Infrastructure for automated torch on based on ambient light (not turned on yet)

git-svn-id: https://zxing.googlecode.com/svn/trunk@2504 59b500cc-1b3d-0410-9834-0bbf25fbcc57

AUTHORS

@@ -68,6 +68,7 @@ mikej06
 Mohamad Fairol
 Morgan Courbet
 Nikolaos Ftylitakis
+Nikolaus Huber
 Olli
 Pablo Orduña (University of Deusto)
 Paul Hackenberger

android/src/com/google/zxing/client/android/AmbientLightManager.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2012 ZXing authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.zxing.client.android;
+
+import android.content.Context;
+import android.hardware.Sensor;
+import android.hardware.SensorEvent;
+import android.hardware.SensorEventListener;
+import android.hardware.SensorManager;
+import com.google.zxing.client.android.camera.CameraManager;
+
+/**
+ * Detects ambient light and switches on the front light when very dark, and off again when sufficiently light.
+ *
+ * @author Sean Owen
+ * @author Nikolaus Huber
+ */
+final class AmbientLightManager implements SensorEventListener {
+
+  private static final float TOO_DARK_LUX = 90.0f;
+  private static final float BRIGHT_ENOUGH_LUX = 225.0f;
+
+  private final Context context;
+  private CameraManager cameraManager;
+  private Sensor lightSensor;
+
+  AmbientLightManager(Context context) {
+    this.context = context;
+  }
+
+  void start(CameraManager cameraManager) {
+    SensorManager sensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);
+    lightSensor = sensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
+    if (lightSensor != null) {
+      sensorManager.registerListener(this, lightSensor, SensorManager.SENSOR_DELAY_NORMAL);
+      this.cameraManager = cameraManager;
+    }
+  }
+
+  void stop() {
+    if (lightSensor != null) {
+      SensorManager sensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);
+      sensorManager.unregisterListener(this);
+      cameraManager = null;
+      lightSensor = null;
+    }
+  }
+
+  @Override
+  public void onSensorChanged(SensorEvent sensorEvent) {
+    float ambientLightLux = sensorEvent.values[0];
+    if (ambientLightLux <= TOO_DARK_LUX) {
+      cameraManager.setTorch(true);
+    } else if (ambientLightLux >= BRIGHT_ENOUGH_LUX) {
+      cameraManager.setTorch(false);
+    }
+  }
+
+  @Override
+  public void onAccuracyChanged(Sensor sensor, int accuracy) {
+    // do nothing
+  }
+
+}

android/src/com/google/zxing/client/android/CaptureActivity.java

@@ -121,6 +121,7 @@ public final class CaptureActivity extends Activity implements SurfaceHolder.Cal
   private HistoryManager historyManager;
   private InactivityTimer inactivityTimer;
   private BeepManager beepManager;
+  private AmbientLightManager ambientLightManager;
 
   ViewfinderView getViewfinderView() {
     return viewfinderView;
@@ -147,6 +148,7 @@ public final class CaptureActivity extends Activity implements SurfaceHolder.Cal
     historyManager.trimHistory();
     inactivityTimer = new InactivityTimer(this);
     beepManager = new BeepManager(this);
+    ambientLightManager = new AmbientLightManager(this);
 
     PreferenceManager.setDefaultValues(this, R.xml.preferences, false);
 
@@ -187,6 +189,7 @@ public final class CaptureActivity extends Activity implements SurfaceHolder.Cal
     }
 
     beepManager.updatePrefs();
+    // ambientLightManager.start(cameraManager);
 
     inactivityTimer.onResume();
 
@@ -270,6 +273,7 @@ public final class CaptureActivity extends Activity implements SurfaceHolder.Cal
       handler = null;
     }
     inactivityTimer.onPause();
+    // ambientLightManager.stop();
     cameraManager.closeDriver();
     if (!hasSurface) {
       SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view);

android/src/com/google/zxing/client/android/camera/CameraConfigurationManager.java

@@ -130,6 +130,11 @@ final class CameraConfigurationManager {
     return screenResolution;
   }
 
+  boolean getTorchSetting() {
+    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
+    return prefs.getBoolean(PreferencesActivity.KEY_FRONT_LIGHT, false);
+  }
+
   void setTorch(Camera camera, boolean newSetting) {
     Camera.Parameters parameters = camera.getParameters();
     doSetTorch(parameters, newSetting, false);

android/src/com/google/zxing/client/android/camera/CameraManager.java

@@ -166,13 +166,15 @@ public final class CameraManager {
    * Convenience method for {@link com.google.zxing.client.android.CaptureActivity}
    */
   public synchronized void setTorch(boolean newSetting) {
-    if (camera != null) {
-      if (autoFocusManager != null) {
-        autoFocusManager.stop();
-      }
-      configManager.setTorch(camera, newSetting);
-      if (autoFocusManager != null) {
-        autoFocusManager.start();
+    if (newSetting != configManager.getTorchSetting()) {
+      if (camera != null) {
+        if (autoFocusManager != null) {
+          autoFocusManager.stop();
+        }
+        configManager.setTorch(camera, newSetting);
+        if (autoFocusManager != null) {
+          autoFocusManager.start();
+        }
       }
     }
   }