Drag done

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

@@ -7,7 +7,8 @@ import androidx.compose.runtime.*
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.PointMode
-import androidx.compose.ui.input.pointer.isPrimaryPressed
+import androidx.compose.ui.unit.DpSize
+import androidx.compose.ui.unit.dp
 import androidx.compose.ui.window.Window
 import androidx.compose.ui.window.application
 import center.sciprog.maps.compose.*
@@ -51,32 +52,24 @@ fun App() {
 
 
         val pointOne = 55.568548 to 37.568604
-        var pointTwo: Pair<Double, Double> by remember { mutableStateOf(55.929444 to 37.518434) }
+        val pointTwo = 55.929444 to 37.518434
         val pointThree = 60.929444 to 37.518434
+
+        val dragPoint = 55.744 to 37.614
+
         MapView(
             mapTileProvider = mapTileProvider,
             initialViewPoint = viewPoint,
             config = MapViewConfig(
                 inferViewBoxFromFeatures = true,
                 onViewChange = { centerCoordinates = focus },
-                dragHandle = { event, start, end ->
-                    if (!event.buttons.isPrimaryPressed) {
-                        true
-                    } else if (start.focus.latitude.degrees.value in (pointTwo.first - 0.05)..(pointTwo.first + 0.05) &&
-                        start.focus.longitude.degrees.value in (pointTwo.second - 0.05)..(pointTwo.second + 0.05)
-                    ) {
-                        pointTwo = pointTwo.first + (end.focus.latitude - start.focus.latitude).degrees.value to
-                                pointTwo.second + (end.focus.longitude - start.focus.longitude).degrees.value
-                        false// returning false, because when we are dragging circle we don't want to drag map
-                    } else {
-                        true
-                    }
-                }
             )
         ) {
 
             image(pointOne, Icons.Filled.Home)
 
+            rectangle(dragPoint, id = "dragMe", size = DpSize(10.dp, 10.dp)).draggable()
+
             points(
                 points = listOf(
                     55.742465 to 37.615812,
@@ -89,7 +82,7 @@ fun App() {
                 pointMode = PointMode.Polygon
             )
 
-            //remember feature Id
+            //remember feature ID
             val circleId: FeatureId = circle(
                 centerCoordinates = pointTwo,
             )

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

@@ -11,16 +11,20 @@ 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 center.sciprog.maps.coordinates.GeodeticMapCoordinates
+import center.sciprog.maps.coordinates.*
-import center.sciprog.maps.coordinates.GmcRectangle
+import kotlin.math.floor
-import center.sciprog.maps.coordinates.wrapAll
 
 public interface MapFeature {
     public val zoomRange: IntRange
-    public fun getBoundingBox(zoom: Int): GmcRectangle?
+    public fun getBoundingBox(zoom: Double): GmcRectangle?
+
 }
 
-public fun Iterable<MapFeature>.computeBoundingBox(zoom: Int): GmcRectangle? =
+public interface DraggableMapFeature : MapFeature {
+    public fun withCoordinates(newCoordinates: GeodeticMapCoordinates): MapFeature
+}
+
+public fun Iterable<MapFeature>.computeBoundingBox(zoom: Double): GmcRectangle? =
     mapNotNull { it.getBoundingBox(zoom) }.wrapAll()
 
 internal fun Pair<Double, Double>.toCoordinates() = GeodeticMapCoordinates.ofDegrees(first, second)
@@ -35,18 +39,21 @@ public class MapFeatureSelector(
 ) : MapFeature {
     override val zoomRange: IntRange get() = defaultZoomRange
 
