Add sliders to set ISO and aperture

app/src/main/java/eu/wa5p/lightmeter/MainActivity.kt

@@ -11,11 +11,11 @@ import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Slider
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.MutableState
@@ -27,6 +27,7 @@ import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import eu.wa5p.lightmeter.ui.theme.LightMeterTheme
+import kotlin.math.roundToInt
 
 const val TAG: String = "lightmeter MainActivity"
 
@@ -104,16 +105,22 @@ fun LightmeterListItem(
 ) {
     Row(modifier = Modifier.padding(bottom = 8.dp)) {
         Text(
-            modifier = Modifier.weight(0.4f).padding(all = 8.dp),
+            modifier = Modifier
+                .weight(0.4f)
+                .padding(all = 8.dp),
             text = label
         )
         Text(
-            modifier = Modifier.weight(0.4f).padding(all = 8.dp),
+            modifier = Modifier
+                .weight(0.4f)
+                .padding(all = 8.dp),
             textAlign = TextAlign.Right,
             text = value
         )
         Text(
-            modifier = Modifier.weight(0.2f).padding(all = 8.dp),
+            modifier = Modifier
+                .weight(0.2f)
+                .padding(all = 8.dp),
             text = unit
         )
     }
@@ -131,14 +138,86 @@ fun LightmeterListItemPreview() {
     }
 }
 
+// TODO: Recalculate state on change
+@Composable
+fun IsoSlider(state: MutableState<LightmeterState>) {
+    Row(
+        modifier = Modifier.padding(all = 8.dp),
+        verticalAlignment = Alignment.CenterVertically
+    ) {
+        Text(
+            modifier = Modifier.weight(0.3f),
+            text = "ISO"
+        )
+        Slider(
+            modifier = Modifier.weight(0.7f),
+            value = state.value.iso.toFloat(),
+            onValueChange = { value ->
+                state.value = state.value.copy(iso = value.roundToInt())
+            },
+            valueRange = 1f..2000f
+        )
+    }
+}
+
+val previewlightmeterState = mutableStateOf(
+    LightmeterState(
+        illuminance = 0.0,
+        aperture = 1.8,
+        iso = 100,
+        shutterSpeed = 0.01
+    )
+)
+
+@Preview(showBackground = true)
+@Composable
+fun IsoSliderPreview() {
+    LightMeterTheme {
+        IsoSlider(
+            state = remember { previewlightmeterState }
+        )
+    }
+}
+
+// TODO: Recalculate state on change
+@Composable
+fun ApertureSlider(state: MutableState<LightmeterState>) {
+    Row(
+        modifier = Modifier.padding(all = 8.dp),
+        verticalAlignment = Alignment.CenterVertically
+    ) {
+        Text(
+            modifier = Modifier.weight(0.3f),
+            text = "Aperture"
+        )
+        Slider(
+            modifier = Modifier.weight(0.7f),
+            value = state.value.aperture.toFloat(),
+            onValueChange = { value ->
+                state.value = state.value.copy(aperture = value.toDouble())
+            },
+            valueRange = 0.85f..22f
+        )
+    }
+}
+
+@Preview(showBackground = true)
+@Composable
+fun ApertureSliderPreview() {
+    LightMeterTheme {
+        ApertureSlider(state = remember { previewlightmeterState })
+    }
+}
+
 @Composable
 fun LightmeterHomeScreen(state: MutableState<LightmeterState>) {
-    Box(
-        modifier = Modifier.fillMaxSize(),
-        contentAlignment = Alignment.Center
+    Column(modifier = Modifier
+        .fillMaxSize()
+        .padding(top = 64.dp)
+        .padding(all = 32.dp)
     ) {
         Column(
-            verticalArrangement = Arrangement.Center
+            verticalArrangement = Arrangement.Top
         ) {
             LightmeterListItem(
                 label = "Illuminance",
@@ -161,6 +240,14 @@ fun LightmeterHomeScreen(state: MutableState<LightmeterState>) {
                 unit = "s"
             )
         }
+
+        Column(
+            modifier = Modifier.padding(top = 64.dp),
+            verticalArrangement = Arrangement.Bottom
+        ) {
+            IsoSlider(state = state)
+            ApertureSlider(state = state)
+        }
     }
 }
 
@@ -169,16 +256,7 @@ fun LightmeterHomeScreen(state: MutableState<LightmeterState>) {
 fun LightmeterHomeScreenPreview() {
     LightMeterTheme {
         LightmeterHomeScreen(
-            state = remember {
-                mutableStateOf(
-                    LightmeterState(
-                        illuminance = 0.0,
-                        aperture = 1.8,
-                        iso = 100,
-                        shutterSpeed = 0.01
-                    )
-                )
-            }
+            state = remember { previewlightmeterState }
         )
     }
 }