SnapdragonCamera: Make direct shutter callbacks configurable

 Calling shutter callbacks directly decreases the
 delay with which 'takePicture' calls are triggered
 during continuous burst capture. As such more time
 is spent processing and starting next snapshots
 resulting in a less responsive UI thread. The preview
 doesn't actually hang or stop but only the UI is not
 be able to update it as frequently as before. In order
 to avoid this but also have the burst perfomance
 enhancement as well a configurable Android property
 is added:
 "persist.camera.direct.cb -> 0/1" which when disabled
 will post shutter event callbacks like before on the
 UI thread and when when enabled will trigger them
 directly.

Change-Id: Id6fd747eeb19026791faa1ce9db20302767a7695
CRs-Fixed: 794460

1 files changed, 17 insertions, 3 deletions

diff --git a/src/com/android/camera/AndroidCameraManagerImpl.java b/src/com/android/camera/AndroidCameraManagerImpl.java
index b985ce315..7f69b329f 100644
--- a/src/com/android/camera/AndroidCameraManagerImpl.java
+++ b/src/com/android/camera/AndroidCameraManagerImpl.java
@@ -46,6 +46,7 @@ import android.hardware.Camera.CameraDataCallback;
 import android.hardware.Camera.CameraMetaDataCallback;
 import com.android.camera.util.ApiHelper;
 import android.os.ConditionVariable;
+import android.os.SystemProperties;
 
 import org.codeaurora.snapcam.R;
 
@@ -104,6 +105,7 @@ class AndroidCameraManagerImpl implements CameraManager {
     private static final int SET_AUTO_HDR_MODE = 801;
     private CameraHandler mCameraHandler;
     private android.hardware.Camera mCamera;
+    private static final String PERSIST_DIRECT_CALLBACK = "persist.camera.direct.cb";
 
     // Used to retain a copy of Parameters for setting parameters.
     private Parameters mParamsToSet;
@@ -733,6 +735,7 @@ class AndroidCameraManagerImpl implements CameraManager {
         private final Handler mHandler;
         private final CameraShutterCallback mCallback;
         private final CameraProxy mCamera;
+        private final boolean mDirectCallback;
 
         /**
          * Returns a new instance of {@link ShutterCallbackForward}.
@@ -754,15 +757,26 @@ class AndroidCameraManagerImpl implements CameraManager {
             mHandler = h;
             mCamera = camera;
             mCallback = cb;
+            mDirectCallback = SystemProperties.getBoolean(
+                    PERSIST_DIRECT_CALLBACK, false);
         }
 
         @Override
         public void onShutter() {
             final android.hardware.Camera currentCamera = mCamera.getCamera();
 
-                if (currentCamera.equals(mCamera.getCamera())) {
-                    mCallback.onShutter(mCamera);
-                }
+            if (mDirectCallback) {
+                mCallback.onShutter(mCamera);
+            } else {
+                mHandler.post(new Runnable() {
+                    @Override
+                    public void run() {
+                        if (currentCamera.equals(mCamera.getCamera())) {
+                            mCallback.onShutter(mCamera);
+                        }
+                    }
+                });
+            }
         }
     }