demo/maps/src/jvmMain/kotlin/AngleConversion.kt

@@ -2,3 +2,5 @@ import kotlin.math.PI
 
 fun Double.toDegrees() = this * 180 / PI
 
+fun Double.toRadians() = this * PI / 180
+

demo/maps/src/jvmMain/kotlin/Main.kt

@@ -5,16 +5,12 @@ 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.graphics.PointMode
 import androidx.compose.ui.window.Window
 import androidx.compose.ui.window.application
 import center.sciprog.maps.compose.*
-import center.sciprog.maps.coordinates.Distance
-import center.sciprog.maps.coordinates.GeodeticMapCoordinates
-import center.sciprog.maps.coordinates.GmcBox
-import center.sciprog.maps.coordinates.MapViewPoint
+import center.sciprog.maps.coordinates.*
 import io.ktor.client.HttpClient
 import io.ktor.client.engine.cio.CIO
 import kotlinx.coroutines.delay
@@ -54,24 +50,11 @@ fun App() {
         val pointOne = 55.568548 to 37.568604
         var pointTwo by remember { mutableStateOf(55.929444 to 37.518434) }
         val pointThree = 60.929444 to 37.518434
+
         val state = MapViewState(
             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// returning false, because when we are dragging circle we don't want to drag map
-                    } else true
-                }
-            )
+            initialViewPoint = { viewPoint },
         ) {
-
             image(pointOne, Icons.Filled.Home)
 
             points(
@@ -132,8 +115,28 @@ fun App() {
                 }
             }
         }
+
+        val config = MapViewConfig(
+            onViewChange = { centerCoordinates = focus },
+            onDrag = { start, end ->
+                val markerRadius = 5f
+                val startPosition = with(state) { start.focus.toOffset(this@MapViewConfig) }
+                val markerLocation = with(state) {
+                    GeodeticMapCoordinates.ofDegrees(pointTwo.first, pointTwo.second).toOffset(this@MapViewConfig)
+                }
+                if (startPosition.x in (markerLocation.x - markerRadius)..(markerLocation.x + markerRadius) &&
+                    startPosition.y in (markerLocation.y - markerRadius)..(markerLocation.y + markerRadius)
+                ) {
+                    pointTwo = pointTwo.first + (end.focus.latitude - start.focus.latitude).toDegrees() to
+                            pointTwo.second + (end.focus.longitude - start.focus.longitude).toDegrees()
+                    false// returning false, because when we are dragging circle we don't want to drag map
+                } else true
+            }
+        )
+
         MapView(
-            mapViewState = state
+            mapViewState = state,
+            mapViewConfig = config
         )
     }
 }

maps-kt-compose/src/commonMain/kotlin/center/sciprog/maps/compose/MapTextFeature.kt

@@ -1,10 +1,15 @@
 package center.sciprog.maps.compose
 
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.NativeCanvas
 import center.sciprog.maps.coordinates.GeodeticMapCoordinates
 import center.sciprog.maps.coordinates.GmcBox
-import org.jetbrains.skia.Font
 
+public expect class Font constructor() {
+    public var size: Float
+}
+
+public expect fun NativeCanvas.drawString(text: String, x: Float, y: Float, font: Font, color: Color)
 
 public class MapTextFeature(
     public val position: GeodeticMapCoordinates,

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

@@ -3,6 +3,7 @@ package center.sciprog.maps.compose
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.Density
 import androidx.compose.ui.unit.DpSize
 import center.sciprog.maps.coordinates.*
 import kotlin.math.PI
@@ -17,9 +18,8 @@ import kotlin.math.min
  */
 public data class MapViewConfig(
     val zoomSpeed: Double = 1.0 / 3.0,
-    val inferViewBoxFromFeatures: Boolean = false,
     val onClick: MapViewPoint.() -> Unit = {},
-    val onDrag: (start: MapViewPoint, end: MapViewPoint) -> Boolean = { _, _ -> true },
+    val onDrag: Density.(start: MapViewPoint, end: MapViewPoint) -> Boolean = { _, _ -> true },
     val onViewChange: MapViewPoint.() -> Unit = {},
     val onSelect: (GmcBox) -> Unit = {},
     val zoomOnSelect: Boolean = true,
@@ -28,8 +28,9 @@ public data class MapViewConfig(
 
 @Composable
 public expect fun MapView(
-    mapViewState: MapViewState,
     modifier: Modifier = Modifier,
+    mapViewState: MapViewState,
+    mapViewConfig: MapViewConfig,
 )
 
