Add depth attribute

maps-kt-compose/src/jvmMain/kotlin/center/sciprog/maps/compose/MapViewJvm.kt

@@ -15,10 +15,7 @@ import androidx.compose.ui.unit.IntOffset
 import androidx.compose.ui.unit.IntSize
 import androidx.compose.ui.unit.dp
 import center.sciprog.maps.coordinates.Gmc
-import center.sciprog.maps.features.FeaturesState
-import center.sciprog.maps.features.PainterFeature
-import center.sciprog.maps.features.ViewConfig
-import center.sciprog.maps.features.drawFeature
+import center.sciprog.maps.features.*
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.supervisorScope
 import mu.KotlinLogging
@@ -130,7 +127,7 @@ public actual fun MapView(
                     )
                 }
 
-                featuresState.features.values.filter { viewPoint.zoom in it.zoomRange }.forEach { feature ->
+                featuresState.features.values.filter { viewPoint.zoom in it.zoomRange }.sortedBy { it.depth }.forEach { feature ->
                     drawFeature(state, painterCache, feature)
                 }
             }

maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/AttributeMap.kt

@@ -3,6 +3,8 @@ package center.sciprog.maps.features
 import androidx.compose.runtime.mutableStateMapOf
 import androidx.compose.ui.graphics.Color
 
+public object DepthAttribute : Feature.Attribute<Float>
+
 public object DraggableAttribute : Feature.Attribute<DragHandle<*>>
 
 public object SelectableAttribute : Feature.Attribute<(FeatureId<*>, SelectableFeature<*>) -> Unit>
@@ -14,7 +16,7 @@ public object ColorAttribute : Feature.Attribute<Color>
 public class AttributeMap {
     public val map: MutableMap<Feature.Attribute<*>, Any> = mutableStateMapOf()
 
-    public fun <T, A : Feature.Attribute<T>> setAttribute(
+    public operator fun <T, A : Feature.Attribute<T>> set(
         attribute: A,
         attrValue: T?,
     ) {
@@ -42,4 +44,10 @@ public class AttributeMap {
     override fun hashCode(): Int = map.hashCode()
 
     override fun toString(): String = "AttributeMap(value=${map.entries})"
-}
+}
+
+public var Feature<*>.depth: Float
+    get() = attributes[DepthAttribute] ?: 0f
+    set(value) {
+        attributes[DepthAttribute] = value
+    }

maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/FeaturesState.kt

@@ -44,7 +44,7 @@ public class FeaturesState<T : Any>(public val coordinateSpace: CoordinateSpace<
 
 
     public fun <F : Feature<T>, V> setAttribute(id: FeatureId<F>, key: Feature.Attribute<V>, value: V?) {
-        getFeature(id).attributes.setAttribute(key, value)
+        getFeature(id).attributes.set(key, value)
     }
 
     //TODO use context receiver for that

maps-kt-scheme/src/commonMain/kotlin/center/sciprog/maps/scheme/schemeFeatures.kt

@@ -23,7 +23,12 @@ fun FeaturesState<XY>.background(
         offset,
         XY(width + offset.x, height + offset.y)
     )
-    return scalableImage(box, id = id, painter = painter)
+    return feature(
+        id,
+        ScalableImageFeature(coordinateSpace, box, painter = painter).apply {
+            depth = -100f
+        }
+    )
 }
 
 fun FeaturesState<XY>.circle(

maps-kt-scheme/src/jvmMain/kotlin/center/sciprog/maps/scheme/SchemeView.kt

@@ -48,14 +48,12 @@ public fun SchemeView(
             }
 
             clipRect {
-                featuresState.features.values.filterIsInstance<ScalableImageFeature<XY>>().forEach { background ->
-                    drawFeature(state, painterCache, background)
-                }
-                featuresState.features.values.filter {
-                    it !is ScalableImageFeature && viewPoint.zoom in it.zoomRange
-                }.forEach { feature ->
-                    drawFeature(state, painterCache, feature)
-                }
+                featuresState.features.values
+                    .filter { viewPoint.zoom in it.zoomRange }
+                    .sortedBy { it.depth }
+                    .forEach { background ->
+                        drawFeature(state, painterCache, background)
+                    }
             }
             selectRect?.let { dpRect ->
                 val rect = dpRect.toRect()