Minor cleanup

app/src/main/java/eu/kanade/presentation/reader/ReaderContentOverlay.kt

@@ -5,6 +5,7 @@ import androidx.annotation.IntRange
 import androidx.compose.foundation.Canvas
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.BlendMode
 import androidx.compose.ui.graphics.Color
@@ -15,14 +16,19 @@ import kotlin.math.abs
 fun ReaderContentOverlay(
     @IntRange(from = -100, to = 100) brightness: Int,
     @ColorInt color: Int?,
-    colorBlendMode: BlendMode? = BlendMode.SrcOver,
+    colorBlendMode: BlendMode?,
+    modifier: Modifier = Modifier,
 ) {
     if (brightness < 0) {
+        val brightnessAlpha = remember(brightness) {
+            abs(brightness) / 100f
+        }
+
         Canvas(
-            modifier = Modifier
+            modifier = modifier
                 .fillMaxSize()
                 .graphicsLayer {
-                    alpha = abs(brightness) / 100f
+                    alpha = brightnessAlpha
                 },
         ) {
             drawRect(Color.Black)
@@ -31,12 +37,12 @@ fun ReaderContentOverlay(
 
     if (color != null) {
         Canvas(
-            modifier = Modifier
+            modifier = modifier
                 .fillMaxSize(),
         ) {
             drawRect(
                 color = Color(color),
-                blendMode = colorBlendMode,
+                blendMode = colorBlendMode ?: BlendMode.SrcOver,
             )
         }
     }

app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt

@@ -88,7 +88,6 @@ import tachiyomi.core.util.lang.launchIO
 import tachiyomi.core.util.lang.launchNonCancellable
 import tachiyomi.core.util.lang.withUIContext
 import tachiyomi.core.util.system.logcat
-import tachiyomi.domain.manga.model.Manga
 import tachiyomi.i18n.MR
 import tachiyomi.presentation.core.util.collectAsState
 import uy.kohesive.injekt.Injekt
@@ -183,7 +182,7 @@ class ReaderActivity : BaseActivity() {
             .map { it.manga }
             .distinctUntilChanged()
             .filterNotNull()
-            .onEach(::setManga)
+            .onEach { updateViewer() }
             .launchIn(lifecycleScope)
 
         viewModel.state
@@ -486,10 +485,9 @@ class ReaderActivity : BaseActivity() {
     }
 
     /**
-     * Called from the presenter when a manga is ready. Used to instantiate the appropriate viewer
-     * and the toolbar title.
+     * Called from the presenter when a manga is ready. Used to instantiate the appropriate viewer.
      */
-    private fun setManga(manga: Manga) {
+    private fun updateViewer() {
         val prevViewer = viewModel.state.value.viewer
         val newViewer = ReadingMode.toViewer(viewModel.getMangaReadingMode(), this)