blame | 历史 | 补丁 | 提交 | 提交对比 | ignore whitespace
xuxiuxi
2017-07-26 e465984927353ef5922b5c1fe9f7dd1cf29e9094 
 VisitFace/DemoForBsk/app/src/main/java/cn/com/basic/face/base/MainActivity.java


@@ -1,37 +1,34 @@


package cn.com.basic.face.base;




import android.Manifest;


import android.app.AlertDialog;


import android.content.Context;


import android.content.DialogInterface;


import android.content.pm.ActivityInfo;


import android.content.pm.PackageManager;


import android.content.res.Configuration;


import android.database.sqlite.SQLiteDatabase;


import android.graphics.Bitmap;


import android.graphics.BitmapFactory;


import android.graphics.Canvas;


import android.graphics.Color;


import android.graphics.ImageFormat;


import android.graphics.Paint;


import android.graphics.PorterDuff;


import android.graphics.SurfaceTexture;


import android.graphics.Paint.Align;


import android.graphics.drawable.ColorDrawable;


import android.hardware.Camera;


import android.hardware.Camera.PreviewCallback;


import android.hardware.Camera.Size;


import android.os.Bundle;


import android.os.Handler;


import android.support.design.widget.TabLayout;


import android.support.v4.app.ActivityCompat;


import android.support.v4.app.Fragment;


import android.support.v4.app.FragmentManager;


import android.support.v4.app.FragmentPagerAdapter;


import android.support.v4.content.ContextCompat;


import android.support.v4.view.ViewPager;


import android.os.Bundle;


import android.view.LayoutInflater;


import android.view.MotionEvent;


import android.view.SurfaceHolder;


import android.view.SurfaceView;


import android.view.TextureView;


import android.view.View;


import android.view.ViewGroup;


import android.view.ViewGroup.LayoutParams;


import android.view.WindowManager;


import android.widget.EditText;


import android.widget.ImageView;


@@ -42,22 +39,7 @@


import com.awsle.aibatis.client.SqlMapClientBuilder;


import com.bsk.zhangbo.demoforbsk.R;


import com.luxand.FSDK;




import cn.com.basic.face.discern.common.CommonVariables;


import cn.com.basic.face.discern.query.item.SurveillanceQueryItem;


import cn.com.basic.face.fragment.AttenderRegisterFragment;


import cn.com.basic.face.fragment.SurveillanceFragment;


import cn.com.basic.face.service.SurveillanceMng;


import cn.com.basic.face.service.sqlite.TestDao;


import cn.com.basic.face.util.FileUtil;


import cn.com.basic.face.util.NativeImg;


import cn.com.basic.face.util.TabNameUtil;


import cn.com.basic.face.fragment.AttendanceFragment;


import cn.com.basic.face.fragment.CheckInFragment;


import cn.com.basic.face.fragment.DeviceFragment;


import cn.com.basic.face.fragment.PhoneCallFragment;


import cn.com.basic.face.fragment.VisitorRegisterFragment;


import cn.com.basic.face.fragment.VisitFragment;


import com.luxand.FSDK.HTracker;




import java.io.File;


import java.io.FileNotFoundException;


@@ -66,9 +48,33 @@


import java.io.InputStream;


import java.util.ArrayList;


import java.util.Arrays;


import java.util.Date;


import java.util.List;


import java.util.concurrent.locks.Lock;


import java.util.concurrent.locks.ReentrantLock;




import cn.com.basic.face.dialog.AttenderRegisterSelectPhotoDialog;


import cn.com.basic.face.dialog.AttenderRegisterUploadPhotoDialog;


import cn.com.basic.face.dialog.VisitorRegisterSelectPhotoDialog;


import cn.com.basic.face.dialog.VisitorRegisterUploadPhotoDialog;


import cn.com.basic.face.discern.common.CommonVariables;


import cn.com.basic.face.discern.query.item.SurveillanceQueryItem;


import cn.com.basic.face.fragment.AttendanceFragment;


