[darwin] update darwin code for fill-extrusion-vertical-gradient

3 files changed, 84 insertions, 0 deletions

diff --git a/platform/darwin/src/MGLFillExtrusionStyleLayer.h b/platform/darwin/src/MGLFillExtrusionStyleLayer.h
index 6e807c1b44..c35a2374ed 100644
--- a/platform/darwin/src/MGLFillExtrusionStyleLayer.h
+++ b/platform/darwin/src/MGLFillExtrusionStyleLayer.h
@@ -334,6 +334,27 @@ MGL_EXPORT
 
 @property (nonatomic, null_resettable) NSExpression *fillExtrusionTranslateAnchor __attribute__((unavailable("Use fillExtrusionTranslationAnchor instead.")));
 
+/**
+ Whether to apply a vertical gradient to the sides of a fill-extrusion layer. If
+ true, sides will be shaded slightly darker farther down.
+ 
+ The default value of this property is an expression that evaluates to `YES`.
+ Set this property to `nil` to reset it to the default value.
+ 
+ You can set this property to an expression containing any of the following:
+ 
+ * Constant Boolean values
+ * Predefined functions, including mathematical and string operators
+ * Conditional expressions
+ * Variable assignments and references to assigned variables
+ * Step functions applied to the `$zoomLevel` variable
+ 
+ This property does not support applying interpolation functions to the
+ `$zoomLevel` variable or applying interpolation or step functions to feature
+ attributes.
+ */
+@property (nonatomic, null_resettable) NSExpression *fillExtrusionVerticalGradient;
+
 @end
 
 /**
diff --git a/platform/darwin/src/MGLFillExtrusionStyleLayer.mm b/platform/darwin/src/MGLFillExtrusionStyleLayer.mm
index 03676a4ed5..ef5b0fcdbe 100644
--- a/platform/darwin/src/MGLFillExtrusionStyleLayer.mm
+++ b/platform/darwin/src/MGLFillExtrusionStyleLayer.mm
@@ -336,6 +336,24 @@ namespace mbgl {
     return self.fillExtrusionTranslationAnchor;
 }
 
+- (void)setFillExtrusionVerticalGradient:(NSExpression *)fillExtrusionVerticalGradient {
+    MGLAssertStyleLayerIsValid();
+    MGLLogDebug(@"Setting fillExtrusionVerticalGradient: %@", fillExtrusionVerticalGradient);
+
+    auto mbglValue = MGLStyleValueTransformer<bool, NSNumber *>().toPropertyValue<mbgl::style::PropertyValue<bool>>(fillExtrusionVerticalGradient, false);
+    self.rawLayer->setFillExtrusionVerticalGradient(mbglValue);
+}
+
+- (NSExpression *)fillExtrusionVerticalGradient {
+    MGLAssertStyleLayerIsValid();
+
+    auto propertyValue = self.rawLayer->getFillExtrusionVerticalGradient();
+    if (propertyValue.isUndefined()) {
+        propertyValue = self.rawLayer->getDefaultFillExtrusionVerticalGradient();
+    }
+    return MGLStyleValueTransformer<bool, NSNumber *>().toExpression(propertyValue);
+}
+
 @end
 
