Fix for TAVRIDA-T-2

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

@@ -16,8 +16,12 @@ data class MapTile(
 
 interface MapTileProvider {
     suspend fun loadTile(id: TileId): MapTile
-    fun toIndex(d: Double): Int = floor(d / DEFAULT_TILE_SIZE).toInt()
+
-    fun toCoordinate(i: Int): Double = (i * DEFAULT_TILE_SIZE).toDouble()
+    val tileSize: Int get() = DEFAULT_TILE_SIZE
+
+    fun toIndex(d: Double): Int = floor(d / tileSize).toInt()
+
+    fun toCoordinate(i: Int): Double = (i * tileSize).toDouble()
 
     companion object {
         const val DEFAULT_TILE_SIZE = 256

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

@@ -4,11 +4,9 @@ import androidx.compose.foundation.Canvas
 import androidx.compose.foundation.gestures.detectDragGestures
 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
-import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.drawscope.DrawScope
 import androidx.compose.ui.graphics.drawscope.clipRect
@@ -20,6 +18,7 @@ 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 androidx.compose.ui.unit.*
 import centre.sciprog.maps.*
 import mu.KotlinLogging
 import org.jetbrains.skia.Font
@@ -46,6 +45,7 @@ actual fun MapView(
     onClick: (GeodeticMapCoordinates) -> Unit,
     modifier: Modifier,
 ) {
+
     var viewPoint by remember { mutableStateOf(initialViewPoint) }
 
     val zoom: Int by derivedStateOf { viewPoint.zoom.roundToInt() }
@@ -53,18 +53,39 @@ actual fun MapView(
     val mapTiles = remember { mutableStateListOf<MapTile>() }
 
     //var mapRectangle by remember { mutableStateOf(initialRectangle) }
-    var canvasSize by remember { mutableStateOf(Size(512f, 512f)) }
+    var canvasSize by remember { mutableStateOf(DpSize(512.dp, 512.dp)) }
 
     val centerCoordinates by derivedStateOf { WebMercatorProjection.toMercator(viewPoint.focus, zoom) }
 
+    fun DpOffset.toMercator(): WebMercatorCoordinates = WebMercatorCoordinates(
+        zoom,
+        (x - canvasSize.width / 2).value + centerCoordinates.x,
+        (y - canvasSize.height / 2).value + centerCoordinates.y,
+    )
+
+    fun DpOffset.toGeodetic() = WebMercatorProjection.toGeodetic(toMercator())
+
+    @OptIn(ExperimentalComposeUiApi::class)
+    val canvasModifier = modifier.onPointerEvent(PointerEventType.Press) {
+        val (xPos, yPos) = it.changes.first().position
+        onClick(DpOffset(xPos.toDp(), yPos.toDp()).toGeodetic())
+    }.onPointerEvent(PointerEventType.Scroll) {
+        viewPoint = viewPoint.zoom(-it.changes.first().scrollDelta.y.toDouble())
+    }.pointerInput(Unit) {
+        detectDragGestures { _: PointerInputChange, dragAmount: Offset ->
+            viewPoint = viewPoint.move(-dragAmount.x, +dragAmount.y)
+        }
+    }.fillMaxSize()
+
+
     // Load tiles asynchronously
     LaunchedEffect(viewPoint, canvasSize) {
-        val left = centerCoordinates.x - canvasSize.width / 2
+        val left = centerCoordinates.x - canvasSize.width.value / 2
-        val right = centerCoordinates.x + canvasSize.width / 2
+        val right = centerCoordinates.x + canvasSize.width.value / 2
         val horizontalIndices = mapTileProvider.toIndex(left)..mapTileProvider.toIndex(right)
 
-        val top = (centerCoordinates.y + canvasSize.height / 2)
+        val top = (centerCoordinates.y + canvasSize.height.value / 2)
-        val bottom = (centerCoordinates.y - canvasSize.height / 2)
+        val bottom = (centerCoordinates.y - canvasSize.height.value / 2)
         val verticalIndices = mapTileProvider.toIndex(bottom)..mapTileProvider.toIndex(top)
 
         mapTiles.clear()
@@ -87,31 +108,16 @@ actual fun MapView(
 
     }
 
-    fun Offset.toMercator(): WebMercatorCoordinates = WebMercatorCoordinates(
-        zoom,
-        x + centerCoordinates.x - canvasSize.width / 2,
-        y + centerCoordinates.y - canvasSize.height / 2,
-    )
 
-    fun Offset.toGeodetic() = WebMercatorProjection.toGeodetic(toMercator())
+    Canvas(canvasModifier) {
 
         fun WebMercatorCoordinates.toOffset(): Offset = Offset(
-        (canvasSize.width / 2 - centerCoordinates.x + x).toFloat(),
+            (canvasSize.width / 2 - centerCoordinates.x.dp + x.dp).toPx(),
-        (canvasSize.height / 2 - centerCoordinates.y + y).toFloat()
+            (canvasSize.height / 2 - centerCoordinates.y.dp + y.dp).toPx()
         )
 
         fun GeodeticMapCoordinates.toOffset(): Offset = WebMercatorProjection.toMercator(this, zoom).toOffset()
 
-    @OptIn(ExperimentalComposeUiApi::class)
-    val canvasModifier = modifier.onPointerEvent(PointerEventType.Press) {
-        onClick(it.changes.first().position.toGeodetic())
-    }.onPointerEvent(PointerEventType.Scroll) {
-        viewPoint = viewPoint.zoom(-it.changes.first().scrollDelta.y.toDouble())
-    }.pointerInput(Unit) {
-        detectDragGestures { _: PointerInputChange, dragAmount: Offset ->
-            viewPoint = viewPoint.move(-dragAmount.x, +dragAmount.y)
-        }
-    }.fillMaxSize()
 
         fun DrawScope.drawFeature(zoom: Int, feature: MapFeature) {
             when (feature) {
@@ -145,22 +151,22 @@ actual fun MapView(
             }
         }
 
-
+        if (canvasSize != size.toDpSize()) {
-    Canvas(canvasModifier) {
+            canvasSize = size.toDpSize()
-        if (canvasSize != size) {
+            logger.debug { "Recalculate canvas. Size: $size" }
-            canvasSize = size
-            logger.debug { "Redraw canvas. Size: $size" }
         }
         clipRect {
+            val tileSize = IntSize(mapTileProvider.tileSize.dp.roundToPx(), mapTileProvider.tileSize.dp.roundToPx())
             mapTiles.forEach { (id, image) ->
                 //converting back from tile index to screen offset
-                val offset = Offset(
+                val offset = IntOffset(
-                    (canvasSize.width / 2 - centerCoordinates.x + mapTileProvider.toCoordinate(id.i)).toFloat(),
+                    (canvasSize.width / 2 - centerCoordinates.x.dp + mapTileProvider.toCoordinate(id.i).dp).roundToPx(),
-                    (canvasSize.height / 2 - centerCoordinates.y + mapTileProvider.toCoordinate(id.j)).toFloat()
+                    (canvasSize.height / 2 - centerCoordinates.y.dp + mapTileProvider.toCoordinate(id.j).dp).roundToPx()
                 )
                 drawImage(
                     image = image,
-                    topLeft = offset
+                    dstOffset = offset,
+                    dstSize = tileSize
                 )
             }
             features.values.filter { zoom in it.zoomRange }.forEach { feature ->