keep the accent blobs dimmer than the primary button

app/src/main/kotlin/com/subtracks/ui/theme/ArtworkTheme.kt

@@ -35,7 +35,8 @@ private const val SEED_ART_SIZE_PX = 128
 private const val PERIOD_SCREENS = 2f
 private const val BLOB_ZONE = 0.62f
 private const val BLOB_COUNT = 4
-private const val ACCENT_MAX_LUMINANCE = 0.34f
+private const val ACCENT_MAX_LUMINANCE = 0.18f
+private const val PRIMARY_MIN_LUMINANCE = 0.30f
 private const val MIN_GRADIENT_SATURATION = 0.30f
 private const val HERO_DARKEN_MAX = 1.0f
 private const val DARKEN_START_SCREENS = 0.5f
@@ -66,7 +67,7 @@ fun artworkColorsFromSeeds(
         l: Float,
     ) = Color.hsl(h % 360f, sat.coerceIn(0f, 1f), l.coerceIn(0f, 1f))
 
-    val primary = tone(hue, s, 0.62f)
+    val primary = tone(hue, s, 0.62f).withMinLuminance(PRIMARY_MIN_LUMINANCE)
     val background = tone(hue, (s * 0.35f).coerceAtMost(0.20f), 0.06f)
     val onBackground = tone(hue, (s * 0.10f).coerceAtMost(0.08f), 0.95f)
 
@@ -138,6 +139,19 @@ private fun Color.withMaxLuminance(max: Float): Color {
     return color
 }
 
+private fun Color.withMinLuminance(min: Float): Color {
+    if (luminance() >= min) return this
+    val (h, s, initial) = toHsl()
+    var lightness = initial
+    var color = this
+    var guard = 0
+    while (color.luminance() < min && guard++ < 40) {
+        lightness = (lightness + 0.02f).coerceAtMost(0.95f)
+        color = Color.hsl(h, s, lightness)
+    }
+    return color
+}
+
 fun ArtworkColors.gradientColorAt(fraction: Float): Color {
     if (fraction.isNaN()) return gradientHigh
     val f = fraction.mod(1f)

app/src/test/kotlin/com/subtracks/ui/AppScreenshotTest.kt

@@ -51,6 +51,7 @@ import com.subtracks.ui.settings.AddSourceState
 import com.subtracks.ui.settings.SettingsScreen
 import com.subtracks.ui.theme.SubtracksTheme
 import com.subtracks.ui.theme.artworkColorsFromSeed
+import com.subtracks.ui.theme.artworkColorsFromSeeds
 import kotlinx.coroutines.flow.flowOf
 import org.junit.After
 import org.junit.Before
@@ -133,6 +134,26 @@ class AppScreenshotTest {
         composeRule.onRoot().captureRoboImage("src/test/screenshots/album_detail.png")
     }
 
+    @Test
+    fun albumDetailCool() {
+        composeRule.setContent {
+            SubtracksTheme {
+                AlbumDetailScreen(
+                    album = Fixtures.albums.first(),
+                    songs = Fixtures.songs,
+                    coverArt = { id, _ -> id?.let { CoverArtRef(it, "test:$it") } },
+                    artwork = artworkColorsFromSeeds(Color.rgb(45, 115, 240), Color.rgb(40, 180, 140)),
+                    onBack = {},
+                    onSongClick = {},
+                    playingSongId = Fixtures.songs.first().id,
+                    modifier = Modifier.fillMaxSize(),
+                )
+            }
+        }
+        awaitText("Everything In Its Right Place")
+        composeRule.onRoot().captureRoboImage("src/test/screenshots/album_detail_cool.png")
+    }
+
     @Test
     fun artistDetail() {
         composeRule.setContent {

app/src/test/kotlin/com/subtracks/ui/theme/ArtworkColorsTest.kt

@@ -35,6 +35,19 @@ class ArtworkColorsTest {
         )
     }
 
+    @Test
+    fun buttonStandsOutFromGradient() {
+        for (seed in seeds) {
+            val colors = artworkColorsFromSeed(seed)
+            val primary = colors.scheme.primary
+            assertTrue("primary vs gradientHigh for $seed", contrast(primary, colors.gradientHigh) >= 2f)
+            assertTrue("primary vs gradientLow for $seed", contrast(primary, colors.gradientLow) >= 2f)
+            for (accent in colors.accents) {
+                assertTrue("accent dimmer than primary for $seed", primary.luminance() > accent.luminance())
+            }
+        }
+    }
+
     private fun contrast(
         a: Color,
         b: Color,