OnFeatureClick removed

Added function to draw custom markers with Kotlin DSL Canvas API

.gitignore

@@ -1,6 +1,6 @@
 build/
 .gradle/
 .idea/
-*.iml
+/*.iml
 
 mapCache/

.space.kts

@@ -0,0 +1,45 @@
+import kotlin.io.path.readText
+
+job("Build") {
+    gradlew("openjdk:11", "build")
+}
+
+job("Publish") {
+    startOn {
+        gitPush { enabled = false }
+    }
+    container("openjdk:11") {
+        env["SPACE_USER"] = Secrets("space_user")
+        env["SPACE_TOKEN"] = Secrets("space_token")
+        kotlinScript { api ->
+
+            val spaceUser = System.getenv("SPACE_USER")
+            val spaceToken = System.getenv("SPACE_TOKEN")
+
+            // write version to the build directory
+            api.gradlew("version")
+
+            //read version from build file
+            val version = java.nio.file.Path.of("build/project-version.txt").readText()
+
+            val revisionSuffix = if (version.endsWith("SNAPSHOT")) {
+                "-" + api.gitRevision().take(7)
+            } else {
+                ""
+            }
+
+            api.space().projects.automation.deployments.start(
+                project = api.projectIdentifier(),
+                targetIdentifier = TargetIdentifier.Key("maps-kt"),
+                version = version+revisionSuffix,
+                // automatically update deployment status based on a status of a job
+                syncWithAutomationJob = true
+            )
+            api.gradlew(
+                "publishAllPublicationsToSpaceRepository",
+                "-Ppublishing.space.user=\"$spaceUser\"",
+                "-Ppublishing.space.token=\"$spaceToken\"",
+            )
+        }
+    }
+}

LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
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+   limitations under the License.

README.md

@@ -0,0 +1 @@
+This repository is a work-in-progress implementation of Map-with-markers component for Compose-Multiplatform

build.gradle.kts

@@ -1,58 +1,90 @@
-import org.jetbrains.compose.compose
-import org.jetbrains.compose.desktop.application.dsl.TargetFormat
-
 plugins {
-    kotlin("multiplatform")
-    id("org.jetbrains.compose")
-    `maven-publish`
-}
-
-group = "center.sciptog"
-version = "1.0-SNAPSHOT"
-
-repositories {
-    google()
-    mavenCentral()
-    maven("https://maven.pkg.jetbrains.space/public/p/compose/dev")
+    base
 }
 
 val ktorVersion by extra("2.0.3")
 
-kotlin {
-    jvm {
-        compilations.all {
-            kotlinOptions.jvmTarget = "11"
-        }
-        withJava()
-    }
-    sourceSets {
-        commonMain{
-            dependencies{
-                api(compose.runtime)
-                api(compose.foundation)
-                api(compose.material)
-                api("io.ktor:ktor-client-core:$ktorVersion")
-                implementation("io.ktor:ktor-client-cio:$ktorVersion")
-                implementation("io.github.microutils:kotlin-logging:2.1.23")
-            }
-        }
-        val jvmMain by getting {
-            dependencies {
-                implementation(compose.desktop.currentOs)
-                implementation("ch.qos.logback:logback-classic:1.2.11")
-            }
-        }
-        val jvmTest by getting
+allprojects {
+    group = "center.sciprog"
+    version = "0.1.0-SNAPSHOT"
+}
+
+tasks.create("version") {
+    group = "publishing"
+    val versionFile = project.buildDir.resolve("project-version.txt")
+    outputs.file(versionFile)
+    doLast {
+        versionFile.createNewFile()
+        versionFile.writeText(project.version.toString())
+        println(project.version)
     }
 }
 
-compose.desktop {
-    application {
-        mainClass = "MainKt"
-        nativeDistributions {
-            targetFormats(TargetFormat.Dmg, TargetFormat.Msi, TargetFormat.Deb)
-            packageName = "maps-kt-compose"
-            packageVersion = "1.0.0"
+subprojects {
+    repositories {
+        google()
+        mavenCentral()
+        maven("https://maven.pkg.jetbrains.space/public/p/compose/dev")
+    }
+
+    plugins.withId("maven-publish") {
+
+        configure<PublishingExtension> {
+            val vcs = "https://github.com/mipt-npm/maps-kt"
+
+            // Process each publication we have in this project
+            publications {
+                withType<MavenPublication> {
+                    pom {
+                        name.set(project.name)
+                        description.set(project.description)
+                        url.set(vcs)
+
+                        licenses {
+                            license {
+                                name.set("The Apache Software License, Version 2.0")
+                                url.set("https://www.apache.org/licenses/LICENSE-2.0.txt")
+                                distribution.set("repo")
+                            }
+                        }
+
+                        developers {
+                            developer {
+                                id.set("SPC")
+                                name.set("Scientific programming centre")
+                                organization.set("MIPT")
+                                organizationUrl.set("https://sciprog.center/")
+                            }
+                        }
+
+                        scm {
+                            url.set(vcs)
+                            tag.set(project.version.toString())
+                        }
+                    }
+                }
+            }
+
+            val spaceRepo = "https://maven.pkg.jetbrains.space/mipt-npm/p/sci/maven"
+            val spaceUser: String? = project.findProperty("publishing.space.user") as? String
+            val spaceToken: String? = project.findProperty("publishing.space.token") as? String
+
+            if (spaceUser != null && spaceToken != null) {
+                project.logger.info("Adding mipt-npm Space publishing to project [${project.name}]")
+
+                repositories.maven {
+                    name = "space"
+                    url = uri(spaceRepo)
+
+                    credentials {
+                        username = spaceUser
+                        password = spaceToken
+                    }
+                }
+            }
         }
     }
 }
+
+
+

demo/build.gradle.kts

@@ -0,0 +1,40 @@
+import org.jetbrains.compose.compose
+import org.jetbrains.compose.desktop.application.dsl.TargetFormat
+
+plugins {
+    kotlin("multiplatform")
+    id("org.jetbrains.compose")
+}
+
+val ktorVersion: String by rootProject.extra
+
+kotlin {
+    jvm {
+        compilations.all {
+            kotlinOptions.jvmTarget = "11"
+        }
+        withJava()
+    }
+    sourceSets {
+        val jvmMain by getting {
+            dependencies {
+                implementation(projects.mapsKtCompose)
+                implementation(compose.desktop.currentOs)
+                implementation("io.ktor:ktor-client-cio:$ktorVersion")
+                implementation("ch.qos.logback:logback-classic:1.2.11")
+            }
+        }
+        val jvmTest by getting
+    }
+}
+
+compose.desktop {
+    application {
+        mainClass = "MainKt"
+        nativeDistributions {
+            targetFormats(TargetFormat.Dmg, TargetFormat.Msi, TargetFormat.Deb)
+            packageName = "maps-kt-compose"
+            packageVersion = "1.0.0"
+        }
+    }
+}

