feat: implement CPU-based metaball rendering and performance classification

app/src/main/java/com/rosetta/messenger/ui/components/metaball/CpuBlurUtils.kt

@@ -0,0 +1,204 @@
+package com.rosetta.messenger.ui.components.metaball
+
+import android.graphics.Bitmap
+import kotlin.math.abs
+import kotlin.math.max
+import kotlin.math.min
+
+/**
+ * Proper Stack Blur algorithm by Mario Klingemann.
+ * Uses a triangular (tent) kernel — each pixel is weighted by (radius + 1 - distance).
+ * Unlike box blur (simple moving average), produces smooth alpha gradients
+ * essential for clean alpha-threshold gooey effects.
+ *
+ * Used by ProfileMetaballOverlayCpu for devices without RenderEffect (API < 31).
+ */
+internal fun stackBlurBitmap(source: Bitmap, radius: Int): Bitmap {
+    if (radius < 1) return source
+    val bitmap = source.copy(source.config, true)
+    stackBlurBitmapInPlace(bitmap, radius)
+    return bitmap
+}
+
+/**
+ * In-place stack blur on a mutable bitmap.
+ */
+internal fun stackBlurBitmapInPlace(bitmap: Bitmap, radius: Int) {
+    if (radius < 1) return
+
+    val w = bitmap.width
+    val h = bitmap.height
+    val pix = IntArray(w * h)
+    bitmap.getPixels(pix, 0, w, 0, 0, w, h)
+
+    stackBlurPixels(pix, w, h, radius)
+
+    bitmap.setPixels(pix, 0, w, 0, 0, w, h)
+}
+
+/**
+ * Core stack blur on raw ARGB pixel array.
+ * Two-pass (horizontal + vertical) with triangular weight kernel.
+ * Divisor = (radius+1)^2, matching the sum of triangular weights.
+ */
+private fun stackBlurPixels(pix: IntArray, w: Int, h: Int, radius: Int) {
+    val wm = w - 1
+    val hm = h - 1
+    val wh = w * h
+    val div = 2 * radius + 1
+
+    // Separate channel arrays for inter-pass storage
+    val aArr = IntArray(wh)
+    val rArr = IntArray(wh)
+    val gArr = IntArray(wh)
+    val bArr = IntArray(wh)
+
+    val vmin = IntArray(max(w, h))
+
+    // Stack blur divisor: sum of triangular weights = (radius+1)^2
+    val r1 = radius + 1
+    val mulSum = r1 * r1
+
+    // Circular buffer: each entry = [a, r, g, b]
+    val stack = Array(div) { IntArray(4) }
+
+    var yi = 0
+    var yw = 0
+
+    // === HORIZONTAL PASS ===
+    for (y in 0 until h) {
+        var asum = 0; var rsum = 0; var gsum = 0; var bsum = 0
+        var ainsum = 0; var rinsum = 0; var ginsum = 0; var binsum = 0
+        var aoutsum = 0; var routsum = 0; var goutsum = 0; var boutsum = 0
+
+        // Initialize stack with edge-clamped pixels, weighted by distance from center
+        for (i in -radius..radius) {
+            val p = pix[yi + min(wm, max(i, 0))]
+            val sir = stack[i + radius]
+            sir[0] = (p shr 24) and 0xff
+            sir[1] = (p shr 16) and 0xff
+            sir[2] = (p shr 8) and 0xff
+            sir[3] = p and 0xff
+
+            val rbs = r1 - abs(i) // triangular weight
+            asum += sir[0] * rbs
+            rsum += sir[1] * rbs
+            gsum += sir[2] * rbs
+            bsum += sir[3] * rbs
+
+            if (i > 0) {
+                ainsum += sir[0]; rinsum += sir[1]; ginsum += sir[2]; binsum += sir[3]
+            } else {
+                aoutsum += sir[0]; routsum += sir[1]; goutsum += sir[2]; boutsum += sir[3]
+            }
+        }
+
+        var stackpointer = radius
+
+        for (x in 0 until w) {
+            aArr[yi] = asum / mulSum
+            rArr[yi] = rsum / mulSum
+            gArr[yi] = gsum / mulSum
+            bArr[yi] = bsum / mulSum
+
+            asum -= aoutsum; rsum -= routsum; gsum -= goutsum; bsum -= boutsum
+
+            val stackstart = stackpointer - radius + div
+            val sir = stack[stackstart % div]
+
+            aoutsum -= sir[0]; routsum -= sir[1]; goutsum -= sir[2]; boutsum -= sir[3]
+
+            if (y == 0) {
+                vmin[x] = min(x + radius + 1, wm)
+            }
+            val p = pix[yw + vmin[x]]
+
+            sir[0] = (p shr 24) and 0xff
+            sir[1] = (p shr 16) and 0xff
+            sir[2] = (p shr 8) and 0xff
+            sir[3] = p and 0xff
+
+            ainsum += sir[0]; rinsum += sir[1]; ginsum += sir[2]; binsum += sir[3]
+            asum += ainsum; rsum += rinsum; gsum += ginsum; bsum += binsum
+
+            stackpointer = (stackpointer + 1) % div
+            val sir2 = stack[stackpointer % div]
+
+            aoutsum += sir2[0]; routsum += sir2[1]; goutsum += sir2[2]; boutsum += sir2[3]
+            ainsum -= sir2[0]; rinsum -= sir2[1]; ginsum -= sir2[2]; binsum -= sir2[3]
+
+            yi++
+        }
+        yw += w
+    }
+
+    // === VERTICAL PASS ===
+    for (x in 0 until w) {
+        var asum = 0; var rsum = 0; var gsum = 0; var bsum = 0
+        var ainsum = 0; var rinsum = 0; var ginsum = 0; var binsum = 0
+        var aoutsum = 0; var routsum = 0; var goutsum = 0; var boutsum = 0
+
+        var yp = -radius * w
+        for (i in -radius..radius) {
+            yi = max(0, yp) + x
+            val sir = stack[i + radius]
+            sir[0] = aArr[yi]
+            sir[1] = rArr[yi]
+            sir[2] = gArr[yi]
+            sir[3] = bArr[yi]
+
+            val rbs = r1 - abs(i)
+            asum += sir[0] * rbs
+            rsum += sir[1] * rbs
+            gsum += sir[2] * rbs
+            bsum += sir[3] * rbs
+
+            if (i > 0) {
+                ainsum += sir[0]; rinsum += sir[1]; ginsum += sir[2]; binsum += sir[3]
+            } else {
+                aoutsum += sir[0]; routsum += sir[1]; goutsum += sir[2]; boutsum += sir[3]
+            }
+            if (i < hm) {
+                yp += w
+            }
+        }
+
+        yi = x
+        var stackpointer = radius
+
+        for (y in 0 until h) {
+            pix[yi] = (min(255, asum / mulSum) shl 24) or
+                    (min(255, rsum / mulSum) shl 16) or
+                    (min(255, gsum / mulSum) shl 8) or
+                    min(255, bsum / mulSum)
+
+            asum -= aoutsum; rsum -= routsum; gsum -= goutsum; bsum -= boutsum
+
+            val stackstart = stackpointer - radius + div
+            val sir = stack[stackstart % div]
+
+            aoutsum -= sir[0]; routsum -= sir[1]; goutsum -= sir[2]; boutsum -= sir[3]
+
+            if (x == 0) {
+                vmin[y] = min(y + r1, hm) * w
+            }
+            val p = x + vmin[y]
+
+            sir[0] = aArr[p]
+            sir[1] = rArr[p]
+            sir[2] = gArr[p]
+            sir[3] = bArr[p]
+
+            ainsum += sir[0]; rinsum += sir[1]; ginsum += sir[2]; binsum += sir[3]
+            asum += ainsum; rsum += rinsum; gsum += ginsum; bsum += binsum
+
+            stackpointer = (stackpointer + 1) % div
+            val sir2 = stack[stackpointer % div]
+
+            aoutsum += sir2[0]; routsum += sir2[1]; goutsum += sir2[2]; boutsum += sir2[3]
+            ainsum -= sir2[0]; rinsum -= sir2[1]; ginsum -= sir2[2]; binsum -= sir2[3]
+
+            yi += w
+        }
+    }
+}