-    override fun getBoundingBox(zoom: Int): GmcRectangle? = selector(zoom).getBoundingBox(zoom)
+    override fun getBoundingBox(zoom: Double): GmcRectangle? = selector(floor(zoom).toInt()).getBoundingBox(zoom)
 }
 
 public class MapDrawFeature(
     public val position: GeodeticMapCoordinates,
     override val zoomRange: IntRange = defaultZoomRange,
     public val drawFeature: DrawScope.() -> Unit,
-) : MapFeature {
+) : DraggableMapFeature {
-    override fun getBoundingBox(zoom: Int): GmcRectangle {
+    override fun getBoundingBox(zoom: Double): GmcRectangle {
         //TODO add box computation
         return GmcRectangle(position, position)
     }
+
+    override fun withCoordinates(newCoordinates: GeodeticMapCoordinates): MapFeature =
+        MapDrawFeature(newCoordinates, zoomRange, drawFeature)
 }
 
 public class MapPointsFeature(
@@ -54,9 +61,9 @@ public class MapPointsFeature(
     override val zoomRange: IntRange = defaultZoomRange,
     public val stroke: Float = 2f,
     public val color: Color = Color.Red,
-    public val pointMode: PointMode = PointMode.Points
+    public val pointMode: PointMode = PointMode.Points,
 ) : MapFeature {
-    override fun getBoundingBox(zoom: Int): GmcRectangle {
+    override fun getBoundingBox(zoom: Double): GmcRectangle {
         return GmcRectangle(points.first(), points.last())
     }
 }
@@ -66,8 +73,14 @@ public class MapCircleFeature(
     override val zoomRange: IntRange = defaultZoomRange,
     public val size: Float = 5f,
     public val color: Color = Color.Red,
-) : MapFeature {
+) : DraggableMapFeature {
-    override fun getBoundingBox(zoom: Int): GmcRectangle = GmcRectangle(center, center)
+    override fun getBoundingBox(zoom: Double): GmcRectangle {
+        val scale = WebMercatorProjection.scaleFactor(zoom)
+        return GmcRectangle.square(center, (size/scale).radians, (size/scale).radians)
+    }
+
+    override fun withCoordinates(newCoordinates: GeodeticMapCoordinates): MapFeature =
+        MapCircleFeature(newCoordinates, zoomRange, size, color)
 }
 
 public class MapRectangleFeature(
@@ -75,8 +88,14 @@ public class MapRectangleFeature(
     override val zoomRange: IntRange = defaultZoomRange,
     public val size: DpSize = DpSize(5.dp, 5.dp),
     public val color: Color = Color.Red,
-) : MapFeature {
+) : DraggableMapFeature {
-    override fun getBoundingBox(zoom: Int): GmcRectangle = GmcRectangle(center, center)
+    override fun getBoundingBox(zoom: Double): GmcRectangle {
+        val scale = WebMercatorProjection.scaleFactor(zoom)
+        return GmcRectangle.square(center, (size.height.value/scale).radians, (size.width.value/scale).radians)
+    }
+
+    override fun withCoordinates(newCoordinates: GeodeticMapCoordinates): MapFeature =
+        MapRectangleFeature(newCoordinates, zoomRange, size, color)
 }
 
 public class MapLineFeature(
@@ -85,7 +104,7 @@ public class MapLineFeature(
     override val zoomRange: IntRange = defaultZoomRange,
     public val color: Color = Color.Red,
 ) : MapFeature {
-    override fun getBoundingBox(zoom: Int): GmcRectangle = GmcRectangle(a, b)
+    override fun getBoundingBox(zoom: Double): GmcRectangle = GmcRectangle(a, b)
 }
 
 public class MapArcFeature(
@@ -95,7 +114,7 @@ public class MapArcFeature(
     override val zoomRange: IntRange = defaultZoomRange,
     public val color: Color = Color.Red,
 ) : MapFeature {
-    override fun getBoundingBox(zoom: Int): GmcRectangle = oval
+    override fun getBoundingBox(zoom: Double): GmcRectangle = oval
 }
 