demo/src/jvmMain/kotlin/Main.kt

@@ -0,0 +1,117 @@
+// Copyright 2000-2021 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+import androidx.compose.desktop.ui.tooling.preview.Preview
+import androidx.compose.material.MaterialTheme
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Home
+import androidx.compose.runtime.*
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.window.Window
+import androidx.compose.ui.window.application
+import centre.sciprog.maps.GeodeticMapCoordinates
+import centre.sciprog.maps.MapViewPoint
+import centre.sciprog.maps.compose.*
+import centre.sciprog.maps.toDegrees
+import io.ktor.client.HttpClient
+import io.ktor.client.engine.cio.CIO
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
+import java.nio.file.Path
+import kotlin.math.PI
+import kotlin.random.Random
+
+private fun GeodeticMapCoordinates.toShortString(): String =
+    "${(latitude * 180.0 / PI).toString().take(6)}:${(longitude * 180.0 / PI).toString().take(6)}"
+
+
+@Composable
+@Preview
+fun App() {
+    MaterialTheme {
+        //create a view point
+        val viewPoint = remember {
+            MapViewPoint(
+                GeodeticMapCoordinates.ofDegrees(55.7558, 37.6173),
+                8.0
+            )
+        }
+
+        val scope = rememberCoroutineScope()
+        val mapTileProvider = remember {
+            OpenStreetMapTileProvider(
+                client = HttpClient(CIO),
+                cacheDirectory = Path.of("mapCache")
+            )
+        }
+
+        var centerCoordinates by remember { mutableStateOf<GeodeticMapCoordinates?>(null) }
+
+        val pointOne = 55.568548 to 37.568604
+        var pointTwo by remember { mutableStateOf(55.929444 to 37.518434) }
+        val pointThree = 60.929444 to 37.518434
+
+        MapView(
+            mapTileProvider = mapTileProvider,
+            initialViewPoint = viewPoint,
+            config = MapViewConfig(
+                inferViewBoxFromFeatures = true,
+                onViewChange = { centerCoordinates = focus },
+                onDrag = { start, end ->
+                    if (start.focus.latitude.toDegrees() in (pointTwo.first - 0.05)..(pointTwo.first + 0.05) &&
+                        start.focus.longitude.toDegrees() in (pointTwo.second - 0.05)..(pointTwo.second + 0.05)
+                    ) {
+                        pointTwo = pointTwo.first + (end.focus.latitude - start.focus.latitude).toDegrees() to
+                                pointTwo.second + (end.focus.longitude - start.focus.longitude).toDegrees()
+                        false
+                    } else true
+                }
+            )
+        ) {
+
+            image(pointOne, Icons.Filled.Home)
+
+            //remember feature Id
+            val circleId: FeatureId = circle(
+                centerCoordinates = pointTwo,
+            )
+
+            custom(position = pointThree) {
+                drawRect(
+                    color = Color.Red,
+                    topLeft = Offset(-10f, -10f),
+                    size = Size(20f, 20f)
+                )
+            }
+
+            line(pointOne, pointTwo, id = "Line")
+            text(pointOne, "Home")
+
+            centerCoordinates?.let {
+                group(id = "center") {
+                    circle(center = it, color = Color.Blue, size = 1f)
+                    text(position = it, it.toShortString(), color = Color.Blue)
+                }
+            }
+
+            scope.launch {
+                while (isActive) {
+                    delay(200)
+                    //Overwrite a feature with new color
+                    circle(
+                        pointTwo,
+                        id = circleId,
+                        color = Color(Random.nextFloat(), Random.nextFloat(), Random.nextFloat())
+                    )
+                }
+            }
+        }
+    }
+}
+
+fun main() = application {
+    Window(onCloseRequest = ::exitApplication) {
+        App()
+    }
+}

gradle.properties

@@ -1,4 +1,5 @@
 kotlin.code.style=official
 kotlin.version=1.6.10
+compose.version=1.1.1
 agp.version=4.2.2
-compose.version=1.1.1
+android.useAndroidX=true

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.3.3-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.5-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

maps-kt-compose/build.gradle.kts

@@ -0,0 +1,29 @@
+import org.jetbrains.compose.compose
+import org.jetbrains.compose.desktop.application.dsl.TargetFormat
+
+plugins {
+    kotlin("multiplatform")
+    id("org.jetbrains.compose")
+    `maven-publish`
+}
+
+val ktorVersion: String by rootProject.extra
+
+kotlin {
+    jvm {
+        compilations.all {
+            kotlinOptions.jvmTarget = "11"
+        }
+    }
+    sourceSets {
+        commonMain{
+            dependencies{
+                api(projects.mapsKtCore)
+                api(compose.foundation)
+                api("io.ktor:ktor-client-core:$ktorVersion")
+            }
+        }
+        val jvmMain by getting
+        val jvmTest by getting
+    }
+}

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

@@ -3,9 +3,12 @@ package centre.sciprog.maps.compose
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.mutableStateMapOf
 import androidx.compose.runtime.snapshots.SnapshotStateMap
-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 androidx.compose.ui.unit.DpSize
+import androidx.compose.ui.unit.dp
+import centre.sciprog.maps.GeodeticMapCoordinates
 
 typealias FeatureId = String
 
@@ -15,7 +18,12 @@ interface FeatureBuilder {
     fun build(): SnapshotStateMap<FeatureId, MapFeature>
 }
 
-internal class MapFeatureBuilder(private val content: SnapshotStateMap<FeatureId, MapFeature> = mutableStateMapOf()) : FeatureBuilder {
+internal class MapFeatureBuilder(initialFeatures: Map<FeatureId, MapFeature>) : FeatureBuilder {
+
+    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 {
@@ -27,6 +35,16 @@ internal class MapFeatureBuilder(private val content: SnapshotStateMap<FeatureId
     override fun build(): SnapshotStateMap<FeatureId, MapFeature> = content
 }
 
