Merge TAVRIDA-MR-4: feature/boundbox

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

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

@@ -0,0 +1,41 @@
+package centre.sciprog.maps
+
+import androidx.compose.ui.unit.DpSize
+import centre.sciprog.maps.compose.MapFeature
+import kotlin.math.*
+
+class GmcBox(val a: GeodeticMapCoordinates, val b: GeodeticMapCoordinates)
+
+fun GmcBox(latitudes: ClosedFloatingPointRange<Double>, longitudes: ClosedFloatingPointRange<Double>) = GmcBox(
+    Gmc.ofRadians(latitudes.start, longitudes.start),
+    Gmc.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)
+}

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

@@ -15,7 +15,11 @@ 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 {

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

@@ -9,9 +9,15 @@ import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.graphics.vector.rememberVectorPainter
 import androidx.compose.ui.unit.IntSize
 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? = map { it.getBoundingBox(zoom) }.wrapAll()
 
 internal fun Pair<Double, Double>.toCoordinates() = GeodeticMapCoordinates.ofDegrees(first, second)
 
@@ -20,35 +26,46 @@ 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 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 (
@@ -56,7 +73,9 @@ class MapVectorImageFeature (
     val painter: Painter,
     val size: Size,
     zoomRange: IntRange = defaultZoomRange,
-) : MapFeature(zoomRange)
+) : MapFeature(zoomRange) {
+    override fun getBoundingBox(zoom: Int): GmcBox = GmcBox(position, position)
+}
 
 @Composable
 fun MapVectorImageFeature(

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

@@ -3,18 +3,22 @@ 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 androidx.compose.ui.unit.DpSize
-import centre.sciprog.maps.MapViewPoint
+import centre.sciprog.maps.*
+import kotlin.math.PI
+import kotlin.math.log2
+import kotlin.math.min
 
 
 data class MapViewConfig(
     val zoomSpeed: Double = 1.0 / 3.0,
+    val inferViewBoxFromFeatures: Boolean = false
 )
 
 @Composable
 expect fun MapView(
-    initialViewPoint: MapViewPoint,
     mapTileProvider: MapTileProvider,
+    computeViewPoint: (canvasSize: DpSize) -> MapViewPoint,
     features: Map<FeatureId, MapFeature>,
     onClick: (GeodeticMapCoordinates) -> Unit = {},
     //TODO consider replacing by modifier
@@ -24,14 +28,39 @@ expect fun MapView(
 
 @Composable
 fun MapView(
-    initialViewPoint: MapViewPoint,
     mapTileProvider: MapTileProvider,
+    initialViewPoint: MapViewPoint,
+    features: Map<FeatureId, MapFeature> = emptyMap(),
     onClick: (GeodeticMapCoordinates) -> Unit = {},
     config: MapViewConfig = MapViewConfig(),
     modifier: Modifier = Modifier.fillMaxSize(),
-    addFeatures: @Composable() (FeatureBuilder.() -> Unit) = {},
+    buildFeatures: @Composable (FeatureBuilder.() -> Unit) = {},
 ) {
-    val featuresBuilder = MapFeatureBuilder()
+    val featuresBuilder = MapFeatureBuilder(features)
-    featuresBuilder.addFeatures()
+    featuresBuilder.buildFeatures()
-    MapView(initialViewPoint, mapTileProvider, featuresBuilder.build(), onClick, config, modifier)
+    MapView(mapTileProvider, { initialViewPoint }, featuresBuilder.build(), onClick, config, modifier)
+}
+
+@Composable
+fun MapView(
+    mapTileProvider: MapTileProvider,
+    box: GmcBox,
+    features: Map<FeatureId, MapFeature> = emptyMap(),
+    onClick: (GeodeticMapCoordinates) -> Unit = {},
+    config: MapViewConfig = MapViewConfig(),
+    modifier: Modifier = Modifier.fillMaxSize(),
+    buildFeatures: @Composable (FeatureBuilder.() -> Unit) = {},
+) {
+    val featuresBuilder = MapFeatureBuilder(features)
+    featuresBuilder.buildFeatures()
+    val computeViewPoint: (canvasSize: DpSize) -> MapViewPoint = { canvasSize ->
+        val zoom = log2(
+            min(
+                canvasSize.width.value / box.width,
+                canvasSize.height.value / box.height
+            ) * PI / mapTileProvider.tileSize
+        )
+        MapViewPoint(box.center, zoom)
+    }
+    MapView(mapTileProvider, computeViewPoint, featuresBuilder.build(), onClick, config, modifier)
 }

src/jvmMain/kotlin/Main.kt

@@ -40,7 +40,12 @@ fun App() {
         Column {
             //display click coordinates
             Text(coordinates?.toString() ?: "")
-            MapView(viewPoint, mapTileProvider, onClick = { gmc: GeodeticMapCoordinates -> coordinates = gmc }) {
+            MapView(
+                mapTileProvider,
+                viewPoint,
+                onClick = { gmc -> coordinates = gmc },
+                config = MapViewConfig(inferViewBoxFromFeatures = true)
+            ) {
                 val pointOne = 55.568548 to 37.568604
                 val pointTwo = 55.929444 to 37.518434
 
@@ -56,7 +61,11 @@ fun App() {
                     while (isActive) {
                         delay(200)
                         //Overwrite a feature with new color
-                        circle(pointTwo, id = circleId, color = Color(Random.nextFloat(), Random.nextFloat(), Random.nextFloat()))
+                        circle(
+                            pointTwo,
+                            id = circleId,
+                            color = Color(Random.nextFloat(), Random.nextFloat(), Random.nextFloat())
+                        )
                     }
                 }
             }

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

@@ -21,10 +21,7 @@ import kotlinx.coroutines.launch
 import mu.KotlinLogging
 import org.jetbrains.skia.Font
 import org.jetbrains.skia.Paint
-import kotlin.math.ceil
+import kotlin.math.*
-import kotlin.math.floor
-import kotlin.math.log2
-import kotlin.math.pow
 
 
 private fun Color.toPaint(): Paint = Paint().apply {
@@ -40,15 +37,32 @@ private val logger = KotlinLogging.logger("MapView")
 @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 by remember { mutableStateOf<MapViewPoint?>(
+        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() }
 
@@ -56,9 +70,6 @@ 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(
@@ -103,7 +114,10 @@ actual fun MapView(
                                 val verticalZoom: Float = log2(canvasSize.height.toPx() / rect.height)
 
 
-                                viewPoint = MapViewPoint(centerGmc, viewPoint.zoom + kotlin.math.min(verticalZoom, horizontalZoom))
+                                viewPointOverride = MapViewPoint(
+                                    centerGmc,
+                                    viewPoint.zoom + kotlin.math.min(verticalZoom, horizontalZoom)
+                                )
                                 selectRect = null
                             }
                         } else {
@@ -112,7 +126,7 @@ actual fun MapView(
                             onClick(dpPos.toGeodetic())
                             drag(change.id) { dragChange ->
                                 val dragAmount = dragChange.position - dragChange.previousPosition
-                                viewPoint = viewPoint.move(
+                                viewPointOverride = viewPoint.move(
                                     -dragAmount.x.toDp().value / tileScale,
                                     +dragAmount.y.toDp().value / tileScale
                                 )
@@ -127,7 +141,7 @@ 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)
+        viewPointOverride = viewPoint.zoom(-change.scrollDelta.y.toDouble() * config.zoomSpeed, invariant)
     }.fillMaxSize()