# Playa - Image Sequence Player
[](https://github.com/ssoj13/playa/actions/workflows/release.yml)
[](https://github.com/ssoj13/playa/releases/latest)
[](https://github.com/ssoj13/playa/releases)
[](LICENSE)
[](https://github.com/ssoj13/playa)
[](CHANGELOG.md)
> **Experimental project**: Built to explore Rust's ecosystem and CI/CD patterns while building some cool tools. Production-ready where tested, rough edges expected elsewhere. Open source contributions welcome.
Image sequence player for VFX workflows. Async loading, LRU caching, OpenGL rendering.
## Features
- **Dual EXR backends**: Choose between pure Rust (exrs) for fast builds or OpenEXR C++ for full DWAA/DWAB compression support
- **Multi-format support**: EXR, PNG, JPEG, TIFF, TGA with fast parallel loading
- **HDR pixel precision**: Native support for 8-bit, 16-bit half-float, and 32-bit float images
- **Drag-and-drop**: Drop any image file - automatically detects and loads the entire sequence
- **Smart sequence detection**: Load one frame (e.g., `render.0001.exr`) - finds all frames automatically
- **Persistent playlist**: Load multiple sequences, auto-saves and restores between sessions
- **Color-coded timeline**: Visual sequence boundaries with real-time frame load indicators
- **Responsive scrubbing**: Instant frame navigation - always responsive even during fast scrubbing, cancels stale loads automatically
- **Cursor-centered zoom**: Mouse wheel zoom centers on cursor position (like Nuke/Houdini)
- **Playback controls**: Standard transport controls (play/pause, JKL shuttle, loop)
- **Viewport controls**: Zoom, pan, fit-to-window, 100% pixel-perfect view
- **Custom GLSL shaders**: Load display shaders from `shaders/` directory - LUTs, color transforms, custom effects
- **Smart memory management**: Automatically manages cache size - never runs out of memory
- **Settings dialog**: Theme switching, font size, preferences (F3)
- **Cinema mode**: Fullscreen playback with hidden UI
- **Persistent settings**: Everything saves automatically - window layout, zoom level, shader selection
## Installation
### Download Pre-built Binaries (Recommended)
Download the latest release for your platform from the [Releases page](https://github.com/ssoj13/playa/releases/latest):
**Two backends available for each platform:**
- **Windows**:
- `playa_x.x.x-exrs-x64-setup.exe` - Pure Rust backend (fast, no DWAA/DWAB)
- `playa_x.x.x-openexr-x64-setup.exe` - OpenEXR C++ backend (full compression support)
- Portable ZIPs: `playa-exrs-x86_64-pc-windows-msvc.zip`, `playa-openexr-x86_64-pc-windows-msvc.zip`
- **Linux**:
- `playa-x.x.x-exrs.AppImage` / `playa-x.x.x-exrs.deb` - Pure Rust backend
- `playa-x.x.x-openexr.AppImage` / `playa-x.x.x-openexr.deb` - OpenEXR C++ backend
- Portable ZIPs: `playa-exrs-x86_64-unknown-linux-gnu.zip`, `playa-openexr-x86_64-unknown-linux-gnu.zip`
- **macOS**: Currently disabled (cross-compilation issues being resolved)
**Which backend to choose?**
- **exrs**: Faster installation, smaller size, pure Rust. Use if you don't need DWAA/DWAB compression.
- **openexr**: Full OpenEXR feature support including DWAA/DWAB. Use for maximum compatibility.
### Build from Source
Playa supports two EXR backends:
| **exrs** (default) | `cargo build --release` | None (pure Rust) | No |
| **OpenEXR** (optional) | `cargo xtask build --release --openexr` | C++ compiler, CMake | Yes |
#### Option 1: Default Build (exrs - Pure Rust)
Fast build with no external dependencies. Suitable for most workflows:
```bash
git clone https://github.com/ssoj13/playa.git
cd playa
# Build with exrs backend (pure Rust, no DLLs)
cargo build --release
```
The compiled binary will be in `target/release/playa` (or `playa.exe` on Windows).
**Limitations**: Cannot load EXR files with DWAA/DWAB compression. Will show helpful error message with build instructions.
