[ios, macos] Mark MGLStyleLayer properties null_resettable

If the property is unset, return the default value.

Fixes #6126.

1 files changed, 3 insertions, 3 deletions

diff --git a/platform/darwin/src/MGLBackgroundStyleLayer.mm b/platform/darwin/src/MGLBackgroundStyleLayer.mm
index 1a991a65e9..32e2e7847e 100644
--- a/platform/darwin/src/MGLBackgroundStyleLayer.mm
+++ b/platform/darwin/src/MGLBackgroundStyleLayer.mm
@@ -37,7 +37,7 @@
 }
 
 - (id <MGLStyleAttributeValue>)backgroundColor {
-    return [MGLStyleAttribute mbgl_colorWithPropertyValueColor:self.layer->getBackgroundColor()];
+    return [MGLStyleAttribute mbgl_colorWithPropertyValueColor:self.layer->getBackgroundColor() ?: self.layer->getDefaultBackgroundColor()];
 }
 
 - (void)setBackgroundPattern:(id <MGLStyleAttributeValue, MGLStyleAttributeValue_Private>)backgroundPattern {
@@ -46,7 +46,7 @@
 }
 
 - (id <MGLStyleAttributeValue>)backgroundPattern {
-    return [MGLStyleAttribute mbgl_stringWithPropertyValueString:self.layer->getBackgroundPattern()];
+    return [MGLStyleAttribute mbgl_stringWithPropertyValueString:self.layer->getBackgroundPattern() ?: self.layer->getDefaultBackgroundPattern()];
 }
 
 - (void)setBackgroundOpacity:(id <MGLStyleAttributeValue, MGLStyleAttributeValue_Private>)backgroundOpacity {
@@ -55,7 +55,7 @@
 }
 
 - (id <MGLStyleAttributeValue>)backgroundOpacity {
-    return [MGLStyleAttribute mbgl_numberWithPropertyValueNumber:self.layer->getBackgroundOpacity()];
+    return [MGLStyleAttribute mbgl_numberWithPropertyValueNumber:self.layer->getBackgroundOpacity() ?: self.layer->getDefaultBackgroundOpacity()];
 }
 
 @end