Custom tile source

[MikhailShavykin]

Hello everyone I don't quite understand how to use third-party map sources.

val tileStreamProvider = TileStreamProvider { row, col, zoomLvl ->
    withContext(Dispatchers.IO) {
        try {
            val url = URL("https://tile.openstreetmap.org/$zoomLvl/$row/$col.png")
            val connection = url.openConnection() as HttpURLConnection
            connection.doInput = true
            connection.connect()
            BufferedInputStream(connection.inputStream)
        } catch (e: Exception) {
            e.printStackTrace()
            null
        }
    }
}

Could you show an example and use maps from open sources.

[MikhailShavykin]

Guys need help please!

[p-lr]

There is a demo app with a "RemoteHttp" demo.
You don't need to switch context with withContext(Dispatchers.IO) { .. }. For example :
https://github.com/p-lr/MapCompose/blob/master/demo/src/main/java/ovh/plrapps/mapcompose/demo/viewmodels/HttpTilesVM.kt

[p-lr]

Here is a complete example (note that OSM blocks some user-agents):

/**
 * Shows how MapCompose behaves with remote HTTP tiles.
 */
class HttpTilesVM : ViewModel() {
    private val tileStreamProvider = makeTileStreamProvider()

    private val lvlCnt = 8  // avoid using level higher than 16
    private val mapSize = mapSizeAtLevel(lvlCnt - 1, tileSize = 256)
    val state: MapState by mutableStateOf(
        MapState(lvlCnt, mapSize, mapSize, workerCount = 16).apply {
            addLayer(tileStreamProvider)
            scale = 0f
        }
    )
}

/**
 * A [TileStreamProvider] which performs HTTP requests.
 */
private fun makeTileStreamProvider() =
    TileStreamProvider { row, col, zoomLvl ->
        try {
            val url = URL("https://tile.openstreetmap.org/$zoomLvl/$col/$row.png")
            val connection = url.openConnection() as HttpURLConnection
            connection.setRequestProperty("User-Agent", "Chrome/120.0.0.0 Safari/537.36")
            connection.doInput = true
            connection.connect()
            BufferedInputStream(connection.inputStream)
        } catch (e: Exception) {
            e.printStackTrace()
            null
        }
    }

/**
 * wmts level are 0 based.
 * At level 0, the map corresponds to just one tile.
 */
private fun mapSizeAtLevel(wmtsLevel: Int, tileSize: Int): Int {
    return tileSize * 2.0.pow(wmtsLevel).toInt()
}

[p-lr]

A useful tool to download tiles between in a given bounding box and a range of levels (in short, to download a map):
https://github.com/feczkob/osm-tile-manager