app/src/main/java/com/rosetta/messenger/ui/components/metaball/DevicePerformanceClass.kt

@@ -0,0 +1,92 @@
+package com.rosetta.messenger.ui.components.metaball
+
+import android.app.ActivityManager
+import android.content.Context
+import android.os.Build
+import android.util.Log
+import java.io.RandomAccessFile
+import java.util.Locale
+import kotlin.math.ceil
+
+/**
+ * Device performance classification - port of Telegram's SharedConfig.measureDevicePerformanceClass()
+ * Used to select the appropriate metaball rendering tier:
+ * - HIGH: GPU path (Android 12+) or CPU path (older Android)
+ * - AVERAGE: GPU path with reduced quality (Android 12+) or Noop (older)
+ * - LOW: Noop (no metaball effect)
+ */
+enum class PerformanceClass {
+    LOW, AVERAGE, HIGH
+}
+
+object DevicePerformanceClass {
+    @Volatile
+    private var cached: PerformanceClass? = null
+
+    fun get(context: Context): PerformanceClass {
+        cached?.let { return it }
+        return measure(context).also {
+            cached = it
+            Log.d("DevicePerformance", "Performance class: $it")
+        }
+    }
+
+    private fun measure(context: Context): PerformanceClass {
+        val androidVersion = Build.VERSION.SDK_INT
+        val cpuCount = Runtime.getRuntime().availableProcessors()
+        val am = context.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
+        val memoryClass = am.memoryClass
+
+        // Read max CPU frequency
+        var totalCpuFreq = 0
+        var freqResolved = 0
+        for (i in 0 until cpuCount) {
+            try {
+                val reader = RandomAccessFile(
+                    String.format(
+                        Locale.ENGLISH,
+                        "/sys/devices/system/cpu/cpu%d/cpufreq/cpuinfo_max_freq", i
+                    ), "r"
+                )
+                val line = reader.readLine()
+                if (line != null) {
+                    totalCpuFreq += line.trim().toInt() / 1000
+                    freqResolved++
+                }
+                reader.close()
+            } catch (_: Throwable) {
+            }
+        }
+        val maxCpuFreq = if (freqResolved == 0) -1
+        else ceil(totalCpuFreq.toFloat() / freqResolved).toInt()
+
+        // Read total RAM
+        val ram: Long = try {
+            val memInfo = ActivityManager.MemoryInfo()
+            am.getMemoryInfo(memInfo)
+            memInfo.totalMem
+        } catch (_: Exception) {
+            -1L
+        }
+
+        // Classification thresholds from Telegram's SharedConfig.measureDevicePerformanceClass()
+        return when {
+            androidVersion < 21 ||
+                    cpuCount <= 2 ||
+                    memoryClass <= 100 ||
+                    (cpuCount <= 4 && maxCpuFreq != -1 && maxCpuFreq <= 1250) ||
+                    (cpuCount <= 4 && maxCpuFreq <= 1600 && memoryClass <= 128 && androidVersion <= 21) ||
+                    (cpuCount <= 4 && maxCpuFreq <= 1300 && memoryClass <= 128 && androidVersion <= 24) ||
+                    (ram != -1L && ram < 2L * 1024L * 1024L * 1024L)
+            -> PerformanceClass.LOW
+
+            cpuCount < 8 ||
+                    memoryClass <= 160 ||
+                    (maxCpuFreq != -1 && maxCpuFreq <= 2055) ||
+                    (maxCpuFreq == -1 && cpuCount == 8 && androidVersion <= 23)
+            -> PerformanceClass.AVERAGE
+
+            else -> PerformanceClass.HIGH
+        }
+    }
+}

app/src/main/java/com/rosetta/messenger/ui/components/metaball/MetaballEffect.kt

@@ -1,74 +1,52 @@
 package com.rosetta.messenger.ui.components.metaball
 
+import android.graphics.ColorMatrixColorFilter
 import android.graphics.RenderEffect
-import android.graphics.RuntimeShader
 import android.graphics.Shader
 import android.os.Build
 import androidx.annotation.RequiresApi
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.BoxScope
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.asComposeRenderEffect
 import androidx.compose.ui.graphics.graphicsLayer
-import org.intellij.lang.annotations.Language
 
 /**
- * AGSL Shader for metaball effect
- * 
- * This shader creates the "liquid merge" effect by:
- * 1. Taking already-blurred content as input
- * 2. Applying alpha threshold cutoff (alpha > cutoff = opaque, else transparent)
- * 
- * When two blurred shapes overlap, their alpha values combine,
- * exceeding the threshold and creating a merged appearance.
+ * Alpha threshold color matrix for metaball effect.
+ * Same as GPU_ALPHA_THRESHOLD_MATRIX in ProfileMetaballOverlay:
+ * newAlpha = oldAlpha * 51 - 6375 → values above ~125/255 become opaque.
+ * Works on API 31+ (Android 12) — no AGSL/RuntimeShader needed.
  */
-@Language("AGSL")
-const val MetaballShaderSource = """
-    uniform shader composable;
-    uniform float cutoff;
-    
-    half4 main(float2 fragCoord) {
-        half4 color = composable.eval(fragCoord);
-        float alpha = color.a;
-        
-        // Hard threshold: if alpha > cutoff, make fully opaque, else transparent
-        if (alpha > cutoff) {
-            alpha = 1.0;
-        } else {
-            alpha = 0.0;
-        }
-        
-        // Return color with modified alpha
-        return half4(color.r, color.g, color.b, alpha);
-    }
-"""
+private val METABALL_ALPHA_THRESHOLD_MATRIX = floatArrayOf(
+    1f, 0f, 0f, 0f, 0f,
+    0f, 1f, 0f, 0f, 0f,
+    0f, 0f, 1f, 0f, 0f,
+    0f, 0f, 0f, 51f, 51f * -125f
+)
 