+fun FeatureBuilder.circle(
+    center: GeodeticMapCoordinates,
+    zoomRange: IntRange = defaultZoomRange,
+    size: Float = 5f,
+    color: Color = Color.Red,
+    id: FeatureId? = null,
+) = addFeature(
+    id, MapCircleFeature(center, zoomRange, size, color)
+)
+
 fun FeatureBuilder.circle(
     centerCoordinates: Pair<Double, Double>,
     zoomRange: IntRange = defaultZoomRange,
@@ -37,6 +55,13 @@ fun FeatureBuilder.circle(
     id, MapCircleFeature(centerCoordinates.toCoordinates(), zoomRange, size, color)
 )
 
+fun FeatureBuilder.custom(
+    position: Pair<Double, Double>,
+    zoomRange: IntRange = defaultZoomRange,
+    id: FeatureId? = null,
+    drawFeature: DrawScope.() -> Unit,
+) = addFeature(id, MapDrawFeature(position.toCoordinates(), zoomRange, drawFeature))
+
 fun FeatureBuilder.line(
     aCoordinates: Pair<Double, Double>,
     bCoordinates: Pair<Double, Double>,
@@ -45,6 +70,14 @@ fun FeatureBuilder.line(
     id: FeatureId? = null,
 ) = addFeature(id, MapLineFeature(aCoordinates.toCoordinates(), bCoordinates.toCoordinates(), zoomRange, color))
 
+fun FeatureBuilder.text(
+    position: GeodeticMapCoordinates,
+    text: String,
+    zoomRange: IntRange = defaultZoomRange,
+    color: Color = Color.Red,
+    id: FeatureId? = null,
+) = addFeature(id, MapTextFeature(position, text, zoomRange, color))
+
 fun FeatureBuilder.text(
     position: Pair<Double, Double>,
     text: String,
@@ -57,7 +90,17 @@ fun FeatureBuilder.text(
 fun FeatureBuilder.image(
     position: Pair<Double, Double>,
     image: ImageVector,
-    size: Size = Size(20f, 20f),
+    size: DpSize = DpSize(20.dp, 20.dp),
     zoomRange: IntRange = defaultZoomRange,
     id: FeatureId? = null,
-) = addFeature(id, MapVectorImageFeature(position.toCoordinates(), image, size, zoomRange))
+) = addFeature(id, MapVectorImageFeature(position.toCoordinates(), image, size, zoomRange))
+
+fun FeatureBuilder.group(
+    zoomRange: IntRange = defaultZoomRange,
+    id: FeatureId? = null,
+    builder: FeatureBuilder.() -> Unit,
+): FeatureId {
+    val map = MapFeatureBuilder(emptyMap()).apply(builder).build()
+    val feature = MapFeatureGroup(map, zoomRange)
+    return addFeature(id, feature)
+}

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

@@ -0,0 +1,42 @@
+package centre.sciprog.maps.compose
+
+import kotlin.jvm.Synchronized
+
+
+internal class LruCache<K, V>(
+    private var capacity: Int,
+) {
+    private val cache = linkedMapOf<K, V>()
+
+    @Synchronized
+    fun put(key: K, value: V){
+        if (cache.size >= capacity) {
+            cache.remove(cache.iterator().next().key)
+        }
+        cache[key] = value
+    }
+
+    operator fun get(key: K): V? {
+        val value = cache[key]
+        if (value != null) {
+            cache.remove(key)
+            cache[key] = value
+        }
+        return value
+    }
+
+    @Synchronized
+    fun remove(key: K) {
+        cache.remove(key)
+    }
+
+    @Synchronized
+    fun getOrPut(key: K, factory: () -> V): V = get(key) ?: factory().also { put(key, it) }
+
+    @Synchronized
+    fun reset(newCapacity: Int? = null) {
+        cache.clear()
+        capacity = newCapacity ?: capacity
+    }
+
+}

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

@@ -1,17 +1,28 @@
 package centre.sciprog.maps.compose
 
 import androidx.compose.runtime.Composable
+import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.ImageBitmap
+import androidx.compose.ui.graphics.drawscope.DrawScope
 import androidx.compose.ui.graphics.painter.Painter
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.graphics.vector.rememberVectorPainter
+import androidx.compose.ui.unit.DpSize
 import androidx.compose.ui.unit.IntSize
+import androidx.compose.ui.unit.dp
 import centre.sciprog.maps.GeodeticMapCoordinates
+import centre.sciprog.maps.GmcBox
+import centre.sciprog.maps.wrapAll
 
 //TODO replace zoom range with zoom-based representation change
-sealed class MapFeature(val zoomRange: IntRange)
+sealed class MapFeature(val zoomRange: IntRange) {
+    abstract fun getBoundingBox(zoom: Int): GmcBox?
+}
+
+fun Iterable<MapFeature>.computeBoundingBox(zoom: Int): GmcBox? =
+    mapNotNull { it.getBoundingBox(zoom) }.wrapAll()
 
 internal fun Pair<Double, Double>.toCoordinates() = GeodeticMapCoordinates.ofDegrees(first, second)
 
@@ -20,48 +31,80 @@ internal val defaultZoomRange = 1..18
 /**
  * A feature that decides what to show depending on the zoom value (it could change size of shape)
  */
-class MapFeatureSelector(val selector: (zoom: Int) -> MapFeature) : MapFeature(defaultZoomRange)
+class MapFeatureSelector(val selector: (zoom: Int) -> MapFeature) : MapFeature(defaultZoomRange) {
+    override fun getBoundingBox(zoom: Int): GmcBox? = selector(zoom).getBoundingBox(zoom)
+}
+
+class MapDrawFeature(
+    val position: GeodeticMapCoordinates,
+    zoomRange: IntRange = defaultZoomRange,
+    val drawFeature: DrawScope.() -> Unit,
+) : MapFeature(zoomRange) {
+    override fun getBoundingBox(zoom: Int): GmcBox {
+        //TODO add box computation
+        return GmcBox(position, position)
+    }
+}
 
 class MapCircleFeature(
     val center: GeodeticMapCoordinates,
     zoomRange: IntRange = defaultZoomRange,
     val size: Float = 5f,
     val color: Color = Color.Red,
-) : MapFeature(zoomRange)
+) : MapFeature(zoomRange) {
+    override fun getBoundingBox(zoom: Int): GmcBox = GmcBox(center, center)
+}
 
 class MapLineFeature(
     val a: GeodeticMapCoordinates,
     val b: GeodeticMapCoordinates,
     zoomRange: IntRange = defaultZoomRange,
     val color: Color = Color.Red,
-) : MapFeature(zoomRange)
+) : MapFeature(zoomRange) {
+    override fun getBoundingBox(zoom: Int): GmcBox = GmcBox(a, b)
+}
 
 class MapTextFeature(
     val position: GeodeticMapCoordinates,
     val text: String,
     zoomRange: IntRange = defaultZoomRange,
     val color: Color = Color.Red,
-) : MapFeature(zoomRange)
+) : MapFeature(zoomRange) {
+    override fun getBoundingBox(zoom: Int): GmcBox = GmcBox(position, position)
+}
 
 class MapBitmapImageFeature(
     val position: GeodeticMapCoordinates,
     val image: ImageBitmap,
     val size: IntSize = IntSize(15, 15),
     zoomRange: IntRange = defaultZoomRange,
-) : MapFeature(zoomRange)
+) : MapFeature(zoomRange) {
+    override fun getBoundingBox(zoom: Int): GmcBox = GmcBox(position, position)
+}
 
