Legen Sie den Fokusbereich der Kamera in Android

Question

nach mehreren Tutorials und Beispielen Ich kam mit dem nächsten Algorithmus, um den Fokus der Kamera auf eine bestimmte Stelle, das Problem ist, dass die Kamera den Spot vollständig ignoriert und führt einen normalen Gesamtfokus statt der rect Bereich, den ich angegeben habe. Gibt es noch etwas, das mir im Algorithmus fehlt? Dies wurde auf mehreren Telefonen mit Android 4.0 und höher getestet, sodass die API für den Fokusbereich auf diesen Geräten unterstützt wird. Beachten Sie, dass die App, die ich schreibe, nur im Querformat funktioniert.

@Override 
public boolean onTouchEvent(final MotionEvent event) 
{ 
    if (event.getAction() == MotionEvent.ACTION_UP) 
    { 
     float x = event.getX(); 
     float y = event.getY(); 
     float touchMajor = event.getTouchMajor(); 
     float touchMinor = event.getTouchMinor(); 

     Rect touchRect = new Rect((int)(x - touchMajor/2), (int)(y - touchMinor/2), (int)(x + touchMajor/2), (int)(y + touchMinor/2)); 

     this.submitFocusAreaRect(touchRect); 
    } 
} 

private void submitFocusAreaRect(final Rect touchRect) 
{ 
    Camera.Parameters cameraParameters = camera.getParameters(); 

    if (cameraParameters.getMaxNumFocusAreas() == 0) 
    { 
     return; 
    } 

    // Convert from View's width and height to +/- 1000 

    Rect focusArea = new Rect(); 

    focusArea.set(touchRect.left * 2000/cameraSurfaceView.getWidth() - 1000, 
         touchRect.top * 2000/cameraSurfaceView.getHeight() - 1000, 
         touchRect.right * 2000/cameraSurfaceView.getWidth() - 1000, 
         touchRect.bottom * 2000/cameraSurfaceView.getHeight() - 1000); 

    // Submit focus area to camera 

    ArrayList<Camera.Area> focusAreas = new ArrayList<Camera.Area>(); 
    focusAreas.add(new Camera.Area(focusArea, 1000)); 

    cameraParameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO); 
    cameraParameters.setFocusAreas(focusAreas); 
    camera.setParameters(cameraParameters); 

    // Start the autofocus operation 

    camera.autoFocus(this); 
} 

Answer 1

vor cameraParameters.setFocusAreas (focusAreas) ;, sollten Sie hinzufügen:

cameraParameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO); 

Answer 2

dies nicht mein Code, aber Sie können es versuchen. Alle Kredite gehen an den Mann/s, die das Beispiel gemacht hier Touch to select focus and metering area

auch ich mit einer kleinen Linie dort Code beigetragen, weil, als ich zum zweiten Mal auf der Oberfläche Sehen Sie sich die App klicken war erdrückend. So plese frei sein, um die Klasse zu verwenden ("AndroidCamera") unten:

import java.io.FileNotFoundException; 
import java.io.IOException; 
import java.io.OutputStream; 
import java.util.ArrayList; 
import java.util.List; 
import java.util.concurrent.Executors; 
import java.util.concurrent.ScheduledExecutorService; 
import java.util.concurrent.TimeUnit; 

import android.app.Activity; 
import android.content.ContentValues; 
import android.content.Context; 
import android.content.pm.ActivityInfo; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.graphics.PixelFormat; 
import android.graphics.Rect; 
import android.hardware.Camera; 
import android.hardware.Camera.AutoFocusCallback; 
import android.hardware.Camera.Face; 
import android.hardware.Camera.FaceDetectionListener; 
import android.hardware.Camera.Parameters; 
import android.hardware.Camera.PictureCallback; 
import android.hardware.Camera.ShutterCallback; 
import android.net.Uri; 
import android.os.Bundle; 
import android.provider.MediaStore.Images.Media; 
import android.view.LayoutInflater; 
import android.view.SurfaceHolder; 
import android.view.View; 
import android.view.ViewGroup.LayoutParams; 
import android.widget.Button; 
import android.widget.TextView; 

public class AndroidCamera extends Activity implements SurfaceHolder.Callback{ 

    Camera camera; 
    CameraSurfaceView cameraSurfaceView; 
    SurfaceHolder surfaceHolder; 
    boolean previewing = false; 
    LayoutInflater controlInflater = null; 

    Button buttonTakePicture; 
    TextView prompt; 

    DrawingView drawingView; 
    Face[] detectedFaces; 

    final int RESULT_SAVEIMAGE = 0; 

    private ScheduledExecutorService myScheduledExecutorService; 

