From d9aebc33ac9350b810763ea13e815e6563c65c28 Mon Sep 17 00:00:00 2001
From: Masashi Katsumata <wf9a5m75@gmail.com>
Date: Sat, 7 Nov 2026 23:35:42 -0800
Subject: [PATCH] Stack overlays in one band order, whatever order they arrive
 in

Google compares one zIndex across polylines, polygons, circles, ground
overlays and tile layers. Each overlay passed its own zIndex through
(all 0 by default; ground overlays and the marker tile layer never set
one), so equal values fell back to add order: a re-sent ground image
covered the polygons, a circle covered the polyline.

The zIndex is now OverlayStacking.globalZIndex (ios-sdk-core): each band
gets its own range, raster layers < ground images < polygons < circles
< polylines < markers, the overlay's zIndex orders within the band.
The marker tile layer is in the marker band. Markers are still drawn
above every non-marker overlay by the SDK itself.

Basemap labels stay above the overlays: Google draws its labels over
polygons and the rest regardless (unchanged).

Requires ios-sdk-core fix/overlay-stacking-order (OverlayStacking).
---
 .../circle/GoogleMapCircleOverlayRenderer.swift        |  6 +++---
 .../GoogleMapGroundImageOverlayRenderer.swift          |  3 ++-
 .../marker/GoogleMapMarkerController.swift             |  3 ++-
 .../marker/GoogleMapMarkerRenderer.swift               |  4 ++--
 .../polygon/GoogleMapPolygonOverlayRenderer.swift      |  6 +++---
 .../polyline/GoogleMapPolylineOverlayRenderer.swift    |  6 +++---
 .../raster/GoogleMapRasterLayerOverlayRenderer.swift   | 10 +++++-----
 7 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/Sources/MapConductorForGoogleMaps/circle/GoogleMapCircleOverlayRenderer.swift b/Sources/MapConductorForGoogleMaps/circle/GoogleMapCircleOverlayRenderer.swift
index ba8a58f..9c90c48 100644
--- a/Sources/MapConductorForGoogleMaps/circle/GoogleMapCircleOverlayRenderer.swift
+++ b/Sources/MapConductorForGoogleMaps/circle/GoogleMapCircleOverlayRenderer.swift
@@ -1,6 +1,6 @@
 import CoreLocation
 import GoogleMaps
-import MapConductorCore
+@_spi(MapConductorDriver) import MapConductorCore
 import UIKit
 
 @MainActor
@@ -25,7 +25,7 @@ final class GoogleMapCircleOverlayRenderer: AbstractCircleOverlayRenderer<GMSPol
         // Use mapView(_:didTapAt:) + CircleManager hit-testing for click handling.
         // If we set this tappable, Google Maps consumes taps and we'd need mapView(_:didTap:) overlay handling.
         polygon.isTappable = false
-        polygon.zIndex = Int32(state.zIndex ?? 0)
+        polygon.zIndex = OverlayStacking.globalZIndex(OverlayStackKey(.circle, zIndex: state.zIndex ?? 0))
         polygon.geodesic = state.geodesic
         polygon.map = mapView
         polygon.userData = state.id
@@ -71,7 +71,7 @@ final class GoogleMapCircleOverlayRenderer: AbstractCircleOverlayRenderer<GMSPol
         }
 
         if finger.zIndex != prevFinger.zIndex {
-            circle.zIndex = Int32(current.state.zIndex ?? 0)
+            circle.zIndex = OverlayStacking.globalZIndex(OverlayStackKey(.circle, zIndex: current.state.zIndex ?? 0))
         }
 
         return circle
diff --git a/Sources/MapConductorForGoogleMaps/groundimage/GoogleMapGroundImageOverlayRenderer.swift b/Sources/MapConductorForGoogleMaps/groundimage/GoogleMapGroundImageOverlayRenderer.swift
index d3401b3..738fbeb 100644
--- a/Sources/MapConductorForGoogleMaps/groundimage/GoogleMapGroundImageOverlayRenderer.swift
+++ b/Sources/MapConductorForGoogleMaps/groundimage/GoogleMapGroundImageOverlayRenderer.swift
@@ -1,6 +1,6 @@
 import CoreLocation
 import GoogleMaps
-import MapConductorCore
+@_spi(MapConductorDriver) import MapConductorCore
 
