[camera] Add support for Torch and Auto Exposure (#19845)

packages/camera/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.5.8
+
+* Add support for Flash and Auto Focus.
+
 ## 0.5.7+5
 
 * Replace deprecated `getFlutterEngine` call on Android.
@@ -75,7 +79,6 @@
 * Fix too large request code for FragmentActivity users.
 
 ## 0.5.3
-
 * Added new quality presets.
 * Now all quality presets can be used to control image capture quality.
 

packages/camera/android/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.10.2-all.zip

packages/camera/android/src/main/java/io/flutter/plugins/camera/Camera.java

@@ -50,6 +50,8 @@ public class Camera {
   private final Size previewSize;
   private final boolean enableAudio;
 
+  private int flashMode;
+  private int autoFocusMode;
   private CameraDevice cameraDevice;
   private CameraCaptureSession cameraCaptureSession;
   private ImageReader pictureImageReader;
@@ -71,20 +73,38 @@ public enum ResolutionPreset {
     max,
   }
 
+  // Flash control setting. (Mirrors FlashMode enum in camera.dart)
+  // Labels respect java convention to avoid conflict with reserved word or any variable name
+  private final int CAMERA_FLASH_MODE_OFF = 0;
+  private final int CAMERA_FLASH_MODE_ALWAYS_FLASH = 1;
+  private final int CAMERA_FLASH_MODE_AUTO_FLASH = 2;
+  private final int CAMERA_FLASH_MODE_TORCH = 3;
+
+  // Auto Focus setting. (Mirrors AutoFocusMode in camera.dart)
+  // Labels respect java convention to avoid conflict with reserved word or any variable name
+  private final int CAMERA_AUTO_FOCUS_MODE_OFF = 0;
+  private final int CAMERA_AUTO_FOCUS_MODE_AUTO = 1;
+  private final int CAMERA_AUTO_FOCUS_MODE_CONTINUOUS = 2;
+  private final int CAMERA_AUTO_FOCUS_MODE_MACRO = 3;
+
   public Camera(
       final Activity activity,
       final SurfaceTextureEntry flutterTexture,
       final DartMessenger dartMessenger,
       final String cameraName,
       final String resolutionPreset,
-      final boolean enableAudio)
+      final boolean enableAudio,
+      final int flashMode,
+      final int autoFocusMode)
       throws CameraAccessException {
     if (activity == null) {
       throw new IllegalStateException("No activity available!");
     }
 
     this.cameraName = cameraName;
     this.enableAudio = enableAudio;
+    this.flashMode = flashMode;
+    this.autoFocusMode = autoFocusMode;
     this.flutterTexture = flutterTexture;
     this.dartMessenger = dartMessenger;
     this.cameraManager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
@@ -249,6 +269,9 @@ public void takePicture(String filePath, @NonNull final Result result) {
           cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
       captureBuilder.addTarget(pictureImageReader.getSurface());
       captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, getMediaOrientation());
+      // Request initial Flash and Auto-Exposure
+      setFlashModeRequest(captureBuilder, flashMode);
+      setAutoFocusModeRequest(captureBuilder, autoFocusMode);
 
       cameraCaptureSession.capture(
           captureBuilder.build(),
@@ -320,6 +343,11 @@ public void onConfigured(@NonNull CameraCaptureSession session) {
               cameraCaptureSession = session;
               captureRequestBuilder.set(
                   CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
+
+              // Request initial Flash and Auto-Exposure
+              setFlashModeRequest(captureRequestBuilder, flashMode);
+              setAutoFocusModeRequest(captureRequestBuilder, autoFocusMode);
+
               cameraCaptureSession.setRepeatingRequest(captureRequestBuilder.build(), null, null);
               if (onSuccessCallback != null) {
                 onSuccessCallback.run();
@@ -475,6 +503,107 @@ private void setImageStreamImageAvailableListener(final EventChannel.EventSink i
         null);
   }
 