 public class MapBitmapImageFeature(
@@ -103,8 +122,11 @@ public class MapBitmapImageFeature(
     public val image: ImageBitmap,
     public val size: IntSize = IntSize(15, 15),
     override val zoomRange: IntRange = defaultZoomRange,
-) : MapFeature {
+) : DraggableMapFeature {
-    override fun getBoundingBox(zoom: Int): GmcRectangle = GmcRectangle(position, position)
+    override fun getBoundingBox(zoom: Double): GmcRectangle = GmcRectangle(position, position)
+
+    override fun withCoordinates(newCoordinates: GeodeticMapCoordinates): MapFeature =
+        MapBitmapImageFeature(newCoordinates, image, size, zoomRange)
 }
 
 public class MapVectorImageFeature(
@@ -112,8 +134,11 @@ public class MapVectorImageFeature(
     public val painter: Painter,
     public val size: DpSize,
     override val zoomRange: IntRange = defaultZoomRange,
-) : MapFeature {
+) : DraggableMapFeature{
-    override fun getBoundingBox(zoom: Int): GmcRectangle = GmcRectangle(position, position)
+    override fun getBoundingBox(zoom: Double): GmcRectangle = GmcRectangle(position, position)
+
+    override fun withCoordinates(newCoordinates: GeodeticMapCoordinates): MapFeature =
+        MapVectorImageFeature(newCoordinates,painter, size, zoomRange)
 }
 
 @Composable
@@ -131,7 +156,8 @@ public class MapFeatureGroup(
     public val children: Map<FeatureId, MapFeature>,
     override val zoomRange: IntRange = defaultZoomRange,
 ) : MapFeature {
-    override fun getBoundingBox(zoom: Int): GmcRectangle? = children.values.mapNotNull { it.getBoundingBox(zoom) }.wrapAll()
+    override fun getBoundingBox(zoom: Double): GmcRectangle? =
+        children.values.mapNotNull { it.getBoundingBox(zoom) }.wrapAll()
 }
 
 public class MapTextFeature(
@@ -140,6 +166,9 @@ public class MapTextFeature(
     override val zoomRange: IntRange = defaultZoomRange,
     public val color: Color,
     public val fontConfig: MapTextFeatureFont.() -> Unit,
-) : MapFeature {
+) : DraggableMapFeature{
-    override fun getBoundingBox(zoom: Int): GmcRectangle = GmcRectangle(position, position)
+    override fun getBoundingBox(zoom: Double): GmcRectangle = GmcRectangle(position, position)
+
+    override fun withCoordinates(newCoordinates: GeodeticMapCoordinates): MapFeature =
+        MapTextFeature(newCoordinates, text, zoomRange, color, fontConfig)
 }

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

@@ -15,27 +15,53 @@ import center.sciprog.maps.coordinates.GmcRectangle
 
 public typealias FeatureId = String
 
+public interface MapFeatureAttributeKey<T>
+
+
+public class MapFeatureAttributeSet(private val map: Map<MapFeatureAttributeKey<*>, *>) {
+    public operator fun <T> get(key: MapFeatureAttributeKey<*>): T? = map[key]?.let {
+        @Suppress("UNCHECKED_CAST")
+        it as T
+    }
+}
+
 public interface MapFeatureBuilder {
     public fun addFeature(id: FeatureId?, feature: MapFeature): FeatureId
 
-    public fun build(): SnapshotStateMap<FeatureId, MapFeature>
+    public fun <T> setAttribute(id: FeatureId, key: MapFeatureAttributeKey<T>, value: T)
+
+    public val features: MutableMap<FeatureId, MapFeature>
+
+    public fun attributes(): Map<FeatureId, MapFeatureAttributeSet>
+
+    //TODO use context receiver for that
+    public fun FeatureId.draggable(enabled: Boolean = true) {
+        setAttribute(this, DraggableAttribute, enabled)
+    }
 }
 
