Merge pull request 'savya' (#14) from savya into main

Reviewed-on: #14

Assets/Darkmatter/Code/Core/Contracts/Features/DrawingCatalog/IDrawingTemplate.cs

@@ -9,6 +9,7 @@ namespace Darkmatter.Core.Contracts.Features.DrawingCatalog
     {
         string Id { get; }
         string DisplayName { get; }
+        int Difficulty { get; }
         Sprite DefaultThumbnail { get; }
         GameObject DrawingPrefab { get; }
         GameObject ColoringPrefab { get; }

Assets/Darkmatter/Code/Core/Contracts/Features/DrawingCatalog/IDrawingTemplateCatalog.cs

@@ -6,9 +6,12 @@ namespace Darkmatter.Core.Contracts.Features.DrawingCatalog
 {
     public interface IDrawingTemplateCatalog
     {
-        UniTask FetchAsync(); 
+        UniTask FetchAsync();
         IReadOnlyList<string> AllTemplateIds { get; }
-        UniTask<Sprite> GetThumbnailAsync(string id);
+        // owned = true when the sprite (and its texture) were created for this call from a
+        // saved thumbnail on disk — the caller must Destroy() both when done. owned = false
+        // means the template's default thumbnail asset, which must NOT be destroyed.
+        UniTask<(Sprite sprite, bool owned)> GetThumbnailAsync(string id);
         UniTask<IDrawingTemplate> LoadAsync(string id);
         void ReleaseAll();
         string GetNextTemplate(string currentId);

Assets/Darkmatter/Code/Core/Contracts/Services/Analytics/AnalyticsEvents.cs

@@ -11,9 +11,9 @@ namespace Darkmatter.Core.Contracts.Services.Analytics
         // Onboarding / activation funnel
         public const string IntroStarted = "intro_started";
         public const string IntroCompleted = "intro_completed";
-        public const string TutorialStarted = "tutorial_started";
+        public const string TutorialStarted = "tutorial_begin";
         public const string TutorialStepCompleted = "tutorial_step_completed";
-        public const string TutorialCompleted = "tutorial_completed";
+        public const string TutorialCompleted = "tutorial_complete";
         public const string PlayClicked = "play_clicked";
         public const string FirstDrawingStarted = "first_drawing_started";
 
@@ -32,9 +32,9 @@ namespace Darkmatter.Core.Contracts.Services.Analytics
         public const string ShapeAssembled = "shape_assembled";
         public const string ColorApplied = "color_applied";
 
-        // Progression & content (GA4 recommended level_start / level_complete)
+        // Progression & content. level_start and level_end are GA4-recommended games events.
         public const string LevelStart = "level_start";
-        public const string LevelComplete = "level_complete";
+        public const string LevelComplete = "level_end";
         public const string AllContentCompleted = "all_content_completed";
 
         // Gallery capture (pre-existing)

Assets/Darkmatter/Code/Core/Contracts/Services/Analytics/AnalyticsParams.cs

@@ -4,14 +4,14 @@ namespace Darkmatter.Core.Contracts.Services.Analytics
     /// Canonical analytics parameter keys. Pass a consistent set on every gameplay event so reports can
     /// answer "which drawing did people quit on", not just "how many quit". Each key used in reports must
     /// be registered as a Custom Dimension in the Firebase console. GA4 limit: 25 params per event.
-    /// GA4-recommended events (level_start/level_complete/ad_impression) reuse GA4's reserved param names
+    /// GA4-recommended events (level_start/level_end/ad_impression) reuse GA4's reserved param names
     /// (level_name, success, value, currency, ad_platform, ad_format, ad_unit_name) so they're recognised.
     /// </summary>
     public static class AnalyticsParams
     {
         // Content identity
         public const string DrawingId = "drawing_id";
-        public const string LevelName = "level_name"; // GA4 reserved (level_start/level_complete)
+        public const string LevelName = "level_name"; // GA4 reserved (level_start/level_end)
 
         // Tutorial
         public const string StepId = "step_id";
@@ -23,7 +23,7 @@ namespace Darkmatter.Core.Contracts.Services.Analytics
         public const string Attempts = "attempts";
         public const string ApplyIndex = "apply_index";
         public const string CompletionCount = "completion_count";
-        public const string Success = "success"; // GA4 reserved (level_complete)
+        public const string Success = "success"; // GA4 reserved (level_end)
 
         // Monetization (GA4 ad_impression reserved names)
         public const string Value = "value";

Assets/Darkmatter/Code/Core/Data/Signals/Features/Capture/GallerySaveCompletedSignal.cs

@@ -1,4 +1,8 @@
 namespace Darkmatter.Core.Data.Signals.Features.Capture
 {
-    public record struct GallerySaveCompletedSignal(bool Success);
+    /// <summary>
+    /// TemplateId identifies which drawing was saved; publishers outside gameplay (art book) must set it
+    /// because there is no active drawing for analytics to fall back on there.
+    /// </summary>
+    public record struct GallerySaveCompletedSignal(bool Success, string TemplateId = null);
 }

Assets/Darkmatter/Code/Core/Data/Signals/Features/DrawingCatalog/ColorbookShownSignal.cs

@@ -0,0 +1,10 @@
+namespace Darkmatter.Core
+{
+    /// <summary>
+    /// The drawing-catalog (colorbook) screen became visible: scene entry (play / back / next) or
+    /// returning from the art book. Distinct from <see cref="OpenColorBookSignal"/>, which is the
+    /// command to show the view and only fires on one navigation path. Analytics keys colorbook_opened
+    /// and abandoned-drawing detection off this.
+    /// </summary>
+    public record struct ColorbookShownSignal;
+}

Assets/Darkmatter/Code/Core/Data/Signals/Features/DrawingCatalog/ColorbookShownSignal.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: fa0fb32346ff54da3a9bbfec9f763cf2

Assets/Darkmatter/Code/Core/Data/Static/Features/DrawingTemplate/DrawingTemplateSO.cs

@@ -12,6 +12,8 @@ namespace Darkmatter.Core.Data.Static.Features.DrawingTemplate
     {
         [SerializeField] private string id;
         [SerializeField] private string displayName;
+        [SerializeField, Min(0), Tooltip("0 = auto (pieces + regions). Any positive value overrides the computed difficulty.")]
+        private int difficultyOverride;
         [SerializeField] private Sprite defaultThumbnail;
         [SerializeField] private GameObject drawingPrefab;
         [SerializeField] private GameObject coloringPrefab;
@@ -22,6 +24,11 @@ namespace Darkmatter.Core.Data.Static.Features.DrawingTemplate
 
         public string Id => id;
         public string DisplayName => displayName;
+        // Workload-based: every shape to place and region to color adds one point.
+        // A positive difficultyOverride replaces the computed value.
+        public int AutoDifficulty => pieces.Count + regions.Count;
+        public int Difficulty => difficultyOverride > 0 ? difficultyOverride : AutoDifficulty;
+        public bool HasDifficultyOverride => difficultyOverride > 0;
         public Sprite DefaultThumbnail => defaultThumbnail;
         public GameObject DrawingPrefab => drawingPrefab;
         public GameObject ColoringPrefab => coloringPrefab;

Assets/Darkmatter/Code/Features/AppBoot/Features.AppBoot.asmdef

@@ -6,7 +6,8 @@
         "GUID:c1c03c0e5b2f4412b9f2be1c20d6a9b1",
         "GUID:b4c9f7fbf1e144933a1797dc208ece5f",
         "GUID:b0214a6008ed146ff8f122a6a9c2f6cc",
-        "GUID:f51ebe6a0ceec4240a699833d6309b23"
+        "GUID:f51ebe6a0ceec4240a699833d6309b23",
+        "GUID:75469ad4d38634e559750d17036d5f7c"
     ],
     "includePlatforms": [],
     "excludePlatforms": [],

Assets/Darkmatter/Code/Features/AppBoot/Flow/AdaptiveFrameRate.cs

@@ -0,0 +1,48 @@
+using UnityEngine;
+using UnityEngine.InputSystem;
+using UnityEngine.Rendering;
+using VContainer.Unity;
+
+namespace Darkmatter.Features.AppBoot.Flow
+{
+    // A coloring page is static most of the time; re-rendering it at a locked 60 fps only
+    // turns battery into heat. Keep the player loop at 60 Hz (input still sampled every
+    // frame, so the first touch never lands on a skipped frame) but render every other
+    // frame while nothing has been touched for a few seconds.
+    public sealed class AdaptiveFrameRate : ITickable
+    {
+        private const float FullRateHoldSeconds = 3f;
+        private const int IdleRenderInterval = 2; // 60 Hz loop -> 30 fps rendering when idle
+
+        private float _lastInteractionTime;
+
+        public AdaptiveFrameRate()
+        {
+            // Treat boot as an interaction so the intro video starts at full rate.
+            _lastInteractionTime = Time.unscaledTime;
+        }
+
+        public void Tick()
+        {
+            if (IsPointerPressed())
+                _lastInteractionTime = Time.unscaledTime;
+
+            var desired = Time.unscaledTime - _lastInteractionTime < FullRateHoldSeconds
+                ? 1
+                : IdleRenderInterval;
+
+            if (OnDemandRendering.renderFrameInterval != desired)
+                OnDemandRendering.renderFrameInterval = desired;
+        }
+
+        private static bool IsPointerPressed()
+        {
+            var touchscreen = Touchscreen.current;
+            if (touchscreen != null && touchscreen.primaryTouch.press.isPressed)
+                return true;
+
+            var mouse = Mouse.current;
+            return mouse != null && mouse.leftButton.isPressed;
+        }
+    }
+}