-
-class MapVectorImageFeature (
+class MapVectorImageFeature(
     val position: GeodeticMapCoordinates,
     val painter: Painter,
-    val size: Size,
+    val size: DpSize,
     zoomRange: IntRange = defaultZoomRange,
-) : MapFeature(zoomRange)
+) : MapFeature(zoomRange) {
+    override fun getBoundingBox(zoom: Int): GmcBox = GmcBox(position, position)
+}
 
 @Composable
 fun MapVectorImageFeature(
     position: GeodeticMapCoordinates,
     image: ImageVector,
-    size: Size = Size(20f, 20f),
+    size: DpSize = DpSize(20.dp, 20.dp),
     zoomRange: IntRange = defaultZoomRange,
 ): MapVectorImageFeature = MapVectorImageFeature(position, rememberVectorPainter(image), size, zoomRange)
+
+/**
+ * A group of other features
+ */
+class MapFeatureGroup(
+    val children: Map<FeatureId, MapFeature>,
+    zoomRange: IntRange = defaultZoomRange,
+) : MapFeature(zoomRange) {
+    override fun getBoundingBox(zoom: Int): GmcBox? = children.values.mapNotNull { it.getBoundingBox(zoom) }.wrapAll()
+}

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

@@ -1,6 +1,8 @@
 package centre.sciprog.maps.compose
 
 import androidx.compose.ui.graphics.ImageBitmap
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Deferred
 import kotlin.math.floor
 
 data class TileId(
@@ -15,7 +17,7 @@ data class MapTile(
 )
 
 interface MapTileProvider {
-    suspend fun loadTile(id: TileId): MapTile
+    fun CoroutineScope.loadTileAsync(tileId: TileId): Deferred<MapTile>
 
     val tileSize: Int get() = DEFAULT_TILE_SIZE
 
@@ -26,4 +28,4 @@ interface MapTileProvider {
     companion object {
         const val DEFAULT_TILE_SIZE = 256
     }
-}
+}

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

@@ -0,0 +1,82 @@
+package centre.sciprog.maps.compose
+
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.DpSize
+import centre.sciprog.maps.*
+import kotlin.math.PI
+import kotlin.math.log2
+import kotlin.math.min
+
+
+//TODO consider replacing by modifier
+data class MapViewConfig(
+    val zoomSpeed: Double = 1.0 / 3.0,
+    val inferViewBoxFromFeatures: Boolean = false,
+    val onClick: MapViewPoint.() -> Unit = {},
+    val onViewChange: MapViewPoint.() -> Unit = {},
+    val onSelect: (GmcBox) -> Unit = {},
+    val onDrag: (MapViewPoint, MapViewPoint) -> Boolean = { _, _ -> true },
+    val zoomOnSelect: Boolean = true
+)
+
+@Composable
+expect fun MapView(
+    mapTileProvider: MapTileProvider,
+    computeViewPoint: (canvasSize: DpSize) -> MapViewPoint,
+    features: Map<FeatureId, MapFeature>,
+    config: MapViewConfig = MapViewConfig(),
+    modifier: Modifier = Modifier.fillMaxSize(),
+)
+
+@Composable
+fun MapView(
+    mapTileProvider: MapTileProvider,
+    initialViewPoint: MapViewPoint,
+    features: Map<FeatureId, MapFeature> = emptyMap(),
+    config: MapViewConfig = MapViewConfig(),
+    modifier: Modifier = Modifier.fillMaxSize(),
+    buildFeatures: @Composable (FeatureBuilder.() -> Unit) = {},
+) {
+    val featuresBuilder = MapFeatureBuilder(features)
+    featuresBuilder.buildFeatures()
+    MapView(
+        mapTileProvider,
+        { initialViewPoint },
+        featuresBuilder.build(),
+        config,
+        modifier
+    )
+}
+
+internal fun GmcBox.getComputeViewPoint(mapTileProvider: MapTileProvider): (canvasSize: DpSize) -> MapViewPoint =
+    { canvasSize ->
+        val zoom = log2(
+            min(
+                canvasSize.width.value / width,
+                canvasSize.height.value / height
+            ) * PI / mapTileProvider.tileSize
+        )
+        MapViewPoint(center, zoom)
+    }
+
+@Composable
+fun MapView(
+    mapTileProvider: MapTileProvider,
+    box: GmcBox,
+    features: Map<FeatureId, MapFeature> = emptyMap(),
+    config: MapViewConfig = MapViewConfig(),
+    modifier: Modifier = Modifier.fillMaxSize(),
+    buildFeatures: @Composable (FeatureBuilder.() -> Unit) = {},
+) {
+    val featuresBuilder = MapFeatureBuilder(features)
+    featuresBuilder.buildFeatures()
+    MapView(
+        mapTileProvider,
+        box.getComputeViewPoint(mapTileProvider),
+        featuresBuilder.build(),
+        config,
+        modifier
+    )
+}

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

@@ -17,13 +17,12 @@ import androidx.compose.ui.graphics.toArgb
 import androidx.compose.ui.input.pointer.*
 import androidx.compose.ui.unit.*
 import centre.sciprog.maps.*
+import io.ktor.utils.io.CancellationException
+import kotlinx.coroutines.launch
 import mu.KotlinLogging
 import org.jetbrains.skia.Font
 import org.jetbrains.skia.Paint
-import kotlin.math.ceil
-import kotlin.math.floor
-import kotlin.math.log2
-import kotlin.math.pow
+import kotlin.math.*
 
 
 private fun Color.toPaint(): Paint = Paint().apply {
@@ -31,23 +30,54 @@ private fun Color.toPaint(): Paint = Paint().apply {
     color = toArgb()
 }
 