 @Composable
@@ -46,10 +47,10 @@ public fun MapView(
     MapView(
         mapViewState = MapViewState(
             mapTileProvider = mapTileProvider,
-            computeViewPoint = { initialViewPoint },
+            initialViewPoint = { initialViewPoint },
             features = featuresBuilder.build(),
-            config = config,
         ),
+        mapViewConfig = config,
         modifier = modifier
     )
 }
@@ -78,11 +79,11 @@ public fun MapView(
     featuresBuilder.buildFeatures()
     MapView(
         mapViewState = MapViewState(
-            config = config,
             mapTileProvider = mapTileProvider,
             features = featuresBuilder.build(),
-            computeViewPoint = box.computeViewPoint(mapTileProvider),
+            initialViewPoint = box.computeViewPoint(mapTileProvider),
         ),
-        modifier
+        modifier = modifier,
+        mapViewConfig = config,
     )
 }

maps-kt-compose/src/commonMain/kotlin/center/sciprog/maps/compose/MapViewState.kt

@@ -15,37 +15,37 @@ import androidx.compose.ui.unit.DpOffset
 import androidx.compose.ui.unit.DpSize
 import androidx.compose.ui.unit.dp
 import center.sciprog.maps.coordinates.*
-import center.sciprog.maps.coordinates.MercatorProjection.Companion.toMercator
+import mu.KotlinLogging
 import kotlin.math.*
 
 @Composable
 public fun MapViewState(
-    computeViewPoint: (canvasSize: DpSize) -> MapViewPoint,
+    initialViewPoint: (canvasSize: DpSize) -> MapViewPoint,
     mapTileProvider: MapTileProvider,
-    config: MapViewConfig = MapViewConfig(),
     features: Map<FeatureId, MapFeature> = emptyMap(),
+    inferViewBoxFromFeatures: Boolean = false,
     buildFeatures: @Composable (MapFeatureBuilder.() -> Unit) = {},
 ): MapViewState {
     val featuresBuilder = MapFeatureBuilderImpl(features)
     featuresBuilder.buildFeatures()
     return MapViewState(
-        computeViewPoint = computeViewPoint,
+        initialViewPoint = initialViewPoint,
         mapTileProvider = mapTileProvider,
-        config = config,
-        features = featuresBuilder.build()
+        features = featuresBuilder.build(),
+        inferViewBoxFromFeatures = inferViewBoxFromFeatures
     )
 }
 
 public class MapViewState(
-    public val computeViewPoint: (canvasSize: DpSize) -> MapViewPoint,
+    public val initialViewPoint: (canvasSize: DpSize) -> MapViewPoint,
     public val mapTileProvider: MapTileProvider,
-    public val config: MapViewConfig = MapViewConfig(),
     public val features: Map<FeatureId, MapFeature> = emptyMap(),
+    inferViewBoxFromFeatures: Boolean = false,
 ) {
     public var canvasSize: DpSize by mutableStateOf(DpSize(512.dp, 512.dp))
     public var viewPointInternal: MapViewPoint? by mutableStateOf(null)
     public val viewPoint: MapViewPoint by derivedStateOf {
-        viewPointInternal ?: if (config.inferViewBoxFromFeatures) {
+        viewPointInternal ?: if (inferViewBoxFromFeatures) {
             features.values.computeBoundingBox(1)?.let { box ->
                 val zoom = log2(
                     min(
@@ -54,9 +54,9 @@ public class MapViewState(
                     ) * PI / mapTileProvider.tileSize
                 )
                 MapViewPoint(box.center, zoom)
-            } ?: computeViewPoint(canvasSize)
+            } ?: initialViewPoint(canvasSize)
         } else {
-            computeViewPoint(canvasSize)
+            initialViewPoint(canvasSize)
         }
     }
     public val zoom: Int by derivedStateOf { floor(viewPoint.zoom).toInt() }
@@ -101,6 +101,8 @@ public class MapViewState(
     public fun GeodeticMapCoordinates.toOffset(density: Density): Offset =
         WebMercatorProjection.toMercator(this, zoom).toOffset(density)
 
+    private val logger = KotlinLogging.logger("MapViewState")
+
     public fun DrawScope.drawFeature(zoom: Int, feature: MapFeature) {
         when (feature) {
             is MapFeatureSelector -> drawFeature(zoom, feature.selector(zoom))
@@ -147,17 +149,17 @@ public class MapViewState(
                 }
             }
             is MapTextFeature -> drawIntoCanvas { canvas ->
-                val offset = toOffset(feature.position, mapViewState)
+                val offset = feature.position.toOffset(this@drawFeature)
                 canvas.nativeCanvas.drawString(
                     feature.text,
                     offset.x + 5,
                     offset.y - 5,
                     Font().apply(feature.fontConfig),
-                    feature.color.toPaint()
+                    feature.color
                 )
             }
             is MapDrawFeature -> {
-                val offset = toOffset(feature.position, mapViewState)
+                val offset = feature.position.toOffset(this)
                 translate(offset.x, offset.y) {
                     feature.drawFeature(this)
                 }