Assets/Darkmatter/Code/Features/AppBoot/Flow/AdaptiveFrameRate.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: ee0bbb69e2ec44637a7f5fb6f18a2518

Assets/Darkmatter/Code/Features/AppBoot/Flow/AppBootFlow.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Threading;
 using Cysharp.Threading.Tasks;
 using Darkmatter.Core.Contracts.Features.Progression;
@@ -14,6 +15,10 @@ namespace Darkmatter.Features.AppBoot.Flow
 {
     public class AppBootFlow : IAsyncStartable
     {
+        private const int IntroPrepareTimeoutMs = 3000;
+        private const float IntroMinimumFallbackSeconds = 6f;
+        private const float IntroFallbackPaddingSeconds = 2f;
+
         private readonly AppBootSceneRefs _sceneRefs;
         private readonly ISceneService _sceneService;
         private readonly IEventBus _eventBus;
@@ -30,36 +35,96 @@ namespace Darkmatter.Features.AppBoot.Flow
 
         public async UniTask StartAsync(CancellationToken cancellation = default)
         {
+            // Entry points run in serviceModules registration order and this module is near the front.
+            // Everything below LoadAsync completes synchronously, so without a real yield the
+            // IntroStartedSignal publish would happen before later-registered subscribers
+            // (e.g. AnalyticsTracker) have run Start() — the event bus has no replay, so they'd miss it.
+            await UniTask.Yield();
+
 #if UNITY_ANDROID || UNITY_IOS
             Application.targetFrameRate = 60;
 #endif
             Screen.sleepTimeout = SleepTimeout.NeverSleep;
             await _progression.LoadAsync();
 
-            var tcs = new UniTaskCompletionSource();
             var player = _sceneRefs.IntroVideoPlayer;
-
-            void OnDone(VideoPlayer vp)
-            {
-                vp.loopPointReached -= OnDone;
-                tcs.TrySetResult();
-            }
-
-            player.loopPointReached += OnDone;
-            player.Play();
-            _eventBus.Publish(new IntroStartedSignal());
+            var introTask = PlayIntroAsync(player, cancellation);
             await _sceneService.LoadSceneAsync(nameof(GameScene.MainMenu), null, cancellation);
 
-            await tcs.Task.AttachExternalCancellation(cancellation);
+            await introTask.AttachExternalCancellation(cancellation);
+
+            CleanupIntro(player);
+            if (_sceneRefs.IntroCanvas != null)
+                UnityEngine.Object.Destroy(_sceneRefs.IntroCanvas.gameObject);
+            _eventBus.Publish(new IntroCompletedSignal());
+        }
+
+        private async UniTask PlayIntroAsync(VideoPlayer player, CancellationToken cancellation)
+        {
+            if (player == null)
+                return;
+
+            var prepared = new UniTaskCompletionSource();
+            var completed = new UniTaskCompletionSource();
+
+            void OnPrepared(VideoPlayer vp) => prepared.TrySetResult();
+
+            void OnDone(VideoPlayer vp) => completed.TrySetResult();
+
+            void OnError(VideoPlayer vp, string message)
+            {
+                Debug.LogWarning($"[AppBootFlow] Intro video error: {message}");
+                completed.TrySetResult();
+                prepared.TrySetResult();
+            }
+
+            player.prepareCompleted += OnPrepared;
+            player.loopPointReached += OnDone;
+            player.errorReceived += OnError;
+
+            try
+            {
+                if (!player.isPrepared)
+                {
+                    player.Prepare();
+                    await UniTask.WhenAny(
+                        prepared.Task,
+                        UniTask.Delay(IntroPrepareTimeoutMs, cancellationToken: cancellation));
+                }
+
+                player.Play();
+                _eventBus.Publish(new IntroStartedSignal());
+
+                await UniTask.WhenAny(
+                    completed.Task,
+                    UniTask.Delay(GetIntroFallbackTimeout(player), cancellationToken: cancellation));
+            }
+            finally
+            {
+                player.prepareCompleted -= OnPrepared;
+                player.loopPointReached -= OnDone;
+                player.errorReceived -= OnError;
+            }
+        }
+
+        private static TimeSpan GetIntroFallbackTimeout(VideoPlayer player)
+        {
+            var length = player != null && player.length > 0d
+                ? (float)player.length
+                : IntroMinimumFallbackSeconds;
+
+            return TimeSpan.FromSeconds(Mathf.Max(IntroMinimumFallbackSeconds, length + IntroFallbackPaddingSeconds));
+        }
+
+        private static void CleanupIntro(VideoPlayer player)
+        {
+            if (player == null)
+                return;
 
             player.Stop();
             var rt = player.targetTexture;
             if (rt != null) rt.Release();
-
-            if (_sceneRefs.IntroCanvas != null)
-                Object.Destroy(_sceneRefs.IntroCanvas.gameObject);
-            Object.Destroy(player.gameObject);
-            _eventBus.Publish(new IntroCompletedSignal());
+            UnityEngine.Object.Destroy(player.gameObject);
         }
     }
-}
+}

Assets/Darkmatter/Code/Features/AppBoot/Installers/AppBootFeatureModule.cs

@@ -16,6 +16,7 @@ namespace Darkmatter.Features.AppBoot.Installers
             if (sceneRefs != null)
                 builder.RegisterComponent(sceneRefs);
             builder.RegisterEntryPoint<AppBootFlow>();
+            builder.RegisterEntryPoint<AdaptiveFrameRate>();
         }
     }
 }

Assets/Darkmatter/Code/Features/ArtBook/UI/ArtbookPresenter.cs

@@ -7,6 +7,7 @@ using Darkmatter.Core.Contracts.Features.DrawingCatalog;
 using Darkmatter.Core.Contracts.Features.Progression;
 using Darkmatter.Core.Contracts.Features.SaveGate;
 using Darkmatter.Core.Contracts.Services.Gallery;
+using Darkmatter.Core.Data.Signals.Features.Capture;
 using Darkmatter.Core.Data.Signals.Features.Drawing;
 using Darkmatter.Libs.Observer;
 using UnityEngine;
@@ -209,7 +210,20 @@ namespace Darkmatter.Features.Artbook
                 texture = await _progression.GetCachedThumbnailAsync(entry.Value.Id);
                 if (texture == null) return;
 
-                await _gallery.SaveImageAsync(texture, entry.Value.Name, ct);
+                // Mirror CaptureSystem's pairing: Started before the write, Completed(success) in
+                // finally — art-book saves land in the same gallery_save_* analytics funnel as
+                // gameplay saves.
+                _eventBus.Publish(new GallerySaveStartedSignal());
+                var success = false;
+                try
+                {
+                    await _gallery.SaveImageAsync(texture, entry.Value.Name, ct);
+                    success = true;
+                }
+                finally
+                {
+                    _eventBus.Publish(new GallerySaveCompletedSignal(success, entry.Value.Id));
+                }
                 // The art book has no success popup of its own, so use the shared toast.
                 await _saveGate.ShowSavedAsync(ct);
             }

Assets/Darkmatter/Code/Features/Capture/Systems/CaptureSystem.cs

@@ -60,12 +60,14 @@ namespace Darkmatter.Features.Capture
 
             var tex = new Texture2D(2, 2, TextureFormat.RGBA32, mipChain: false);
             var success = false;
+            // Started must pair 1:1 with the Completed publish in finally — a failed LoadImage or a
+            // throw in BuildFileNameAsync would otherwise emit Completed(false) with no Started.
+            _bus.Publish(new GallerySaveStartedSignal());
             try
             {
                 if (tex.LoadImage(png))
                 {
                     var fileName = await BuildFileNameAsync();
-                    _bus.Publish(new GallerySaveStartedSignal());
                     await _galleryService.SaveImageAsync(tex, fileName, ct);
                     success = true;
                 }
@@ -73,7 +75,7 @@ namespace Darkmatter.Features.Capture
             finally
             {
                 UnityEngine.Object.Destroy(tex);
-                _bus.Publish(new GallerySaveCompletedSignal(success));
+                _bus.Publish(new GallerySaveCompletedSignal(success, _progression.LastOpenedTemplateId));
             }
             return png;
         }

Assets/Darkmatter/Code/Features/ColorbookFlow/System/ColorbookFlowController.cs

@@ -68,7 +68,13 @@ public class ColorbookFlowController : IAsyncStartable, IDisposable
         // one VContainer cancels on teardown, and the linked _scopeCts may lag the callback order.
         if (cancellation.IsCancellationRequested || ct.IsCancellationRequested) return;
 