+private fun IntRange.intersect(other: IntRange) = max(first, other.first)..min(last, other.last)
+
+internal fun MapViewPoint.move(deltaX: Double, deltaY: Double): MapViewPoint {
+    val newCoordinates = GeodeticMapCoordinates.ofRadians(
+        (focus.latitude + deltaY / scaleFactor).coerceIn(
+            -MercatorProjection.MAXIMUM_LATITUDE,
+            MercatorProjection.MAXIMUM_LATITUDE
+        ),
+        focus.longitude + deltaX / scaleFactor
+    )
+    return MapViewPoint(newCoordinates, zoom)
+}
+
 private val logger = KotlinLogging.logger("MapView")
 
 /**
  * A component that renders map and provides basic map manipulation capabilities
  */
-@OptIn(ExperimentalComposeUiApi::class)
+
 @Composable
 actual fun MapView(
-    initialViewPoint: MapViewPoint,
     mapTileProvider: MapTileProvider,
+    computeViewPoint: (canvasSize: DpSize) -> MapViewPoint,
     features: Map<FeatureId, MapFeature>,
-    onClick: (GeodeticMapCoordinates) -> Unit,
     config: MapViewConfig,
     modifier: Modifier,
 ) {
+    var canvasSize by remember { mutableStateOf(DpSize(512.dp, 512.dp)) }
 
-    var viewPoint by remember { mutableStateOf(initialViewPoint) }
+    var viewPointOverride: MapViewPoint? by remember {
+        mutableStateOf(
+            if (config.inferViewBoxFromFeatures) {
+                features.values.computeBoundingBox(1)?.let { box ->
+                    val zoom = log2(
+                        min(
+                            canvasSize.width.value / box.width,
+                            canvasSize.height.value / box.height
+                        ) * PI / mapTileProvider.tileSize
+                    )
+                    MapViewPoint(box.center, zoom)
+                }
+            } else {
+                null
+            }
+        )
+    }
+
+    val viewPoint by derivedStateOf { viewPointOverride ?: computeViewPoint(canvasSize) }
 
     val zoom: Int by derivedStateOf { floor(viewPoint.zoom).toInt() }
 
@@ -55,9 +85,6 @@ actual fun MapView(
 
     val mapTiles = remember { mutableStateListOf<MapTile>() }
 
-    //var mapRectangle by remember { mutableStateOf(initialRectangle) }
-    var canvasSize by remember { mutableStateOf(DpSize(512.dp, 512.dp)) }
-
     val centerCoordinates by derivedStateOf { WebMercatorProjection.toMercator(viewPoint.focus, zoom) }
 
     fun DpOffset.toMercator(): WebMercatorCoordinates = WebMercatorCoordinates(
@@ -74,9 +101,12 @@ actual fun MapView(
     // Selection rectangle. If null - no selection
     var selectRect by remember { mutableStateOf<Rect?>(null) }
 
+    @OptIn(ExperimentalComposeUiApi::class)
     val canvasModifier = modifier.pointerInput(Unit) {
         forEachGesture {
             awaitPointerEventScope {
+                fun Offset.toDpOffset() = DpOffset(x.toDp(), y.toDp())
+
                 val event: PointerEvent = awaitPointerEvent()
                 event.changes.forEach { change ->
                     if (event.buttons.isPrimaryPressed) {
@@ -87,34 +117,48 @@ actual fun MapView(
                                 selectRect?.let { rect ->
                                     val offset = dragChange.position
                                     selectRect = Rect(
-                                        kotlin.math.min(offset.x, rect.left),
-                                        kotlin.math.min(offset.y, rect.top),
-                                        kotlin.math.max(offset.x, rect.right),
-                                        kotlin.math.max(offset.y, rect.bottom)
+                                        min(offset.x, rect.left),
+                                        min(offset.y, rect.top),
+                                        max(offset.x, rect.right),
+                                        max(offset.y, rect.bottom)
                                     )
                                 }
                             }
                             selectRect?.let { rect ->
-                                val (centerX, centerY) = rect.center
-                                val centerGmc = DpOffset(centerX.toDp(), centerY.toDp()).toGeodetic()
+                                //Use selection override if it is defined
+                                val gmcBox = GmcBox(
+                                    rect.topLeft.toDpOffset().toGeodetic(),
+                                    rect.bottomRight.toDpOffset().toGeodetic()
+                                )
+                                config.onSelect(gmcBox)
+                                if (config.zoomOnSelect) {
+                                    val newViewPoint = gmcBox.getComputeViewPoint(mapTileProvider).invoke(canvasSize)
 
-                                val horizontalZoom: Float = log2(canvasSize.width.toPx() / rect.width)
-                                val verticalZoom: Float = log2(canvasSize.height.toPx() / rect.height)
-
-
-                                viewPoint = MapViewPoint(centerGmc, viewPoint.zoom + kotlin.math.min(verticalZoom, horizontalZoom))
+                                    config.onViewChange(newViewPoint)
+                                    viewPointOverride = newViewPoint
+                                }
                                 selectRect = null
                             }
                         } else {
                             val dragStart = change.position
                             val dpPos = DpOffset(dragStart.x.toDp(), dragStart.y.toDp())
-                            onClick(dpPos.toGeodetic())
+                            config.onClick(MapViewPoint(dpPos.toGeodetic(), viewPoint.zoom))
                             drag(change.id) { dragChange ->
+                                val dpStartPos =
+                                    DpOffset(dragChange.previousPosition.x.toDp(), dragChange.previousPosition.y.toDp())
+                                val dpEndPos = DpOffset(dragChange.position.x.toDp(), dragChange.position.y.toDp())
+                                if (!config.onDrag(
+                                        MapViewPoint(dpStartPos.toGeodetic(), viewPoint.zoom),
+                                        MapViewPoint(dpEndPos.toGeodetic(), viewPoint.zoom)
+                                    )
+                                ) return@drag
                                 val dragAmount = dragChange.position - dragChange.previousPosition
-                                viewPoint = viewPoint.move(
+                                val newViewPoint = viewPoint.move(
                                     -dragAmount.x.toDp().value / tileScale,
                                     +dragAmount.y.toDp().value / tileScale
                                 )
+                                config.onViewChange(newViewPoint)
+                                viewPointOverride = newViewPoint
                             }
                         }
                     }
@@ -126,43 +170,50 @@ actual fun MapView(
         val (xPos, yPos) = change.position
         //compute invariant point of translation
         val invariant = DpOffset(xPos.toDp(), yPos.toDp()).toGeodetic()
-        viewPoint = viewPoint.zoom(-change.scrollDelta.y.toDouble() * config.zoomSpeed, invariant)
+        val newViewPoint = viewPoint.zoom(-change.scrollDelta.y.toDouble() * config.zoomSpeed, invariant)
+        config.onViewChange(newViewPoint)
+        viewPointOverride = newViewPoint
     }.fillMaxSize()
 