-internal class MapFeatureBuilderImpl(initialFeatures: Map<FeatureId, MapFeature>) : MapFeatureBuilder {
+internal class MapFeatureBuilderImpl(
+    override val features: SnapshotStateMap<FeatureId, MapFeature>,
+) : MapFeatureBuilder {
+
+    private val attributes = SnapshotStateMap<FeatureId, SnapshotStateMap<MapFeatureAttributeKey<out Any?>, in Any?>>()
 
-    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 {
         val safeId = id ?: generateID(feature)
-        content[id ?: generateID(feature)] = feature
+        features[id ?: generateID(feature)] = feature
         return safeId
     }
 
-    override fun build(): SnapshotStateMap<FeatureId, MapFeature> = content
+    override fun <T> setAttribute(id: FeatureId, key: MapFeatureAttributeKey<T>, value: T) {
+        attributes.getOrPut(id) { SnapshotStateMap() }[key] = value
+    }
+
+    override fun attributes(): Map<FeatureId, MapFeatureAttributeSet> =
+        attributes.mapValues { MapFeatureAttributeSet(it.value) }
+
 }
 
 public fun MapFeatureBuilder.circle(
@@ -123,7 +149,7 @@ public fun MapFeatureBuilder.points(
     stroke: Float = 2f,
     color: Color = Color.Red,
     pointMode: PointMode = PointMode.Points,
-    id: FeatureId? = null
+    id: FeatureId? = null,
 ): FeatureId = addFeature(id, MapPointsFeature(points.map { it.toCoordinates() }, zoomRange, stroke, color, pointMode))
 
 @Composable
@@ -140,7 +166,7 @@ public fun MapFeatureBuilder.group(
     id: FeatureId? = null,
     builder: MapFeatureBuilder.() -> Unit,
 ): FeatureId {
-    val map = MapFeatureBuilderImpl(emptyMap()).apply(builder).build()
+    val map = MapFeatureBuilderImpl(mutableStateMapOf()).apply(builder).features
     val feature = MapFeatureGroup(map, zoomRange)
     return addFeature(id, feature)
 }

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

@@ -1,9 +1,10 @@
 package center.sciprog.maps.compose
 
 import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.runtime.Composable
+import androidx.compose.runtime.*
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.input.pointer.PointerEvent
+import androidx.compose.ui.input.pointer.isPrimaryPressed
 import androidx.compose.ui.unit.DpSize
 import center.sciprog.maps.coordinates.*
 import kotlin.math.PI
@@ -19,10 +20,33 @@ public fun interface DragHandle {
      *
      * @return true if default event processors should be used after this one
      */
-    public fun drag(event: PointerEvent, start: MapViewPoint, end: MapViewPoint): Boolean
+    public fun handle(event: PointerEvent, start: MapViewPoint, end: MapViewPoint): Boolean
 
     public companion object {
         public val BYPASS: DragHandle = DragHandle { _, _, _ -> true }
+
+        /**
+         * Process only events with primary button pressed
+         */
+        public fun withPrimaryButton(
+            block: (event: PointerEvent, start: MapViewPoint, end: MapViewPoint) -> Boolean,
+        ): DragHandle = DragHandle { event, start, end ->
+            if (event.buttons.isPrimaryPressed) {
+                block(event, start, end)
+            } else {
+                false
+            }
+        }
+
+        /**
+         * Combine several handles into one
+         */
+        public fun combine(vararg handles: DragHandle): DragHandle = DragHandle { event, start, end ->
+            handles.forEach {
+                if (!it.handle(event, start, end)) return@DragHandle false
+            }
+            return@DragHandle true
+        }
     }
 }
 
@@ -49,53 +73,83 @@ public expect fun MapView(
     modifier: Modifier = Modifier.fillMaxSize(),
 )
 