 @MainActor
 final class GoogleMapGroundImageOverlayRenderer: AbstractGroundImageOverlayRenderer<GMSGroundOverlay> {
@@ -16,6 +16,7 @@ final class GoogleMapGroundImageOverlayRenderer: AbstractGroundImageOverlayRende
         guard let bounds = toCoordinateBounds(state.bounds) else { return nil }
 
         let overlay = GMSGroundOverlay(bounds: bounds, icon: state.image)
+        overlay.zIndex = OverlayStacking.globalZIndex(OverlayStackKey(.groundImage, zIndex: 0))
         overlay.opacity = Float(state.opacity)
         overlay.isTappable = false
         overlay.userData = state.id
diff --git a/Sources/MapConductorForGoogleMaps/marker/GoogleMapMarkerController.swift b/Sources/MapConductorForGoogleMaps/marker/GoogleMapMarkerController.swift
index 85738e5..c75b776 100644
--- a/Sources/MapConductorForGoogleMaps/marker/GoogleMapMarkerController.swift
+++ b/Sources/MapConductorForGoogleMaps/marker/GoogleMapMarkerController.swift
@@ -359,7 +359,8 @@ final class GoogleMapMarkerController: AbstractMarkerController<GMSMarker, Googl
         // タイル差し替え時のフェードを切る。フェード中の升は古い絵と新しい絵の
         // 合成で、そこにジェスチャが重なると途中の絵が残ることがある。
         layer.fadeIn = false
-        layer.zIndex = 0
+        // マーカーのタイルはマーカーと同じ帯（GMSTileLayer の zIndex はポリゴン等と比べられる）。
+        layer.zIndex = OverlayStacking.globalZIndex(OverlayStackKey(.marker, zIndex: 0))
         layer.map = mapView
         tileTileLayer = layer
     }
diff --git a/Sources/MapConductorForGoogleMaps/marker/GoogleMapMarkerRenderer.swift b/Sources/MapConductorForGoogleMaps/marker/GoogleMapMarkerRenderer.swift
index ba075dc..471dd1d 100644
--- a/Sources/MapConductorForGoogleMaps/marker/GoogleMapMarkerRenderer.swift
+++ b/Sources/MapConductorForGoogleMaps/marker/GoogleMapMarkerRenderer.swift
@@ -1,7 +1,7 @@
 import CoreGraphics
 import CoreLocation
 import GoogleMaps
-import MapConductorCore
+@_spi(MapConductorDriver) import MapConductorCore
 
 @MainActor
 final class GoogleMapMarkerRenderer: MarkerOverlayRendererProtocol {
@@ -295,7 +295,7 @@ final class GoogleMapMarkerRenderer: MarkerOverlayRendererProtocol {
         marker.isTappable = state.clickable
         marker.icon = bitmapIcon.bitmap
         marker.groundAnchor = bitmapIcon.anchor
-        marker.zIndex = Int32(state.zIndex ?? 0)
+        marker.zIndex = OverlayStacking.globalZIndex(OverlayStackKey(.marker, zIndex: state.zIndex ?? 0))
         // Avoid a 1-frame "flash" at the target position when an animation is specified at
         // construction (or during a state update). Keep it hidden until `onAnimate` repositions
         // it to the offscreen start point.
diff --git a/Sources/MapConductorForGoogleMaps/polygon/GoogleMapPolygonOverlayRenderer.swift b/Sources/MapConductorForGoogleMaps/polygon/GoogleMapPolygonOverlayRenderer.swift
index b9c57cc..d6715cd 100644
--- a/Sources/MapConductorForGoogleMaps/polygon/GoogleMapPolygonOverlayRenderer.swift
+++ b/Sources/MapConductorForGoogleMaps/polygon/GoogleMapPolygonOverlayRenderer.swift
@@ -1,5 +1,5 @@
 import GoogleMaps
-import MapConductorCore
+@_spi(MapConductorDriver) import MapConductorCore
 import UIKit
 
 @MainActor
@@ -22,7 +22,7 @@ final class GoogleMapPolygonOverlayRenderer: AbstractPolygonOverlayRenderer<GMSP
         polygon.strokeWidth = CGFloat(resolved.strokeWidth)
         polygon.fillColor = resolved.fillColor
         polygon.geodesic = resolved.geodesic
-        polygon.zIndex = Int32(truncatingIfNeeded: resolved.zIndex)
+        polygon.zIndex = OverlayStacking.globalZIndex(OverlayStackKey(.polygon, zIndex: resolved.zIndex))
         polygon.holes = resolved.holes.map { holePoints in
             ringPath(for: holePoints, geodesic: resolved.geodesic, mapView: mapView)
         }
@@ -62,7 +62,7 @@ final class GoogleMapPolygonOverlayRenderer: AbstractPolygonOverlayRenderer<GMSP
         }
 
         if finger.zIndex != prevFinger.zIndex {
-            polygon.zIndex = Int32(truncatingIfNeeded: current.state.zIndex)
+            polygon.zIndex = OverlayStacking.globalZIndex(OverlayStackKey(.polygon, zIndex: current.state.zIndex))
         }
 
         return polygon
diff --git a/Sources/MapConductorForGoogleMaps/polyline/GoogleMapPolylineOverlayRenderer.swift b/Sources/MapConductorForGoogleMaps/polyline/GoogleMapPolylineOverlayRenderer.swift
index e2e1b63..b5cff0e 100644
--- a/Sources/MapConductorForGoogleMaps/polyline/GoogleMapPolylineOverlayRenderer.swift
+++ b/Sources/MapConductorForGoogleMaps/polyline/GoogleMapPolylineOverlayRenderer.swift
@@ -1,5 +1,5 @@
 import GoogleMaps
-import MapConductorCore
+@_spi(MapConductorDriver) import MapConductorCore
 import UIKit
 