#### Option 2: Full OpenEXR Support (C++ Backend)
Supports all EXR compression formats including DWAA/DWAB:
**Prerequisites:**
- Rust 1.70+
- C++ compiler and CMake
```bash
git clone https://github.com/ssoj13/playa.git
cd playa
# Build with OpenEXR backend (full format support)
cargo xtask build --release --openexr
# Or use the wrapper script
./build.sh
```
**Note:** OpenEXR backend compiles C++ libraries (~5-10 minutes first build, then cached).
### Using xtask - Project Build Automation
**What is xtask?**
`xtask` is an idiomatic Rust pattern for build automation using a workspace helper binary. It provides cross-platform task automation without external dependencies (no Makefiles, no Python, no shell scripts).
**Why xtask?**
- **Cross-platform**: Same commands work identically on Windows, Linux, and macOS
- **No external tools**: Pure Rust, uses project's existing toolchain
- **Type-safe**: Catch errors at compile time, not runtime
- **Self-documenting**: Built-in `--help` with structured command definitions
- **Integrated**: Direct access to project workspace and Cargo metadata
- **Maintainable**: Refactor-friendly Rust code instead of brittle shell scripts
**Quick Start (New Contributors):**
```bash
# Bootstrap script handles everything
./bootstrap.cmd # Windows
./bootstrap.sh # Linux/macOS
# Shows xtask help and available commands
# Automatically installs missing dependencies (cargo-release, cargo-packager)
# Builds xtask binary if needed
```
**Available Commands:**
```bash
# Build automation
cargo xtask build [--release] [--openexr] # Full build (default: exrs, --openexr: C++ backend)
cargo xtask post [--release] # Copy native libraries and shaders (OpenEXR only)
cargo xtask verify [--release] # Verify all dependencies present
cargo xtask deploy [--install-dir] # Install to system (local testing)
# Release management
cargo xtask tag-dev [level] # Create dev tag (v0.1.x-dev), trigger Build workflow
cargo xtask tag-rel [level] # Create release tag (v0.1.x) on main, trigger Release workflow
cargo xtask pr [version] # Create Pull Request from dev to main with all commits
cargo xtask changelog # Generate changelog preview from unreleased commits
# Platform-specific (Linux only, OpenEXR backend)
cargo xtask pre # Patch OpenEXR headers for GCC 11+ compatibility
```
**What `cargo xtask build` does:**
**Without `--openexr` (default - exrs backend):**
1. Runs `cargo build [--release]` with pure Rust exrs backend
2. No external dependencies copied (self-contained binary)
**With `--openexr` (OpenEXR C++ backend):**
1. **Linux**: Patches OpenEXR headers for GCC 11+ compatibility
2. **All platforms**: Runs `cargo build [--release] --features openexr`
3. **All platforms**: Copies native libraries (OpenEXR, Imath, zlib) to target directory
4. **All platforms**: Copies shaders from project root
5. **Linux**: Creates necessary symlinks for library loading
**Common Workflows:**
```bash
# Development build (exrs backend - fast, no external deps)
cargo build
# Development build with full OpenEXR support
cargo xtask build --openexr
# Release build and local install (exrs)
cargo build --release
cargo xtask deploy
# Release build and local install (OpenEXR)
cargo xtask build --release --openexr
cargo xtask deploy
# Create dev tag and push (triggers CI Build workflow)
cargo xtask tag-dev patch
# Preview unreleased changelog
cargo xtask changelog
# Create PR from dev to main (typical release workflow)
cargo xtask pr v0.2.0
# Create release from main branch (after merging PR)
git checkout main
git pull
cargo xtask tag-rel patch
```
### Cargo Features
Playa uses Cargo features to provide flexible EXR backend selection:
| (none) | ✅ Yes | Pure Rust `exrs` backend | Fast builds, no external dependencies |
| `openexr` | ❌ No | C++ OpenEXR backend via `openexr-rs` | Full DWAA/DWAB compression support |
**Build commands:**
```bash
# Default (exrs backend)
cargo build --release
# OpenEXR backend (full compression support)
cargo build --release --features openexr
# Using xtask (handles dependencies automatically)
cargo xtask build # exrs backend
cargo xtask build --openexr # OpenEXR backend
```
**Backend comparison:**
- **exrs (default)**:
- ✅ Pure Rust, fast compilation (~2-3 minutes)
- ✅ No external dependencies
- ❌ No DWAA/DWAB compression support
- Use for: Development, quick iterations
- **openexr (feature flag)**:
- ✅ Full OpenEXR feature support (DWAA/DWAB/etc)
- ✅ Battle-tested C++ implementation
- ❌ Requires C++ compiler, CMake
- ❌ Slower compilation (~3-4 minutes)
- Use for: Production builds, full compatibility
### Development Dependencies
**Auto-installed by bootstrap script:**
- `cargo-release` - Version bumping and tag creation
- `cargo-packager` - Cross-platform installer generation (v0.11.7)
**Standard Rust tools (usually pre-installed):**
- `rustup` - Rust toolchain manager
- `cargo` - Rust package manager
- `clippy` - Linter (`rustup component add clippy`)
- `rustfmt` - Code formatter (`rustup component add rustfmt`)
**Required for PR workflow:**
- `gh` - GitHub CLI (used by `cargo xtask pr`) - [Installation](https://cli.github.com/)
**Optional tools:**
- `git-cliff` - Changelog generation (used by `cargo xtask changelog`)
- `cargo-audit` - Security vulnerability scanning
- `cargo-llvm-cov` - Code coverage
### GitHub Actions CI/CD
Automated builds on Windows and Linux with optimized multi-tier caching.
