package center.sciprog.maps.compose import androidx.compose.foundation.layout.fillMaxSize 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 androidx.compose.ui.unit.dp import center.sciprog.maps.coordinates.* import kotlin.math.PI import kotlin.math.log2 import kotlin.math.min public fun interface DragHandle { /** * @param event - qualifiers of the event used for drag * @param start - is a point where drag begins, end is a point where drag ends * @param end - end point of the drag * * @return true if default event processors should be used after this one */ 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 } } } //TODO consider replacing by modifier /** */ public data class MapViewConfig( val zoomSpeed: Double = 1.0 / 3.0, val onClick: MapViewPoint.(PointerEvent) -> Unit = {}, val dragHandle: DragHandle = DragHandle.BYPASS, val onViewChange: MapViewPoint.() -> Unit = {}, val onSelect: (GmcRectangle) -> Unit = {}, val zoomOnSelect: Boolean = true, val onCanvasSizeChange: (DpSize) -> Unit = {}, ) @Composable public expect fun MapView( mapTileProvider: MapTileProvider, initialViewPoint: MapViewPoint, features: MapFeaturesState, config: MapViewConfig = MapViewConfig(), modifier: Modifier = Modifier.fillMaxSize(), ) internal fun GmcRectangle.computeViewPoint( mapTileProvider: MapTileProvider, canvasSize: DpSize, ): MapViewPoint { val zoom = log2( min( canvasSize.width.value / longitudeDelta.radians.value, canvasSize.height.value / latitudeDelta.radians.value ) * PI / mapTileProvider.tileSize ) return MapViewPoint(center, zoom) } internal val defaultCanvasSize = DpSize(512.dp, 512.dp) /** * Draw a map using convenient parameters. If neither [initialViewPoint], noe [initialRectangle] is defined, * use map features to infer view region. * @param initialViewPoint The view point of the map using center and zoom. Is used if provided * @param initialRectangle The rectangle to be used for view point computation. Used if [initialViewPoint] is not defined. * @param buildFeatures - a builder for features */ @Composable public fun MapView( mapTileProvider: MapTileProvider, initialViewPoint: MapViewPoint? = null, initialRectangle: GmcRectangle? = null, config: MapViewConfig = MapViewConfig(), modifier: Modifier = Modifier.fillMaxSize(), buildFeatures: MapFeaturesState.() -> Unit = {}, ): Unit = key(buildFeatures) { val featureState = rememberMapFeatureState(buildFeatures) val features = featureState.features() val viewPointOverride: MapViewPoint = remember(initialViewPoint, initialRectangle) { initialViewPoint ?: initialRectangle?.computeViewPoint(mapTileProvider, defaultCanvasSize) ?: features.values.computeBoundingBox(1.0)?.computeViewPoint(mapTileProvider, defaultCanvasSize) ?: MapViewPoint.globe } val featureDrag by remember { derivedStateOf { DragHandle.withPrimaryButton { _, start, end -> val zoom = start.zoom featureState.findAllWithAttribute(DraggableAttribute) { it }.forEach { id -> val feature = features[id] as? DraggableMapFeature ?: return@forEach val boundingBox = feature.getBoundingBox(zoom) ?: return@forEach if (start.focus in boundingBox) { featureState.addFeature(id, feature.withCoordinates(end.focus)) return@withPrimaryButton false } } return@withPrimaryButton true } } } val newConfig by remember { derivedStateOf { config.copy( dragHandle = DragHandle.combine(featureDrag, config.dragHandle) ) } } MapView( mapTileProvider = mapTileProvider, initialViewPoint = viewPointOverride, features = featureState, config = newConfig, modifier = modifier, ) }