kscience/maps-kt
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Added proper file cache and map drag

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This commit is contained in:
Alexander Nozik 2022-07-09 22:45:54 +03:00
parent f7151548e5
commit ea16a02a48
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5 changed files with 107 additions and 51 deletions
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1
.gitignore vendored
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@ -1,5 +1,6 @@
build/
.gradle/
.idea/
mapCache/
*.iml

5
src/jvmMain/kotlin/Main.kt
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@ -11,16 +11,17 @@ import androidx.compose.ui.window.application
import centre.sciprog.maps.compose.GeodeticMapCoordinates
import centre.sciprog.maps.compose.MapRectangle
import centre.sciprog.maps.compose.MapView
import java.nio.file.Path
@Composable
@Preview
fun App() {
MaterialTheme {
val map = MapRectangle(
val map = MapRectangle.of(
GeodeticMapCoordinates.ofDegrees(66.513260, 0.0),
GeodeticMapCoordinates.ofDegrees(40.979897, 44.999999),
)
MapView(map, modifier = Modifier.fillMaxSize())
MapView(map, modifier = Modifier.fillMaxSize(), initialZoom = 4.0, cacheDirectory = Path.of("mapCache"))
}
}

72
src/jvmMain/kotlin/centre/sciprog/maps/compose/MapView.kt
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@ -1,18 +1,21 @@
package centre.sciprog.maps.compose
import androidx.compose.foundation.Canvas
import androidx.compose.foundation.gestures.detectDragGestures
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material.Text
import androidx.compose.runtime.*
import androidx.compose.ui.ExperimentalComposeUiApi
import androidx.compose.ui.Modifier
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Size
import androidx.compose.ui.graphics.ImageBitmap
import androidx.compose.ui.graphics.drawscope.clipRect
import androidx.compose.ui.graphics.toComposeImageBitmap
import androidx.compose.ui.input.pointer.PointerEventType
import androidx.compose.ui.input.pointer.PointerInputChange
import androidx.compose.ui.input.pointer.onPointerEvent
import androidx.compose.ui.input.pointer.pointerInput
import io.ktor.client.HttpClient
import io.ktor.client.engine.cio.CIO
import io.ktor.client.request.get
@ -24,6 +27,8 @@ import kotlinx.coroutines.async
import mu.KotlinLogging
import org.jetbrains.skia.Image
import java.net.URL
import java.nio.file.Path
import kotlin.io.path.*
import kotlin.math.*
@ -36,26 +41,48 @@ private data class OsMapTileId(
val j: Int,
)
private fun OsMapTileId.osmUrl() = URL("https://tile.openstreetmap.org/${zoom.toInt()}/${i}/${j}.png")
private data class OsMapTile(
val id: OsMapTileId,
val image: ImageBitmap,
)
private class OsMapCache(val scope: CoroutineScope, val client: HttpClient) {
private class OsMapCache(val scope: CoroutineScope, val client: HttpClient, private val cacheDirectory: Path? = null) {
private val cache = HashMap<OsMapTileId, Deferred<ImageBitmap>>()
public suspend fun loadTile(id: OsMapTileId): OsMapTile {
val image = cache.getOrPut(id) {
scope.async(Dispatchers.IO) {
private fun OsMapTileId.osmUrl() = URL("https://tile.openstreetmap.org/${zoom}/${i}/${j}.png")
private fun OsMapTileId.cacheFilePath() = cacheDirectory?.resolve("${zoom}/${i}/${j}.png")
private fun CoroutineScope.downloadImageAsync(id: OsMapTileId) = scope.async(Dispatchers.IO) {
id.cacheFilePath()?.let { path ->
if (path.exists()) {
try {
return@async Image.makeFromEncoded(path.readBytes()).toComposeImageBitmap()
} catch (ex: Exception) {
logger.debug { "Failed to load image from $path" }
path.deleteIfExists()
}
}
}
val url = id.osmUrl()
val byteArray = client.get(url).readBytes()
logger.debug { "Finished downloading map tile with id $id from $url" }
id.cacheFilePath()?.let { path ->
logger.debug { "Caching map tile $id to $path" }
path.parent.createDirectories()
path.writeBytes(byteArray)
}
Image.makeFromEncoded(byteArray).toComposeImageBitmap()
}
public suspend fun loadTile(id: OsMapTileId): OsMapTile {
val image = cache.getOrPut(id) {
scope.downloadImageAsync(id)
}.await()
return OsMapTile(id, image)
@ -71,15 +98,14 @@ fun MapView(
initialRectangle: MapRectangle,
modifier: Modifier,
client: HttpClient = remember { HttpClient(CIO) },
cacheDirectory: Path? = null,
initialZoom: Double? = null,
) {
val mapRectangle by remember { mutableStateOf(initialRectangle) }
val scope = rememberCoroutineScope()
val mapCache = remember { OsMapCache(scope, client) }
val mapTiles = mutableStateListOf<OsMapTile>()
val mapCache = remember { OsMapCache(scope, client, cacheDirectory) }
val mapTiles = remember { mutableStateListOf<OsMapTile>()}
var mapRectangle by remember { mutableStateOf(initialRectangle) }
var canvasSize by remember { mutableStateOf(Size(512f, 512f)) }
//TODO provide override for tiling
@ -107,11 +133,11 @@ fun MapView(
)
}
//val scaleFactor = WebMercatorProjection.scaleFactor(computedZoom)
val scaleFactor by derivedStateOf { WebMercatorProjection.scaleFactor(zoom) }
val topLeft by derivedStateOf { with(WebMercatorProjection) { mapRectangle.topLeft.toMercator(zoom) } }
LaunchedEffect(canvasSize, zoom) {
LaunchedEffect(mapRectangle, canvasSize, zoom) {
val startIndexHorizontal = (topLeft.x / TILE_SIZE).toInt()
val startIndexVertical = (topLeft.y / TILE_SIZE).toInt()
@ -142,17 +168,12 @@ fun MapView(
}
}.onPointerEvent(PointerEventType.Press) {
println(coordinates)
}.pointerInput(Unit) {
detectDragGestures { change: PointerInputChange, dragAmount: Offset ->
mapRectangle = mapRectangle.move(dragAmount.y / scaleFactor, -dragAmount.x / scaleFactor)
}
}.fillMaxSize()
// .pointerInput(Unit) {
// forEachGesture {
// awaitPointerEventScope {
// val down = awaitFirstDown()
// drag(down.id) {
// println(currentEvent.mouseEvent?.button)
// }
// }
// }
// }
Column {
//Text(coordinates.toString())
@ -161,7 +182,7 @@ fun MapView(
canvasSize = size
logger.debug { "Redraw canvas. Size: $size" }
}
clipRect {
mapTiles.forEach { (id, image) ->
//converting back from tile index to screen offset
logger.debug { "Drawing tile $id" }
@ -177,3 +198,4 @@ fun MapView(
}
}
}
}