#### Workflow Triggers
- **Push to main**: Updates release cache, no artifacts
- **Tags `v*` on main**: Triggers `release.yml` → GitHub Release with both backends (exrs + OpenEXR)
- **Tags `v*` NOT on main**: Triggers `build.yml` → Dev artifacts for both backends (exrs + OpenEXR)
- **Manual dispatch**: Available for both workflows
#### Caching Strategy
**Backend-specific caches for both release and dev builds:**
| `playa-windows-release-exrs-v1` | Main branch releases (exrs backend) | Registry, git, bin, target |
| `playa-windows-release-openexr-v1` | Main branch releases (OpenEXR backend) | Registry, git, bin, target |
| `playa-linux-release-exrs-v1` | Main branch releases (exrs backend) | Registry, git, bin, target |
| `playa-linux-release-openexr-v1` | Main branch releases (OpenEXR backend) | Registry, git, bin, target |
| `playa-windows-dev-exrs-v1` | Dev tag builds (exrs backend) | Registry, git, bin, target |
| `playa-windows-dev-openexr-v1` | Dev tag builds (OpenEXR backend) | Registry, git, bin, target |
| `playa-linux-dev-exrs-v1` | Dev tag builds (exrs backend) | Registry, git, bin, target |
| `playa-linux-dev-openexr-v1` | Dev tag builds (OpenEXR backend) | Registry, git, bin, target |
**Key optimizations:**
- **cargo-packager binary cached** in `~/.cargo/bin/` - saves ~2-3 min/build
- **Conditional install**: Checks if binary exists before `cargo install`
- **Conditional save**: Skips cache save if successfully restored (cache-hit)
- **Split restore/save**: Release workflow saves only from main branch
#### Build Performance
**Typical times:**
- **First build (cold cache)**: ~20-25 minutes (includes OpenEXR compilation)
- **Subsequent builds (warm cache)**: ~10-12 minutes
- **cargo-packager**: Cached (~10 sec check) or installed fresh (~2-3 min)
- **Cache restore/save**: ~1-2 minutes
**Cache benefits:**
- Rust dependencies: Saves ~10-15 minutes
- cargo-packager binary: Saves ~2-3 minutes
- Total speedup: ~13-18 minutes per build
**Problem solved:**
Previous approach compiled OpenEXR (~20 min) and cargo-packager (~2-3 min) every run. New caching brings this down to ~10-12 min for warm builds.
#### GitHub Actions Cache Ref Scoping
**The Problem:**
GitHub Actions caches are scoped by ref (branch/tag). Each tag creates a unique ref:
- Tag `v0.1.54` → ref `refs/tags/v0.1.54`
- Tag `v0.1.55` → ref `refs/tags/v0.1.55`
By default, caches created on one ref cannot be accessed by another ref. This means:
- Each tag would rebuild from scratch (~20 minutes with OpenEXR)
- No cache reuse between releases
- Wasted CI time and resources
**The Solution:**
Use **parent ref inheritance** with split cache operations:
1. **Main branch creates canonical cache**:
- `actions/cache/save@v4` with condition: `if: github.ref == 'refs/heads/main'`
- Creates cache with key `playa-windows-release-v1`
- Ref: `refs/heads/main`
2. **Tags inherit from main**:
- `actions/cache/restore@v4` (no condition)
- Looks for key `playa-windows-release-v1`
- GitHub Actions allows reading caches from parent refs
- Tags on main automatically find main's cache
3. **Conditional save with cache-hit check**:
- Skip save if cache was restored: `steps.cache.outputs.cache-hit != 'true'`
- Prevents redundant cache uploads
**Result:**
- First push to main: ~20 min, creates cache
- Tags on main: ~10 min, reuse main's cache
- Dev tags (not on main): Use separate `*-dev-v1` caches
**Key insight:** GitHub Actions allows child refs (tags) to read caches from parent refs (branches they're based on), but not vice versa. Main branch is the "source of truth" for release caches.