 /**
- * Container that applies the metaball shader effect to its children.
- * 
+ * Container that applies the metaball alpha-threshold effect to its children.
+ *
  * Children should use [customBlur] modifier to be part of the metaball effect.
- * When blurred shapes overlap, they appear to "merge" like liquid blobs.
- * 
+ * When blurred shapes overlap, their alpha values combine,
+ * exceeding the threshold and creating a merged "liquid" appearance.
+ *
+ * Uses ColorMatrixColorFilter instead of AGSL shader — works on API 31+ (Android 12).
+ *
  * @param modifier Modifier for the container
- * @param cutoff Alpha threshold (0-1). Higher = harder edges. Default 0.5
  * @param content Composable content (should contain MetaEntity elements)
  */
-@RequiresApi(Build.VERSION_CODES.TIRAMISU)
+@RequiresApi(Build.VERSION_CODES.S)
 @Composable
 fun MetaContainer(
     modifier: Modifier = Modifier,
-    cutoff: Float = 0.5f,
     content: @Composable BoxScope.() -> Unit,
 ) {
-    val metaShader = remember { RuntimeShader(MetaballShaderSource) }
-    
     Box(
         modifier = modifier.graphicsLayer {
-            metaShader.setFloatUniform("cutoff", cutoff)
-            renderEffect = RenderEffect.createRuntimeShaderEffect(
-                metaShader, "composable"
+            renderEffect = RenderEffect.createColorFilterEffect(
+                ColorMatrixColorFilter(METABALL_ALPHA_THRESHOLD_MATRIX)
             ).asComposeRenderEffect()
         },
         content = content,
@@ -77,10 +55,10 @@ fun MetaContainer(
 
 /**
  * Modifier that applies GPU-accelerated blur effect.
- * 
+ *
  * Use this on shapes inside [MetaContainer] to create the metaball effect.
  * The blur radius determines how "soft" the edges are before threshold is applied.
- * 
+ *
  * @param blur Blur radius in pixels. Higher = softer edges, larger merge area
  */
 @RequiresApi(Build.VERSION_CODES.S)
@@ -100,11 +78,11 @@ fun Modifier.customBlur(blur: Float) = this.then(
 
 /**
  * A composable that wraps content with metaball-capable blur.
- * 
+ *
  * This creates a layered effect:
  * - metaContent: The blurred shape that participates in metaball merging
  * - content: The actual visible content (not blurred)
- * 
+ *
  * @param modifier Modifier for the entity
  * @param blur Blur radius for the metaball effect
  * @param metaContent The shape that will be blurred and merged (usually a solid color Box)
@@ -119,12 +97,10 @@ fun MetaEntity(
     content: @Composable BoxScope.() -> Unit = {},
 ) {
     Box(modifier = modifier) {
-        // Blurred layer for metaball effect
         Box(
             modifier = Modifier.customBlur(blur),
             content = metaContent,
         )
-        // Visible content on top
         content()
     }
 }

app/src/main/java/com/rosetta/messenger/ui/components/metaball/ProfileMetaballOverlay.kt

@@ -1,28 +1,42 @@
 package com.rosetta.messenger.ui.components.metaball
 
+import android.graphics.ColorMatrixColorFilter
 import android.graphics.Path
 import android.graphics.RectF
 import android.util.Log
 import android.graphics.RenderEffect
-import android.graphics.RuntimeShader
 import android.graphics.Shader
 import android.os.Build
 import android.view.Gravity
 import androidx.annotation.RequiresApi
 import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.BoxScope
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.offset
+import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.Switch
+import androidx.compose.material3.SwitchDefaults
+import androidx.compose.material3.Text
 import androidx.compose.ui.graphics.RectangleShape
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
@@ -33,9 +47,10 @@ import androidx.compose.ui.graphics.nativeCanvas
 import androidx.compose.ui.platform.LocalConfiguration
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
-import org.intellij.lang.annotations.Language
+import androidx.compose.ui.unit.sp
 import kotlin.math.abs
 import kotlin.math.max
 import kotlin.math.min
@@ -94,7 +109,6 @@ object ProfileMetaballConstants {
     
     // Blur settings for gooey effect (like Telegram's intensity = 15f)
     const val BLUR_RADIUS = 15f
-    const val CUTOFF = 0.5f
     
     // Blur range for avatar (like Telegram: 2 + (1-fraction) * 20)
     const val BLUR_MIN = 2f
@@ -108,28 +122,27 @@ object ProfileMetaballConstants {
 }
 
 /**
- * AGSL Shader for metaball alpha threshold effect
- * Same as Telegram's ColorMatrixColorFilter with alpha threshold
+ * GPU alpha threshold via ColorMatrixColorFilter (API 31+)
+ * Replaces AGSL RuntimeShader — same gooey effect, works on Android 12+
+ *
+ * From Telegram's ProfileGooeyView.GPUImpl:
+ * Alpha row: newAlpha = oldAlpha * 51 - 6375
+ * Values above ~125/255 become opaque, below become transparent.
+ * Equivalent to AGSL cutoff=0.5 but without requiring API 33.
  */
-@Language("AGSL")
-private const val ProfileMetaballShaderSource = """
-    uniform shader composable;
-    uniform float cutoff;
-    
-    half4 main(float2 fragCoord) {
-        half4 color = composable.eval(fragCoord);
-        float alpha = color.a;
-        
-        // Hard threshold for gooey effect
-        if (alpha > cutoff) {
-            alpha = 1.0;
-        } else {
-            alpha = 0.0;
-        }
-        
-        return half4(color.r, color.g, color.b, alpha);
-    }
-"""
+private val GPU_ALPHA_THRESHOLD_MATRIX = floatArrayOf(
+    1f, 0f, 0f, 0f, 0f,
+    0f, 1f, 0f, 0f, 0f,
+    0f, 0f, 1f, 0f, 0f,
+    0f, 0f, 0f, 51f, 51f * -125f
+)
+
+/**
+ * No-notch fallback: black bar height at the top of the screen.
+ * Matches Telegram's BLACK_KING_BAR = 32dp.
+ * When no notch is detected, the avatar merges into this bar instead.
+ */
+private const val BLACK_BAR_HEIGHT_DP = 32f
 
