Camera2 support for Flash.TORCH

cameraview/src/main/java/com/otaliastudios/cameraview/CameraOptions.java

@@ -180,6 +180,12 @@ public class CameraOptions {
                 Flash value = mapper.unmapFlash(aeMode);
                 if (value != null) supportedFlash.add(value);
             }
+            // Check for torch specifically since the Mapper flash support is not so good.
+            // If OFF works, it means we have AE_MODE_OFF or AE_MODE_ON. This means we can use
+            // the torch control.
+            if (supportedFlash.contains(Flash.OFF)) {
+                supportedFlash.add(Flash.TORCH);
+            }
         }
 
         // HDR

cameraview/src/main/java/com/otaliastudios/cameraview/engine/Camera1Engine.java

@@ -55,6 +55,8 @@ public class Camera1Engine extends CameraEngine implements Camera.PreviewCallbac
 
     private Camera mCamera;
     @VisibleForTesting int mCameraId;
+    private int mPreviewStreamFormat;
+
 
     private Runnable mFocusEndRunnable;
     private final Runnable mFocusResetRunnable = new Runnable() {
@@ -196,6 +198,7 @@ public class Camera1Engine extends CameraEngine implements Camera.PreviewCallbac
             mVideoRecorder.stop();
             mVideoRecorder = null;
         }
+        mPictureRecorder = null;
         mPreviewStreamFormat = 0;
         getFrameManager().release();
         mCamera.setPreviewCallbackWithBuffer(null); // Release anything left
@@ -763,6 +766,10 @@ public class Camera1Engine extends CameraEngine implements Camera.PreviewCallbac
     // -----------------
     // Size stuff.
 
+    public final int getPreviewStreamFormat() {
+        return mPreviewStreamFormat;
+    }
+
 
     @NonNull
     @Override

cameraview/src/main/java/com/otaliastudios/cameraview/engine/Camera2Engine.java

@@ -2,6 +2,7 @@ package com.otaliastudios.cameraview.engine;
 
 import android.annotation.SuppressLint;
 import android.content.Context;
+import android.graphics.ImageFormat;
 import android.graphics.PointF;
 import android.graphics.Rect;
 import android.graphics.SurfaceTexture;
@@ -52,11 +53,11 @@ import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 import androidx.annotation.WorkerThread;
 
-// TODO fix flash, it's not that simple
 // TODO zoom
 // TODO exposure correction
 // TODO autofocus
 // TODO pictures
+// TODO frame processor
 @RequiresApi(Build.VERSION_CODES.LOLLIPOP)
 public class Camera2Engine extends CameraEngine {
 
@@ -330,7 +331,6 @@ public class Camera2Engine extends CameraEngine {
         // Set the preview rotation.
         mPreview.setDrawRotation(mDisplayOffset);
 
-        // TODO mPreviewStreamFormat = params.getPreviewFormat();
         // TODO mCamera.setPreviewCallbackWithBuffer(null); // Release anything left
         // TODO mCamera.setPreviewCallbackWithBuffer(this); // Add ourselves
         // TODO mFrameManager.setUp(ImageFormat.getBitsPerPixel(mPreviewStreamFormat), mPreviewStreamSize);
@@ -365,7 +365,7 @@ public class Camera2Engine extends CameraEngine {
             mVideoRecorder.stop();
             mVideoRecorder = null;
         }
-        mPreviewStreamFormat = 0;
+        mPictureRecorder = null;
         getFrameManager().release();
         // TODO mCamera.setPreviewCallbackWithBuffer(null); // Release anything left
         try {
@@ -610,6 +610,17 @@ public class Camera2Engine extends CameraEngine {
      * - {@link CaptureRequest#CONTROL_AE_MODE_ON}
      * - {@link CaptureRequest#CONTROL_AE_MODE_ON_AUTO_FLASH}
      * - {@link CaptureRequest#CONTROL_AE_MODE_ON_ALWAYS_FLASH}
+     *
+     * The API offers a high level control through {@link CaptureRequest#CONTROL_AE_MODE},
+     * which is what the mapper looks at. It will trigger (if specified) flash only for still captures
+     * which is exactly what we want.
+     *
+     * However, we set CONTROL_AE_MODE to ON/OFF (depending
+     * on which is available) with both {@link Flash#OFF} and {@link Flash#TORCH}.
+     *
+     * When CONTROL_AE_MODE is ON or OFF, the low level control, called {@link CaptureRequest#FLASH_MODE},
+     * becomes effective, and that's where we can actually distinguish between a turned off flash
+     * and a torch flash.
      */
     private boolean applyFlash(@NonNull CaptureRequest.Builder builder,
                                @NonNull Flash oldFlash) {
@@ -620,6 +631,11 @@ public class Camera2Engine extends CameraEngine {
                 for (int availableMode : availableModes) {
                     if (mode == availableMode) {
                         builder.set(CaptureRequest.CONTROL_AE_MODE, mode);
+                        if (mFlash == Flash.TORCH) {
+                            builder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_TORCH);
+                        } else if (mFlash == Flash.OFF) {
+                            builder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_OFF);
+                        }
                         return true;
                     }
                 }

cameraview/src/main/java/com/otaliastudios/cameraview/engine/CameraEngine.java

@@ -184,7 +184,6 @@ public abstract class CameraEngine implements
     protected int mAudioBitRate;
     protected Size mCaptureSize;
     protected Size mPreviewStreamSize;
-    protected int mPreviewStreamFormat;
     protected long mAutoFocusResetDelayMillis;
 
     protected int mSensorOffset;
@@ -1064,10 +1063,6 @@ public abstract class CameraEngine implements
         return mFrameManager;
     }
 
-    public final int getPreviewStreamFormat() {
-        return mPreviewStreamFormat;
-    }
-
     @Nullable
     public final CameraOptions getCameraOptions() {
         return mCameraOptions;

cameraview/src/main/java/com/otaliastudios/cameraview/engine/Mapper.java

@@ -160,7 +160,10 @@ public abstract class Mapper {
         private static final HashMap<Hdr, Integer> HDR = new HashMap<>();
 
         static {
+            // OFF and TORCH have also a second condition - to CameraCharacteristics.CONTROL_FLASH_MODE - but that does not
+            // fit into the Mapper interface. TODO review this
             FLASH.put(Flash.OFF, Arrays.asList(CameraCharacteristics.CONTROL_AE_MODE_ON, CameraCharacteristics.CONTROL_AE_MODE_OFF));
+            FLASH.put(Flash.TORCH, Arrays.asList(CameraCharacteristics.CONTROL_AE_MODE_ON, CameraCharacteristics.CONTROL_AE_MODE_OFF));
             FLASH.put(Flash.AUTO, Arrays.asList(CameraCharacteristics.CONTROL_AE_MODE_ON_AUTO_FLASH, CameraCharacteristics.CONTROL_AE_MODE_ON_AUTO_FLASH_REDEYE));
             FLASH.put(Flash.ON, Collections.singletonList(CameraCharacteristics.CONTROL_AE_MODE_ON_ALWAYS_FLASH));
             FACING.put(Facing.BACK, CameraCharacteristics.LENS_FACING_BACK);