-        if (!_navigatingToGameplay) _loadingScreen.Hide();
+        if (!_navigatingToGameplay)
+        {
+            _loadingScreen.Hide();
+            // Catalog genuinely on screen — not a transit hop toward gameplay (edit/next relays land
+            // in this scene with _navigatingToGameplay already latched and never reveal the catalog).
+            _bus.Publish(new ColorbookShownSignal());
+        }
 
         PrewarmInterstitialAdAsync().Forget();
     }

Assets/Darkmatter/Code/Features/Coloring/Systems/ColoringPinchZoomController.cs

@@ -1,5 +1,6 @@
 using System;
 using UnityEngine;
+using UnityEngine.EventSystems;
 using UnityEngine.InputSystem;
 
 namespace Darkmatter.Features.Coloring.Systems
@@ -8,6 +9,7 @@ namespace Darkmatter.Features.Coloring.Systems
     public sealed class ColoringPinchZoomController : MonoBehaviour
     {
         private const float MinimumPinchDistance = 8f;
+        private const float PanZoomEpsilon = 0.0001f;
 
         [SerializeField] private float minZoom = 1f;
         [SerializeField] private float maxZoom = 3f;
@@ -22,6 +24,7 @@ namespace Darkmatter.Features.Coloring.Systems
         private float _currentZoom = 1f;
         private Vector3 _baseScale = Vector3.one;
         private Vector2 _baseAnchoredPosition;
+        private PanDragRelay _panRelay;
 
         public void SetTarget(RectTransform target)
         {
@@ -34,6 +37,26 @@ namespace Darkmatter.Features.Coloring.Systems
             _baseAnchoredPosition = target != null ? target.anchoredPosition : Vector2.zero;
             _currentZoom = 1f;
             enabled = _target != null && _parent != null;
+
+            _panRelay = null;
+            if (_target != null)
+            {
+                _panRelay = _target.gameObject.GetComponent<PanDragRelay>();
+                if (_panRelay == null)
+                    _panRelay = _target.gameObject.AddComponent<PanDragRelay>();
+                _panRelay.Controller = this;
+            }
+
+            UpdatePanRelayState();
+        }
+
+        // While not zoomed the relay is disabled so the event system never resolves it as a
+        // drag target — sloppy kid taps keep registering as clicks (paints) exactly as before.
+        // Zoomed in, drags become pans and are suppressed as clicks by uGUI.
+        private void UpdatePanRelayState()
+        {
+            if (_panRelay != null)
+                _panRelay.enabled = _currentZoom > 1f + PanZoomEpsilon;
         }
 
         public void ResetZoom()
@@ -46,6 +69,7 @@ namespace Darkmatter.Features.Coloring.Systems
 
             _currentZoom = 1f;
             _isPinching = false;
+            UpdatePanRelayState();
         }
 
         public IDisposable UseNonZoomedView()
@@ -78,6 +102,7 @@ namespace Darkmatter.Features.Coloring.Systems
 
             _isPinching = false;
             TryApplyScrollZoom();
+            TryApplyMousePan();
         }
 
         private bool TryApplyPinchZoom()
@@ -111,8 +136,16 @@ namespace Darkmatter.Features.Coloring.Systems
                 return true;
             }
 
+            // Anchor the content point that was under the previous midpoint to the current
+            // midpoint: distance change zooms, midpoint movement pans — one gesture does both.
+            Vector2 previousMidpoint = (firstTouch.PreviousPosition + secondTouch.PreviousPosition) * 0.5f;
+            if (!TryGetParentLocalPoint(previousMidpoint, out Vector2 previousMidpointLocal))
+            {
+                return true;
+            }
+
             float targetZoom = Mathf.Clamp(_currentZoom * (distance / previousDistance), minZoom, maxZoom);
-            ZoomTowards(midpointLocal, targetZoom);
+            ApplyZoomPan(previousMidpointLocal, midpointLocal, targetZoom);
             return true;
         }
 
@@ -152,12 +185,123 @@ namespace Darkmatter.Features.Coloring.Systems
                 return;
             }
 
-            Vector2 contentPoint = (parentLocalPoint - _target.anchoredPosition) / _currentZoom;
+            ApplyZoomPan(parentLocalPoint, parentLocalPoint, targetZoom);
+        }
+
+        private void ApplyZoomPan(Vector2 previousLocalPoint, Vector2 currentLocalPoint, float targetZoom)
+        {
+            Vector2 contentPoint = (previousLocalPoint - _target.anchoredPosition) / _currentZoom;
             _currentZoom = targetZoom;
             _target.localScale = _baseScale * _currentZoom;
-            _target.anchoredPosition = Mathf.Approximately(_currentZoom, minZoom)
-                ? _baseAnchoredPosition
-                : parentLocalPoint - contentPoint * _currentZoom;
+            _target.anchoredPosition = ClampPan(currentLocalPoint - contentPoint * _currentZoom);
+            UpdatePanRelayState();
+        }
+
+        // Editor/desktop convenience: drag with the right or middle mouse button to pan while zoomed.
+        private void TryApplyMousePan()
+        {
+            Mouse mouse = Mouse.current;
+            if (mouse == null || (!mouse.rightButton.isPressed && !mouse.middleButton.isPressed))
+            {
+                return;
+            }
+
+            if (_currentZoom <= 1f + PanZoomEpsilon)
+            {
+                return;
+            }
+
+            Vector2 delta = mouse.delta.ReadValue();
+            if (delta == Vector2.zero)
+            {
+                return;
+            }
+
+            Vector2 screenPosition = mouse.position.ReadValue();
+            if (!IsInputPointAllowed(screenPosition))
+            {
+                return;
+            }
+
+            if (!TryGetParentLocalPoint(screenPosition, out Vector2 currentLocal) ||
+                !TryGetParentLocalPoint(screenPosition - delta, out Vector2 previousLocal))
+            {
+                return;
+            }
+
+            _target.anchoredPosition = ClampPan(_target.anchoredPosition + (currentLocal - previousLocal));
+        }
+
+        // Single-finger (or left-mouse) drag pan, fed by PanDragRelay on the paper root.
+        // Going through uGUI's drag pipeline matters: once the drag threshold is crossed the
+        // event system cancels the pending click, so a pan can never paint the region the
+        // finger ends on — a plain tap still paints.
+        private void OnPanDrag(PointerEventData eventData, Transform source)
+        {
+            if (_target == null || source != _target.transform)
+            {
+                return;
+            }
+
+            if (_isPinching || HasMultiTouch())
+            {
+                return; // two-finger gesture owns the view
+            }
+
+            if (_currentZoom <= 1f + PanZoomEpsilon)
+            {
+                return;
+            }
+
+            if (!TryGetParentLocalPoint(eventData.position, out Vector2 currentLocal) ||
+                !TryGetParentLocalPoint(eventData.position - eventData.delta, out Vector2 previousLocal))
+            {
+                return;
+            }
+
+            _target.anchoredPosition = ClampPan(_target.anchoredPosition + (currentLocal - previousLocal));
+        }
+
+        private static bool HasMultiTouch()
+        {
+            Touchscreen touchscreen = Touchscreen.current;
+            if (touchscreen == null)
+            {
+                return false;
+            }
+
+            int count = 0;
+            foreach (var touchControl in touchscreen.touches)
+            {
+                if (touchControl.press.isPressed && ++count > 1)
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        // The scaled paper must keep covering its zoom-1 footprint: panning can never expose
+        // background inside the area the drawing occupies when not zoomed.
+        private Vector2 ClampPan(Vector2 anchoredPosition)
+        {
+            if (_currentZoom <= 1f + PanZoomEpsilon)
+            {
+                return _baseAnchoredPosition;
+            }
+
+            Rect rect = _target.rect;
+            float growth = 1f - _currentZoom; // negative while zoomed in
+
+            float minX = _baseAnchoredPosition.x + rect.xMax * _baseScale.x * growth;
+            float maxX = _baseAnchoredPosition.x + rect.xMin * _baseScale.x * growth;
+            float minY = _baseAnchoredPosition.y + rect.yMax * _baseScale.y * growth;
+            float maxY = _baseAnchoredPosition.y + rect.yMin * _baseScale.y * growth;
+
+            return new Vector2(
+                Mathf.Clamp(anchoredPosition.x, minX, maxX),
+                Mathf.Clamp(anchoredPosition.y, minY, maxY));
         }
 
         private bool TryGetParentLocalPoint(Vector2 screenPoint, out Vector2 localPoint)
@@ -233,6 +377,7 @@ namespace Darkmatter.Features.Coloring.Systems
             _target.anchoredPosition = state.AnchoredPosition;
             _currentZoom = state.CurrentZoom;
             _isPinching = false;
+            UpdatePanRelayState();
         }
 
         private readonly struct ViewState
@@ -285,5 +430,25 @@ namespace Darkmatter.Features.Coloring.Systems
                 Delta = delta;
             }
         }
+
+        // Runtime-attached to the paper root (SetTarget); regions are its children, so drags
+        // that start on a region bubble up here while taps stay clicks. Implementing the uGUI
+        // drag interfaces is what makes the event system suppress the region click on drag.
+        private sealed class PanDragRelay : MonoBehaviour, IBeginDragHandler, IDragHandler
+        {
+            internal ColoringPinchZoomController Controller;
+
+            public void OnBeginDrag(PointerEventData eventData)
+            {
+            }
+
+            public void OnDrag(PointerEventData eventData)
+            {
+                if (Controller != null)
+                {
+                    Controller.OnPanDrag(eventData, transform);
+                }
+            }
+        }
     }
 }