 /**
  * State for avatar position and size during animation
@@ -336,7 +349,7 @@ private fun lerpFloat(start: Float, stop: Float, fraction: Float): Float {
  * 
  * IMPORTANT: Blur is applied ONLY to the metaball shapes, NOT to the avatar content!
  */
-@RequiresApi(Build.VERSION_CODES.TIRAMISU)
+@RequiresApi(Build.VERSION_CODES.S)
 @Composable
 fun ProfileMetaballOverlay(
     collapseProgress: Float,
@@ -345,6 +358,7 @@ fun ProfileMetaballOverlay(
     headerHeight: Dp,
     hasAvatar: Boolean,
     @Suppress("UNUSED_PARAMETER") avatarColor: ComposeColor,
+    factorMult: Float = 1f,
     modifier: Modifier = Modifier,
     avatarContent: @Composable BoxScope.() -> Unit = {},
 ) {
@@ -445,27 +459,26 @@ fun ProfileMetaballOverlay(
         }
     }
     
-    // Metaball shader
-    val metaShader = remember { RuntimeShader(ProfileMetaballShaderSource) }
-    
     // Path for metaball connector
     val metaballPath = remember { Path() }
     val c1 = remember { Point() } // Notch center
     val c2 = remember { Point() } // Avatar center
-    
-    // 🔥 Reusable RectF like Telegram's AndroidUtilities.rectTmp
-    // Avoid creating new RectF objects every frame
+
+    // Reusable RectF like Telegram's AndroidUtilities.rectTmp
     val rectTmp = remember { RectF() }
-    
+
+    // Black bar height for no-notch fallback (Telegram's BLACK_KING_BAR)
+    val blackBarHeightPx = with(density) { BLACK_BAR_HEIGHT_DP.dp.toPx() }
+
+    // Detect if device has a real centered notch (debug override supported)
+    val hasRealNotch = !MetaballDebug.forceNoNotch &&
+            notchInfo != null && notchInfo.gravity == Gravity.CENTER && notchInfo.bounds.width() > 0
+
     // Calculate "v" parameter - thickness of connector based on distance
-    // Like Telegram: v = clamp((1f - c / 1.3f) / 2f, 0.8f, 0)
     val distance = avatarState.centerY - notchCenterY
     val maxDist = avatarSizeExpandedPx
     val c = (distance / maxDist).coerceIn(-1f, 1f)
-    
-    // Like Telegram: when NOT near, reduce v
-    // float near = isNear ? 1f : 1f - (vr - dp(32)) / dp(40 - 32);
-    // v = Math.min(lerp(0f, 0.2f, near), v);
+
     val baseV = ((1f - c / 1.3f) / 2f).coerceIn(0f, 0.8f)
     val near = if (avatarState.isNear) 1f else 1f - (avatarState.radius - dp32) / (dp40 - dp32)
     val v = if (!avatarState.isNear) {
@@ -473,37 +486,37 @@ fun ProfileMetaballOverlay(
     } else {
         baseV
     }
-    
-    // Show connector only when avatar is small enough (like Telegram isDrawing)
-    // AND not when expanding (no metaball effect when expanded)
-    // AND only when hasAvatar is true (no drop animation for placeholder)
-    // AND only when device has real centered notch (Dynamic Island, punch-hole camera)
-    val hasRealNotch = notchInfo != null && notchInfo.gravity == Gravity.CENTER && notchInfo.bounds.width() > 0
-    val showConnector = hasRealNotch && hasAvatar && expansionProgress == 0f && avatarState.isDrawing && avatarState.showBlob && distance < maxDist * 1.5f
-    
-    // Don't show black metaball shapes when expanded or when no avatar or no real notch
-    val showMetaballLayer = hasRealNotch && hasAvatar && expansionProgress == 0f
-    
+
+    // Show connector when avatar is small enough (isDrawing) and not expanding
+    // No longer requires hasRealNotch — works with black bar fallback too
+    val showConnector = hasAvatar && expansionProgress == 0f && avatarState.isDrawing && avatarState.showBlob && distance < maxDist * 1.5f
+
+    // Show metaball layer when collapsing with avatar
+    val showMetaballLayer = hasAvatar && expansionProgress == 0f
+
+    // Adjusted blur radius based on device performance (factorMult)
+    val adjustedBlurRadius = ProfileMetaballConstants.BLUR_RADIUS / factorMult
+
     Box(modifier = modifier
         .fillMaxSize()
-        .clip(RectangleShape)  // Clip to bounds - prevents avatar overflow when expanded
+        .clip(RectangleShape)
     ) {
-        // LAYER 1: Metaball shapes with blur effect (BLACK shapes only)
-        // HIDDEN when expanded - only show avatar content
+        // LAYER 1: Metaball shapes with blur + alpha threshold (BLACK shapes only)
         if (showMetaballLayer) {
             Canvas(
                 modifier = Modifier
                     .fillMaxSize()
                     .graphicsLayer {
-                        metaShader.setFloatUniform("cutoff", ProfileMetaballConstants.CUTOFF)
-                        // IMPORTANT: First blur, THEN threshold shader
-                        // createChainEffect(outer, inner) - inner is applied first
+                        // ColorMatrixColorFilter for alpha threshold (API 31+)
+                        // Replaces AGSL RuntimeShader — same gooey effect
                         val blurEffect = RenderEffect.createBlurEffect(
-                            ProfileMetaballConstants.BLUR_RADIUS,
-                            ProfileMetaballConstants.BLUR_RADIUS,
+                            adjustedBlurRadius,
+                            adjustedBlurRadius,
                             Shader.TileMode.DECAL
                         )
-                        val thresholdEffect = RenderEffect.createRuntimeShaderEffect(metaShader, "composable")
+                        val thresholdEffect = RenderEffect.createColorFilterEffect(
+                            ColorMatrixColorFilter(GPU_ALPHA_THRESHOLD_MATRIX)
+                        )
                         // Chain: blur first (inner), then threshold (outer)
                         renderEffect = RenderEffect.createChainEffect(thresholdEffect, blurEffect)
                             .asComposeRenderEffect()
@@ -513,36 +526,29 @@ fun ProfileMetaballOverlay(
                     color = android.graphics.Color.BLACK
                     style = android.graphics.Paint.Style.FILL
                 }
-                
+
                 drawIntoCanvas { canvas ->
                     val nativeCanvas = canvas.nativeCanvas
-                    
-                    // Draw notch/camera circle (small circle at top)
+
+                    // Draw target shape at top (notch or black bar fallback)
                     if (showConnector) {
-                        if (notchInfo != null && notchInfo.isLikelyCircle) {
-                            // Draw circle at actual notch position
+                        if (hasRealNotch && notchInfo != null && notchInfo.isLikelyCircle) {
                             nativeCanvas.drawCircle(
                                 notchCenterX,
                                 notchCenterY,
                                 notchRadiusPx,
                                 paint
                             )
-                        } else if (notchInfo != null && notchInfo.isAccurate && notchInfo.path != null) {
-                            // Draw actual notch path
+                        } else if (hasRealNotch && notchInfo != null && notchInfo.isAccurate && notchInfo.path != null) {
                             nativeCanvas.drawPath(notchInfo.path, paint)
-                        } else if (notchInfo != null) {
-                            // Draw rounded rect for non-accurate notch
+                        } else if (hasRealNotch && notchInfo != null) {
                             val bounds = notchInfo.bounds
                             val rad = kotlin.math.max(bounds.width(), bounds.height()) / 2f
                             nativeCanvas.drawRoundRect(bounds, rad, rad, paint)
                         } else {
-                            // No notch - draw small circle at status bar center
-                            nativeCanvas.drawCircle(
-                                screenWidthPx / 2f,
-                                statusBarHeightPx / 2f,
-                                notchRadiusPx,
-                                paint
-                            )
+                            // No notch fallback: full-width black bar at top
+                            // Like Telegram's ProfileGooeyView when notchInfo == null
+                            nativeCanvas.drawRect(0f, 0f, screenWidthPx, blackBarHeightPx, paint)
                         }
                     }
                 