+private fun prepareConfig(initialConfig: MapViewConfig, featureBuilder: MapFeatureBuilder): MapViewConfig {
+    val draggableFeatureIds: Set<FeatureId> = featureBuilder.attributes().filterValues {
+        it[DraggableAttribute] ?: false
+    }.keys
+
+    val features = featureBuilder.features
+
+    val featureDrag = DragHandle.withPrimaryButton { _, start, end ->
+        val zoom = start.zoom
+        draggableFeatureIds.forEach { id ->
+            val feature = features[id] as? DraggableMapFeature ?: return@forEach
+            //val border = WebMercatorProjection.scaleFactor(zoom)
+            val boundingBox = feature.getBoundingBox(zoom) ?: return@forEach
+            if (start.focus in boundingBox) {
+                features[id] = feature.withCoordinates(end.focus)
+                return@withPrimaryButton false
+            }
+        }
+        return@withPrimaryButton true
+    }
+    return initialConfig.copy(
+        dragHandle = DragHandle.combine(featureDrag, initialConfig.dragHandle),
+    )
+}
+
 @Composable
 public fun MapView(
     mapTileProvider: MapTileProvider,
     initialViewPoint: MapViewPoint,
-    features: Map<FeatureId, MapFeature> = emptyMap(),
     config: MapViewConfig = MapViewConfig(),
     modifier: Modifier = Modifier.fillMaxSize(),
     buildFeatures: @Composable (MapFeatureBuilder.() -> Unit) = {},
 ) {
-    val featuresBuilder = MapFeatureBuilderImpl(features)
+    val featuresBuilder = MapFeatureBuilderImpl(mutableStateMapOf())
     featuresBuilder.buildFeatures()
+    val features = remember { featuresBuilder.features }
+
+    val newConfig = remember(features) {
+        prepareConfig(config, featuresBuilder)
+    }
+
     MapView(
         mapTileProvider,
         { initialViewPoint },
-        featuresBuilder.build(),
+        features,
-        config,
+        newConfig,
         modifier
     )
 }
 
-internal fun GmcRectangle.computeViewPoint(mapTileProvider: MapTileProvider): (canvasSize: DpSize) -> MapViewPoint =
+internal fun GmcRectangle.computeViewPoint(
-    { canvasSize ->
-        val zoom = log2(
-            min(
-                canvasSize.width.value / longitudeDelta.radians.value,
-                canvasSize.height.value / latitudeDelta.radians.value
-            ) * PI / mapTileProvider.tileSize
-        )
-        MapViewPoint(center, zoom)
-    }
-
-@Composable
-public fun MapView(
     mapTileProvider: MapTileProvider,
-    box: GmcRectangle,
+): (canvasSize: DpSize) -> MapViewPoint = { canvasSize ->
-    features: Map<FeatureId, MapFeature> = emptyMap(),
+    val zoom = log2(
-    config: MapViewConfig = MapViewConfig(),
+        min(
-    modifier: Modifier = Modifier.fillMaxSize(),
+            canvasSize.width.value / longitudeDelta.radians.value,
-    buildFeatures: @Composable (MapFeatureBuilder.() -> Unit) = {},
+            canvasSize.height.value / latitudeDelta.radians.value
-) {
+        ) * PI / mapTileProvider.tileSize
-    val featuresBuilder = MapFeatureBuilderImpl(features)
-    featuresBuilder.buildFeatures()
-    MapView(
-        mapTileProvider,
-        box.computeViewPoint(mapTileProvider),
-        featuresBuilder.build(),
-        config,
-        modifier
     )
-}
+    MapViewPoint(center, zoom)
+}
+//
+//@Composable
+//public fun MapView(
+//    mapTileProvider: MapTileProvider,
+//    box: GmcRectangle,
+//    config: MapViewConfig = MapViewConfig(),
+//    modifier: Modifier = Modifier.fillMaxSize(),
+//    buildFeatures: @Composable (MapFeatureBuilder.() -> Unit) = {},
+//) {
+//    val builder by derivedStateOf { MapFeatureBuilderImpl().apply(buildFeatures) }
+//
+//    MapView(
+//        mapTileProvider,
+//        box.computeViewPoint(mapTileProvider),
+//        builder.features,
+//        prepareConfig(config, builder),
+//        modifier
+//    )
+//}

