2 files changed, 85 insertions, 0 deletions

diff --git a/platform/darwin/src/MGLSymbolStyleLayer.h b/platform/darwin/src/MGLSymbolStyleLayer.h
index 5df995aa01..f8df073efe 100644
--- a/platform/darwin/src/MGLSymbolStyleLayer.h
+++ b/platform/darwin/src/MGLSymbolStyleLayer.h
@@ -8,6 +8,27 @@
 NS_ASSUME_NONNULL_BEGIN
 
 /**
+ Orientation of icon when map is pitched.
+
+ Values of this type are used in the `MGLSymbolStyleLayer.iconPitchAlignment`
+ property.
+ */
+typedef NS_ENUM(NSUInteger, MGLIconPitchAlignment) {
+    /**
+     The icon is aligned to the plane of the map.
+     */
+    MGLIconPitchAlignmentMap,
+    /**
+     The icon is aligned to the plane of the viewport.
+     */
+    MGLIconPitchAlignmentViewport,
+    /**
+     Automatically matches the value of `iconRotationAlignment`.
+     */
+    MGLIconPitchAlignmentAuto,
+};
+
+/**
  In combination with `symbolPlacement`, determines the rotation behavior of
  icons.
 
@@ -477,6 +498,24 @@ MGL_EXPORT
 @property (nonatomic, null_resettable) MGLStyleValue<NSNumber *> *iconPadding;
 
 /**
+ Orientation of icon when map is pitched.
+ 
+ The default value of this property is an `MGLStyleValue` object containing an
+ `NSValue` object containing `MGLIconPitchAlignmentAuto`. Set this property to
+ `nil` to reset it to the default value.
+ 
+ This property is only applied to the style if `iconImageName` is non-`nil`.
+ Otherwise, it is ignored.
+ 
+ You can set this property to an instance of:
+ 
+ * `MGLConstantStyleValue`
+ * `MGLCameraStyleFunction` with an interpolation mode of
+ `MGLInterpolationModeInterval`
+ */
+@property (nonatomic, null_resettable) MGLStyleValue<NSValue *> *iconPitchAlignment;
+
+/**
  Rotates the icon clockwise.
  
  This property is measured in degrees.
@@ -1925,6 +1964,19 @@ MGL_EXPORT
 #pragma mark Working with Symbol Style Layer Attribute Values
 
 /**
+ Creates a new value object containing the given `MGLIconPitchAlignment` enumeration.
+
+ @param iconPitchAlignment The value for the new object.
+ @return A new value object that contains the enumeration value.
+ */
++ (instancetype)valueWithMGLIconPitchAlignment:(MGLIconPitchAlignment)iconPitchAlignment;
+
+/**
+ The `MGLIconPitchAlignment` enumeration representation of the value.
+ */
+@property (readonly) MGLIconPitchAlignment MGLIconPitchAlignmentValue;
+
+/**
  Creates a new value object containing the given `MGLIconRotationAlignment` enumeration.
 
  @param iconRotationAlignment The value for the new object.
diff --git a/platform/darwin/src/MGLSymbolStyleLayer.mm b/platform/darwin/src/MGLSymbolStyleLayer.mm
index 5a8f8c6084..dd43ebd73c 100644
--- a/platform/darwin/src/MGLSymbolStyleLayer.mm
+++ b/platform/darwin/src/MGLSymbolStyleLayer.mm
@@ -13,6 +13,12 @@
 
 namespace mbgl {
 
+    MBGL_DEFINE_ENUM(MGLIconPitchAlignment, {
+        { MGLIconPitchAlignmentMap, "map" },
+        { MGLIconPitchAlignmentViewport, "viewport" },
+        { MGLIconPitchAlignmentAuto, "auto" },
+    });
+
     MBGL_DEFINE_ENUM(MGLIconRotationAlignment, {
         { MGLIconRotationAlignmentMap, "map" },
         { MGLIconRotationAlignmentViewport, "viewport" },
@@ -259,6 +265,23 @@ namespace mbgl {
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
+- (void)setIconPitchAlignment:(MGLStyleValue<NSValue *> *)iconPitchAlignment {
+    MGLAssertStyleLayerIsValid();
+
+    auto mbglValue = MGLStyleValueTransformer<mbgl::style::AlignmentType, NSValue *, mbgl::style::AlignmentType, MGLIconPitchAlignment>().toEnumPropertyValue(iconPitchAlignment);
+    self.rawLayer->setIconPitchAlignment(mbglValue);
+}
+
+- (MGLStyleValue<NSValue *> *)iconPitchAlignment {
+    MGLAssertStyleLayerIsValid();
+
+    auto propertyValue = self.rawLayer->getIconPitchAlignment();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::AlignmentType, NSValue *, mbgl::style::AlignmentType, MGLIconPitchAlignment>().toEnumStyleValue(self.rawLayer->getDefaultIconPitchAlignment());
+    }
+    return MGLStyleValueTransformer<mbgl::style::AlignmentType, NSValue *, mbgl::style::AlignmentType, MGLIconPitchAlignment>().toEnumStyleValue(propertyValue);
+}
+
 - (void)setIconRotation:(MGLStyleValue<NSNumber *> *)iconRotation {
     MGLAssertStyleLayerIsValid();
 
@@ -1321,6 +1344,16 @@ namespace mbgl {
 
 @implementation NSValue (MGLSymbolStyleLayerAdditions)
 
++ (NSValue *)valueWithMGLIconPitchAlignment:(MGLIconPitchAlignment)iconPitchAlignment {
+    return [NSValue value:&iconPitchAlignment withObjCType:@encode(MGLIconPitchAlignment)];
+}
+
+- (MGLIconPitchAlignment)MGLIconPitchAlignmentValue {
+    MGLIconPitchAlignment iconPitchAlignment;
+    [self getValue:&iconPitchAlignment];
+    return iconPitchAlignment;
+}
+
 + (NSValue *)valueWithMGLIconRotationAlignment:(MGLIconRotationAlignment)iconRotationAlignment {
     return [NSValue value:&iconRotationAlignment withObjCType:@encode(MGLIconRotationAlignment)];
 }