### Standard Rust Development
```bash
# Testing
cargo test # Run all unit tests
cargo test --release # Run tests in release mode
# Documentation
cargo doc --open # Generate and open rustdoc documentation
cargo doc --no-deps --open # Only document this crate
# Code quality
cargo clippy # Run linter
cargo clippy -- -D warnings # Treat warnings as errors
cargo fmt # Format code
cargo fmt -- --check # Check formatting without modifying
# Build variants
cargo build # Debug build
cargo build --release # Release build (optimized)
cargo clean # Clean build artifacts
```
#### Linux-Specific Build Notes
**Note:** These instructions apply only to the OpenEXR C++ backend (`--openexr` feature). The default exrs backend requires no external dependencies.
**OpenEXR GCC 11+ Header Patching:**
OpenEXR 3.0.5 headers are missing `#include <cstdint>`, causing compilation errors with GCC 11+:
```
error: 'uint64_t' has not been declared
```
`cargo xtask pre` automatically patches 3 header files in `~/.cargo/registry/src/`:
- `ImfTiledMisc.h`
- `ImfDeepTiledInputFile.h`
- `ImfDeepTiledInputPart.h`
The patching is **idempotent** and **version-agnostic** - safe to run multiple times.
See: https://github.com/AcademySoftwareFoundation/openexr/issues/1157
**Native Libraries (7 Required):**
| OpenEXR Core (4 libs) | EXR reading/writing, utilities, threading, exceptions |
| Imath | Math library |
| Zlib | Compression |
| OpenEXR-C | C API wrapper from openexr-sys |
**Library Copy Process (`cargo xtask post`):**
1. **Locate libraries** compiled by `openexr-sys`:
- Searches `target/release/build/openexr-sys-*/out/` for versioned `.so` files
- Example: `libOpenEXR-3_2.so.31.0.0`, `libImath-3_1.so.29.9.0`
2. **Copy to target directory**:
- Destination: `target/release/` (next to `playa` binary)
- Preserves original versioned filenames
3. **Create SONAME symlinks**:
- `libOpenEXR-3_2.so -> libOpenEXR-3_2.so.31.0.0`
- `libOpenEXRCore-3_2.so -> libOpenEXRCore-3_2.so.31.0.0`
- `libOpenEXRUtil-3_2.so -> libOpenEXRUtil-3_2.so.31.0.0`
- `libImath-3_1.so -> libImath-3_1.so.29.9.0`
- Plus OpenEXR-C wrapper lib
**Why this is needed:**
- `openexr-sys` build creates libraries with full SONAME versions
- Rust linker expects generic `.so` names without version suffixes
- Without symlinks: `error while loading shared libraries: libOpenEXR-3_2.so: cannot open shared object file`
**RPATH Configuration:**
`.cargo/config.toml` sets RPATH to `$ORIGIN`, so the executable searches for `.so` files in its own directory:
```toml
[target.x86_64-unknown-linux-gnu]
rustflags = ["-C", "link-arg=-Wl,-rpath,$ORIGIN"]
```
No `LD_LIBRARY_PATH` needed! Combined with symlinks from `cargo xtask post`, the binary is fully self-contained.
**Troubleshooting:**
Build fails with "uint64_t has not been declared":
```bash
cargo xtask pre
cargo build --release
```
Libraries not found when running:
```bash
cargo xtask verify --release
cargo xtask post --release # If missing
```
After `cargo clean`:
```bash
cargo xtask build --release # Re-patches automatically
```
#### Windows-Specific Build Notes
**Note:** These instructions apply only to the OpenEXR C++ backend (`--openexr` feature). The default exrs backend requires no external DLLs.
**Native Libraries (DLL Management):**
Windows requires `.dll` files alongside the executable. The same 7 OpenEXR/Imath/zlib libraries are needed, just as `.dll` instead of `.so`.