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

@@ -0,0 +1,3 @@
+package center.sciprog.maps.compose
+
+public object DraggableAttribute: MapFeatureAttributeKey<Boolean>

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

@@ -5,6 +5,7 @@ import androidx.compose.foundation.gestures.drag
 import androidx.compose.foundation.gestures.forEachGesture
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.*
+import androidx.compose.runtime.snapshots.SnapshotStateMap
 import androidx.compose.ui.ExperimentalComposeUiApi
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.geometry.Offset
@@ -66,7 +67,7 @@ public actual fun MapView(
 
     val viewPoint: MapViewPoint by derivedStateOf {
         viewPointInternal ?: if (config.inferViewBoxFromFeatures) {
-            features.values.computeBoundingBox(1)?.let { box ->
+            features.values.computeBoundingBox(1.0)?.let { box ->
                 val zoom = log2(
                     min(
                         canvasSize.width.value / box.longitudeDelta.radians.value,
@@ -132,8 +133,9 @@ public actual fun MapView(
                         )
                         val dpEnd = DpOffset(dragChange.position.x.toDp(), dragChange.position.y.toDp())
 
+                        //apply drag handle and check if it prohibits the drag even propagation
                         if (
-                            !config.dragHandle.drag(
+                            !config.dragHandle.handle(
                                 event,
                                 MapViewPoint(dpStart.toGeodetic(), viewPoint.zoom),
                                 MapViewPoint(dpEnd.toGeodetic(), viewPoint.zoom)

maps-kt-core/src/commonMain/kotlin/center/sciprog/maps/coordinates/GeodeticMapCoordinates.kt

@@ -50,7 +50,7 @@ public class GeodeticMapCoordinates(
 /**
  * Short name for GeodeticMapCoordinates
  */
-public typealias GMC = GeodeticMapCoordinates
+public typealias Gmc = GeodeticMapCoordinates
 
 //public interface GeoToScreenConversion {
 //    public fun getScreenX(gmc: GeodeticMapCoordinates): Double

maps-kt-core/src/commonMain/kotlin/center/sciprog/maps/coordinates/GmcCurve.kt

@@ -57,8 +57,8 @@ public fun GeoEllipsoid.meridianCurve(
     }
 
     return GmcCurve(
-        forward = GmcPose(GMC(fromLatitude, longitude), if (up) zero else pi),
+        forward = GmcPose(Gmc(fromLatitude, longitude), if (up) zero else pi),
-        backward = GmcPose(GMC(toLatitude, longitude), if (up) pi else zero),
+        backward = GmcPose(Gmc(toLatitude, longitude), if (up) pi else zero),
         distance = s
     )
 }
@@ -70,8 +70,8 @@ public fun GeoEllipsoid.parallelCurve(latitude: Angle, fromLongitude: Angle, toL
     require(latitude in (-piDiv2)..(piDiv2)) { "Latitude must be in (-90, 90) degrees range" }
     val right = toLongitude > fromLongitude
     return GmcCurve(
-        forward = GmcPose(GMC(latitude, fromLongitude), if (right) piDiv2.radians else -piDiv2.radians),
+        forward = GmcPose(Gmc(latitude, fromLongitude), if (right) piDiv2.radians else -piDiv2.radians),
-        backward = GmcPose(GMC(latitude, toLongitude), if (right) -piDiv2.radians else piDiv2.radians),
+        backward = GmcPose(Gmc(latitude, toLongitude), if (right) -piDiv2.radians else piDiv2.radians),
         distance = reducedRadius(latitude) * abs((fromLongitude - toLongitude).radians.value)
     )
 }
@@ -186,7 +186,7 @@ public fun GeoEllipsoid.curveInDirection(
     val L = lambda - (1 - C) * f * sinAlpha *
             (sigma.value + C * sinSigma * (cosSigmaM2 + C * cosSigma * (-1 + 2 * cos2SigmaM2)))
 
