refactor custom feature -> draw feature

maps-kt-compose/src/commonMain/kotlin/centre/sciprog/maps/compose/FeatureBuilder.kt

@@ -8,7 +8,6 @@ import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.drawscope.DrawScope
 import androidx.compose.ui.graphics.vector.ImageVector
-import centre.sciprog.maps.GmcBox
 
 typealias FeatureId = String
 
@@ -23,6 +22,7 @@ internal class MapFeatureBuilder(initialFeatures: Map<FeatureId, MapFeature>) :
     private val content: SnapshotStateMap<FeatureId, MapFeature> = mutableStateMapOf<FeatureId, MapFeature>().apply {
         putAll(initialFeatures)
     }
+
     private fun generateID(feature: MapFeature): FeatureId = "@feature[${feature.hashCode().toUInt()}]"
 
     override fun addFeature(id: FeatureId?, feature: MapFeature): FeatureId {
@@ -46,18 +46,10 @@ fun FeatureBuilder.circle(
 
 fun FeatureBuilder.custom(
     position: Pair<Double, Double>,
+    zoomRange: IntRange = defaultZoomRange,
     id: FeatureId? = null,
-    customFeatureBuilder: DrawScope.(Offset) -> Unit,
-) = addFeature(id, object : MapCustomFeature(position = position.toCoordinates()) {
-    override fun drawFeature(drawScope: DrawScope, offset: Offset) {
-        customFeatureBuilder(drawScope, offset)
-    }
-
-    override fun getBoundingBox(zoom: Int): GmcBox {
-        return GmcBox(position.toCoordinates(), position.toCoordinates())
-    }
-
-})
+    drawFeature: DrawScope.(Offset) -> Unit,
+) = addFeature(id, MapDrawFeature(position.toCoordinates(), zoomRange, drawFeature))
 
 fun FeatureBuilder.line(
     aCoordinates: Pair<Double, Double>,

maps-kt-compose/src/commonMain/kotlin/centre/sciprog/maps/compose/MapFeature.kt

@@ -30,14 +30,17 @@ internal val defaultZoomRange = 1..18
  */
 class MapFeatureSelector(val selector: (zoom: Int) -> MapFeature) : MapFeature(defaultZoomRange) {
     override fun getBoundingBox(zoom: Int): GmcBox = selector(zoom).getBoundingBox(zoom)
-
 }
 
-abstract class MapCustomFeature(
+class MapDrawFeature(
+    val position: GeodeticMapCoordinates,
     zoomRange: IntRange = defaultZoomRange,
-    val position: GeodeticMapCoordinates
+    val drawFeature: DrawScope.(Offset) -> Unit,
 ) : MapFeature(zoomRange) {
-    abstract fun drawFeature(drawScope: DrawScope, offset: Offset)
+    override fun getBoundingBox(zoom: Int): GmcBox {
+        //TODO add box computation
+        return GmcBox(position, position)
+    }
 }
 
 class MapCircleFeature(

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

@@ -236,7 +236,7 @@ actual fun MapView(
                         feature.color.toPaint()
                     )
                 }
-                is MapCustomFeature -> drawIntoCanvas { canvas ->
+                is MapDrawFeature -> {
                     val offset = feature.position.toOffset()
                     feature.drawFeature(this, offset)
                 }