Scale slider

app/src/main/java/com/mirenkov/ktheightmap/MainActivity.kt

@@ -7,23 +7,34 @@ import android.util.Log
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
+import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.BoxWithConstraints
+import androidx.compose.foundation.layout.absoluteOffset
+import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.offset
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.safeDrawingPadding
+import androidx.compose.foundation.layout.size
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Build
 import androidx.compose.material3.FloatingActionButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme.colorScheme
 import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Slider
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.mutableFloatStateOf
+import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.rotate
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.dp
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.viewmodel.compose.LocalViewModelStoreOwner
@@ -62,19 +73,35 @@ class MainActivity : ComponentActivity() {
 
 @Composable
 fun Main(vm: TileViewModel = viewModel()) {
+    var sliderValue = rememberSaveable { mutableFloatStateOf(1F) }
     KtHeightMapTheme {
-        Surface {
+        Box(modifier = Modifier.background(color = colorScheme.background)) {
             Scaffold(
                 modifier = Modifier.fillMaxSize()
-                    .safeDrawingPadding(),
+                    .safeDrawingPadding()
+                    .align(Alignment.Center),
                 floatingActionButton = { ToolButton() }
             ) { innerPadding ->
                 MapCanvas(
                     gridColor = colorScheme.primary,
                     backColor = colorScheme.background,
+                    scale = sliderValue,
                     modifier = Modifier.padding(innerPadding),
                 )
             }
+            Box(modifier = Modifier.safeDrawingPadding()
+                .align(Alignment.CenterEnd)
+                .rotate(-90F)
+                .size(240.dp, 40.dp)
+                .offset(0.dp, 80.dp)
+            ) {
+                Slider(
+                    value = sliderValue.floatValue,
+                    onValueChange = { sliderValue.floatValue = it },
+                    valueRange = 1F..14F,
+                    modifier = Modifier.align(Alignment.CenterStart)
+                )
+            }
         }
     }
 }

app/src/main/java/com/mirenkov/ktheightmap/MapCanvas.kt

@@ -2,8 +2,11 @@ package com.mirenkov.ktheightmap
 
 import androidx.compose.foundation.Canvas
 import androidx.compose.foundation.gestures.detectDragGestures
+import androidx.compose.foundation.gestures.rememberTransformableState
+import androidx.compose.foundation.gestures.transformable
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.MutableFloatState
 import androidx.compose.runtime.mutableFloatStateOf
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.ui.Modifier
@@ -17,10 +20,12 @@ import androidx.compose.ui.input.pointer.pointerInput
 fun MapCanvas(
     backColor: Color,
     gridColor: Color,
+    scale: MutableFloatState,
     modifier: Modifier = Modifier
 ) {
     val offsetX = rememberSaveable { mutableFloatStateOf(0F) }
     val offsetY = rememberSaveable { mutableFloatStateOf(0F) }
+
     Canvas(
         modifier = modifier.fillMaxSize()
             .pointerInput(Unit) {
@@ -39,17 +44,21 @@ fun MapCanvas(
         val strippedOffsetX = offsetX.floatValue % TILE_SIZE
         val strippedOffsetY = offsetY.floatValue % TILE_SIZE
 
+        val level = scale.floatValue.toInt()
+        val strippedScale = scale.floatValue + 1 - level
+        val actualTileSize = TILE_SIZE * strippedScale
+
         val offset = Offset(strippedOffsetX, strippedOffsetY)
-        val grid = size / TILE_SIZE
+        val grid = size / actualTileSize
         val gridWidth = grid.width.toInt()
         val gridHeight = grid.height.toInt()
         for (cellX in 0 .. gridWidth + 2) {
-            val offsetX = TILE_SIZE * (cellX - 1)
+            val offsetX = actualTileSize * (cellX - 1)
             for (cellY in 0 .. gridHeight + 2) {
-                val offsetY = TILE_SIZE * (cellY - 1)
+                val offsetY = actualTileSize * (cellY - 1)
                 drawRect(
                     color = gridColor,
-                    size = Size(TILE_SIZE, TILE_SIZE),
+                    size = Size(actualTileSize, actualTileSize),
                     topLeft = offset + Offset(offsetX, offsetY),
                     style = Stroke(width = 4F)
                 )