zgredexandPatryk Radtke
c4f5c8e931
## Problem Custom sleep wallpapers feel repetitive — the same image appearing multiple times in a short session. Only the single most-recently-shown index was stored (`uint8_t lastSleepImage`), so on collections of 3–5 images, two-pick cycles were common. On larger collections, any image could reappear within the next few picks. ## Solution Add a 16-entry circular recency buffer to `CrossPointState` that excludes recently shown wallpapers from selection. **Recency buffer** (`recentSleepImages[16]`, `recentSleepPos`, `recentSleepFill` — 34 bytes DRAM): - Tracks the last 16 shown wallpaper indices - On each pick, rerolls up to 20 times if the candidate was recently shown - Window auto-shrinks to `numFiles - 1` for small collections (guarantees a non-repeat is always possible) - `isRecentSleep()` clamps to `recentSleepFill` to avoid false positives on unwritten buffer slots - State persisted to `state.json` so the buffer survives sleep/wake cycles **Migration**: - Binary (`state.bin`): old `lastSleepImage` field seeded into the new buffer if valid - JSON (`state.json`): legacy `lastSleepImage` key detected and seeded into the buffer when upgrading from older firmware ## Index type fix `randomFileIndex` upgraded from `uint8_t` to `uint16_t` — silently truncated for collections larger than 255 wallpapers. ## Repeat probability: before vs after Chance of seeing a recently-shown image on the next pick. After: `(numFiles - 16) / numFiles` once collection exceeds the window; 0% while ≤17. | Collection | Before | After | |---|---|---| | 3 | 50% | 0% | | 5 | 75% | 0% | | 10 | 89% | 0% | | 17 | 94% | 0% | | 18 | 94% | 6% | | 20 | 95% | 20% | | 25 | 96% | 36% | | 30 | 97% | 47% | | 50 | 98% | 68% | | 100 | 99% | 84% | ## Memory impact | Addition | Size | |---|---| | `recentSleepImages[16]` | 32 bytes DRAM | | `recentSleepPos` + `recentSleepFill` | 2 bytes DRAM | | **Total** | **34 bytes DRAM** | ## Files changed - `src/CrossPointState.h` — recency buffer fields + `isRecentSleep()` / `pushRecentSleep()` declarations - `src/CrossPointState.cpp` — `isRecentSleep()` / `pushRecentSleep()` implementations + binary migration path - `src/JsonSettingsIO.cpp` — JSON serialisation of buffer state + JSON migration - `src/activities/boot_sleep/SleepActivity.cpp` — retry loop with recency check Co-authored-by: Patryk Radtke <patryk@Patryks-MacBook-Pro.local>
39 lines
1.1 KiB
C++
39 lines
1.1 KiB
C++
#pragma once
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#include <cstdint>
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#include <string>
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class CrossPointState {
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// Static instance
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static CrossPointState instance;
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public:
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static constexpr uint8_t SLEEP_RECENT_COUNT = 16;
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std::string openEpubPath;
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uint16_t recentSleepImages[SLEEP_RECENT_COUNT] = {}; // circular buffer of recent wallpaper indices
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uint8_t recentSleepPos = 0; // next write slot
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uint8_t recentSleepFill = 0; // valid entries (0..SLEEP_RECENT_COUNT)
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uint8_t readerActivityLoadCount = 0;
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bool lastSleepFromReader = false;
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// Returns true if idx was shown within the last checkCount picks.
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// Walks backwards from the most recently written slot.
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bool isRecentSleep(uint16_t idx, uint8_t checkCount) const;
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void pushRecentSleep(uint16_t idx);
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~CrossPointState() = default;
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// Get singleton instance
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static CrossPointState& getInstance() { return instance; }
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bool saveToFile() const;
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bool loadFromFile();
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private:
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bool loadFromBinaryFile();
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};
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// Helper macro to access settings
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#define APP_STATE CrossPointState::getInstance()
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