4
src/jvmMain/kotlin/centre/sciprog/maps/compose/coordinates.kt
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@ -27,13 +27,13 @@ public class GeodeticMapCoordinates private constructor(public val latitude: Dou
}
override fun toString(): String {
return "GeodeticCoordinates(latitude=${latitude / PI * 180}, longitude=${longitude / PI * 180})"
return "GeodeticCoordinates(latitude=${latitude / PI * 180} deg, longitude=${longitude / PI * 180} deg)"
}
public companion object {
public fun ofRadians(latitude: Double, longitude: Double): GeodeticMapCoordinates {
require(longitude in (-PI)..(PI)) { "Longitude $longitude is not in (-PI)..(PI)" }
require(latitude in (-PI/2)..(PI/2)) { "Latitude $latitude is not in (-PI/2)..(PI/2)" }
return GeodeticMapCoordinates(latitude, longitude.rem(PI / 2))
}

40
src/jvmMain/kotlin/centre/sciprog/maps/compose/model.kt
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@ -1,8 +1,9 @@
package centre.sciprog.maps.compose
import kotlin.math.abs
import kotlin.math.max
import kotlin.math.min
class MapRectangle(
class MapRectangle private constructor(
var topLeft: GeodeticMapCoordinates,
var bottomRight: GeodeticMapCoordinates,
) {
@ -10,8 +11,39 @@ class MapRectangle(
require(topLeft.latitude >= bottomRight.latitude)
require(topLeft.longitude <= bottomRight.longitude)
}
val topRight: GeodeticMapCoordinates = GeodeticMapCoordinates.ofRadians(topLeft.latitude, bottomRight.longitude)
val bottomLeft: GeodeticMapCoordinates = GeodeticMapCoordinates.ofRadians(bottomRight.latitude, topLeft.longitude)
val topRight: GeodeticMapCoordinates get() = GeodeticMapCoordinates.ofRadians(topLeft.latitude, bottomRight.longitude)
val bottomLeft: GeodeticMapCoordinates get() = GeodeticMapCoordinates.ofRadians(bottomRight.latitude, topLeft.longitude)
val topLatitude get() = topLeft.latitude
val bottomLatitude get() = bottomRight.latitude
val leftLongitude get() = topLeft.longitude
val rightLongitude get() = bottomRight.longitude
companion object{
fun of(
a: GeodeticMapCoordinates,
b: GeodeticMapCoordinates
) = MapRectangle(
GeodeticMapCoordinates.ofRadians(max(a.latitude, b.latitude), min(a.longitude,b.longitude)),
GeodeticMapCoordinates.ofRadians(min(a.latitude, b.latitude), max(a.longitude,b.longitude)),
)
}
}
internal fun MapRectangle.move(latitudeDelta: Double, longitudeDelta: Double): MapRectangle {
val safeLatitudeDelta: Double = if(topLatitude + latitudeDelta > MercatorProjection.MAXIMUM_LATITUDE){
0.0
} else if(bottomLatitude + latitudeDelta < -MercatorProjection.MAXIMUM_LATITUDE){
0.0
} else {
latitudeDelta
}
return MapRectangle.of(
GeodeticMapCoordinates.ofRadians(topLeft.latitude + safeLatitudeDelta, topLeft.longitude + longitudeDelta),
GeodeticMapCoordinates.ofRadians(bottomRight.latitude + safeLatitudeDelta, bottomRight.longitude + longitudeDelta)
)
}
sealed interface MapFeature