fix: performance HUD cycles colors with the Inner Gamer theme (#1932)

app/src/main/java/com/droiddeck/launcher/hud/DroidDeckHudView.kt

@@ -22,12 +22,16 @@ import android.graphics.Paint
 import android.graphics.Path
 import android.graphics.RectF
 import android.graphics.Typeface
+import android.os.SystemClock
 import android.text.format.DateFormat
 import android.view.GestureDetector
 import android.view.MotionEvent
 import android.view.View
 import androidx.annotation.VisibleForTesting
 import androidx.compose.ui.graphics.toArgb
+import com.droiddeck.launcher.session.SessionPrefs
+import com.droiddeck.launcher.ui.Motion
+import com.droiddeck.launcher.ui.Palette
 import com.droiddeck.launcher.ui.Themes
 import java.util.Date
 import java.util.Locale
@@ -43,6 +47,7 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -75,6 +80,7 @@ class DroidDeckHudView(context: Context) : View(context) {
 
     private val scope = CoroutineScope(SupervisorJob() + Dispatchers.Main.immediate)
     private var updateJob: Job? = null
+    private var hueJob: Job? = null
     private val metrics = HudMetrics(context)
 
     private val density = resources.displayMetrics.density
@@ -370,9 +376,11 @@ class DroidDeckHudView(context: Context) : View(context) {
 
     private fun stopUpdates() {
         updateJob?.cancel(); updateJob = null
+        hueJob?.cancel(); hueJob = null
     }
 
     private fun startUpdates() {
+        startHueCycle()
         if (updateJob?.isActive == true) return
         updateJob = scope.launch {
             while (isActive) {
@@ -399,13 +407,50 @@ class DroidDeckHudView(context: Context) : View(context) {
     var onRefresh: Runnable? = null
 
     private fun applyTheme() {
-        val palette = Themes.current(context)
+        applyPalette(Themes.current(context))
+        if (isAttachedToWindow && isShown) startHueCycle()
+    }
+
+    private fun applyPalette(palette: Palette) {
         accent = palette.primary.toArgb()
         surfaceRgb = palette.surface.toArgb() and 0xFFFFFF
         colFps = accent
         colGraph = lighten(accent, 0.3f)
     }
 
+    /**
+     * Inner Gamer turns the colour wheel inside the app's Compose UI, which is not running while the drawer is
+     * closed, so the HUD turns it here and shares the hue so the drawer picks up where the HUD is.
+     */
+    private fun startHueCycle() {
+        if (hueJob?.isActive == true) return
+        if (SessionPrefs.theme(context) != Themes.INNER_GAMER) return
+        hueJob = scope.launch {
+            var hue = Themes.rgbHue
+            var shown = Float.NaN
+            var last = SystemClock.uptimeMillis()
+            while (isActive && SessionPrefs.theme(context) == Themes.INNER_GAMER) {
+                val now = SystemClock.uptimeMillis()
+                val cycle = Themes.rgbCycleMillis(Themes.rgbSpeed).toFloat()
+                if (Motion.scale == 0f) {
+                    last = now
+                    delay(HUE_IDLE_MS)
+                    continue
+                }
+                hue = (hue + (now - last) / cycle * 360f) % 360f
+                last = now
+                val stepped = (hue / Themes.RGB_HUE_STEP).toInt() * Themes.RGB_HUE_STEP
+                if (stepped != shown) {
+                    shown = stepped
+                    Themes.moveRgbHue(stepped)
+                    applyPalette(Themes.innerGamer(stepped))
+                    rebuildAndInvalidate()
+                }
+                delay((cycle * Themes.RGB_HUE_STEP / 360f).toLong().coerceAtLeast(16L))
+            }
+        }
+    }
+
     private fun lighten(color: Int, amount: Float): Int = Color.rgb(
         (Color.red(color) + (255 - Color.red(color)) * amount).roundToInt(),
         (Color.green(color) + (255 - Color.green(color)) * amount).roundToInt(),
@@ -1557,6 +1602,7 @@ class DroidDeckHudView(context: Context) : View(context) {
 
     private companion object {
         const val REFRESH_MS = 500L
+        private const val HUE_IDLE_MS = 500L
         const val MIN_SCALE = 0.5f
         const val MAX_SCALE = 2f
         const val GRAPH_CLIP_MS = 49.9f