**Library Copy Process (`cargo xtask post`):**
1. **Locate DLLs** compiled by `openexr-sys`:
- Searches `target/release/build/openexr-sys-*/out/bin/` for `.dll` files
- Example: `OpenEXR-3_2.dll`, `Imath-3_1.dll`, `zlib.dll`
2. **Copy to target directory**:
- Destination: `target/release/` (next to `playa.exe`)
- Windows DLLs don't use versioned SONAME - simpler than Linux
**Why this is needed:**
- Windows searches for DLLs in the same directory as the executable
- Without DLLs: `The code execution cannot proceed because OpenEXR-3_2.dll was not found`
- No PATH modification needed - self-contained binary
**No RPATH equivalent:**
- Windows automatically searches the executable's directory first
- No special linker flags required (unlike Linux `$ORIGIN`)
## Usage
### Launch
```bash
# Start with empty player (drag-and-drop or file dialog)
playa
# Load specific file or sequence
playa path/to/image.0001.exr
```
### Keyboard Shortcuts
**Playback Controls:**
- `Space` - Play/Pause
- `J` / `,` / `←` - Jog backward / decrease speed
- `K` / `↓` - Stop playback / decrease FPS
- `L` / `.` / `→` - Jog forward / increase speed
- `↑` - Go to start
- `Ctrl+←` - Jump to start
- `Ctrl+→` - Jump to end
- `'` / `` ` `` - Toggle loop
**Viewport:**
- `F` - Fit to window (auto-fit mode)
- `A` / `1` / `Home` / `H` - 100% zoom
- `Mouse Wheel` - Zoom in/out (center on cursor)
- `Middle Mouse Drag` - Pan
- `Left Click + Drag` - Scrub timeline
**UI:**
- `F1` - Toggle help overlay
- `F2` - Toggle playlist panel
- `F3` - Toggle settings dialog
- `Z` - Toggle fullscreen (cinema mode)
- `ESC` - Exit fullscreen / Quit
- `Q` - Quit
- `Ctrl+R` - Reset settings to default
### Visual Sequence Navigation
The time slider provides visual feedback for multi-sequence playback:
- **Color-coded zones**: Each loaded sequence is displayed with a unique color on the timeline
- **Sequence boundaries**: White vertical dividers mark where sequences start/end
- **Load indicator bar**: Colored blocks below timeline show frame load status:
- Dark gray: Placeholder (not requested)
- Blue: Header only (detected but not loaded)
- Orange: Currently loading
- Green: Fully loaded
- Red: Load error
- **Adaptive labels**: Sequence names appear on the timeline when space permits
- **Instant navigation**: Click or drag anywhere on the timeline to jump to that frame
This makes it easy to identify and navigate between different sequences in your playlist at a glance.
### Settings Dialog
Press `F3` to open the settings dialog with TreeView categories:
**UI Category:**
- **Font Size**: Adjust global UI font size (10-18px, default 13px)
- **Dark Mode**: Toggle between dark and light themes
Settings are automatically persisted to `playa.json`.
## Architecture
### Core Components
```
┌─────────────┐
│ PlayaApp │ Main application (egui/eframe)
└──────┬──────┘
│
├──── Player ───────┐
│ │
│ ┌────▼────┐
│ │ Cache │ LRU cache + async loader + epoch counter
│ └────┬────┘
│ │
│ ┌────▼────────┐
│ │ Sequences │ Pattern-based frame lists
│ └────┬────────┘
│ │
│ ┌────▼────┐
│ │ Frames │ Individual images with status
│ └─────────┘
│
├──── Viewport ────┐
│ │
│ ┌─────▼──────────┐
│ │ ViewportState │ Zoom/pan/fit modes
│ └────────────────┘
│
├──── Scrubber ──── Timeline interaction
│
├──── TimeSlider ── Custom time slider widget + load indicator
│
├──── Shaders ───── OpenGL display shaders
│
└──── Prefs ─────── Settings dialog with TreeView
```
### Module Breakdown
#### `main.rs`
Entry point and main application loop. Handles:
- CLI argument parsing
- Window initialization (egui/eframe)
- Event loop and UI rendering
- Keyboard/mouse input routing
- Settings persistence (JSON)
- Global font size application
#### `player.rs`
Playback state manager. Controls:
- Play/pause/stop
- Frame navigation (jog, shuttle)
- FPS control with presets
- Loop mode
- Delegates frame access to Cache
#### `cache.rs`
Intelligent caching system with multi-threaded architecture:
- **LRU eviction**: Manages memory budget (default 50% system RAM)
- **Epoch counter**: Atomic counter for cancelling stale load requests during scrubbing