Assets/Darkmatter/Code/Features/DrawingCatalog/Systems/DrawingCatalogController.cs

@@ -57,8 +57,8 @@ public sealed class DrawingCatalogController : IDrawingCatalogController
     private void Refresh()
     {
         _visible.Clear();
+        // Catalog already orders ids by difficulty (easiest first), then id.
         _visible.AddRange(_catalog.AllTemplateIds);
-        _visible.Sort(StringComparer.OrdinalIgnoreCase);
         ListChanged?.Invoke();
     }
 }

Assets/Darkmatter/Code/Features/DrawingCatalog/UI/DrawingCatalogButton.cs

@@ -13,8 +13,8 @@ namespace Darkmatter.Features.DrawingCatalog
         {
             Id = id;
             thumbnail.sprite = thumbnailSprite;
+            button.onClick.RemoveAllListeners();
             button.onClick.AddListener(onClick);
         }
     }
 }
-

Assets/Darkmatter/Code/Features/DrawingCatalog/UI/DrawingCatalogPresenter.cs

@@ -15,6 +15,7 @@ namespace Darkmatter.Features.DrawingCatalog
 
         private int _currentPage = 0;
         private int _totalPages = 1;
+        private const int RowCount = 2;
         private const int ItemPerPage = 8; //2 rows x 4 columns
 
         private readonly DrawingCatalogView _view;
@@ -24,6 +25,12 @@ namespace Darkmatter.Features.DrawingCatalog
         private readonly CancellationTokenSource _cts = new();
         private IDisposable _openSubscription;
 
+        // Sprites/textures decoded from saved thumbnails are created fresh on every refresh
+        // and are owned by this presenter — without destroying the previous batch each
+        // Colorbook visit leaks several MB per painted drawing until the OS kills the app.
+        private readonly List<Sprite> _ownedSprites = new();
+        private readonly List<Texture2D> _ownedTextures = new();
+
         public DrawingCatalogPresenter(DrawingCatalogView view, IDrawingCatalogController controller,
             IDrawingTemplateCatalog catalog, IEventBus eventBus)
         {
@@ -48,8 +55,14 @@ namespace Darkmatter.Features.DrawingCatalog
         }
 
         private void HandleOpenColorBookSignal(OpenColorBookSignal signal)
+        {
+            ShowCatalog();
+        }
+
+        private void ShowCatalog()
         {
             _view.Show();
+            _eventBus.Publish(new ColorbookShownSignal());
         }
 
         private void OnRightPageBtnClicked()
@@ -84,7 +97,7 @@ namespace Darkmatter.Features.DrawingCatalog
 
         private void OnArtBookBtnClicked()
         {
-           _eventBus.Publish(new OpenArtBookSignal(()=> _view.Show()));
+           _eventBus.Publish(new OpenArtBookSignal(ShowCatalog));
            _view.Hide();
         }
 
@@ -102,29 +115,86 @@ namespace Darkmatter.Features.DrawingCatalog
 
         private async UniTask RefreshAsync(CancellationToken ct)
         {
-            var ids = _controller.VisibleIds;
-            var vms = new List<CatalogItemVM>(ids.Count);
+            var newSprites = new List<Sprite>();
+            var newTextures = new List<Texture2D>();
+            var applied = false;
 
-            _totalPages = (int)Math.Ceiling(ids.Count / (float)ItemPerPage);
-            _currentPage = 0;
-
-            foreach (var id in ids)
+            try
             {
+                var ids = ToFixedRowGridOrder(_controller.VisibleIds);
+                var vms = new List<CatalogItemVM>(ids.Count);
+
+                _totalPages = (int)Math.Ceiling(ids.Count / (float)ItemPerPage);
+                _currentPage = 0;
+
+                foreach (var id in ids)
+                {
+                    if (ct.IsCancellationRequested) return;
+                    var (thumb, owned) = await _catalog.GetThumbnailAsync(id);
+                    if (owned)
+                    {
+                        newSprites.Add(thumb);
+                        newTextures.Add(thumb.texture);
+                    }
+
+                    vms.Add(new CatalogItemVM(id, thumb));
+                }
+
                 if (ct.IsCancellationRequested) return;
-                var thumb = await _catalog.GetThumbnailAsync(id);
-                vms.Add(new CatalogItemVM(id, thumb));
+                _view.ResetScrollPosition();
+                _view.SetItems(vms);
+                _view.SetPagination(_currentPage, _totalPages);
+
+                // Buttons now reference the new batch; the previous one can go.
+                DestroyOwnedThumbnails();
+                _ownedSprites.AddRange(newSprites);
+                _ownedTextures.AddRange(newTextures);
+                applied = true;
+
+                // Unblock InitializeAsync: items are now on screen, so the loading screen can hide.
+                _controller.NotifyPopulated();
+
+                // Cue the first-run tutorial that the catalog grid is on screen and tappable.
+                _eventBus.Publish(new DrawingCatalogReadySignal());
+            }
+            catch (Exception e)
+            {
+                Debug.LogError($"[DrawingCatalog] Failed to refresh catalog: {e}");
+            }
+            finally
+            {
+                // Aborted refresh (cancelled or threw): don't strand the freshly decoded batch.
+                if (!applied)
+                {
+                    foreach (var s in newSprites) UnityEngine.Object.Destroy(s);
+                    foreach (var t in newTextures) UnityEngine.Object.Destroy(t);
+                }
+
+                // Idempotent — always unblock the flow; a stuck loading screen is worse than
+                // an empty catalog.
+                _controller.NotifyPopulated();
+            }
+        }
+
+        private void DestroyOwnedThumbnails()
+        {
+            foreach (var s in _ownedSprites) UnityEngine.Object.Destroy(s);
+            foreach (var t in _ownedTextures) UnityEngine.Object.Destroy(t);
+            _ownedSprites.Clear();
+            _ownedTextures.Clear();
+        }
+
+        private static List<string> ToFixedRowGridOrder(IReadOnlyList<string> ids)
+        {
+            var ordered = new List<string>(ids.Count);
+
+            for (var row = 0; row < RowCount; row++)
+            {
+                for (var index = row; index < ids.Count; index += RowCount)
+                    ordered.Add(ids[index]);
             }
 
-            if (ct.IsCancellationRequested) return;
-            _view.ResetScrollPosition();
-            _view.SetItems(vms);
-            _view.SetPagination(_currentPage, _totalPages);
-
-            // Unblock InitializeAsync: items are now on screen, so the loading screen can hide.
-            _controller.NotifyPopulated();
-
-            // Cue the first-run tutorial that the catalog grid is on screen and tappable.
-            _eventBus.Publish(new DrawingCatalogReadySignal());
+            return ordered;
         }
 
         public void Dispose()
@@ -140,6 +210,7 @@ namespace Darkmatter.Features.DrawingCatalog
             _openSubscription?.Dispose();
             _cts.Cancel();
             _cts.Dispose();
+            DestroyOwnedThumbnails();
         }
     }
-}
+}

Assets/Darkmatter/Code/Features/DrawingCatalog/UI/DrawingCatalogView.cs

@@ -62,9 +62,6 @@ namespace Darkmatter.Features.DrawingCatalog
             while (_buttons.Count < items.Count)
             {
                 var button = Instantiate(buttonPrefab, content);
-                var item = items[_buttons.Count];
-                button.Initialize(item.Id, item.Thumbnail,
-                    () => { OnItemClicked?.Invoke(item.Id); });
                 _buttons.Add(button);
             }
 
@@ -75,6 +72,13 @@ namespace Darkmatter.Features.DrawingCatalog
                 Destroy(last.gameObject);
             }
 
+            for (var i = 0; i < items.Count; i++)
+            {
+                var item = items[i];
+                _buttons[i].Initialize(item.Id, item.Thumbnail,
+                    () => { OnItemClicked?.Invoke(item.Id); });
+            }
+
             LayoutRebuilder.ForceRebuildLayoutImmediate(content);
         }
 
@@ -178,4 +182,4 @@ namespace Darkmatter.Features.DrawingCatalog
             _suppressScrollEvents = false;
         }
     }
-}
+}

Assets/Darkmatter/Code/Features/DrawingTemplate/Editor/DrawingTemplateEditorWindow.cs