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

@@ -0,0 +1,23 @@
+package center.sciprog.maps.compose
+
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.NativeCanvas
+import androidx.compose.ui.graphics.toArgb
+import org.jetbrains.skia.Paint
+
+public actual typealias Font = org.jetbrains.skia.Font
+
+public actual fun NativeCanvas.drawString(
+    text: String,
+    x: Float,
+    y: Float,
+    font: Font,
+    color: Color
+) {
+    drawString(text, x, y, font, color.toPaint())
+}
+
+private fun Color.toPaint(): Paint = Paint().apply {
+    isAntiAlias = true
+    color = toArgb()
+}

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

@@ -17,15 +17,10 @@ import center.sciprog.maps.coordinates.*
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.launch
 import mu.KotlinLogging
-import org.jetbrains.skia.Font
-import org.jetbrains.skia.Paint
 import kotlin.math.*
 
 
-private fun Color.toPaint(): Paint = Paint().apply {
-    isAntiAlias = true
-    color = toArgb()
-}
+
 
 private fun IntRange.intersect(other: IntRange) = max(first, other.first)..min(last, other.last)
 
@@ -48,8 +43,9 @@ private val logger = KotlinLogging.logger("MapView")
 
 @Composable
 public actual fun MapView(
-    mapViewState: MapViewState,
     modifier: Modifier,
+    mapViewState: MapViewState,
+    mapViewConfig: MapViewConfig,
 ) {
     with(mapViewState) {
         @OptIn(ExperimentalComposeUiApi::class)
@@ -82,11 +78,11 @@ public actual fun MapView(
                                             rect.bottomRight.toDpOffset().toGeodetic()
                                         )
 
-                                    config.onSelect(gmcBox)
-                                    if (config.zoomOnSelect) {
+                                    mapViewConfig.onSelect(gmcBox)
+                                    if (mapViewConfig.zoomOnSelect) {
                                         val newViewPoint = gmcBox.computeViewPoint(mapTileProvider).invoke(canvasSize)
 
-                                        config.onViewChange(newViewPoint)
+                                        mapViewConfig.onViewChange(newViewPoint)
                                         viewPointInternal = newViewPoint
                                     }
                                     selectRect = null
@@ -94,7 +90,7 @@ public actual fun MapView(
                             } else {
                                 val dragStart = change.position
                                 val dpPos = DpOffset(dragStart.x.toDp(), dragStart.y.toDp())
-                                config.onClick(
+                                mapViewConfig.onClick(
                                     MapViewPoint(
                                          dpPos.toGeodetic() ,
                                         viewPoint.zoom
@@ -108,7 +104,8 @@ public actual fun MapView(
                                             dragChange.previousPosition.y.toDp()
                                         )
                                     val dpEnd = DpOffset(dragChange.position.x.toDp(), dragChange.position.y.toDp())
-                                    if (!config.onDrag(
+                                    if (!mapViewConfig.onDrag(
+                                            this,
                                             MapViewPoint(dpStart.toGeodetic(), viewPoint.zoom),
                                             MapViewPoint(dpEnd.toGeodetic(), viewPoint.zoom)
                                         )
@@ -117,7 +114,7 @@ public actual fun MapView(
                                         -dragAmount.x.toDp().value / tileScale,
                                         +dragAmount.y.toDp().value / tileScale
                                     )
-                                    config.onViewChange(newViewPoint)
+                                    mapViewConfig.onViewChange(newViewPoint)
                                     viewPointInternal = newViewPoint
                                 }
                             }
@@ -130,8 +127,8 @@ public actual fun MapView(
             val (xPos, yPos) = change.position
             //compute invariant point of translation
             val invariant = DpOffset(xPos.toDp(), yPos.toDp()).toGeodetic()
-            val newViewPoint = viewPoint.zoom(-change.scrollDelta.y.toDouble() * config.zoomSpeed, invariant)
-            config.onViewChange(newViewPoint)
+            val newViewPoint = viewPoint.zoom(-change.scrollDelta.y.toDouble() * mapViewConfig.zoomSpeed, invariant)
+            mapViewConfig.onViewChange(newViewPoint)
             viewPointInternal = newViewPoint
         }.fillMaxSize()