 
     // Load tiles asynchronously
     LaunchedEffect(viewPoint, canvasSize) {
-        val left = centerCoordinates.x - canvasSize.width.value / 2 / tileScale
-        val right = centerCoordinates.x + canvasSize.width.value / 2 / tileScale
-        val horizontalIndices = mapTileProvider.toIndex(left)..mapTileProvider.toIndex(right)
+        with(mapTileProvider) {
+            val indexRange = 0 until 2.0.pow(zoom).toInt()
 
-        val top = (centerCoordinates.y + canvasSize.height.value / 2 / tileScale)
-        val bottom = (centerCoordinates.y - canvasSize.height.value / 2 / tileScale)
-        val verticalIndices = mapTileProvider.toIndex(bottom)..mapTileProvider.toIndex(top)
+            val left = centerCoordinates.x - canvasSize.width.value / 2 / tileScale
+            val right = centerCoordinates.x + canvasSize.width.value / 2 / tileScale
+            val horizontalIndices: IntRange = (toIndex(left)..toIndex(right)).intersect(indexRange)
 
-        mapTiles.clear()
+            val top = (centerCoordinates.y + canvasSize.height.value / 2 / tileScale)
+            val bottom = (centerCoordinates.y - canvasSize.height.value / 2 / tileScale)
+            val verticalIndices: IntRange = (toIndex(bottom)..toIndex(top)).intersect(indexRange)
 
-        val indexRange = 0 until 2.0.pow(zoom).toInt()
+            mapTiles.clear()
 
-        for (j in verticalIndices) {
-            for (i in horizontalIndices) {
-                if (i in indexRange && j in indexRange) {
-                    val tileId = TileId(zoom, i, j)
-                    try {
-                        val tile = mapTileProvider.loadTile(tileId)
-                        mapTiles.add(tile)
-                    } catch (ex: Exception) {
-                        logger.error(ex) { "Failed to load tile $tileId" }
+            for (j in verticalIndices) {
+                for (i in horizontalIndices) {
+                    val id = TileId(zoom, i, j)
+                    //start all
+                    val deferred = loadTileAsync(id)
+                    //wait asynchronously for it to finish
+                    launch {
+                        try {
+                            mapTiles += deferred.await()
+                        } catch (ex: Exception) {
+                            if (ex !is CancellationException) {
+                                //displaying the error is maps responsibility
+                                logger.error(ex) { "Failed to load tile with id=$id" }
+                            }
+                        }
                     }
                 }
             }
         }
-
     }
 
-    // d
-    Canvas(canvasModifier) {
 
+    Canvas(canvasModifier) {
         fun WebMercatorCoordinates.toOffset(): Offset = Offset(
             (canvasSize.width / 2 + (x.dp - centerCoordinates.x.dp) * tileScale.toFloat()).toPx(),
             (canvasSize.height / 2 + (y.dp - centerCoordinates.y.dp) * tileScale.toFloat()).toPx()
@@ -184,9 +235,10 @@ actual fun MapView(
                 is MapBitmapImageFeature -> drawImage(feature.image, feature.position.toOffset())
                 is MapVectorImageFeature -> {
                     val offset = feature.position.toOffset()
-                    translate(offset.x - feature.size.width / 2, offset.y - feature.size.height / 2) {
+                    val size = feature.size.toSize()
+                    translate(offset.x - size.width / 2, offset.y - size.height / 2) {
                         with(feature.painter) {
-                            draw(feature.size)
+                            draw(size)
                         }
                     }
                 }
@@ -200,7 +252,17 @@ actual fun MapView(
                         feature.color.toPaint()
                     )
                 }
-
+                is MapDrawFeature -> {
+                    val offset = feature.position.toOffset()
+                    translate(offset.x, offset.y) {
+                        feature.drawFeature(this)
+                    }
+                }
+                is MapFeatureGroup -> {
+                    feature.children.values.forEach {
+                        drawFeature(zoom, it)
+                    }
+                }
             }
         }
 
@@ -242,4 +304,4 @@ actual fun MapView(
             )
         }
     }
-}
+}

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

@@ -0,0 +1,99 @@
+package centre.sciprog.maps.compose
+
+import androidx.compose.ui.graphics.ImageBitmap
+import androidx.compose.ui.graphics.toComposeImageBitmap
+import io.ktor.client.HttpClient
+import io.ktor.client.request.get
+import io.ktor.client.statement.readBytes
+import io.ktor.utils.io.CancellationException
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Deferred
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.async
+import kotlinx.coroutines.sync.Semaphore
+import kotlinx.coroutines.sync.withPermit
+import mu.KotlinLogging
+import org.jetbrains.skia.Image
+import java.net.URL
+import java.nio.file.Path
+import kotlin.io.path.*
+
+/**
+ * A [MapTileProvider] based on Open Street Map API. With in-memory and file cache
+ */
+class OpenStreetMapTileProvider(
+    private val client: HttpClient,
+    private val cacheDirectory: Path,
+    parallelism: Int = 1,
+    cacheCapacity: Int = 200,
+) : MapTileProvider {
+    private val semaphore = Semaphore(parallelism)
+    private val cache = LruCache<TileId, Deferred<ImageBitmap>>(cacheCapacity)
+
+    private fun TileId.osmUrl() = URL("https://tile.openstreetmap.org/${zoom}/${i}/${j}.png")
+
+    private fun TileId.cacheFilePath() = cacheDirectory.resolve("${zoom}/${i}/${j}.png")
+
+    /**
+     * Download and cache the tile image
+     */
+    private fun CoroutineScope.downloadImageAsync(id: TileId) = async(Dispatchers.IO) {
+
+        id.cacheFilePath()?.let { path ->
+            if (path.exists()) {
+                try {
+                    return@async Image.makeFromEncoded(path.readBytes()).toComposeImageBitmap()
+                } catch (ex: Exception) {
+                    logger.debug { "Failed to load image from $path" }
+                    path.deleteIfExists()
+                }
+            }
+        }
+
+        //semaphore works only for actual download
+        semaphore.withPermit {
+            val url = id.osmUrl()
+            val byteArray = client.get(url).readBytes()
+
+            logger.debug { "Finished downloading map tile with id $id from $url" }
+
+            id.cacheFilePath()?.let { path ->
+                logger.debug { "Caching map tile $id to $path" }
+
+                path.parent.createDirectories()
+                path.writeBytes(byteArray)
+            }
+
+            Image.makeFromEncoded(byteArray).toComposeImageBitmap()
+        }
+    }
+
+    override fun CoroutineScope.loadTileAsync(
+        tileId: TileId,
+    ): Deferred<MapTile> {
+
+        //start image download
+        val imageDeferred = cache.getOrPut(tileId) {
+            downloadImageAsync(tileId)
+        }
+
+        //collect the result asynchronously
+        return async {
+            val image = try {
+                imageDeferred.await()
+            } catch (ex: Exception) {
+                cache.remove(tileId)
+                if(ex !is CancellationException) {
+                    logger.error(ex) { "Failed to load tile image with id=$tileId" }
+                }
+                throw ex
+            }
+            MapTile(tileId, image)
+        }
+    }
+
+
+    companion object {
+        private val logger = KotlinLogging.logger("OpenStreetMapCache")
+    }
+}