@@ -68,7 +68,9 @@ namespace Darkmatter.Features.DrawingTemplates.Editor
             _templates.Clear();
             _shapes.Clear();
             _palettes.Clear();
-            _templates.AddRange(FindAllOfType<DrawingTemplateSO>());
+            _templates.AddRange(FindAllOfType<DrawingTemplateSO>()
+                .OrderBy(t => t.Difficulty)
+                .ThenBy(t => t.Id, StringComparer.OrdinalIgnoreCase));
             _shapes.AddRange(FindAllOfType<ShapeSO>());
             _palettes.AddRange(FindAllOfType<ColorPaletteSO>());
         }
@@ -169,7 +171,7 @@ namespace Darkmatter.Features.DrawingTemplates.Editor
                 using (new EditorGUILayout.VerticalScope())
                 {
                     GUILayout.Label(string.IsNullOrEmpty(t.DisplayName) ? t.name : t.DisplayName, EditorStyles.boldLabel);
-                    GUILayout.Label("id: " + (string.IsNullOrEmpty(t.Id) ? "<unset>" : t.Id), EditorStyles.miniLabel);
+                    GUILayout.Label($"id: {(string.IsNullOrEmpty(t.Id) ? "<unset>" : t.Id)}  •  diff: {t.Difficulty}{(t.HasDifficultyOverride ? "*" : $" ({t.Pieces.Count}p+{t.AuthoredRegions.Count}r)")}", EditorStyles.miniLabel);
                 }
                 if (GUILayout.Button("Select", GUILayout.Width(54)))
                     Select(t);
@@ -206,6 +208,13 @@ namespace Darkmatter.Features.DrawingTemplates.Editor
                 EditorGUILayout.LabelField("Basics", EditorStyles.boldLabel);
                 EditorGUILayout.PropertyField(so.FindProperty("id"), new GUIContent("Id (Addressable Key)"));
                 EditorGUILayout.PropertyField(so.FindProperty("displayName"));
+                EditorGUILayout.PropertyField(so.FindProperty("difficultyOverride"),
+                    new GUIContent("Difficulty Override", "0 = auto (pieces + regions). Any positive value overrides."));
+                EditorGUILayout.LabelField(
+                    new GUIContent("Difficulty (effective)", "Sorts the catalog, lowest first."),
+                    new GUIContent(t.HasDifficultyOverride
+                        ? $"{t.Difficulty}  (override; auto would be {t.AutoDifficulty})"
+                        : $"{t.Difficulty}  (auto: {t.Pieces.Count} pieces + {t.AuthoredRegions.Count} regions)"));
                 EditorGUILayout.PropertyField(so.FindProperty("defaultThumbnail"));
 
                 EditorGUILayout.Space(6);

Assets/Darkmatter/Code/Features/DrawingTemplate/Systems/AddressableDrawingTemplateCatalog.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Threading;
 using Cysharp.Threading.Tasks;
@@ -48,11 +49,11 @@ namespace Darkmatter.Features.DrawingTemplates.Systems
                 _byId[t.Id] = t;
             }
 
-            _allIds.Sort();
+            SortIds();
             _initialized = true;
         }
 
-        public async UniTask<Sprite> GetThumbnailAsync(string id)
+        public async UniTask<(Sprite sprite, bool owned)> GetThumbnailAsync(string id)
         {
             if (!_byId.TryGetValue(id, out var t))
                 throw new KeyNotFoundException($"Template '{id}' not in catalog. Did InitializeAsync run?");
@@ -61,9 +62,9 @@ namespace Darkmatter.Features.DrawingTemplates.Systems
             if (savedTex != null)
             {
                 var rect = new Rect(0, 0, savedTex.width, savedTex.height);
-                return Sprite.Create(savedTex, rect, new Vector2(0.5f, 0.5f));
+                return (Sprite.Create(savedTex, rect, new Vector2(0.5f, 0.5f)), true);
             }
-            return t.DefaultThumbnail;
+            return (t.DefaultThumbnail, false);
         }
 
         public UniTask<IDrawingTemplate> LoadAsync(string id)
@@ -84,12 +85,22 @@ namespace Darkmatter.Features.DrawingTemplates.Systems
             if (!_allIds.Contains(id))
             {
                 _allIds.Add(id);
-                _allIds.Sort();
+                SortIds();
             }
 
             return t;
         }
 
+        // Easiest drawings first; ties broken by id so the order is stable.
+        private void SortIds()
+        {
+            _allIds.Sort((a, b) =>
+            {
+                var byDifficulty = _byId[a].Difficulty.CompareTo(_byId[b].Difficulty);
+                return byDifficulty != 0 ? byDifficulty : string.Compare(a, b, StringComparison.OrdinalIgnoreCase);
+            });
+        }
+
         public void ReleaseAll()
         {
             if (!_initialized) return;

Assets/Darkmatter/Code/Features/GameplayFlow/Systems/GameplayFlowController.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Threading;
 using Cysharp.Threading.Tasks;
+using Darkmatter.Core;
 using Darkmatter.Core.Contracts.Features.Capture;
 using Darkmatter.Core.Contracts.Features.Coloring;
 using Darkmatter.Core.Contracts.Features.DrawingCatalog;
@@ -28,6 +29,7 @@ namespace Darkmatter.Features.GameplayFlow.Systems
     public sealed class GameplayFlowController : IAsyncStartable, IGameplayFlowController, IDisposable
     {
         private const int AutosaveDebounceMs = 500;
+        private const float ThumbnailMinIntervalSec = 30f;
 
         private readonly IProgressionSystem _progression;
         private readonly IDrawingTemplateCatalog _catalog;
@@ -44,10 +46,12 @@ namespace Darkmatter.Features.GameplayFlow.Systems
         private string _templateId;
         private DrawingPhase _phase = DrawingPhase.ShapeBuilding;
         private bool _allContentReported;
+        private float _lastThumbnailTime = float.NegativeInfinity;
 
         private IDisposable _assembledSub;
         private IDisposable _colorAppliedSub;
         private IDisposable _drawingSelectedSub;
+        private IDisposable _openColorbookSub;
         private CancellationTokenSource _autosaveCts;
         private CancellationTokenSource _scopeCts;
 
@@ -76,6 +80,27 @@ namespace Darkmatter.Features.GameplayFlow.Systems
         }
 
         public async UniTask StartAsync(CancellationToken cancellation)
+        {
+            try
+            {
+                await StartCoreAsync(cancellation);
+            }
+            catch (OperationCanceledException)
+            {
+                // Scene torn down mid-init; nothing to recover.
+            }
+            catch (Exception e)
+            {
+                // Any throw here (missing template id, failed Addressables load, region init)
+                // would otherwise skip _loadingScreen.Hide() and strand the kid on a frozen
+                // loader forever. Log it and route back to the Colorbook, whose flow hides the
+                // loading screen once its catalog is populated.
+                Debug.LogError($"[GameplayFlow] Failed to start gameplay, returning to Colorbook: {e}");
+                await RecoverToColorbookAsync();
+            }
+        }
+
+        private async UniTask StartCoreAsync(CancellationToken cancellation)
         {
             _scopeCts = CancellationTokenSource.CreateLinkedTokenSource(cancellation);
             var ct = _scopeCts.Token;
@@ -104,6 +129,10 @@ namespace Darkmatter.Features.GameplayFlow.Systems
             _assembledSub = _bus.Subscribe<ShapeAssembledSignal>(OnShapeAssembled);
             _colorAppliedSub = _bus.Subscribe<ColorAppliedSignal>(OnColorApplied);
             _drawingSelectedSub = _bus.Subscribe<DrawingSelectedSignal>(OnDrawingSelected);
+            // The art book's "colorbook" button publishes OpenColorBookSignal. In the Colorbook
+            // scene DrawingCatalogPresenter shows the catalog; during gameplay that presenter is
+            // dead, so treat the signal as "leave gameplay for the colorbook" (same as back).
+            _openColorbookSub = _bus.Subscribe<OpenColorBookSignal>(OnOpenColorBook);
 
             _loadingScreen.SetProgress(1f);
             if (_phase == DrawingPhase.Coloring)
@@ -119,6 +148,22 @@ namespace Darkmatter.Features.GameplayFlow.Systems
             _loadingScreen.Hide();
         }
 
+        private async UniTask RecoverToColorbookAsync()
+        {
+            try
+            {
+                _shapeBuilder.Clear();
+                _coloring.Clear();
+                await _scenes.LoadSceneAsync(nameof(GameScene.Colorbook), progress: null, cancellationToken: default);
+                await _scenes.UnloadSceneAsync(nameof(GameScene.Gameplay), progress: null, cancellationToken: default);
+            }
+            catch (Exception e)
+            {
+                Debug.LogError($"[GameplayFlow] Recovery to Colorbook failed: {e}");
+                _loadingScreen.Hide();
+            }
+        }
+
         public async UniTask BackAsync(CancellationToken ct)
         {
             await SaveCurrentAsync(CancellationToken.None);
@@ -131,8 +176,10 @@ namespace Darkmatter.Features.GameplayFlow.Systems
 
         public async UniTask SaveAsync(CancellationToken ct)
         {
-            await SaveCurrentAsync(ct);
-            await _capture.CapturePngAsync(saveToGallery: true, ct);
+            // One capture serves both the gallery write and the progress thumbnail — this used to
+            // run the full capture pipeline twice back to back.
+            var png = await _capture.CapturePngAsync(saveToGallery: true, ct);
+            await SaveCurrentAsync(ct, captureThumbnail: false, precapturedThumbnail: png);
         }
 
         public async UniTask NextAsync(CancellationToken ct)
@@ -209,6 +256,11 @@ namespace Darkmatter.Features.GameplayFlow.Systems
             DebouncedAutosaveAsync(_autosaveCts.Token).Forget();
         }
 
