maps-kt-features/src/commonMain/kotlin/space/kscience/maps/features/FeatureDrawScope.kt

@@ -4,7 +4,6 @@ import androidx.compose.foundation.Canvas
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.key
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.graphics.Color
@@ -19,9 +18,13 @@ import androidx.compose.ui.text.drawText
 import androidx.compose.ui.text.rememberTextMeasurer
 import androidx.compose.ui.unit.DpRect
 import io.github.oshai.kotlinlogging.KotlinLogging
+import kotlinx.coroutines.FlowPreview
 import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.sample
 import space.kscience.attributes.Attributes
 import space.kscience.attributes.plus
+import kotlin.time.Duration
+import kotlin.time.Duration.Companion.milliseconds
 
 /**
  * An extension of [DrawScope] to include map-specific features
@@ -76,22 +79,23 @@ public class ComposeFeatureDrawScope<T : Any>(
 /**
  * Create a canvas with extended functionality (e.g., drawing text)
  */
+@OptIn(FlowPreview::class)
 @Composable
 public fun <T : Any> FeatureCanvas(
     state: CanvasState<T>,
     featureFlow: StateFlow<Map<String, Feature<T>>>,
     modifier: Modifier = Modifier,
+    sampleDuration: Duration = 20.milliseconds,
     draw: FeatureDrawScope<T>.() -> Unit = {},
 ) {
     val textMeasurer = rememberTextMeasurer(0)
 
-    val features by featureFlow.collectAsState()
+    val features by featureFlow.sample(sampleDuration).collectAsState(featureFlow.value)
+
+    val painterCache = features.values
+        .filterIsInstance<PainterFeature<T>>()
+        .associateWith { it.getPainter() }
 
-    val painterCache = key(features) {
-        features.values
-            .filterIsInstance<PainterFeature<T>>()
-            .associateWith { it.getPainter() }
-    }
 
     Canvas(modifier) {
         if (state.canvasSize != size.toDpSize()) {
@@ -102,12 +106,13 @@ public fun <T : Any> FeatureCanvas(
 
                 val attributesCache = mutableMapOf<List<String>, Attributes>()
 
-                fun computeGroupAttributes(path: List<String>): Attributes = attributesCache.getOrPut(path){
+                fun computeGroupAttributes(path: List<String>): Attributes = attributesCache.getOrPut(path) {
                     if (path.isEmpty()) return Attributes.EMPTY
                     else if (path.size == 1) {
                         features[path.first()]?.attributes ?: Attributes.EMPTY
                     } else {
-                        computeGroupAttributes(path.dropLast(1)) + (features[path.first()]?.attributes ?: Attributes.EMPTY)
+                        computeGroupAttributes(path.dropLast(1)) + (features[path.first()]?.attributes
+                            ?: Attributes.EMPTY)
                     }
                 }
 

maps-kt-features/src/commonMain/kotlin/space/kscience/maps/features/FeatureStore.kt

@@ -46,10 +46,12 @@ public interface FeatureBuilder<T : Any> {
     public val space: CoordinateSpace<T>
 
     /**
-     * Add or replace feature. If [id] is null, then a unique id is genertated
+     * Add or replace feature. If [id] is null, then a unique id is generated
      */
     public fun <F : Feature<T>> feature(id: String?, feature: F): FeatureRef<T, F>
 
+    public fun putFeatures(features: Map<String, Feature<T>?>)
+
     /**
      * Update existing feature if it is present and is of type [F]
      */
@@ -89,6 +91,18 @@ public class FeatureStore<T : Any>(
         return FeatureRef(this, safeId)
     }
 
+    public override fun putFeatures(features: Map<String, Feature<T>?>) {
+        _featureFlow.value = _featureFlow.value.toMutableMap().apply {
+            features.forEach { (key, value) ->
+                if (value == null) {
+                    remove(key)
+                } else {
+                    put(key, value)
+                }
+            }
+        }
+    }
+
     @Suppress("UNCHECKED_CAST")
     override fun <F : Feature<T>> updateFeature(id: String, block: (F?) -> F): FeatureRef<T, F> =
         feature(id, block(features[id] as? F))
@@ -159,10 +173,13 @@ public data class FeatureGroup<T : Any> internal constructor(
     override fun withAttributes(modify: Attributes.() -> Attributes): FeatureGroup<T> =
         FeatureGroup(store, groupId, modify(attributes))
 
-
     override fun <F : Feature<T>> feature(id: String?, feature: F): FeatureRef<T, F> =
         store.feature("$groupId/${id ?: generateFeatureId(feature)}", feature)
 
+    public override fun putFeatures(features: Map<String, Feature<T>?>) {
+        store.putFeatures(features.mapKeys { "$groupId/${it.key}" })
+    }
+
     override fun <F : Feature<T>> updateFeature(id: String, block: (F?) -> F): FeatureRef<T, F> =
         store.updateFeature("$groupId/$id", block)
 

maps-kt-features/src/commonMain/kotlin/space/kscience/maps/features/drawFeature.kt

@@ -98,13 +98,6 @@ public fun <T : Any> FeatureDrawScope<T>.drawFeature(
 
         is FeatureGroup -> {
             //ignore groups
-//            feature.features.values.forEach {
-//                drawFeature(
-//                    it.withAttributes {
-//                        feature.attributes + this
-//                    }
-//                )
-//            }
         }
 
         is PathFeature -> {