+  public void setFlash(@NonNull final Result result, int mode) {
+    try {
+      // Force turning off the torch to avoid keeping the
+      // light on when another flash mode is selected
+      if (mode != CAMERA_FLASH_MODE_TORCH && flashMode == CAMERA_FLASH_MODE_TORCH) {
+        setFlashModeRequest(captureRequestBuilder, CAMERA_FLASH_MODE_OFF);
+        setAutoFocusModeRequest(captureRequestBuilder, autoFocusMode);
+        CaptureRequest request = captureRequestBuilder.build();
+        cameraCaptureSession.setRepeatingRequest(request, null, null);
+      }
+
+      // Keep the new mode
+      flashMode = mode;
+
+      // Rebuild Capture Session with flash and focus settings
+      setFlashModeRequest(captureRequestBuilder, flashMode);
+      setAutoFocusModeRequest(captureRequestBuilder, autoFocusMode);
+      CaptureRequest request = captureRequestBuilder.build();
+      cameraCaptureSession.setRepeatingRequest(request, null, null);
+
+      result.success(null);
+    } catch (Exception e) {
+      result.error("cameraFlashFailed", e.getMessage(), null);
+    }
+  }
+
+  private void setFlashModeRequest(CaptureRequest.Builder builderRequest, int mode) {
+    // Request Flash mode and set the tightly coupled auto Exposure mode
+    int flashRequestMode;
+    int autoExposureRequestMode;
+    switch (mode) {
+      case CAMERA_FLASH_MODE_ALWAYS_FLASH:
+        flashRequestMode = CameraMetadata.FLASH_MODE_OFF;
+        autoExposureRequestMode = CameraMetadata.CONTROL_AE_MODE_ON_ALWAYS_FLASH;
+        break;
+      case CAMERA_FLASH_MODE_AUTO_FLASH:
+        flashRequestMode = CameraMetadata.FLASH_MODE_OFF;
+        autoExposureRequestMode = CameraMetadata.CONTROL_AE_MODE_ON_AUTO_FLASH;
+        break;
+      case CAMERA_FLASH_MODE_TORCH:
+        flashRequestMode = CameraMetadata.FLASH_MODE_TORCH;
+        autoExposureRequestMode = CameraMetadata.CONTROL_AE_MODE_ON;
+        break;
+      default:
+        flashRequestMode = CameraMetadata.FLASH_MODE_OFF;
+        autoExposureRequestMode = CameraMetadata.CONTROL_AE_MODE_ON;
+    }
+
+    builderRequest.set(CaptureRequest.FLASH_MODE, flashRequestMode);
+    builderRequest.set(CaptureRequest.CONTROL_AE_MODE, autoExposureRequestMode);
+
+    // Request Auto Exposure mode as recommended when you switch the Flash
+    // more information:
+    // https://developer.android.com/reference/android/hardware/camera2/CaptureRequest.html#FLASH_MODE
+    builderRequest.set(
+        CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER,
+        CameraMetadata.CONTROL_AE_PRECAPTURE_TRIGGER_START);
+  }
+
+  public void setAutoFocus(@NonNull final Result result, int mode) {
+    try {
+      // Keep the mode
+      autoFocusMode = mode;
+
+      // Rebuild Capture Session with flash and focus settings
+      setFlashModeRequest(captureRequestBuilder, flashMode);
+      setAutoFocusModeRequest(captureRequestBuilder, autoFocusMode);
+      CaptureRequest request = captureRequestBuilder.build();
+      cameraCaptureSession.setRepeatingRequest(request, null, null);
+
+      result.success(null);
+    } catch (Exception e) {
+      result.error("cameraAutoFocusFailed", e.getMessage(), null);
+    }
+  }
+
+  private void setAutoFocusModeRequest(CaptureRequest.Builder builderRequest, int mode) {
+    // Request Auto Focus Mode
+    int autoFocusRequestMode;
+    switch (mode) {
+      case CAMERA_AUTO_FOCUS_MODE_OFF:
+        autoFocusRequestMode = CameraMetadata.CONTROL_AF_MODE_AUTO;
+        break;
+      case CAMERA_AUTO_FOCUS_MODE_CONTINUOUS:
+        autoFocusRequestMode = CameraMetadata.CONTROL_AF_MODE_CONTINUOUS_PICTURE;
+        break;
+      case CAMERA_AUTO_FOCUS_MODE_MACRO:
+        autoFocusRequestMode = CameraMetadata.CONTROL_AF_MODE_MACRO;
+        break;
+      default:
+        autoFocusRequestMode = CameraMetadata.CONTROL_AF_MODE_AUTO;
+    }
+
+    builderRequest.set(CaptureRequest.CONTROL_AF_MODE, autoFocusRequestMode);
+
+    if (mode != CAMERA_AUTO_FOCUS_MODE_OFF && mode != CAMERA_AUTO_FOCUS_MODE_CONTINUOUS) {
+      builderRequest.set(
+          CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_START);
+    }
+  }
+
   private void closeCaptureSession() {
     if (cameraCaptureSession != null) {
       cameraCaptureSession.close();

packages/camera/android/src/main/java/io/flutter/plugins/camera/MethodCallHandlerImpl.java

@@ -1,6 +1,7 @@
 package io.flutter.plugins.camera;
 
 import android.app.Activity;
+import android.content.pm.PackageManager;
 import android.hardware.camera2.CameraAccessException;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -123,6 +124,21 @@ public void onMethodCall(@NonNull MethodCall call, @NonNull final Result result)
           }
           break;
         }
+      case "setFlash":
+        {
+          camera.setFlash(result, call.argument("mode"));
+          break;
+        }
+      case "hasFlash":
+        {
+          result.success(hasFlash());
+          break;
+        }
+      case "setAutoFocus":
+        {
+          camera.setAutoFocus(result, call.argument("mode"));
+          break;
+        }
       case "dispose":
         {
           if (camera != null) {
@@ -141,10 +157,19 @@ void stopListening() {
     methodChannel.setMethodCallHandler(null);
   }
 
+  private boolean hasFlash() {
+    return activity
+        .getApplicationContext()
+        .getPackageManager()
+        .hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);
+  }
+
   private void instantiateCamera(MethodCall call, Result result) throws CameraAccessException {
     String cameraName = call.argument("cameraName");
     String resolutionPreset = call.argument("resolutionPreset");
     boolean enableAudio = call.argument("enableAudio");
+    int flashMode = call.argument("flashMode");
+    int autoFocusMode = call.argument("autoFocusMode");
     TextureRegistry.SurfaceTextureEntry flutterSurfaceTexture =
         textureRegistry.createSurfaceTexture();
     DartMessenger dartMessenger = new DartMessenger(messenger, flutterSurfaceTexture.id());
@@ -155,7 +180,9 @@ private void instantiateCamera(MethodCall call, Result result) throws CameraAcce
             dartMessenger,
             cameraName,
             resolutionPreset,
-            enableAudio);
+            enableAudio, 
+            flashMode,
+            autoFocusMode);
 
     camera.open(result);
   }