    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 
     setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE); 

     getWindow().setFormat(PixelFormat.UNKNOWN); 
     cameraSurfaceView = (CameraSurfaceView)findViewById(R.id.camerapreview); 
     surfaceHolder = cameraSurfaceView.getHolder(); 
     surfaceHolder.addCallback(this); 
     surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); 

     drawingView = new DrawingView(this); 
     LayoutParams layoutParamsDrawing 
       = new LayoutParams(LayoutParams.FILL_PARENT, 
       LayoutParams.FILL_PARENT); 
     this.addContentView(drawingView, layoutParamsDrawing); 

     controlInflater = LayoutInflater.from(getBaseContext()); 
     View viewControl = controlInflater.inflate(R.layout.control, null); 
     LayoutParams layoutParamsControl 
       = new LayoutParams(LayoutParams.FILL_PARENT, 
       LayoutParams.FILL_PARENT); 
     this.addContentView(viewControl, layoutParamsControl); 

     buttonTakePicture = (Button)findViewById(R.id.takepicture); 
     buttonTakePicture.setOnClickListener(new Button.OnClickListener(){ 

      @Override 
      public void onClick(View arg0) { 
       // TODO Auto-generated method stub 
       camera.takePicture(myShutterCallback, 
         myPictureCallback_RAW, myPictureCallback_JPG); 
      }}); 

     /* 
     LinearLayout layoutBackground = (LinearLayout)findViewById(R.id.background); 
     layoutBackground.setOnClickListener(new LinearLayout.OnClickListener(){ 

    @Override 
    public void onClick(View arg0) { 
    // TODO Auto-generated method stub 

    buttonTakePicture.setEnabled(false); 
    camera.autoFocus(myAutoFocusCallback); 
    }}); 
    */ 

     prompt = (TextView)findViewById(R.id.prompt); 
    } 

    public void touchFocus(final Rect tfocusRect){ 

     buttonTakePicture.setEnabled(false); 
     camera.stopFaceDetection(); 

     //Convert from View's width and height to +/- 1000 
     final Rect targetFocusRect = new Rect(
       tfocusRect.left * 2000/drawingView.getWidth() - 1000, 
       tfocusRect.top * 2000/drawingView.getHeight() - 1000, 
       tfocusRect.right * 2000/drawingView.getWidth() - 1000, 
       tfocusRect.bottom * 2000/drawingView.getHeight() - 1000); 

     final List<Camera.Area> focusList = new ArrayList<Camera.Area>(); 
     Camera.Area focusArea = new Camera.Area(targetFocusRect, 1000); 
     focusList.add(focusArea); 

     Parameters para = camera.getParameters(); 
     para.setFocusAreas(focusList); 
     para.setMeteringAreas(focusList); 
     camera.setParameters(para); 

     camera.autoFocus(myAutoFocusCallback); 

     drawingView.setHaveTouch(true, tfocusRect); 
     drawingView.invalidate(); 
     camera.startFaceDetection(); 
    } 

    FaceDetectionListener faceDetectionListener 
      = new FaceDetectionListener(){ 

     @Override 
     public void onFaceDetection(Face[] faces, Camera tcamera) { 

      if (faces.length == 0){ 
       //prompt.setText(" No Face Detected! "); 
       drawingView.setHaveFace(false); 
      }else{ 
       //prompt.setText(String.valueOf(faces.length) + " Face Detected :) "); 
       drawingView.setHaveFace(true); 
       detectedFaces = faces; 

       //Set the FocusAreas using the first detected face 
       List<Camera.Area> focusList = new ArrayList<Camera.Area>(); 
       Camera.Area firstFace = new Camera.Area(faces[0].rect, 1000); 
       focusList.add(firstFace); 

       Parameters para = camera.getParameters(); 

       if(para.getMaxNumFocusAreas()>0){ 
        para.setFocusAreas(focusList); 
       } 

       if(para.getMaxNumMeteringAreas()>0){ 
        para.setMeteringAreas(focusList); 
       } 

       camera.setParameters(para); 

       buttonTakePicture.setEnabled(false); 

       //Stop further Face Detection 
       camera.stopFaceDetection(); 

       buttonTakePicture.setEnabled(false); 

    /* 
    * Allways throw java.lang.RuntimeException: autoFocus failed 
    * if I call autoFocus(myAutoFocusCallback) here! 
    * 
    camera.autoFocus(myAutoFocusCallback); 
    */ 

       //Delay call autoFocus(myAutoFocusCallback) 
       myScheduledExecutorService = Executors.newScheduledThreadPool(1); 
       myScheduledExecutorService.schedule(new Runnable(){ 
        public void run() { 
         camera.autoFocus(myAutoFocusCallback); 
        } 
       }, 500, TimeUnit.MILLISECONDS); 

      } 

      drawingView.invalidate(); 

     }}; 

    AutoFocusCallback myAutoFocusCallback = new AutoFocusCallback(){ 

     @Override 
     public void onAutoFocus(boolean arg0, Camera arg1) { 
      // TODO Auto-generated method stub 
      if (arg0){ 
       buttonTakePicture.setEnabled(true); 
       camera.cancelAutoFocus(); 
      } 

      float focusDistances[] = new float[3]; 
      arg1.getParameters().getFocusDistances(focusDistances); 
      prompt.setText("Optimal Focus Distance(meters): " 
        + focusDistances[Camera.Parameters.FOCUS_DISTANCE_OPTIMAL_INDEX]); 