maps-kt-core/build.gradle.kts

@@ -0,0 +1,26 @@
+plugins {
+    kotlin("multiplatform")
+    `maven-publish`
+}
+
+val ktorVersion: String by rootProject.extra
+
+kotlin {
+    jvm {
+        compilations.all {
+            kotlinOptions.jvmTarget = "11"
+        }
+    }
+    js(IR){
+        browser()
+    }
+    sourceSets {
+        commonMain{
+            dependencies{
+                api("io.github.microutils:kotlin-logging:2.1.23")
+            }
+        }
+        val jvmMain by getting
+        val jvmTest by getting
+    }
+}

maps-kt-core/src/commonMain/kotlin/centre/sciprog/maps/GeodeticMapCoordinates.kt

@@ -43,6 +43,8 @@ public class GeodeticMapCoordinates private constructor(public val latitude: Dou
     }
 }
 
+internal typealias Gmc = GeodeticMapCoordinates
+
 
 //public interface GeoToScreenConversion {
 //    public fun getScreenX(gmc: GeodeticMapCoordinates): Double

maps-kt-core/src/commonMain/kotlin/centre/sciprog/maps/GmcBox.kt

@@ -0,0 +1,39 @@
+package centre.sciprog.maps
+
+import kotlin.math.*
+
+class GmcBox(val a: GeodeticMapCoordinates, val b: GeodeticMapCoordinates)
+
+fun GmcBox(latitudes: ClosedFloatingPointRange<Double>, longitudes: ClosedFloatingPointRange<Double>) = GmcBox(
+    GeodeticMapCoordinates.ofRadians(latitudes.start, longitudes.start),
+    GeodeticMapCoordinates.ofRadians(latitudes.endInclusive, longitudes.endInclusive)
+)
+
+val GmcBox.center
+    get() = GeodeticMapCoordinates.ofRadians(
+        (a.latitude + b.latitude) / 2,
+        (a.longitude + b.longitude) / 2
+    )
+
+val GmcBox.left get() = min(a.longitude, b.longitude)
+val GmcBox.right get() = max(a.longitude, b.longitude)
+
+val GmcBox.top get() = max(a.latitude, b.latitude)
+val GmcBox.bottom get() = min(a.latitude, b.latitude)
+
+//TODO take curvature into account
+val GmcBox.width get() = abs(a.longitude - b.longitude)
+val GmcBox.height get() = abs(a.latitude - b.latitude)
+
+/**
+ * Compute a minimal bounding box including all given boxes. Return null if collection is empty
+ */
+fun Collection<GmcBox>.wrapAll(): GmcBox? {
+    if (isEmpty()) return null
+    //TODO optimize computation
+    val minLat = minOf { it.bottom }
+    val maxLat = maxOf { it.top }
+    val minLong = minOf { it.left }
+    val maxLong = maxOf { it.right }
+    return GmcBox(minLat..maxLat, minLong..maxLong)
+}

maps-kt-core/src/commonMain/kotlin/centre/sciprog/maps/MapViewPoint.kt

@@ -1,7 +1,6 @@
 package centre.sciprog.maps
 
 import kotlin.math.pow
-import kotlin.math.roundToInt
 
 /**
  * Observable position on the map. Includes observation coordinate and [zoom] factor
@@ -13,20 +12,6 @@ data class MapViewPoint(
     val scaleFactor by lazy { WebMercatorProjection.scaleFactor(zoom) }
 }
 
-/**
- *
- */
-internal fun MapViewPoint.move(deltaX: Double, deltaY: Double): MapViewPoint {
-    val newCoordinates = GeodeticMapCoordinates.ofRadians(
-        (focus.latitude + deltaY / scaleFactor).coerceIn(
-            -MercatorProjection.MAXIMUM_LATITUDE,
-            MercatorProjection.MAXIMUM_LATITUDE
-        ),
-        focus.longitude + deltaX / scaleFactor
-    )
-    return MapViewPoint(newCoordinates, zoom)
-}
-
 fun MapViewPoint.move(delta: GeodeticMapCoordinates): MapViewPoint {
     val newCoordinates = GeodeticMapCoordinates.ofRadians(
         (focus.latitude + delta.latitude).coerceIn(

maps-kt-core/src/commonMain/kotlin/centre/sciprog/maps/Utils.kt

@@ -0,0 +1,7 @@
+package centre.sciprog.maps
+
+import kotlin.math.PI
+
+fun Double.toDegrees() = this * 180 / PI
+
+fun Double.toRadians() = this * PI / 180

settings.gradle.kts

@@ -1,4 +1,7 @@
-// Copyright 2000-2022 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+rootProject.name = "maps-kt"
+
+enableFeaturePreview("TYPESAFE_PROJECT_ACCESSORS")
+
 pluginManagement {
     repositories {
         google()
@@ -9,9 +12,17 @@ pluginManagement {
 
     plugins {
         kotlin("multiplatform").version(extra["kotlin.version"] as String)
+        kotlin("android").version(extra["kotlin.version"] as String)
+        id("com.android.application").version(extra["agp.version"] as String)
+        id("com.android.library").version(extra["agp.version"] as String)
         id("org.jetbrains.compose").version(extra["compose.version"] as String)
     }
 }
 