 @implementation NSValue (MGLFillExtrusionStyleLayerAdditions)
diff --git a/platform/darwin/test/MGLFillExtrusionStyleLayerTests.mm b/platform/darwin/test/MGLFillExtrusionStyleLayerTests.mm
index ecfa2134a0..dfec719d2a 100644
--- a/platform/darwin/test/MGLFillExtrusionStyleLayerTests.mm
+++ b/platform/darwin/test/MGLFillExtrusionStyleLayerTests.mm
@@ -476,6 +476,50 @@
         functionExpression = [NSExpression expressionWithFormat:@"mgl_interpolate:withCurveType:parameters:stops:($zoomLevel, 'linear', nil, %@)", @{@10: functionExpression}];
         XCTAssertThrowsSpecificNamed(layer.fillExtrusionTranslationAnchor = functionExpression, NSException, NSInvalidArgumentException, @"MGLFillExtrusionLayer should raise an exception if a camera-data expression is applied to a property that does not support key paths to feature attributes.");
     }
+
+    // fill-extrusion-vertical-gradient
+    {
+        XCTAssertTrue(rawLayer->getFillExtrusionVerticalGradient().isUndefined(),
+                      @"fill-extrusion-vertical-gradient should be unset initially.");
+        NSExpression *defaultExpression = layer.fillExtrusionVerticalGradient;
+
+        NSExpression *constantExpression = [NSExpression expressionWithFormat:@"false"];
+        layer.fillExtrusionVerticalGradient = constantExpression;
+        mbgl::style::PropertyValue<bool> propertyValue = { false };
+        XCTAssertEqual(rawLayer->getFillExtrusionVerticalGradient(), propertyValue,
+                       @"Setting fillExtrusionVerticalGradient to a constant value expression should update fill-extrusion-vertical-gradient.");
+        XCTAssertEqualObjects(layer.fillExtrusionVerticalGradient, constantExpression,
+                              @"fillExtrusionVerticalGradient should round-trip constant value expressions.");
+
+        constantExpression = [NSExpression expressionWithFormat:@"false"];
+        NSExpression *functionExpression = [NSExpression expressionWithFormat:@"mgl_step:from:stops:($zoomLevel, %@, %@)", constantExpression, @{@18: constantExpression}];
+        layer.fillExtrusionVerticalGradient = functionExpression;
+
+        {
+            using namespace mbgl::style::expression::dsl;
+            propertyValue = mbgl::style::PropertyExpression<bool>(
+                step(zoom(), literal(false), 18.0, literal(false))
+            );
+        }
+
+        XCTAssertEqual(rawLayer->getFillExtrusionVerticalGradient(), propertyValue,
+                       @"Setting fillExtrusionVerticalGradient to a camera expression should update fill-extrusion-vertical-gradient.");
+        XCTAssertEqualObjects(layer.fillExtrusionVerticalGradient, functionExpression,
+                              @"fillExtrusionVerticalGradient should round-trip camera expressions.");
+
+
+        layer.fillExtrusionVerticalGradient = nil;
+        XCTAssertTrue(rawLayer->getFillExtrusionVerticalGradient().isUndefined(),
+                      @"Unsetting fillExtrusionVerticalGradient should return fill-extrusion-vertical-gradient to the default value.");
+        XCTAssertEqualObjects(layer.fillExtrusionVerticalGradient, defaultExpression,
+                              @"fillExtrusionVerticalGradient should return the default value after being unset.");
+
+        functionExpression = [NSExpression expressionForKeyPath:@"bogus"];
+        XCTAssertThrowsSpecificNamed(layer.fillExtrusionVerticalGradient = functionExpression, NSException, NSInvalidArgumentException, @"MGLFillExtrusionLayer should raise an exception if a camera-data expression is applied to a property that does not support key paths to feature attributes.");
+        functionExpression = [NSExpression expressionWithFormat:@"mgl_step:from:stops:(bogus, %@, %@)", constantExpression, @{@18: constantExpression}];
+        functionExpression = [NSExpression expressionWithFormat:@"mgl_interpolate:withCurveType:parameters:stops:($zoomLevel, 'linear', nil, %@)", @{@10: functionExpression}];
+        XCTAssertThrowsSpecificNamed(layer.fillExtrusionVerticalGradient = functionExpression, NSException, NSInvalidArgumentException, @"MGLFillExtrusionLayer should raise an exception if a camera-data expression is applied to a property that does not support key paths to feature attributes.");
+    }
 }
 
 - (void)testPropertyNames {
@@ -486,6 +530,7 @@
     [self testPropertyName:@"fill-extrusion-pattern" isBoolean:NO];
     [self testPropertyName:@"fill-extrusion-translation" isBoolean:NO];
     [self testPropertyName:@"fill-extrusion-translation-anchor" isBoolean:NO];
+    [self testPropertyName:@"fill-extrusion-vertical-gradient" isBoolean:YES];
 }
 
 - (void)testValueAdditions {