@@ -699,8 +705,10 @@ fun ProfileMetaballOverlayCompat(
     val avatarSizeMinPx = with(density) { ProfileMetaballConstants.AVATAR_SIZE_MIN.toPx() }
     
     // Fallback notch values for compat mode
-    val notchCenterX = screenWidthPx / 2f  // Center of screen for compat mode
-    val notchCenterY = statusBarHeightPx / 2f
+    // Use black bar center as target (like Telegram's BLACK_KING_BAR)
+    val blackBarHeightPx = with(density) { BLACK_BAR_HEIGHT_DP.dp.toPx() }
+    val notchCenterX = screenWidthPx / 2f
+    val notchCenterY = blackBarHeightPx / 2f
     val notchRadiusPx = with(density) { ProfileMetaballConstants.FALLBACK_CAMERA_SIZE.toPx() }
     
     // Telegram thresholds in pixels
@@ -804,7 +812,432 @@ fun ProfileMetaballOverlayCompat(
 }
 
 /**
- * Auto-selecting wrapper based on Android version
+ * CPU alpha threshold matrix — from Telegram's ProfileGooeyView.CPUImpl.
+ * Operates on downscaled black shapes:
+ * Alpha row: newAlpha = oldAlpha * 60 - 7500
+ * Threshold at alpha ~125/255. RGB forced to 0 (black mask).
+ */
+private val CPU_ALPHA_THRESHOLD_MATRIX = floatArrayOf(
+    0f, 0f, 0f, 0f, 0f,
+    0f, 0f, 0f, 0f, 0f,
+    0f, 0f, 0f, 0f, 0f,
+    0f, 0f, 0f, 51f, -6375f  // Match GPU threshold: cutoff at alpha ~125/255
+)
+
+/**
+ * CPU path for metaball effect — works on any Android version.
+ * Matches Telegram's ProfileGooeyView.CPUImpl:
+ * 1. Draw black shapes (target + avatar + connector) into a downscaled bitmap
+ * 2. Apply stack blur on CPU
+ * 3. Draw with ColorMatrixColorFilter for alpha threshold
+ * 4. Composite with SRC_ATOP
+ */
+@Composable
+fun ProfileMetaballOverlayCpu(
+    collapseProgress: Float,
+    expansionProgress: Float,
+    statusBarHeight: Dp,
+    headerHeight: Dp,
+    hasAvatar: Boolean,
+    @Suppress("UNUSED_PARAMETER") avatarColor: ComposeColor,
+    modifier: Modifier = Modifier,
+    avatarContent: @Composable BoxScope.() -> Unit = {},
+) {
+    val context = LocalContext.current
+    val configuration = LocalConfiguration.current
+    val screenWidth = configuration.screenWidthDp.dp
+    val density = LocalDensity.current
+
+    val screenWidthPx = with(density) { screenWidth.toPx() }
+    val statusBarHeightPx = with(density) { statusBarHeight.toPx() }
+    val headerHeightPx = with(density) { headerHeight.toPx() }
+    val avatarSizeExpandedPx = with(density) { ProfileMetaballConstants.AVATAR_SIZE_EXPANDED.toPx() }
+    val avatarSizeMinPx = with(density) { ProfileMetaballConstants.AVATAR_SIZE_MIN.toPx() }
+
+    // Get notch info (debug override supported)
+    val notchInfo = remember { NotchInfoUtils.getInfo(context) }
+    val hasRealNotch = !MetaballDebug.forceNoNotch &&
+            notchInfo != null && notchInfo.gravity == Gravity.CENTER && notchInfo.bounds.width() > 0
+    val blackBarHeightPx = with(density) { BLACK_BAR_HEIGHT_DP.dp.toPx() }
+
+    val notchRadiusPx = remember(notchInfo) {
+        if (hasRealNotch && notchInfo != null) {
+            if (notchInfo.isLikelyCircle) {
+                min(notchInfo.bounds.width(), notchInfo.bounds.height()) / 2f
+            } else {
+                kotlin.math.max(notchInfo.bounds.width(), notchInfo.bounds.height()) / 2f
+            }
+        } else {
+            with(density) { ProfileMetaballConstants.FALLBACK_CAMERA_SIZE.toPx() }
+        }
+    }
+    val notchCenterX = remember(notchInfo, screenWidthPx) {
+        if (hasRealNotch && notchInfo != null) notchInfo.bounds.centerX() else screenWidthPx / 2f
+    }
+    val notchCenterY = remember(notchInfo) {
+        if (hasRealNotch && notchInfo != null && notchInfo.isLikelyCircle) {
+            notchInfo.bounds.bottom - notchInfo.bounds.width() / 2f
+        } else if (hasRealNotch && notchInfo != null) {
+            notchInfo.bounds.centerY()
+        } else {
+            blackBarHeightPx / 2f
+        }
+    }
+
+    // Thresholds
+    val dp40 = with(density) { ProfileMetaballConstants.THRESHOLD_DRAWING.toPx() }
+    val dp34 = with(density) { ProfileMetaballConstants.THRESHOLD_SHAPE_END.toPx() }
+    val dp32 = with(density) { ProfileMetaballConstants.THRESHOLD_NEAR.toPx() }
+    val dp18 = with(density) { ProfileMetaballConstants.THRESHOLD_ALPHA_END.toPx() }
+    val dp22 = with(density) { ProfileMetaballConstants.ROUNDED_RECT_RADIUS.toPx() }
+
+    val avatarState by remember(screenWidthPx, statusBarHeightPx, headerHeightPx, notchCenterX, notchCenterY, notchRadiusPx) {
+        derivedStateOf {
+            computeAvatarState(
+                collapseProgress = collapseProgress,
+                expansionProgress = expansionProgress,
+                screenWidthPx = screenWidthPx,
+                statusBarHeightPx = statusBarHeightPx,
+                headerHeightPx = headerHeightPx,
+                avatarSizeExpandedPx = avatarSizeExpandedPx,
+                avatarSizeMinPx = avatarSizeMinPx,
+                hasAvatar = hasAvatar,
+                notchCenterX = notchCenterX,
+                notchCenterY = notchCenterY,
+                notchRadiusPx = notchRadiusPx,
+                dp40 = dp40, dp34 = dp34, dp32 = dp32, dp18 = dp18, dp22 = dp22,
+                fullCornerRadius = avatarSizeExpandedPx / 2f
+            )
+        }
+    }
+
+    // Reusable objects
+    val metaballPath = remember { android.graphics.Path() }
+    val c1 = remember { Point() }
+    val c2 = remember { Point() }
+    val rectTmp = remember { RectF() }
+
+    // Connector calculations
+    val distance = avatarState.centerY - notchCenterY
+    val maxDist = avatarSizeExpandedPx
+    val cParam = (distance / maxDist).coerceIn(-1f, 1f)
+    val baseV = ((1f - cParam / 1.3f) / 2f).coerceIn(0f, 0.8f)
+    val near = if (avatarState.isNear) 1f else 1f - (avatarState.radius - dp32) / (dp40 - dp32)
+    val v = if (!avatarState.isNear) min(lerpFloat(0f, 0.2f, near), baseV) else baseV
+
+    val showConnector = hasAvatar && expansionProgress == 0f && avatarState.isDrawing && avatarState.showBlob && distance < maxDist * 1.5f