 @MainActor
@@ -21,7 +21,7 @@ final class GoogleMapPolylineOverlayRenderer: AbstractPolylineOverlayRenderer<GM
         polyline.strokeWidth = CGFloat(state.strokeWidth)
         polyline.geodesic = state.geodesic
         polyline.isTappable = false
-        polyline.zIndex = Int32(state.zIndex)
+        polyline.zIndex = OverlayStacking.globalZIndex(OverlayStackKey(.polyline, zIndex: state.zIndex))
         polyline.map = mapView
         polyline.userData = state.id
         return polyline
@@ -50,7 +50,7 @@ final class GoogleMapPolylineOverlayRenderer: AbstractPolylineOverlayRenderer<GM
         }
 
         if finger.zIndex != prevFinger.zIndex {
-            polyline.zIndex = Int32(current.state.zIndex)
+            polyline.zIndex = OverlayStacking.globalZIndex(OverlayStackKey(.polyline, zIndex: current.state.zIndex))
         }
 
         return polyline
diff --git a/Sources/MapConductorForGoogleMaps/raster/GoogleMapRasterLayerOverlayRenderer.swift b/Sources/MapConductorForGoogleMaps/raster/GoogleMapRasterLayerOverlayRenderer.swift
index a260f4d..c95d4be 100644
--- a/Sources/MapConductorForGoogleMaps/raster/GoogleMapRasterLayerOverlayRenderer.swift
+++ b/Sources/MapConductorForGoogleMaps/raster/GoogleMapRasterLayerOverlayRenderer.swift
@@ -1,5 +1,5 @@
 import GoogleMaps
-import MapConductorCore
+@_spi(MapConductorDriver) import MapConductorCore
 import UIKit
 
 @MainActor
@@ -18,7 +18,7 @@ final class GoogleMapRasterLayerOverlayRenderer: AbstractRasterLayerOverlayRende
         guard let mapView else { return nil }
         guard let layer = makeTileLayer(from: state) else { return nil }
         layer.opacity = Float(state.opacity)
-        layer.zIndex = Int32(clamping: state.zIndex)
+        layer.zIndex = OverlayStacking.globalZIndex(OverlayStacking.rasterKey(stateId: state.id, zIndex: state.zIndex))
         applyVisibility(layer: layer, state: state, mapView: mapView)
         return layer
     }
@@ -48,7 +48,7 @@ final class GoogleMapRasterLayerOverlayRenderer: AbstractRasterLayerOverlayRende
             guard let mapView else { return nil }
             guard let newLayer = makeTileLayer(from: current.state) else { return nil }
             newLayer.opacity = Float(current.state.opacity)
-            newLayer.zIndex = Int32(clamping: current.state.zIndex)
+            newLayer.zIndex = OverlayStacking.globalZIndex(OverlayStacking.rasterKey(stateId: current.state.id, zIndex: current.state.zIndex))
             applyVisibility(layer: newLayer, state: current.state, mapView: mapView)
             return newLayer
         }
@@ -58,7 +58,7 @@ final class GoogleMapRasterLayerOverlayRenderer: AbstractRasterLayerOverlayRende
         }
 
         if finger.zIndex != prevFinger.zIndex {
-            layer.zIndex = Int32(clamping: current.state.zIndex)
+            layer.zIndex = OverlayStacking.globalZIndex(OverlayStacking.rasterKey(stateId: current.state.id, zIndex: current.state.zIndex))
         }
 
         if finger.visible != prevFinger.visible {
@@ -84,7 +84,7 @@ final class GoogleMapRasterLayerOverlayRenderer: AbstractRasterLayerOverlayRende
             tileSources.removeValue(forKey: ObjectIdentifier(local))
             localLayers.removeValue(forKey: ObjectIdentifier(local))
             next.opacity = Float(current.state.opacity)
-            next.zIndex = Int32(clamping: current.state.zIndex)
+            next.zIndex = OverlayStacking.globalZIndex(OverlayStacking.rasterKey(stateId: current.state.id, zIndex: current.state.zIndex))
             applyVisibility(layer: next, state: current.state, mapView: mapView)
             return next
         }