Improve CameraPreviewView to avoid lots of GC.

Improve shutdown logic of CameraPreviewView.

android/src/org/ros/rosjava/android/views/CameraPreviewView.java

@@ -34,42 +34,45 @@ import org.ros.exception.RosRuntimeException;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.util.ArrayList;
 import java.util.List;
 
 /**
  * @author damonkohler@google.com (Damon Kohler)
  */
 public class CameraPreviewView extends ViewGroup {
-  
+
   private final static double ASPECT_TOLERANCE = 0.1;
 
+  private final ByteArrayOutputStream stream = new ByteArrayOutputStream(512);
+
   private SurfaceHolder surfaceHolder;
   private Size previewSize;
   private Camera camera;
   private PreviewCallback previewCallback;
-  private BufferingPreviewCallback bufferingPreviewCallback;
-  private ArrayList<byte[]> previewBuffers;
 
   private final class BufferingPreviewCallback implements PreviewCallback {
+
+    private final byte[] previewBuffer;
+    private final YuvImage yuvImage;
+    private final Rect rect;
+
+    public BufferingPreviewCallback(byte[] previewBuffer) {
+      this.previewBuffer = previewBuffer;
+      yuvImage =
+          new YuvImage(previewBuffer, ImageFormat.NV21, previewSize.width, previewSize.height, null);
+      rect = new Rect(0, 0, previewSize.width, previewSize.height);
+    }
+
     @Override
-    public void onPreviewFrame(byte[] data, Camera camera) {
-      // TODO(damonkohler): There should be a way to avoid this case?
-      Size size;
-      try {
-        size = camera.getParameters().getPreviewSize();
-      } catch (RuntimeException e) {
-        // Camera not available.
-        return;
-      }
-      // TODO(damonkohler): This is pretty awful and causing a lot of GC.
-      YuvImage image = new YuvImage(data, ImageFormat.NV21, size.width, size.height, null);
-      ByteArrayOutputStream stream = new ByteArrayOutputStream(512);
-      Preconditions.checkState(image.compressToJpeg(new Rect(0, 0, size.width, size.height), 80, stream));
+    public void onPreviewFrame(byte[] data, Camera unused) {
+      Preconditions.checkNotNull(camera);
+      Preconditions.checkArgument(data == previewBuffer);
+      Preconditions.checkState(yuvImage.compressToJpeg(rect, 80, stream));
       if (previewCallback != null) {
         previewCallback.onPreviewFrame(stream.toByteArray(), camera);
+        stream.reset();
       }
-      camera.addCallbackBuffer(data);
+      camera.addCallbackBuffer(previewBuffer);
     }
   }
 
@@ -101,7 +104,6 @@ public class CameraPreviewView extends ViewGroup {
     surfaceHolder = surfaceView.getHolder();
     surfaceHolder.addCallback(new SurfaceHolderCallback());
     surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
-    bufferingPreviewCallback = new BufferingPreviewCallback();
   }
 
   public CameraPreviewView(Context context) {
@@ -123,6 +125,7 @@ public class CameraPreviewView extends ViewGroup {
     if (camera == null) {
       return;
     }
+    camera.setPreviewCallbackWithBuffer(null);
     camera.stopPreview();
     camera.release();
     camera = null;
@@ -183,21 +186,17 @@ public class CameraPreviewView extends ViewGroup {
         }
       }
     }
-    
+
     Preconditions.checkNotNull(optimalSize);
     return optimalSize;
   }
 
   private void setupBufferingPreviewCallback() {
-    previewBuffers = new ArrayList<byte[]>();
-    Size size = camera.getParameters().getPreviewSize();
     int format = camera.getParameters().getPreviewFormat();
     int bits_per_pixel = ImageFormat.getBitsPerPixel(format);
-    previewBuffers.add(new byte[size.height * size.width * bits_per_pixel / 8]);
-    for (byte[] x : previewBuffers) {
-      camera.addCallbackBuffer(x);
-    }
-    camera.setPreviewCallbackWithBuffer(bufferingPreviewCallback);
+    byte[] previewBuffer = new byte[previewSize.height * previewSize.width * bits_per_pixel / 8];
+    camera.addCallbackBuffer(previewBuffer);
+    camera.setPreviewCallbackWithBuffer(new BufferingPreviewCallback(previewBuffer));
   }
 
   @Override
@@ -224,5 +223,4 @@ public class CameraPreviewView extends ViewGroup {
       }
     }
   }
-
 }

android/src/org/ros/rosjava/android/views/PublishingPreviewCallback.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ * 
+ * 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 org.ros.rosjava.android.views;
+
+import com.google.common.base.Preconditions;
+
+import android.hardware.Camera;
+import android.hardware.Camera.PreviewCallback;
+import android.hardware.Camera.Size;
+import org.ros.message.sensor_msgs.CameraInfo;
+import org.ros.message.sensor_msgs.CompressedImage;
+import org.ros.node.Node;
+import org.ros.node.topic.Publisher;
+
+/**
+ * @author damonkohler@google.com (Damon Kohler)
+ */
+class PublishingPreviewCallback implements PreviewCallback {
+
+  private final Node node;
+  private final Publisher<CompressedImage> imagePublisher;
+  private final Publisher<CameraInfo> cameraInfoPublisher;
+
+  public PublishingPreviewCallback(Node node, Publisher<CompressedImage> imagePublisher,
+      Publisher<CameraInfo> cameraInfoPublisher) {
+    this.node = node;
+    this.imagePublisher = imagePublisher;
+    this.cameraInfoPublisher = cameraInfoPublisher;
+  }
+
+  @Override
+  public void onPreviewFrame(byte[] data, Camera camera) {
+    Preconditions.checkNotNull(data);
+    Preconditions.checkNotNull(camera);
+
+    CompressedImage image = new CompressedImage();
+    CameraInfo cameraInfo = new CameraInfo();
+    String frameId = "camera";
+
+    // TODO(ethan): Right now serialization is deferred. When serialization
+    // happens inline, we won't need to copy.
+    image.data = new byte[data.length];
+    System.arraycopy(data, 0, image.data, 0, data.length);
+
+    image.format = "jpeg";
+    image.header.stamp = node.getCurrentTime();
+    image.header.frame_id = frameId;
+    imagePublisher.publish(image);
+
+    cameraInfo.header.stamp = image.header.stamp;
+    cameraInfo.header.frame_id = frameId;
+
+    Size previewSize = camera.getParameters().getPreviewSize();
+    cameraInfo.width = previewSize.width;
+    cameraInfo.height = previewSize.height;
+    cameraInfoPublisher.publish(cameraInfo);
+  }
+}