+    val showMetaballLayer = hasAvatar && expansionProgress == 0f
+
+    // CPU-specific: downscaled bitmap for blur
+    // Reduced from 5 to 3 for higher resolution — smoother edges after alpha threshold
+    val scaleConst = 3f
+    val optimizedW = min(with(density) { 120.dp.toPx() }.toInt(), screenWidthPx.toInt())
+    val optimizedH = min(with(density) { 220.dp.toPx() }.toInt(), headerHeightPx.toInt() + blackBarHeightPx.toInt())
+    val bitmapW = (optimizedW / scaleConst).toInt().coerceAtLeast(1)
+    val bitmapH = (optimizedH / scaleConst).toInt().coerceAtLeast(1)
+
+    val offscreenBitmap = remember(bitmapW, bitmapH) {
+        android.graphics.Bitmap.createBitmap(bitmapW, bitmapH, android.graphics.Bitmap.Config.ARGB_8888)
+    }
+    val offscreenCanvas = remember(offscreenBitmap) {
+        android.graphics.Canvas(offscreenBitmap)
+    }
+
+    // Reusable paints
+    val blackPaint = remember {
+        android.graphics.Paint(android.graphics.Paint.ANTI_ALIAS_FLAG).apply {
+            color = android.graphics.Color.BLACK
+            style = android.graphics.Paint.Style.FILL
+        }
+    }
+    val filterPaint = remember {
+        android.graphics.Paint(android.graphics.Paint.FILTER_BITMAP_FLAG or android.graphics.Paint.ANTI_ALIAS_FLAG).apply {
+            isFilterBitmap = true
+            colorFilter = ColorMatrixColorFilter(CPU_ALPHA_THRESHOLD_MATRIX)
+        }
+    }
+
+    // Cleanup bitmap on dispose
+    DisposableEffect(offscreenBitmap) {
+        onDispose {
+            if (!offscreenBitmap.isRecycled) {
+                offscreenBitmap.recycle()
+            }
+        }
+    }
+
+    Box(modifier = modifier
+        .fillMaxSize()
+        .clip(RectangleShape)
+    ) {
+        // LAYER 1: CPU-rendered metaball shapes
+        if (showMetaballLayer) {
+            Canvas(modifier = Modifier.fillMaxSize()) {
+                drawIntoCanvas { canvas ->
+                    val nativeCanvas = canvas.nativeCanvas
+                    val optimizedOffsetX = (screenWidthPx - optimizedW) / 2f
+
+                    // Clear offscreen bitmap
+                    offscreenBitmap.eraseColor(0)
+
+                    // Draw shapes into downscaled bitmap
+                    offscreenCanvas.save()
+                    offscreenCanvas.scale(
+                        offscreenBitmap.width.toFloat() / optimizedW,
+                        offscreenBitmap.height.toFloat() / optimizedH
+                    )
+                    offscreenCanvas.translate(-optimizedOffsetX, 0f)
+
+                    // Draw target (notch or black bar)
+                    if (showConnector) {
+                        if (hasRealNotch && notchInfo != null && notchInfo.isLikelyCircle) {
+                            val rad = min(notchInfo.bounds.width(), notchInfo.bounds.height()) / 2f
+                            offscreenCanvas.drawCircle(
+                                notchInfo.bounds.centerX(),
+                                notchInfo.bounds.bottom - notchInfo.bounds.width() / 2f,
+                                rad, blackPaint
+                            )
+                        } else if (hasRealNotch && notchInfo != null && notchInfo.isAccurate && notchInfo.path != null) {
+                            offscreenCanvas.drawPath(notchInfo.path, blackPaint)
+                        } else if (hasRealNotch && notchInfo != null) {
+                            val bounds = notchInfo.bounds
+                            val rad = kotlin.math.max(bounds.width(), bounds.height()) / 2f
+                            offscreenCanvas.drawRoundRect(bounds, rad, rad, blackPaint)
+                        } else {
+                            // No notch: draw black bar
+                            offscreenCanvas.drawRect(0f, 0f, screenWidthPx, blackBarHeightPx, blackPaint)
+                        }
+                    }
+
+                    // Draw avatar shape
+                    if (avatarState.showBlob) {
+                        val cx = avatarState.centerX
+                        val cy = avatarState.centerY
+                        val r = avatarState.radius
+                        val cornerR = avatarState.cornerRadius
+
+                        if (cornerR >= r * 0.95f) {
+                            offscreenCanvas.drawCircle(cx, cy, r, blackPaint)
+                        } else {
+                            rectTmp.set(cx - r, cy - r, cx + r, cy + r)
+                            offscreenCanvas.drawRoundRect(rectTmp, cornerR, cornerR, blackPaint)
+                        }
+                    }
+
+                    // Draw metaball connector
+                    if (showConnector && avatarState.showBlob) {
+                        c1.x = notchCenterX
+                        c1.y = notchCenterY
+                        c2.x = avatarState.centerX
+                        c2.y = avatarState.centerY
+
+                        if (createMetaballPath(c1, c2, notchRadiusPx, avatarState.radius, v, metaballPath)) {
+                            offscreenCanvas.drawPath(metaballPath, blackPaint)
+                        }
+                    }
+
+                    offscreenCanvas.restore()
+
+                    // Apply stack blur on CPU
+                    val blurRadius = (ProfileMetaballConstants.BLUR_RADIUS * 2 / scaleConst).toInt().coerceAtLeast(1)
+                    stackBlurBitmapInPlace(offscreenBitmap, blurRadius)
+
+                    // Draw blurred bitmap with color matrix filter (alpha threshold)
+                    nativeCanvas.save()
+                    nativeCanvas.translate(optimizedOffsetX, 0f)
+                    nativeCanvas.scale(
+                        optimizedW.toFloat() / offscreenBitmap.width,
+                        optimizedH.toFloat() / offscreenBitmap.height
+                    )
+                    nativeCanvas.drawBitmap(offscreenBitmap, 0f, 0f, filterPaint)
+                    nativeCanvas.restore()