- **Worker pool**: 75% of CPU cores for parallel loading
- **Load queue**: mpsc channel-based task distribution with epoch tagging
- **Preload thread**: Background spiral loading from current frame
- **Sequence management**: Multi-sequence playlist support
- **Frame status tracking**: Provides frame load state for visualization
**Caching strategy:**
1. On-demand loading: Loads frame when accessed
2. Spiral preload: Loads frames in order: 0, +1, -1, +2, -2, ...
3. Epoch-based cancellation: Workers skip requests with old epoch on scrub/seek
4. Memory-aware: Evicts least-recently-used frames when over budget
5. Status sync: Updates frame status (Header → Loading → Loaded/Error)
**Epoch Counter Pattern:**
- `current_epoch: Arc<AtomicU64>` increments on every scrub/seek
- Workers check `req.epoch != current_epoch` and skip stale requests
- Prevents wasted work on frames user has already moved past
#### `sequence.rs`
Pattern-based frame sequence detection:
- Auto-detects sequences from single file (e.g., `render.0001.exr` → `render.*.exr`)
- Glob pattern matching
- Frame number extraction with padding detection
- Directory scanning for multiple sequences
- Header-only resolution reading (fast)
#### `frame.rs`
Individual frame with thread-safe async loading:
- **Status states**: Placeholder → Header → Loading → Loaded/Error
- **Arc<Mutex<FrameData>>**: Thread-safe shared ownership
- **Format loaders**: EXR (OpenEXR), PNG/JPEG/TIFF (image-rs)
- **Color conversion**: Linear → sRGB for EXR
- **Green placeholder**: Visible indicator for unloaded frames
- **Status API**: `frame.status()` for load indicator visualization
#### `viewport.rs`
Display transformation and interaction:
- **Modes**: AutoFit (scales to window), Auto100 (1:1 pixels), Manual (user control)
- **Zoom**: Mouse wheel with cursor-centered scaling
- **Pan**: Middle-mouse drag
- **OpenGL rendering**: Custom shader pipeline
#### `scrub.rs`
Interactive timeline scrubbing:
- Left-click/drag to navigate frames
- Visual feedback (vertical line + frame number)
- Auto-pauses playback during scrub
- Maps mouse X to frame based on image bounds
- Triggers epoch counter increment for stale request cancellation
#### `timeslider.rs`
Custom time slider widget with sequence visualization:
- **Color-coded zones**: Each sequence rendered with unique color (hash-based)
- **Visual dividers**: Vertical lines marking sequence boundaries
- **Adaptive labels**: Sequence names/numbers displayed when space permits
- **Load indicator**: Colored blocks showing frame status (cached for performance)
- **Cache invalidation**: Uses `cached_frames_count()` to detect when to rebuild
- **Stateless immediate mode**: Fully synchronized with player state
- **Interactive**: Click/drag to navigate, automatic playhead tracking
- **HSV color generation**: Stable colors derived from sequence pattern hash
**Load Indicator Implementation:**
- Queries `cache.get_frame_stats()` for all frame statuses
- Caches result in `egui::Memory` with version key
- Invalidates cache when `cached_frames_count()` changes
- Draws colored blocks: Dark gray (Placeholder), Blue (Header), Orange (Loading), Green (Loaded), Red (Error)
#### `shaders.rs`
OpenGL shader management:
- Built-in shaders (default, checker, etc.)