android/src/org/ros/rosjava/android/views/RosCameraPreviewView.java

@@ -19,11 +19,7 @@ package org.ros.rosjava.android.views;
 import com.google.common.base.Preconditions;
 
 import android.content.Context;
-import android.hardware.Camera;
-import android.hardware.Camera.PreviewCallback;
-import android.hardware.Camera.Size;
 import android.util.AttributeSet;
-import org.ros.message.Time;
 import org.ros.message.sensor_msgs.CameraInfo;
 import org.ros.message.sensor_msgs.CompressedImage;
 import org.ros.namespace.GraphName;
@@ -40,35 +36,6 @@ import org.ros.node.topic.Publisher;
 public class RosCameraPreviewView extends CameraPreviewView implements NodeMain {
 
   private Node node;
-  private Publisher<CompressedImage> imagePublisher;
-  private Publisher<CameraInfo> cameraInfoPublisher;
-
-  private final class PublishingPreviewCallback implements PreviewCallback {
-    @Override
-    public void onPreviewFrame(byte[] data, Camera camera) {
-      CompressedImage image = new CompressedImage();
-      CameraInfo cameraInfo = new CameraInfo();
-      String frameId = "camera";
-
-      // TODO(ethan): Right now serialization is deferred. When serialization
-      // happens inline, we won't need to copy.
-      image.data = new byte[data.length];
-      System.arraycopy(data, 0, image.data, 0, data.length);
-
-      image.format = "jpeg";
-      image.header.stamp = Time.fromMillis(System.currentTimeMillis());
-      image.header.frame_id = frameId;
-      imagePublisher.publish(image);
-
-      cameraInfo.header.stamp = image.header.stamp;
-      cameraInfo.header.frame_id = frameId;
-
-      Size previewSize = camera.getParameters().getPreviewSize();
-      cameraInfo.width = previewSize.width;
-      cameraInfo.height = previewSize.height;
-      cameraInfoPublisher.publish(cameraInfo);
-    }
-  }
 
   public RosCameraPreviewView(Context context) {
     super(context);
@@ -86,12 +53,12 @@ public class RosCameraPreviewView extends CameraPreviewView implements NodeMain
   public void main(NodeConfiguration nodeConfiguration) throws Exception {
     Preconditions.checkState(node == null);
     node = new DefaultNodeFactory().newNode("android/camera_preview_view", nodeConfiguration);
-    NameResolver resolver = node.getResolver().createResolver(new GraphName("android/camera"));
-    imagePublisher =
+    NameResolver resolver = node.getResolver().createResolver(new GraphName("camera"));
+    Publisher<CompressedImage> imagePublisher =
         node.newPublisher(resolver.resolve("image_raw"), "sensor_msgs/CompressedImage");
-    cameraInfoPublisher =
+    Publisher<CameraInfo> cameraInfoPublisher =
         node.newPublisher(resolver.resolve("camera_info"), "sensor_msgs/CameraInfo");
-    setPreviewCallback(new PublishingPreviewCallback());
+    setPreviewCallback(new PublishingPreviewCallback(node, imagePublisher, cameraInfoPublisher));
   }
 
   @Override

android_tutorial_camera/res/layout/main.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+  xmlns:android="http://schemas.android.com/apk/res/android"
+  android:orientation="vertical"
+  android:layout_width="fill_parent"
+  android:layout_height="fill_parent">
+  <org.ros.rosjava.android.views.RosCameraPreviewView
+    android:layout_height="fill_parent"
+    android:layout_width="fill_parent"
+    android:id="@+id/camera_preview" />
+</LinearLayout>

android_tutorial_camera/src/org/ros/android/camera/MainActivity.java

@@ -54,17 +54,17 @@ public class MainActivity extends Activity {
     super.onCreate(savedInstanceState);
     requestWindowFeature(Window.FEATURE_NO_TITLE);
     getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
-    preview = new RosCameraPreviewView(this);
-    setContentView(preview);
+    setContentView(R.layout.main);
+    preview = (RosCameraPreviewView) findViewById(R.id.camera_preview);
     startActivityForResult(new Intent(this, MasterChooser.class), 0);
   }
 
   @Override
   protected void onResume() {
     super.onResume();
-    cameraId = 0;
-    preview.setCamera(Camera.open(cameraId));
     if (masterUri != null) {
+      cameraId = 0;
+      preview.setCamera(Camera.open(cameraId));
       NodeConfiguration nodeConfiguration =
           NodeConfiguration.newPublic(InetAddressFactory.newNonLoopback().getHostName());
       nodeConfiguration.setMasterUri(masterUri);