeStyleLayer.h"
 #import "MGLBackgroundStyleLayer.h"
 #import "MGLOpenGLStyleLayer.h"
diff --git a/platform/macos/jazzy.yml b/platform/macos/jazzy.yml
index 682ccd99ff..b4dccb620f 100644
--- a/platform/macos/jazzy.yml
+++ b/platform/macos/jazzy.yml
@@ -80,6 +80,7 @@ custom_categories:
       - MGLCircleStyleLayer
       - MGLFillStyleLayer
       - MGLFillExtrusionStyleLayer
+      - MGLHeatmapStyleLayer
       - MGLHillshadeStyleLayer
       - MGLLineStyleLayer
       - MGLSymbolStyleLayer
diff --git a/platform/macos/macos.xcodeproj/project.pbxproj b/platform/macos/macos.xcodeproj/project.pbxproj
index 7f51981647..30458d92fe 100644
--- a/platform/macos/macos.xcodeproj/project.pbxproj
+++ b/platform/macos/macos.xcodeproj/project.pbxproj
@@ -86,7 +86,7 @@
 		55D120A51F790A0C004B6D81 /* libmbgl-filesource.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 55D120A41F7906E6004B6D81 /* libmbgl-filesource.a */; };
 		55E2AD111E5B0A6900E8C587 /* MGLOfflineStorageTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 55E2AD101E5B0A6900E8C587 /* MGLOfflineStorageTests.mm */; };
 		89462399200D199100DA8EF2 /* heatmap.json in Resources */ = {isa = PBXBuildFile; fileRef = 89462398200D199100DA8EF2 /* heatmap.json */; };
-		8946239D200E744800DA8EF2 /* MGLHeatmapStyleLayer.h in Headers */ = {isa = PBXBuildFile; fileRef = 8946239A200E73CA00DA8EF2 /* MGLHeatmapStyleLayer.h */; };
+		8946239D200E744800DA8EF2 /* MGLHeatmapStyleLayer.h in Headers */ = {isa = PBXBuildFile; fileRef = 8946239A200E73CA00DA8EF2 /* MGLHeatmapStyleLayer.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		894623A0200E748000DA8EF2 /* MGLHeatmapStyleLayer.mm in Sources */ = {isa = PBXBuildFile; fileRef = 8946239B200E73CA00DA8EF2 /* MGLHeatmapStyleLayer.mm */; };
 		92092EF01F5EB10E00AF5130 /* MGLMapSnapshotter.h in Headers */ = {isa = PBXBuildFile; fileRef = 92092EEE1F5EB10E00AF5130 /* MGLMapSnapshotter.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		92092EF11F5EB10E00AF5130 /* MGLMapSnapshotter.mm in Sources */ = {isa = PBXBuildFile; fileRef = 92092EEF1F5EB10E00AF5130 /* MGLMapSnapshotter.mm */; };
@@ -668,8 +668,6 @@
 		35136D471D42295400C20EFD /* Layers */ = {
 			isa = PBXGroup;
 			children = (
-				8946239A200E73CA00DA8EF2 /* MGLHeatmapStyleLayer.h */,
-				8946239B200E73CA00DA8EF2 /* MGLHeatmapStyleLayer.mm */,
 				DA8F25851D51C9E10010E6B5 /* MGLBackgroundStyleLayer.h */,
 				DA8F25861D51C9E10010E6B5 /* MGLBackgroundStyleLayer.mm */,
 				3527428B1D4C24AB00A1ECE6 /* MGLCircleStyleLayer.h */,
@@ -680,6 +678,8 @@
 				35602BF91D3EA99F0050646F /* MGLFillStyleLayer.mm */,
 				35602BFD1D3EA9B40050646F /* MGLForegroundStyleLayer.h */,
 				35602BFE1D3EA9B40050646F /* MGLForegroundStyleLayer.mm */,
+				8946239A200E73CA00DA8EF2 /* MGLHeatmapStyleLayer.h */,
+				8946239B200E73CA00DA8EF2 /* MGLHeatmapStyleLayer.mm */,
 				DAF25714201901C200367EF5 /* MGLHillshadeStyleLayer.h */,
 				DAF25713201901C100367EF5 /* MGLHillshadeStyleLayer.mm */,
 				DA8F25891D51CA540010E6B5 /* MGLLineStyleLayer.h */,
diff --git a/platform/macos/src/Mapbox.h b/platform/macos/src/Mapbox.h
index 7ea9a9dd1d..3e7ec469f2 100644
--- a/platform/macos/src/Mapbox.h
+++ b/platform/macos/src/Mapbox.h
@@ -43,6 +43,7 @@ FOUNDATION_EXPORT MGL_EXPORT const unsigned char MapboxVersionString[];
 #import "MGLSymbolStyleLayer.h"
 #import "MGLRasterStyleLayer.h"
 #import "MGLCircleStyleLayer.h"
+#import "MGLHeatmapStyleLayer.h"
 #import "MGLBackgroundStyleLayer.h"
 #import "MGLHillshadeStyleLayer.h"
 #import "MGLOpenGLStyleLayer.h"