+        private void OnOpenColorBook(OpenColorBookSignal _)
+        {
+            BackAsync(CancellationToken.None).Forget();
+        }
+
         private void OnDrawingSelected(DrawingSelectedSignal signal)
         {
             if (string.IsNullOrEmpty(signal.TemplateId)) return;
@@ -232,7 +284,13 @@ namespace Darkmatter.Features.GameplayFlow.Systems
             try
             {
                 await UniTask.Delay(AutosaveDebounceMs, cancellationToken: ct);
-                await SaveCurrentAsync(ct);
+                // Autosaves fire after every paint pause; capturing a thumbnail each time renders the
+                // scene to an RT and PNG-encodes it, which OOM-kills long sessions on low-RAM devices.
+                // Colors always persist; the thumbnail refreshes at most every ThumbnailMinIntervalSec
+                // here and unconditionally on the exit paths (back / next / select-away).
+                bool refreshThumbnail =
+                    Time.realtimeSinceStartup - _lastThumbnailTime >= ThumbnailMinIntervalSec;
+                await SaveCurrentAsync(ct, captureThumbnail: refreshThumbnail);
             }
             catch (OperationCanceledException)
             {
@@ -240,7 +298,8 @@ namespace Darkmatter.Features.GameplayFlow.Systems
             }
         }
 
-        private async UniTask SaveCurrentAsync(CancellationToken ct)
+        private async UniTask SaveCurrentAsync(CancellationToken ct, bool captureThumbnail = true,
+            byte[] precapturedThumbnail = null)
         {
             if (string.IsNullOrEmpty(_templateId)) return;
 
@@ -263,7 +322,10 @@ namespace Darkmatter.Features.GameplayFlow.Systems
                 FirstCompletedUtc = existing?.FirstCompletedUtc,
             };
 
-            var thumbnailPng = await _capture.CapturePngAsync(saveToGallery: false, ct);
+            byte[] thumbnailPng = precapturedThumbnail;
+            if (thumbnailPng == null && captureThumbnail)
+                thumbnailPng = await _capture.CapturePngAsync(saveToGallery: false, ct);
+            if (thumbnailPng != null) _lastThumbnailTime = Time.realtimeSinceStartup;
 
             await _progression.SaveProgressAsync(progress, thumbnailPng);
         }
@@ -284,6 +346,7 @@ namespace Darkmatter.Features.GameplayFlow.Systems
             _assembledSub?.Dispose();
             _colorAppliedSub?.Dispose();
             _drawingSelectedSub?.Dispose();
+            _openColorbookSub?.Dispose();
             _autosaveCts?.Cancel();
             _autosaveCts?.Dispose();
             _scopeCts?.Cancel();

Assets/Darkmatter/Code/Features/MainMenu/UI/MainMenuPresenter.cs

@@ -13,6 +13,7 @@ namespace Darkmatter.Features.Mainmenu
         private readonly IEventBus _eventBus;
         private readonly MainMenuView _view;
         private readonly ISfxPlayer _sfxPlayer;
+        private IDisposable _introSubscription;
 
 
         public MainMenuPresenter(MainMenuView view, IEventBus eventBus, ISfxPlayer sfxPlayer)
@@ -26,7 +27,7 @@ namespace Darkmatter.Features.Mainmenu
         {
             _view.OnPlayBtnPressedEvent += OnPlayBtnPressed;
             _view.OnPlayBtnClickedEvent += OnPlayBtnClicked;
-            _eventBus.Subscribe<IntroCompletedSignal>(OnIntroComplete);
+            _introSubscription = _eventBus.Subscribe<IntroCompletedSignal>(OnIntroComplete);
         }
 
         private void OnIntroComplete(IntroCompletedSignal signal)
@@ -48,6 +49,7 @@ namespace Darkmatter.Features.Mainmenu
         {
             _view.OnPlayBtnPressedEvent -= OnPlayBtnPressed;
             _view.OnPlayBtnClickedEvent -= OnPlayBtnClicked;
+            _introSubscription?.Dispose();
         }
     }
 }

Assets/Darkmatter/Code/Features/Progression/Systems/ProgressionRepository.cs

@@ -86,16 +86,27 @@ public sealed class ProgressionRepository
     {
         if (string.IsNullOrEmpty(templateId) || png == null || png.Length == 0) return;
 
-        Directory.CreateDirectory(ThumbnailDirectory());
-        var path = ThumbnailPath(templateId);
-        var tmp = path + ".tmp";
-
-        await UniTask.RunOnThreadPool(() =>
+        // Never let thumbnail IO (disk full, permission churn) throw into the save path:
+        // saves run before every Back/Next navigation, and an unhandled IOException there
+        // aborts the scene transition and traps the user in gameplay. Losing a thumbnail
+        // is fine — the colors themselves persist via PlayerPrefs.
+        try
         {
-            File.WriteAllBytes(tmp, png);
-            if (File.Exists(path)) File.Delete(path);
-            File.Move(tmp, path);
-        });
+            Directory.CreateDirectory(ThumbnailDirectory());
+            var path = ThumbnailPath(templateId);
+            var tmp = path + ".tmp";
+
+            await UniTask.RunOnThreadPool(() =>
+            {
+                File.WriteAllBytes(tmp, png);
+                if (File.Exists(path)) File.Delete(path);
+                File.Move(tmp, path);
+            });
+        }
+        catch (Exception e)
+        {
+            Debug.LogWarning($"[Progression] Failed writing thumbnail '{templateId}': {e.Message}");
+        }
     }
 
     public async UniTask<Texture2D> LoadThumbnailAsync(string templateId)

Assets/Darkmatter/Code/Libs/Observer/Systems/EventBus.cs

@@ -15,7 +15,23 @@ namespace Darkmatter.Libs.Observer
             if (_map.TryGetValue(typeof(T), out var handlerObj))
             {
                 var action = (Action<T>)handlerObj;
-                action?.Invoke(evt);
+                if (action == null) return;
+
+                // Invoke handlers one by one: a multicast invoke would let one throwing
+                // subscriber silently starve every later subscriber and rethrow into the
+                // publisher (paint / scene-transition code), turning a local bug into a
+                // stuck flow.
+                foreach (var handler in action.GetInvocationList())
+                {
+                    try
+                    {
+                        ((Action<T>)handler).Invoke(evt);
+                    }
+                    catch (Exception e)
+                    {
+                        UnityEngine.Debug.LogException(e);
+                    }
+                }
             }
         }
 

Assets/Darkmatter/Code/Services/Ads/Systems/AdMobAdService.cs

@@ -39,6 +39,11 @@ namespace Darkmatter.Services.Ads
         [SerializeField, Min(0)]
         private int maxInterstitialsPerSession = 8;
 
+        [Tooltip(
+            "Enable only after verifying Firebase/AdMob is not already auto-logging ad_impression for the same ads. Leaving this off avoids duplicate ad_impression counts in GA4/Firebase.")]
+        [SerializeField]
+        private bool logManualAdImpressionEvents;
+
         public bool IsInitialized => _initialized;
         public event Action<AdFormat, AdLoadState> LoadStateChanged;
 
@@ -653,11 +658,12 @@ namespace Darkmatter.Services.Ads
             ad.OnAdClicked += () => LogAdClicked(format);
         }
 
-        // Ad revenue: GA4-recommended ad_impression carries value+currency from AdMob's paid callback —
-        // this is what surfaces ad revenue in Firebase/GA4. Ad callbacks fire on the Unity main thread
-        // (RaiseAdEventsOnUnityMainThread = true), so logging straight to analytics is safe.
+        // AdMob/Firebase can auto-log ad_impression for linked apps. Manual logging is opt-in so one
+        // shown ad does not become two GA4 ad_impression events.
         private void LogAdImpression(AdFormat format, AdValue value)
         {
+            if (!logManualAdImpressionEvents) return;
+
             _analytics?.LogEvent(AnalyticsEvents.AdImpression, new Dictionary<string, object>
             {
                 [AnalyticsParams.AdPlatform] = "AdMob",
@@ -736,4 +742,4 @@ namespace Darkmatter.Services.Ads
             LoadStateChanged?.Invoke(format, state);
         }
     }
-}
+}

Assets/Darkmatter/Code/Services/Analytics/Systems/AnalyticsTracker.cs

@@ -56,8 +56,9 @@ namespace Darkmatter.Services.Analytics
             _subs.Add(_bus.Subscribe<IntroCompletedSignal>(_ => _analytics.LogEvent(AnalyticsEvents.IntroCompleted)));
             _subs.Add(_bus.Subscribe<PlayBtnClickedSignal>(_ => _analytics.LogEvent(AnalyticsEvents.PlayClicked)));
 
