fix: Expose auto-focus system for Android (#2455)

* fix: Expose auto-focus system for Android

* Add `autoFocusSystem` to filter

* Update CameraDeviceDetails.kt

* Update getCameraFormat.ts

package/android/src/main/java/com/mrousavy/camera/core/CameraDeviceDetails.kt

@@ -76,6 +76,7 @@ class CameraDeviceDetails(val cameraManager: CameraManager, val cameraId: String
     characteristics.get(CameraCharacteristics.LENS_INFO_AVAILABLE_OPTICAL_STABILIZATION) ?: IntArray(0)
   val supportsPhotoHdr = extensions.contains(3) // TODO: CameraExtensionCharacteristics.EXTENSION_HDR
   val supportsVideoHdr = getHasVideoHdr()
+  val autoFocusSystem = getAutoFocusSystemMode()
 
   val videoFormat = ImageFormat.YUV_420_888
 
@@ -132,6 +133,18 @@ class CameraDeviceDetails(val cameraManager: CameraManager, val cameraId: String
     return deviceTypes
   }
 
+  private fun getAutoFocusSystemMode(): AutoFocusSystem {
+    val supportedAFModes = characteristics.get(CameraCharacteristics.CONTROL_AF_AVAILABLE_MODES)
+    val supportsAF = supportedAFModes?.contains(CameraCharacteristics.CONTROL_AF_MODE_AUTO) == true
+    if (!supportsAF) return AutoFocusSystem.NONE
+
+    val focusCalibrationSystem = characteristics.get(CameraCharacteristics.LENS_INFO_FOCUS_DISTANCE_CALIBRATION)
+    return when (focusCalibrationSystem) {
+      CameraCharacteristics.LENS_INFO_FOCUS_DISTANCE_CALIBRATION_CALIBRATED -> AutoFocusSystem.PHASE_DETECTION
+      else -> AutoFocusSystem.CONTRAST_DETECTION
+    }
+  }
+
   private fun getFieldOfView(focalLength: Float): Double {
     val sensorDiagonal = sqrt((sensorSize.width * sensorSize.width + sensorSize.height * sensorSize.height).toDouble())
     val fovRadians = 2.0 * atan2(sensorDiagonal, (2.0 * focalLength))
@@ -190,7 +203,7 @@ class CameraDeviceDetails(val cameraManager: CameraManager, val cameraId: String
     map.putBoolean("supportsVideoHdr", supportsVideoHdr)
     map.putBoolean("supportsPhotoHdr", supportsPhotoHdr)
     map.putBoolean("supportsDepthCapture", supportsDepthCapture)
-    map.putString("autoFocusSystem", AutoFocusSystem.CONTRAST_DETECTION.unionValue)
+    map.putString("autoFocusSystem", autoFocusSystem.unionValue)
     map.putArray("videoStabilizationModes", createStabilizationModes())
     map.putArray("pixelFormats", createPixelFormats())
     return map

package/android/src/main/java/com/mrousavy/camera/types/AutoFocusSystem.kt

@@ -1,6 +1,7 @@
 package com.mrousavy.camera.types
 
 enum class AutoFocusSystem(override val unionValue: String) : JSUnionValue {
+  PHASE_DETECTION("phase-detection"),
   CONTRAST_DETECTION("contrast-detection"),
   NONE("none");
 

package/src/devices/getCameraFormat.ts

@@ -1,4 +1,4 @@
-import type { CameraDevice, CameraDeviceFormat, VideoStabilizationMode } from '../CameraDevice'
+import type { AutoFocusSystem, CameraDevice, CameraDeviceFormat, VideoStabilizationMode } from '../CameraDevice'
 import { CameraRuntimeError } from '../CameraError'
 import { PixelFormat } from '../PixelFormat'
 
@@ -74,6 +74,12 @@ export interface FormatFilter {
    * Lower ISO values tend to capture photos quicker.
    */
   iso?: number | 'max' | 'min'
+  /**
+   * The target auto-focus system.
+   * While `phase-detection` is generally the best system available,
+   * you might want to choose a different auto-focus system.
+   */
+  autoFocusSystem?: AutoFocusSystem
 }
 
 type FilterWithPriority<T> = {
@@ -234,6 +240,12 @@ export function getCameraFormat(device: CameraDevice, filters: FormatFilter[]):
       if (format.supportsVideoHdr === filter.videoHdr.target) rightPoints++
     }
 
+    // phase-detection is generally the best AF system
+    if (filter.autoFocusSystem != null) {
+      if (bestFormat.autoFocusSystem === filter.autoFocusSystem.target) leftPoints++
+      if (format.autoFocusSystem === filter.autoFocusSystem.target) rightPoints++
+    }
+
     if (rightPoints > leftPoints) bestFormat = format
   }