> ## Documentation Index
> Fetch the complete documentation index at: https://docs.facebetter.net/llms.txt
> Use this file to discover all available pages before exploring further.

# API Reference

> Flutter API Reference

## FBEngineConfig

| Field             | Type      | Description                                            |
| ----------------- | --------- | ------------------------------------------------------ |
| `appId`           | `String`  | App ID (optional if `licenseJson` provided)            |
| `appKey`          | `String`  | App key (optional if `licenseJson` provided)           |
| `licenseJson`     | `String?` | License JSON string (takes priority over appId/appKey) |
| `externalContext` | `bool`    | Use external OpenGL context (default `false`)          |

## FBBeautyEffectEngine

### Static Methods

| Method                                          | Description                       |
| ----------------------------------------------- | --------------------------------- |
| `Future<String> getSdkVersion()`                | Get SDK version                   |
| `Future<void> setLogConfig(FBLogConfig config)` | Set log config (call before init) |
| `Future<void> init(FBEngineConfig config)`      | Initialize engine                 |
| `FBBeautyEffectEngine get sharedInstance`       | Get singleton instance            |

### Beauty Parameters

| Method                                                                        | Description                        |
| ----------------------------------------------------------------------------- | ---------------------------------- |
| `Future<int> setBasicParam(FBBasicParam param, double value)`                 | Set basic beauty param \[0.0, 1.0] |
| `Future<int> setReshapeParam(FBReshapeParam param, double value)`             | Set face reshape param \[0.0, 1.0] |
| `Future<int> setMakeupParam(FBMakeupParam param, double value)`               | Set makeup param \[0.0, 1.0]       |
| `Future<int> setLipstickStyle(FBLipstickStyle style)`                         | Set lipstick style                 |
| `Future<int> setBlushStyle(FBBlushStyle style)`                               | Set blush style                    |
| `Future<int> setSkinOnlyBeauty(bool enabled)`                                 | Apply beauty to skin only          |
| `Future<int> setVirtualBackground(FBBackgroundMode mode, {FBImageFrame? bg})` | Set virtual background             |

### Filters & Stickers

| Method                                                       | Description                      |
| ------------------------------------------------------------ | -------------------------------- |
| `Future<int> setFilter(String filterId)`                     | Apply filter                     |
| `Future<int> setFilterIntensity(double intensity)`           | Set filter intensity \[0.0, 1.0] |
| `Future<int> setSticker(String stickerId)`                   | Apply sticker (empty to clear)   |
| `Future<int> registerFilter(String id, String path)`         | Register filter from file        |
| `Future<int> registerFilterData(String id, Uint8List data)`  | Register filter from data        |
| `Future<int> registerSticker(String id, String path)`        | Register sticker from file       |
| `Future<int> registerStickerData(String id, Uint8List data)` | Register sticker from data       |
| `Future<int> unregisterFilter(String id)`                    | Unregister filter                |
| `Future<int> unregisterAllFilters()`                         | Unregister all filters           |
| `Future<int> unregisterSticker(String id)`                   | Unregister sticker               |
| `Future<int> unregisterAllStickers()`                        | Unregister all stickers          |

### Image Processing

| Method                                                      | Description            |
| ----------------------------------------------------------- | ---------------------- |
| `Future<FBImageFrame?> processImage(FBImageFrame input)`    | Process an image frame |
| `Future<int> processImageFile(String input, String output)` | Process an image file  |

### Callbacks

| Property          | Type                            | Description          |
| ----------------- | ------------------------------- | -------------------- |
| `onFaceLandmarks` | `Stream<FBFaceDetectionResult>` | Face landmark stream |
| `onEngineEvent`   | `Stream<FBEngineEvent>`         | Engine event stream  |

### Lifecycle

| Method                   | Description              |
| ------------------------ | ------------------------ |
| `Future<void> release()` | Release engine resources |

**Return values:** `0` = success, `-1` = engine not initialized, `null` = processing failed.

## Enumerations

### FBBasicParam

| Value           | Description    |
| --------------- | -------------- |
| `smoothing(0)`  | Skin smoothing |
| `sharpening(1)` | Sharpening     |
| `whitening(2)`  | Skin whitening |
| `rosiness(3)`   | Skin rosiness  |

### FBReshapeParam

| Value           | Description             |
| --------------- | ----------------------- |
| `faceThin(0)`   | Face thin               |
| `faceVShape(1)` | V-shape face            |
| `eyeSize(8)`    | Eye enlargement         |
| `noseSlim(7)`   | Nose slimming           |
| ...             | See full list in source |

### FBImageFormat

| Value     | Description                 |
| --------- | --------------------------- |
| `i420(0)` | YUV 4:2:0 planar            |
| `nv12(1)` | YUV 4:2:0 semi-planar       |
| `nv21(2)` | YUV 4:2:0 (Android default) |
| `bgra(3)` | BGRA 32bpp                  |
| `rgba(4)` | RGBA 32bpp                  |
| `bgr(5)`  | BGR 24bpp                   |
| `rgb(6)`  | RGB 24bpp                   |

## Native Engine Access

For streaming SDK integration (TRTC, etc.):

**iOS (Swift):**

```swift theme={null}
let engine = FacebetterPlugin.sharedInstance().engine
```

**Android (Kotlin):**

```kotlin theme={null}
val engine = FacebetterPlugin.sharedInstance?.getEngine()
```