-    val endPoint = GMC(phi2, L.radians)
+    val endPoint = Gmc(phi2, L.radians)
 
     // eq. 12
 
@@ -212,7 +212,7 @@ public fun GeoEllipsoid.curveInDirection(
  * @return solution to the inverse geodetic problem
  */
 @Suppress("SpellCheckingInspection", "LocalVariableName")
-public fun GeoEllipsoid.curveBetween(start: GMC, end: GMC, precision: Double = 1e-6): GmcCurve {
+public fun GeoEllipsoid.curveBetween(start: Gmc, end: Gmc, precision: Double = 1e-6): GmcCurve {
     //
     // All equation numbers refer back to Vincenty's publication:
     // See http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf

maps-kt-core/src/commonMain/kotlin/center/sciprog/maps/coordinates/GmcRectangle.kt

@@ -9,29 +9,39 @@ package center.sciprog.maps.coordinates
 public data class GmcRectangle(
     public val a: GeodeticMapCoordinates,
     public val b: GeodeticMapCoordinates,
-    public val ellipsoid: GeoEllipsoid = GeoEllipsoid.WGS84,
 ) {
     public companion object {
 
+        /**
+         * A quasi-square section.
+         */
+        public fun square(
+            center: GeodeticMapCoordinates,
+            height: Angle,
+            width: Angle,
+        ): GmcRectangle {
+            val a = GeodeticMapCoordinates(
+                center.latitude - (height / 2),
+                center.longitude - (width / 2)
+            )
+            val b = GeodeticMapCoordinates(
+                center.latitude + (height / 2),
+                center.longitude + (width / 2)
+            )
+            return GmcRectangle(a, b)
+        }
+
         /**
          * A quasi-square section. Note that latitudinal distance could be imprecise for large distances
          */
         public fun square(
             center: GeodeticMapCoordinates,
-            width: Distance,
             height: Distance,
+            width: Distance,
             ellipsoid: GeoEllipsoid = GeoEllipsoid.WGS84,
         ): GmcRectangle {
             val reducedRadius = ellipsoid.reducedRadius(center.latitude)
-            val a = GeodeticMapCoordinates(
+            return square(center, (height / ellipsoid.polarRadius).radians, (width / reducedRadius).radians)
-                center.latitude - (height / ellipsoid.polarRadius / 2).radians,
-                center.longitude - (width / reducedRadius / 2).radians
-            )
-            val b = GeodeticMapCoordinates(
-                center.latitude + (height / ellipsoid.polarRadius / 2).radians,
-                center.longitude + (width / reducedRadius / 2).radians
-            )
-            return GmcRectangle(a, b, ellipsoid)
         }
     }
 }
@@ -68,6 +78,30 @@ public val GmcRectangle.latitudeDelta: Angle get() = abs(a.latitude - b.latitude
 public val GmcRectangle.topLeft: GeodeticMapCoordinates get() = GeodeticMapCoordinates(top, left)
 public val GmcRectangle.bottomRight: GeodeticMapCoordinates get() = GeodeticMapCoordinates(bottom, right)
 
+//public fun GmcRectangle.enlarge(
+//    top: Distance,
+//    bottom: Distance = top,
+//    left: Distance = top,
+//    right: Distance = left,
+//): GmcRectangle {
+//
+//}
+//
+//public fun GmcRectangle.enlarge(
+//    top: Angle,
+//    bottom: Angle = top,
+//    left: Angle = top,
+//    right: Angle = left,
+//): GmcRectangle {
+//
+//}
+
+/**
+ * Check if coordinate is inside the box
+ */
+public operator fun GmcRectangle.contains(coordinate: Gmc): Boolean =
+    coordinate.latitude in (bottom..top) && coordinate.longitude in (left..right)
+
 /**
  * Compute a minimal bounding box including all given boxes. Return null if collection is empty
  */