-rootProject.name = "maps-kt-compose"
+
+include(
+    ":maps-kt-core",
+    ":maps-kt-compose",
+    ":demo"
+)
 

src/commonMain/kotlin/centre/sciprog/maps/compose/MapView.kt

@@ -1,37 +0,0 @@
-package centre.sciprog.maps.compose
-
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.runtime.Composable
-import androidx.compose.ui.Modifier
-import centre.sciprog.maps.GeodeticMapCoordinates
-import centre.sciprog.maps.MapViewPoint
-
-
-data class MapViewConfig(
-    val zoomSpeed: Double = 1.0 / 3.0,
-)
-
-@Composable
-expect fun MapView(
-    initialViewPoint: MapViewPoint,
-    mapTileProvider: MapTileProvider,
-    features: Map<FeatureId, MapFeature>,
-    onClick: (GeodeticMapCoordinates) -> Unit = {},
-    //TODO consider replacing by modifier
-    config: MapViewConfig = MapViewConfig(),
-    modifier: Modifier = Modifier.fillMaxSize(),
-)
-
-@Composable
-fun MapView(
-    initialViewPoint: MapViewPoint,
-    mapTileProvider: MapTileProvider,
-    onClick: (GeodeticMapCoordinates) -> Unit = {},
-    config: MapViewConfig = MapViewConfig(),
-    modifier: Modifier = Modifier.fillMaxSize(),
-    addFeatures: @Composable() (FeatureBuilder.() -> Unit) = {},
-) {
-    val featuresBuilder = MapFeatureBuilder()
-    featuresBuilder.addFeatures()
-    MapView(initialViewPoint, mapTileProvider, featuresBuilder.build(), onClick, config, modifier)
-}

src/jvmMain/kotlin/Main.kt

@@ -1,71 +0,0 @@
-// Copyright 2000-2021 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
-import androidx.compose.desktop.ui.tooling.preview.Preview
-import androidx.compose.foundation.layout.Column
-import androidx.compose.material.MaterialTheme
-import androidx.compose.material.Text
-import androidx.compose.material.icons.Icons
-import androidx.compose.material.icons.filled.Home
-import androidx.compose.runtime.*
-import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.window.Window
-import androidx.compose.ui.window.application
-import centre.sciprog.maps.GeodeticMapCoordinates
-import centre.sciprog.maps.MapViewPoint
-import centre.sciprog.maps.compose.*
-import io.ktor.client.HttpClient
-import io.ktor.client.engine.cio.CIO
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.isActive
-import kotlinx.coroutines.launch
-import java.nio.file.Path
-import kotlin.random.Random
-
-@Composable
-@Preview
-fun App() {
-    MaterialTheme {
-        //create a view point
-        val viewPoint = remember {
-            MapViewPoint(
-                GeodeticMapCoordinates.ofDegrees(55.7558, 37.6173),
-                8.0
-            )
-        }
-
-        val scope = rememberCoroutineScope()
-        val mapTileProvider = remember { OpenStreetMapTileProvider(scope, HttpClient(CIO), Path.of("mapCache")) }
-
-        var coordinates by remember { mutableStateOf<GeodeticMapCoordinates?>(null) }
-
-        Column {
-            //display click coordinates
-            Text(coordinates?.toString() ?: "")
-            MapView(viewPoint, mapTileProvider, onClick = { gmc: GeodeticMapCoordinates -> coordinates = gmc }) {
-                val pointOne = 55.568548 to 37.568604
-                val pointTwo = 55.929444 to 37.518434
-
-                image(pointOne, Icons.Filled.Home)
-
-                //remember feature Id
-                val circleId: FeatureId = circle(pointTwo)
-
-                line(pointOne, pointTwo)
-                text(pointOne, "Home")
-
-                scope.launch {
-                    while (isActive){
-                        delay(200)
-                        //Overwrite a feature with new color
-                        circle(pointTwo, id = circleId, color = Color(Random.nextFloat(), Random.nextFloat(), Random.nextFloat()))
-                    }
-                }
-            }
-        }
-    }
-}
-
-fun main() = application {
-    Window(onCloseRequest = ::exitApplication) {
-        App()
-    }
-}

src/jvmMain/kotlin/centre/sciprog/maps/compose/OpenStreetMapTileProvider.kt

@@ -1,73 +0,0 @@
-package centre.sciprog.maps.compose
-
-import androidx.compose.ui.graphics.ImageBitmap
-import androidx.compose.ui.graphics.toComposeImageBitmap
-import io.ktor.client.HttpClient
-import io.ktor.client.request.get
-import io.ktor.client.statement.readBytes
-import kotlinx.coroutines.*
-import mu.KotlinLogging
-import org.jetbrains.skia.Image
-import java.net.URL
-import java.nio.file.Path
-import kotlin.io.path.*
-import kotlin.math.pow
-
-/**
- * A [MapTileProvider] based on Open Street Map API. With in-memory and file cache
- */
-public class OpenStreetMapTileProvider(private val scope: CoroutineScope, private val client: HttpClient, private val cacheDirectory: Path): MapTileProvider {
-    private val cache = HashMap<TileId, Deferred<ImageBitmap>>()
-
-    private fun TileId.osmUrl() = URL("https://tile.openstreetmap.org/${zoom}/${i}/${j}.png")
-
-    private fun TileId.cacheFilePath() = cacheDirectory.resolve("${zoom}/${i}/${j}.png")
-
-    /**
-     * Download and cache the tile image
-     */
-    private fun downloadImageAsync(id: TileId) = scope.async(Dispatchers.IO) {
-        id.cacheFilePath()?.let { path ->
-            if (path.exists()) {
-                try {
-                    return@async Image.makeFromEncoded(path.readBytes()).toComposeImageBitmap()
-                } catch (ex: Exception) {
-                    logger.debug { "Failed to load image from $path" }
-                    path.deleteIfExists()
-                }
-            }
-        }
-
-        val url = id.osmUrl()
-        val byteArray = client.get(url).readBytes()
-
-        logger.debug { "Finished downloading map tile with id $id from $url" }
-
-        id.cacheFilePath()?.let { path ->
-            logger.debug { "Caching map tile $id to $path" }
-
-            path.parent.createDirectories()
-            path.writeBytes(byteArray)
-        }
-
-        Image.makeFromEncoded(byteArray).toComposeImageBitmap()
-    }
-
-    override suspend fun loadTile(id: TileId): MapTile {
-        val indexRange = indexRange(id.zoom)
-        if(id.i !in indexRange || id.j !in indexRange){
-            error("Indices (${id.i}, ${id.j}) are not in index range $indexRange for zoom ${id.zoom}")
-        }
-
-        val image = cache.getOrPut(id) {
-            downloadImageAsync(id)
-        }.await()
-
-        return MapTile(id, image)
-    }
-
-    companion object{
-        private val logger = KotlinLogging.logger("OpenStreetMapCache")
-        private fun indexRange(zoom: Int): IntRange = 0 until 2.0.pow(zoom).toInt()
-    }
-}