+                }
+            }
+        }
+
+        // LAYER 2: Avatar content (same as GPU path)
+        if (avatarState.showBlob) {
+            val baseSizeDp = ProfileMetaballConstants.AVATAR_SIZE_EXPANDED
+            val baseSizePx = with(density) { baseSizeDp.toPx() }
+
+            val baseScale = (avatarState.radius * 2f) / baseSizePx
+            val targetExpansionScale = screenWidthPx / baseSizePx
+            val uniformScale = if (expansionProgress > 0f) {
+                lerpFloat(baseScale, targetExpansionScale, expansionProgress)
+            } else {
+                baseScale
+            }.coerceAtLeast(0.01f)
+
+            val avatarCenterX = avatarState.centerX
+            val avatarCenterY = avatarState.centerY
+            val targetCenterX = screenWidthPx / 2f
+            val targetCenterY = headerHeightPx / 2f
+            val currentCenterX = if (expansionProgress > 0f) lerpFloat(avatarCenterX, targetCenterX, expansionProgress) else avatarCenterX
+            val currentCenterY = if (expansionProgress > 0f) lerpFloat(avatarCenterY, targetCenterY, expansionProgress) else avatarCenterY
+
+            val cornerRadiusPx: Float = if (expansionProgress > 0f) {
+                lerpFloat(baseSizePx / 2f, 0f, expansionProgress)
+            } else {
+                (avatarState.cornerRadius / baseScale).coerceAtMost(baseSizePx / 2f)
+            }
+
+            val offsetX = with(density) { (currentCenterX - baseSizePx / 2f).toDp() }
+            val offsetY = with(density) { (currentCenterY - baseSizePx / 2f).toDp() }
+            val cornerRadiusDp = with(density) { cornerRadiusPx.toDp() }
+
+            Box(
+                modifier = Modifier
+                    .offset(x = offsetX, y = offsetY)
+                    .width(baseSizeDp)
+                    .height(baseSizeDp)
+                    .graphicsLayer {
+                        scaleX = uniformScale
+                        scaleY = uniformScale
+                        alpha = avatarState.opacity
+                    }
+                    .clip(RoundedCornerShape(cornerRadiusDp)),
+                contentAlignment = Alignment.Center,
+                content = avatarContent
+            )
+        }
+    }
+}
+
+/**
+ * DEBUG: Temporary toggle to force a specific rendering path.
+ * Set forceMode to test different paths on your device:
+ * - null: auto-detect (default production behavior)
+ * - "gpu": force GPU path (requires API 31+)
+ * - "cpu": force CPU bitmap path
+ * - "compat": force compat/noop path
+ *
+ * Set forceNoNotch = true to simulate no-notch device (black bar fallback).
+ *
+ * TODO: Remove before release!
+ */
+object MetaballDebug {
+    var forceMode: String? = null      // "gpu", "cpu", "compat", or null
+    var forceNoNotch: Boolean = false   // true = pretend no notch exists
+}
+
+/**
+ * DEBUG: Floating panel with buttons to switch metaball rendering path.
+ * Place inside a Box (e.g. profile header) — it aligns to bottom-center.
+ * TODO: Remove before release!
+ */
+@Composable
+fun MetaballDebugPanel(modifier: Modifier = Modifier) {
+    var currentMode by remember { mutableStateOf(MetaballDebug.forceMode) }
+    var noNotch by remember { mutableStateOf(MetaballDebug.forceNoNotch) }
+
+    val context = LocalContext.current
+    val perfClass = remember { DevicePerformanceClass.get(context) }
+
+    Column(
+        modifier = modifier
+            .fillMaxWidth()
+            .padding(horizontal = 12.dp)
+            .background(
+                ComposeColor.Black.copy(alpha = 0.75f),
+                RoundedCornerShape(12.dp)
+            )
+            .padding(12.dp),
+        verticalArrangement = Arrangement.spacedBy(8.dp)
+    ) {
+        // Title
+        Text(
+            text = "Metaball Debug  |  API ${Build.VERSION.SDK_INT}  |  $perfClass",
+            color = ComposeColor.White,
+            fontSize = 11.sp,
+            fontWeight = FontWeight.Bold
+        )
+
+        // Mode buttons row
+        Row(
+            horizontalArrangement = Arrangement.spacedBy(6.dp),
+            modifier = Modifier.fillMaxWidth()
+        ) {
+            val modes = listOf(null to "Auto", "gpu" to "GPU", "cpu" to "CPU", "compat" to "Compat")
+            modes.forEach { (mode, label) ->
+                val isSelected = currentMode == mode
+                Box(
+                    modifier = Modifier
+                        .weight(1f)
+                        .clip(RoundedCornerShape(8.dp))
+                        .background(
+                            if (isSelected) ComposeColor(0xFF4CAF50) else ComposeColor.White.copy(alpha = 0.15f)
+                        )
+                        .border(
+                            width = 1.dp,
+                            color = if (isSelected) ComposeColor(0xFF4CAF50) else ComposeColor.White.copy(alpha = 0.3f),
+                            shape = RoundedCornerShape(8.dp)
+                        )
+                        .clickable {
+                            MetaballDebug.forceMode = mode
+                            currentMode = mode
+                        }
+                        .padding(vertical = 8.dp),
+                    contentAlignment = Alignment.Center
+                ) {
+                    Text(
+                        text = label,
+                        color = ComposeColor.White,
+                        fontSize = 12.sp,
+                        fontWeight = if (isSelected) FontWeight.Bold else FontWeight.Normal
+                    )
+                }
+            }
+        }
+
+        // No-notch toggle
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.SpaceBetween,
+            modifier = Modifier.fillMaxWidth()
+        ) {
+            Text(
+                text = "Force no-notch (black bar)",
+                color = ComposeColor.White,
+                fontSize = 12.sp
+            )
+            Switch(
+                checked = noNotch,