-            // Navigation
-            _subs.Add(_bus.Subscribe<OpenColorBookSignal>(_ => _analytics.LogEvent(AnalyticsEvents.ColorbookOpened)));
+            // Navigation. ColorbookShownSignal (not OpenColorBookSignal, which is the show-view command
+            // and misses scene-entry paths) fires on every way the catalog becomes visible.
+            _subs.Add(_bus.Subscribe<ColorbookShownSignal>(_ => OnColorbookShown()));
             _subs.Add(_bus.Subscribe<OpenArtBookSignal>(_ => _analytics.LogEvent(AnalyticsEvents.ArtbookOpened)));
             _subs.Add(_bus.Subscribe<ReturnToMainMenuSignal>(_ => OnReturnToMainMenu()));
 
@@ -90,6 +91,10 @@ namespace Darkmatter.Services.Analytics
 
         private void OnDrawingSelected(string drawingId)
         {
+            // GameplayFlowController relays the selection a second time after the scene swap
+            // (artbook edit path) — same id while already active is that relay, not a new selection.
+            if (drawingId == _activeDrawingId) return;
+
             // A new selection while a drawing is still open (uncompleted) = the previous one was abandoned.
             EndActiveDrawingIfAbandoned();
 
@@ -156,7 +161,7 @@ namespace Darkmatter.Services.Analytics
             if (dur >= 0f) p[AnalyticsParams.DurationSeconds] = dur;
             _analytics.LogEvent(AnalyticsEvents.DrawingCompleted, p);
 
-            // GA4 recommended games event (lights up built-in level funnels).
+            // Companion to GA4's level_start.
             _analytics.LogEvent(AnalyticsEvents.LevelComplete, new Dictionary<string, object>
             {
                 [AnalyticsParams.LevelName] = s.TemplateId,
@@ -171,16 +176,24 @@ namespace Darkmatter.Services.Analytics
             if (PlayerPrefs.GetInt(AllContentKey, 0) == 1) return; // once ever
             PlayerPrefs.SetInt(AllContentKey, 1);
             PlayerPrefs.Save();
-            _analytics.LogEvent(AnalyticsEvents.AllContentCompleted,
-                AnalyticsParams.CompletionCount, s.CompletedCount.ToString());
+            _analytics.LogEvent(AnalyticsEvents.AllContentCompleted, new Dictionary<string, object>
+            {
+                [AnalyticsParams.CompletionCount] = s.CompletedCount,
+            });
         }
 
         private void OnGallerySaveCompleted(GallerySaveCompletedSignal s)
         {
-            _analytics.LogEvent(AnalyticsEvents.GallerySaveCompleted, AnalyticsParams.Success, s.Success ? "true" : "false");
+            // Prefer the id carried by the signal: art-book saves happen with no active drawing.
+            string drawingId = string.IsNullOrEmpty(s.TemplateId) ? _activeDrawingId ?? string.Empty : s.TemplateId;
+            _analytics.LogEvent(AnalyticsEvents.GallerySaveCompleted, new Dictionary<string, object>
+            {
+                [AnalyticsParams.DrawingId] = drawingId,
+                [AnalyticsParams.Success] = s.Success ? 1 : 0,
+            });
             _analytics.LogEvent(AnalyticsEvents.DrawingSaved, new Dictionary<string, object>
             {
-                [AnalyticsParams.DrawingId] = _activeDrawingId ?? string.Empty,
+                [AnalyticsParams.DrawingId] = drawingId,
                 [AnalyticsParams.Success] = s.Success ? 1 : 0,
             });
         }
@@ -191,6 +204,15 @@ namespace Darkmatter.Services.Analytics
             _analytics.LogEvent(AnalyticsEvents.MainMenuReturned);
         }
 
+        private void OnColorbookShown()
+        {
+            // Reaching the catalog with a drawing still open means the player backed out of gameplay
+            // mid-drawing — the abandon moment. (Completion clears the active drawing before the
+            // catalog reloads, so the finish path never lands here with one open.)
+            EndActiveDrawingIfAbandoned();
+            _analytics.LogEvent(AnalyticsEvents.ColorbookOpened);
+        }
+
         // Emits drawing_abandoned for an open, uncompleted drawing. Completion clears _activeDrawingId, so
         // reaching here with a non-null id means the drawing was left without finishing — the leak signal.
         private void EndActiveDrawingIfAbandoned()

Assets/Darkmatter/Code/Services/Audio/Systems/AudioService.cs

@@ -350,7 +350,9 @@ namespace Darkmatter.Services.Audio
             if (!source.gameObject.activeInHierarchy) source.gameObject.SetActive(true);
 
             source.Play();
+#if UNITY_EDITOR || DEVELOPMENT_BUILD
             Debug.Log($"[AudioService] Play clip='{(request.Clip != null ? request.Clip.name : "null")}' ch={request.Channel} vol={source.volume:F2} mixer={(source.outputAudioMixerGroup != null ? source.outputAudioMixerGroup.name : "none")} listener={(AudioListener.volume)} muted={AudioListener.pause} isPlaying={source.isPlaying}");
+#endif
             if (IsChannelPaused(request.Channel))
             {
                 source.Pause();

Assets/Darkmatter/Code/Services/Capture/Systems/CaptureService.cs

@@ -68,54 +68,58 @@ namespace Darkmatter.Services.Capture
 
                 var prevActive = RenderTexture.active;
                 RenderTexture.active = rt;
-                var fullScreen = new Texture2D(sw, sh, TextureFormat.RGBA32, mipChain: false);
-                fullScreen.ReadPixels(new Rect(0, 0, sw, sh), 0, 0);
-                fullScreen.Apply();
-                RenderTexture.active = prevActive;
-                captureViewScope?.Dispose();
-                captureViewScope = null;
-
+                // Read only the crop region straight off the RT. A full-screen ReadPixels followed by
+                // GetPixels/SetPixels cropping allocated a managed Color[] at 16 bytes/pixel (tens of MB)
+                // on every capture — autosave runs this after each paint, OOM-killing low-RAM devices.
+                var cropped = new Texture2D(cropW, cropH, TextureFormat.RGBA32, mipChain: false);
                 try
                 {
-                    var cropped = new Texture2D(cropW, cropH, TextureFormat.RGBA32, mipChain: false);
+                    cropped.ReadPixels(new Rect(crop.x, crop.y, cropW, cropH), 0, 0);
+                    cropped.Apply();
+                    RenderTexture.active = prevActive;
+                    captureViewScope?.Dispose();
+                    captureViewScope = null;
+
+                    int targetW = Mathf.Max(1, Mathf.RoundToInt(cropW * scale));
+                    int targetH = Mathf.Max(1, Mathf.RoundToInt(cropH * scale));
+                    Texture2D output = cropped;
+                    if (output.width != targetW || output.height != targetH)
+                        output = Resize(cropped, targetW, targetH);
+
                     try
                     {
-                        cropped.SetPixels(fullScreen.GetPixels((int)crop.x, (int)crop.y, cropW, cropH));
-                        cropped.Apply();
-
-                        int targetW = Mathf.Max(1, Mathf.RoundToInt(cropW * scale));
-                        int targetH = Mathf.Max(1, Mathf.RoundToInt(cropH * scale));
-                        Texture2D output = cropped;
-                        if (output.width != targetW || output.height != targetH)
-                            output = Resize(cropped, targetW, targetH);
-
-                        try
-                        {
-                            return output.EncodeToPNG();
-                        }
-                        finally
-                        {
-                            if (output != cropped) Object.Destroy(output);
-                        }
+                        return output.EncodeToPNG();
                     }
                     finally
                     {
-                        Object.Destroy(cropped);
+                        if (output != cropped) Object.Destroy(output);
                     }
                 }
                 finally
                 {
-                    Object.Destroy(fullScreen);
+                    RenderTexture.active = prevActive;
+                    Object.Destroy(cropped);
                 }
             }
             finally
             {
-                paperCanvas.renderMode = prevMode;
-                paperCanvas.worldCamera = prevWorldCam;
-                paperCanvas.planeDistance = prevPlaneDist;
-                cam.targetTexture = prevTarget;
-                cam.clearFlags = prevFlags;
-                cam.backgroundColor = prevBg;
+                // The awaits above give scene teardown (autosave racing an unload) a chance to
+                // destroy the canvas or camera; touching them then would throw from finally and
+                // skip the rest of the restore.
+                if (paperCanvas != null)
+                {
+                    paperCanvas.renderMode = prevMode;
+                    paperCanvas.worldCamera = prevWorldCam;
+                    paperCanvas.planeDistance = prevPlaneDist;
+                }
+
+                if (cam != null)
+                {
+                    cam.targetTexture = prevTarget;
+                    cam.clearFlags = prevFlags;
+                    cam.backgroundColor = prevBg;
+                }
+
                 RenderTexture.ReleaseTemporary(rt);
                 if (disabledGraphics != null)
                     foreach (var g in disabledGraphics)