- Custom shader loading from `shaders/` directory
- Runtime shader switching
#### `prefs.rs`
Settings dialog with TreeView navigation:
- **AppSettings struct**: Centralizes all user preferences
- **SettingsCategory enum**: General, UI categories
- **TreeView integration**: Uses `egui_ltreeview` for hierarchical navigation
- **Font size control**: Global UI font size (10-18px with live preview)
- **Theme toggle**: Dark/light mode switching
- **Persistence**: Selected category and all settings saved to JSON
- **Window layout**: 700×500 default, resizable with ScrollArea
## Data Flow
```
User Action (drag-drop / file dialog / CLI arg)
│
▼
load_sequence(PathBuf)
│
├──► cache.ingest(paths)
│ │
│ ├──► Sequence::detect() ──► Parse patterns
│ │ Extract frame numbers
│ │ Create Frame objects (status: Header)
│ │
│ └──► append_seq() ──────► Add to cache.sequences
│ Update global frame range
│ Rebuild frame_paths_cache
│
└──► signal_preload() ─────────► Preload thread wakes up
Increments epoch counter
Sends LoadRequests with current epoch
Playback Update Loop
│
▼
player.update()
│
├──► Advance frame based on FPS/direction
│
└──► cache.get_frame(idx)
│
├──► Check LRU cache ───► HIT: update access time, return frame
│
└──► MISS: Send LoadRequest with current epoch
│
▼
Worker threads (75% cores)
│
├──► Check epoch ────► Stale? Skip request
│
├──► frame.load() ─────► Detect format (EXR/PNG/etc)
│ Update status: Loading
│ Load pixels from disk
│ Convert color space
│ Update status: Loaded/Error
│
└──► Send LoadedFrame via channel
│
▼
cache.process_loaded_frames()
│
├──► Ensure space (LRU eviction)
├──► Insert into cache
├──► Update sequence frame reference
└──► Send CacheMessage for UI updates
Scrub/Seek Event
│
▼
├──► Increment epoch counter ────► Cancel all in-flight requests
│
└──► Trigger preload with new epoch
Render Loop
│
▼
UI update
│
├──► Apply global font size from settings
│
├──► Apply theme (dark/light) from settings
│
├──► Get current frame from cache
│
├──► Upload texture to GPU (if frame changed)
│
├──► TimeSlider with load indicator
│ │
│ ├──► Check cached_frames_count()
│ ├──► Rebuild indicator cache if changed
│ └──► Draw colored blocks for each frame
│
└──► ViewportRenderer.render()
│
└──► Apply viewport transform (zoom/pan)
Apply shader
Draw quad with texture
Settings Dialog (F3)
│
▼
├──► TreeView navigation (General / UI)
│
├──► Font size slider ───► Update AppSettings.font_size
│ Apply globally on next frame
│
├──► Dark mode toggle ───► Update AppSettings.dark_mode
│ Switch theme immediately
│
└──► Auto-save to playa.json
```
## Performance Characteristics
- **Startup**: Instant (lazy loading)
- **Sequence detection**: Fast (header-only reads, ~1-5ms per file)
- **Frame loading**: Parallel (75% CPU cores)
- **Memory**: Self-limiting (50% system RAM, configurable)
- **Scrubbing**: Responsive (epoch-based cancellation + preloaded cache)
- **Playback**: Smooth (async loading stays ahead of playback)
- **Load indicator**: Efficient (cached, O(1) status lookups, rebuilds only on cache changes)
- **LRU cache**: Optimized (no stale keys in access_order, skips dead entries during eviction)
## Configuration
Settings auto-save to `playa.json` in the working directory:
- FPS
- Loop mode
- Shader selection
- Font size (global UI)
- Dark/light theme
- Viewport state (zoom/pan/mode)
- Playlist (sequence references)
- Window position/size
- Panel widths (playlist)
- Settings dialog state (selected category)
Cache state (sequences + current frame) auto-saves to `playa_cache.json` for instant restoration on restart.
## Technical Stack
- **UI**: egui 0.33 + eframe
- **TreeView**: egui_ltreeview 0.6.0 (with persistence feature)
- **Graphics**: OpenGL via glow + egui_glow
- **Image**:
- **EXR (default)**: exrs via image 0.25 (pure Rust)
- **EXR (optional)**: openexr 0.11 (C++ bindings, `openexr` feature)
- **Other formats**: image 0.25 (PNG/JPEG/TIFF/TGA/HDR)
- **Async**: std::thread + crossbeam-channel + mpsc
- **Concurrency**: AtomicU64 for epoch counter, Arc<Mutex> for shared state
- **CLI**: clap 4.5
- **Logging**: env_logger (set `RUST_LOG=debug` for verbose output)
## License
See LICENSE file for details.
## Contributing
We welcome contributions! Please see our [Contributing Guide](CONTRIBUTING.md) for details on:
- Commit message conventions (Conventional Commits)
- Development workflow and tools
- Release process
- CI/CD architecture
See [CHANGELOG.md](CHANGELOG.md) for project history.