+                onCheckedChange = {
+                    MetaballDebug.forceNoNotch = it
+                    noNotch = it
+                },
+                colors = SwitchDefaults.colors(
+                    checkedThumbColor = ComposeColor(0xFF4CAF50),
+                    checkedTrackColor = ComposeColor(0xFF4CAF50).copy(alpha = 0.5f)
+                )
+            )
+        }
+
+        // Current active path info
+        val activePath = when (currentMode) {
+            "gpu" -> if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) "GPU (forced)" else "GPU needs API 31!"
+            "cpu" -> "CPU (forced)"
+            "compat" -> "Compat (forced)"
+            else -> when {
+                Build.VERSION.SDK_INT >= Build.VERSION_CODES.S && perfClass >= PerformanceClass.AVERAGE -> "GPU (auto)"
+                perfClass >= PerformanceClass.HIGH -> "CPU (auto)"
+                else -> "Compat (auto)"
+            }
+        }
+        Text(
+            text = "Active: $activePath" + if (noNotch) " + no-notch" else "",
+            color = ComposeColor(0xFF4CAF50),
+            fontSize = 11.sp,
+            fontWeight = FontWeight.Medium
+        )
+    }
+}
+
+/**
+ * Auto-selecting wrapper — 3-tier architecture matching Telegram's ProfileGooeyView:
+ * 1. GPU path (Android 12+, average+ performance): RenderEffect blur + ColorMatrixColorFilter
+ * 2. CPU path (any Android, high performance): Bitmap blur + ColorMatrixColorFilter
+ * 3. Noop path (low-end devices): Simple scale/opacity animation
  */
 @Composable
 fun ProfileMetaballEffect(
@@ -817,27 +1250,76 @@ fun ProfileMetaballEffect(
     modifier: Modifier = Modifier,
     avatarContent: @Composable BoxScope.() -> Unit = {},
 ) {
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
-        ProfileMetaballOverlay(
-            collapseProgress = collapseProgress,
-            expansionProgress = expansionProgress,
-            statusBarHeight = statusBarHeight,
-            headerHeight = headerHeight,
-            hasAvatar = hasAvatar,
-            avatarColor = avatarColor,
-            modifier = modifier,
-            avatarContent = avatarContent
-        )
-    } else {
-        ProfileMetaballOverlayCompat(
-            collapseProgress = collapseProgress,
-            expansionProgress = expansionProgress,
-            statusBarHeight = statusBarHeight,
-            headerHeight = headerHeight,
-            hasAvatar = hasAvatar,
-            avatarColor = avatarColor,
-            modifier = modifier,
-            avatarContent = avatarContent
-        )
+    val context = LocalContext.current
+    val performanceClass = remember { DevicePerformanceClass.get(context) }
+
+    // Debug: log which path is selected
+    val selectedPath = when (MetaballDebug.forceMode) {
+        "gpu" -> "GPU (forced)"
+        "cpu" -> "CPU (forced)"
+        "compat" -> "Compat (forced)"
+        else -> when {
+            Build.VERSION.SDK_INT >= Build.VERSION_CODES.S && performanceClass >= PerformanceClass.AVERAGE -> "GPU (auto)"
+            performanceClass >= PerformanceClass.HIGH -> "CPU (auto)"
+            else -> "Compat (auto)"
+        }
+    }
+    LaunchedEffect(selectedPath) {
+        Log.d("MetaballDebug", "Rendering path: $selectedPath, forceNoNotch: ${MetaballDebug.forceNoNotch}, perf: $performanceClass, API: ${Build.VERSION.SDK_INT}")
+    }
+
+    // Resolve actual mode
+    val useGpu = when (MetaballDebug.forceMode) {
+        "gpu" -> Build.VERSION.SDK_INT >= Build.VERSION_CODES.S // still need API 31
+        "cpu" -> false
+        "compat" -> false
+        else -> Build.VERSION.SDK_INT >= Build.VERSION_CODES.S && performanceClass >= PerformanceClass.AVERAGE
+    }
+    val useCpu = when (MetaballDebug.forceMode) {
+        "gpu" -> false
+        "cpu" -> true
+        "compat" -> false
+        else -> !useGpu && performanceClass >= PerformanceClass.HIGH
+    }
+
+    when {
+        useGpu -> {
+            val factorMult = if (performanceClass == PerformanceClass.HIGH) 1f else 1.5f
+            ProfileMetaballOverlay(
+                collapseProgress = collapseProgress,
+                expansionProgress = expansionProgress,
+                statusBarHeight = statusBarHeight,
+                headerHeight = headerHeight,
+                hasAvatar = hasAvatar,
+                avatarColor = avatarColor,
+                factorMult = factorMult,
+                modifier = modifier,
+                avatarContent = avatarContent
+            )
+        }
+        useCpu -> {
+            ProfileMetaballOverlayCpu(
+                collapseProgress = collapseProgress,
+                expansionProgress = expansionProgress,
+                statusBarHeight = statusBarHeight,
+                headerHeight = headerHeight,
+                hasAvatar = hasAvatar,
+                avatarColor = avatarColor,
+                modifier = modifier,
+                avatarContent = avatarContent
+            )
+        }
+        else -> {
+            ProfileMetaballOverlayCompat(
+                collapseProgress = collapseProgress,
+                expansionProgress = expansionProgress,
+                statusBarHeight = statusBarHeight,
+                headerHeight = headerHeight,
+                hasAvatar = hasAvatar,
+                avatarColor = avatarColor,
+                modifier = modifier,
+                avatarContent = avatarContent
+            )
+        }
     }
 }

app/src/main/java/com/rosetta/messenger/ui/settings/ProfileScreen.kt

@@ -55,6 +55,7 @@ import com.rosetta.messenger.biometric.BiometricAvailability
 import com.rosetta.messenger.biometric.BiometricPreferences
 import com.rosetta.messenger.repository.AvatarRepository
 import com.rosetta.messenger.ui.components.BlurredAvatarBackground
+
 import com.rosetta.messenger.ui.components.metaball.ProfileMetaballEffect
 import com.rosetta.messenger.utils.AvatarFileManager
 import com.rosetta.messenger.utils.ImageCropHelper