Assets/Darkmatter/Code/Services/Gallery/Core/GalleryService.cs

@@ -118,8 +118,17 @@ namespace Darkmatter.Services.Gallery
                 GL.PopMatrix();
 
                 var output = new Texture2D(bgW, bgH, TextureFormat.RGBA32, mipChain: false);
-                output.ReadPixels(new Rect(0, 0, bgW, bgH), 0, 0);
-                output.Apply();
+                try
+                {
+                    output.ReadPixels(new Rect(0, 0, bgW, bgH), 0, 0);
+                    output.Apply();
+                }
+                catch
+                {
+                    UnityEngine.Object.Destroy(output);
+                    throw;
+                }
+
                 return output;
             }
             finally

Assets/Darkmatter/Content/Colorbook UI/DrawingItems/Aeroplane/Areroplane Reference.png.meta

@@ -21,7 +21,7 @@ TextureImporter:
     heightScale: 0.25
     normalMapFilter: 0
     flipGreenChannel: 0
-  isReadable: 1
+  isReadable: 0
   streamingMipmaps: 0
   streamingMipmapsPriority: 0
   vTOnly: 0

Assets/Darkmatter/Content/Colorbook UI/DrawingItems/Apple/apple reference.png.meta

@@ -21,7 +21,7 @@ TextureImporter:
     heightScale: 0.25
     normalMapFilter: 0
     flipGreenChannel: 0
-  isReadable: 1
+  isReadable: 0
   streamingMipmaps: 0
   streamingMipmapsPriority: 0
   vTOnly: 0

Assets/Darkmatter/Content/Colorbook UI/DrawingItems/Bus1/bus reference.png.meta

@@ -21,7 +21,7 @@ TextureImporter:
     heightScale: 0.25
     normalMapFilter: 0
     flipGreenChannel: 0
-  isReadable: 1
+  isReadable: 0
   streamingMipmaps: 0
   streamingMipmapsPriority: 0
   vTOnly: 0

Assets/Darkmatter/Content/Colorbook UI/DrawingItems/Car1/Car1_Reference(1).png.meta

@@ -21,7 +21,7 @@ TextureImporter:
     heightScale: 0.25
     normalMapFilter: 0
     flipGreenChannel: 0
-  isReadable: 1
+  isReadable: 0
   streamingMipmaps: 0
   streamingMipmapsPriority: 0
   vTOnly: 0

Assets/Darkmatter/Content/Colorbook UI/DrawingItems/Elephant/Elephant Reference.png.meta

@@ -21,7 +21,7 @@ TextureImporter:
     heightScale: 0.25
     normalMapFilter: 0
     flipGreenChannel: 0
-  isReadable: 1
+  isReadable: 0
   streamingMipmaps: 0
   streamingMipmapsPriority: 0
   vTOnly: 0

Assets/Darkmatter/Content/Colorbook UI/DrawingItems/dog/dog reference.png.meta

@@ -21,7 +21,7 @@ TextureImporter:
     heightScale: 0.25
     normalMapFilter: 0
     flipGreenChannel: 0
-  isReadable: 1
+  isReadable: 0
   streamingMipmaps: 0
   streamingMipmapsPriority: 0
   vTOnly: 0

Assets/Darkmatter/Data/Drawings/Templates/Bag.asset

@@ -14,6 +14,7 @@ MonoBehaviour:
   m_EditorClassIdentifier: Core::Darkmatter.Core.Data.Static.Features.DrawingTemplate.DrawingTemplateSO
   id: Bag
   displayName: Bag
+  difficultyOverride: 0
   defaultThumbnail: {fileID: 8766740682603709380, guid: ecad1a66623031f4a91dbcee6f10a295, type: 3}
   drawingPrefab: {fileID: 8396209140419971077, guid: ab15e2395fec7be429926e140d9f4a61, type: 3}
   coloringPrefab: {fileID: 222817150442217502, guid: b8b22ebdfe861214c8edef5e46743323, type: 3}

Assets/Darkmatter/Data/Settings/Rendering/UniversalRP.asset

@@ -23,7 +23,7 @@ MonoBehaviour:
   m_RequireOpaqueTexture: 0
   m_OpaqueDownsampling: 1
   m_SupportsTerrainHoles: 1
-  m_SupportsHDR: 1
+  m_SupportsHDR: 0
   m_HDRColorBufferPrecision: 0
   m_MSAA: 1
   m_RenderScale: 1
@@ -42,7 +42,7 @@ MonoBehaviour:
   m_SupportProbeVolumeScenarioBlending: 0
   m_ProbeVolumeSHBands: 1
   m_MainLightRenderingMode: 1
-  m_MainLightShadowsSupported: 1
+  m_MainLightShadowsSupported: 0
   m_MainLightShadowmapResolution: 2048
   m_AdditionalLightsRenderingMode: 1
   m_AdditionalLightsPerObjectLimit: 4

Assets/Darkmatter/Scenes/Colorbook.unity

@@ -977,8 +977,8 @@ RectTransform:
   m_LocalEulerAnglesHint: {x: 0, y: 0, z: 0}
   m_AnchorMin: {x: 0, y: 0}
   m_AnchorMax: {x: 1, y: 1}
-  m_AnchoredPosition: {x: 118.53375, y: -50.553192}
-  m_SizeDelta: {x: -305.9775, y: -178.6848}
+  m_AnchoredPosition: {x: 149.13885, y: -50.553192}
+  m_SizeDelta: {x: -336.5826, y: -178.6848}
   m_Pivot: {x: 0, y: 1}
 --- !u!114 &1157581244
 MonoBehaviour:
@@ -1743,7 +1743,7 @@ MonoBehaviour:
   m_Name: 
   m_EditorClassIdentifier: UnityEngine.UI::UnityEngine.UI.GridLayoutGroup
   m_Padding:
-    m_Left: 20
+    m_Left: 0
     m_Right: 0
     m_Top: 0
     m_Bottom: 0

Assets/Plugins/Android/FirebaseCrashlytics.androidlib/res/values/crashlytics_build_id.xml

@@ -1 +1 @@
-<?xml version="1.0" encoding="utf-8"?><resources><string name="com.crashlytics.android.build_id" translatable="false">8fc48ed6-41de-4dcf-a980-9aa3316fad11</string></resources>
+<?xml version="1.0" encoding="utf-8"?><resources><string name="com.crashlytics.android.build_id" translatable="false">b468c378-10c7-4fe5-a4e9-6ae4bf5078cd</string></resources>

Assets/Smartlook/SmartlookAnalytics/Resources/SmartlookSettings.asset

@@ -13,4 +13,4 @@ MonoBehaviour:
   m_Name: SmartlookSettings
   m_EditorClassIdentifier: 
   ProjectKey: 3bcfb098c5c4f6f1f48d8bbef4c0c94d7c2f9bc9
-  FPS: 30
+  FPS: 2

Assets/TextMesh Pro/Shaders/TMP_SDF-URP Unlit.shadergraph.meta

@@ -8,3 +8,13 @@ ScriptedImporter:
   assetBundleName: 
   assetBundleVariant: 
   script: {fileID: 11500000, guid: 625f186215c104763be7675aa2d941aa, type: 3}
+  useAsTemplate: 0
+  exposeTemplateAsShader: 0
+  indexedData: {instanceID: 0}
+  template:
+    name: 
+    category: 
+    description: 
+    icon: {instanceID: 0}
+    thumbnail: {instanceID: 0}
+    order: 0

Assets/_Recovery.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: f8a91ab8cce424696bd7b4cbbac110fe
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/_Recovery/0.unity.meta

@@ -0,0 +1,7 @@
+fileFormatVersion: 2
+guid: 90078c122328b4902a1e67255b30525a
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

ProjectSettings/ProjectSettings.asset

@@ -11,7 +11,7 @@ PlayerSettings:
   defaultScreenOrientation: 4
   targetDevice: 2
   useOnDemandResources: 0
-  accelerometerFrequency: 60
+  accelerometerFrequency: 0
   companyName: Darkmatter Game Production
   productName: Kidsage Colorbook
   defaultCursor: {fileID: 0}
@@ -148,7 +148,7 @@ PlayerSettings:
   loadStoreDebugModeEnabled: 0
   visionOSBundleVersion: 1.0
   tvOSBundleVersion: 1.0
-  bundleVersion: 1.9
+  bundleVersion: 2.1
   preloadedAssets:
   - {fileID: 11400000, guid: cc969dbecb228fa49b16da9273753a8f, type: 2}
   - {fileID: -944628639613478452, guid: 2bcd2660ca9b64942af0de543d8d7100, type: 3}
@@ -180,7 +180,7 @@ PlayerSettings:
     iPhone: 1
     tvOS: 0
   overrideDefaultApplicationIdentifier: 1
-  AndroidBundleVersionCode: 9
+  AndroidBundleVersionCode: 11
   AndroidMinSdkVersion: 26
   AndroidTargetSdkVersion: 0
   AndroidPreferredInstallLocation: 1