     }}; 

    ShutterCallback myShutterCallback = new ShutterCallback(){ 

     @Override 
     public void onShutter() { 
      // TODO Auto-generated method stub 

     }}; 

    PictureCallback myPictureCallback_RAW = new PictureCallback(){ 

     @Override 
     public void onPictureTaken(byte[] arg0, Camera arg1) { 
      // TODO Auto-generated method stub 

     }}; 

    PictureCallback myPictureCallback_JPG = new PictureCallback(){ 

     @Override 
     public void onPictureTaken(byte[] arg0, Camera arg1) { 
      // TODO Auto-generated method stub 
    /*Bitmap bitmapPicture 
    = BitmapFactory.decodeByteArray(arg0, 0, arg0.length); */ 

      Uri uriTarget = getContentResolver().insert(Media.EXTERNAL_CONTENT_URI, new ContentValues()); 

      OutputStream imageFileOS; 
      try { 
       imageFileOS = getContentResolver().openOutputStream(uriTarget); 
       imageFileOS.write(arg0); 
       imageFileOS.flush(); 
       imageFileOS.close(); 

       prompt.setText("Image saved: " + uriTarget.toString()); 

      } catch (FileNotFoundException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 
      } catch (IOException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 
      } 

      camera.startPreview(); 
      camera.startFaceDetection(); 
     }}; 

    @Override 
    public void surfaceChanged(SurfaceHolder holder, int format, int width, 
           int height) { 
     // TODO Auto-generated method stub 
     if(previewing){ 
      camera.stopFaceDetection(); 
      camera.stopPreview(); 
      previewing = false; 
     } 

     if (camera != null){ 
      try { 
       camera.setPreviewDisplay(surfaceHolder); 
       camera.startPreview(); 

       prompt.setText(String.valueOf(
         "Max Face: " + camera.getParameters().getMaxNumDetectedFaces())); 
       camera.startFaceDetection(); 
       previewing = true; 
      } catch (IOException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 
      } 
     } 
    } 

    @Override 
    public void surfaceCreated(SurfaceHolder holder) { 
     // TODO Auto-generated method stub 
     camera = Camera.open(); 
     camera.setFaceDetectionListener(faceDetectionListener); 
    } 

    @Override 
    public void surfaceDestroyed(SurfaceHolder holder) { 
     // TODO Auto-generated method stub 
     camera.stopFaceDetection(); 
     camera.stopPreview(); 
     camera.release(); 
     camera = null; 
     previewing = false; 
    } 

    private class DrawingView extends View{ 

     boolean haveFace; 
     Paint drawingPaint; 

     boolean haveTouch; 
     Rect touchArea; 

     public DrawingView(Context context) { 
      super(context); 
      haveFace = false; 
      drawingPaint = new Paint(); 
      drawingPaint.setColor(Color.GREEN); 
      drawingPaint.setStyle(Paint.Style.STROKE); 
      drawingPaint.setStrokeWidth(2); 

      haveTouch = false; 
     } 

     public void setHaveFace(boolean h){ 
      haveFace = h; 
     } 

     public void setHaveTouch(boolean t, Rect tArea){ 
      haveTouch = t; 
      touchArea = tArea; 
     } 

     @Override 
     protected void onDraw(Canvas canvas) { 
      // TODO Auto-generated method stub 
      if(haveFace){ 

       // Camera driver coordinates range from (-1000, -1000) to (1000, 1000). 
       // UI coordinates range from (0, 0) to (width, height). 

       int vWidth = getWidth(); 
       int vHeight = getHeight(); 

       for(int i=0; i<detectedFaces.length; i++){ 

        if(i == 0){ 
         drawingPaint.setColor(Color.GREEN); 
        }else{ 
         drawingPaint.setColor(Color.RED); 
        } 

        int l = detectedFaces[i].rect.left; 
        int t = detectedFaces[i].rect.top; 
        int r = detectedFaces[i].rect.right; 
        int b = detectedFaces[i].rect.bottom; 
        int left = (l+1000) * vWidth/2000; 
        int top = (t+1000) * vHeight/2000; 
        int right = (r+1000) * vWidth/2000; 
        int bottom = (b+1000) * vHeight/2000; 
        canvas.drawRect(
          left, top, right, bottom, 
          drawingPaint); 
       } 
      }else{ 
       canvas.drawColor(Color.TRANSPARENT); 
      } 

      if(haveTouch){ 
       drawingPaint.setColor(Color.BLUE); 
       canvas.drawRect(
         touchArea.left, touchArea.top, touchArea.right, touchArea.bottom, 
         drawingPaint); 
      } 
     } 

    } 
} 

Alles, was ich tat, war camera.startFaceDetection(); nach drawingView.invalidate(); hinzufügen

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