import cn.com.basic.face.fragment.CheckInFragment;


import cn.com.basic.face.fragment.DeviceFragment;


import cn.com.basic.face.fragment.PhoneCallFragment;


import cn.com.basic.face.fragment.SurveillanceFragment;


import cn.com.basic.face.fragment.VisitFragment;


import cn.com.basic.face.fragment.VisitorRegisterFragment;


import cn.com.basic.face.service.DeviceMng;


import cn.com.basic.face.service.InternetAccessThread;


import cn.com.basic.face.service.SurveillanceMng;


import cn.com.basic.face.service.sqlite.SurveillanceDao;


import cn.com.basic.face.service.sqlite.TestDao;


import cn.com.basic.face.service.sync.up.BaseSync;


import cn.com.basic.face.util.FileUtil;


import cn.com.basic.face.util.NativeImg;


import cn.com.basic.face.util.TabNameUtil;




public class MainActivity extends BaseActivity implements View.OnClickListener{




@@ -76,6 +82,16 @@




    private static TabLayout mTabLayout;


    public static ViewPager mViewPager;


    public SQLiteDatabase db;


    private int internetAccessible = CommonVariables.InternetAccess.INTERNET_NOT_INITIALIZE;




    public int getInternetAccessible() {


        return internetAccessible;


    }




    public void setInternetAccessible(int internetAccessible) {


        this.internetAccessible = internetAccessible;


    }




    public static void selectPage(int pageNum) {


        mTabLayout.getTabAt(pageNum).select();


@@ -92,6 +108,7 @@


        mViewPager = (ViewPager) findViewById(R.id.viewpager);


        mTabLayout.setTabGravity(TabLayout.GRAVITY_FILL);


        instance = this;


        internetAccessThread.start();


    }




    public MyFragmentPagerAdapter myFragmentPagerAdapter;


@@ -126,8 +143,7 @@


            myThread = new MyThread();


            myThread.start();


        }


        initDb();


        initSqlMap();


//        initSqlMap();


    }




    public static MainActivity getInstance() {


@@ -334,23 +350,37 @@




    public static float sDensity = 1.0f;




    InternetAccessThread internetAccessThread = new InternetAccessThread();




    @Override


    public void onCreate(Bundle savedInstanceState) {


        super.onCreate(savedInstanceState);


        initDb();


        db=openOrCreateDatabase("/data/data/com.bsk.zhangbo.demoforbsk/databases/aibatis_test_db", Context.MODE_PRIVATE, null);


        TestDao.getInstance().test();


        DeviceMng.getInstance().findDevice();


        if (CommonVariables.FACE_SERVER) {


            sDensity = getResources().getDisplayMetrics().scaledDensity;




            int res = 0;


            String s = FileUtil.getStringFromFile("/system/a");


            int res = FSDK.ActivateLibrary(s);


            if (res != FSDK.FSDKE_OK) {


                mIsFailed = true;


                showErrorAndClose("failed", res);


            } else {


                FSDK.Initialize();




                // Hide the window title (it is done in manifest too)


                getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);


                //requestWindowFeature(Window.FEATURE_NO_TITLE);




                // Lock orientation


                setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);




                // Camera layer and drawing layer


                mDraw = new ProcessImageAndDrawResults(this);


                mPreview = new Preview(this, mDraw);


                mDraw.mTracker = new FSDK.HTracker();


                mDraw.mTracker = new HTracker();


                String templatePath = this.getApplicationInfo().dataDir + "/" + database;


                if (FSDK.FSDKE_OK != FSDK.LoadTrackerMemoryFromFile(mDraw.mTracker, templatePath)) {


                    res = FSDK.CreateTracker(mDraw.mTracker);


@@ -358,10 +388,40 @@


                        showErrorAndClose("Error creating tracker", res);


                    }


                }




                resetTrackerParameters();




                this.getWindow().setBackgroundDrawable(new ColorDrawable()); //black background




                //setContentView(mPreview); //creates MainActivity contents


                //addContentView(mDraw, new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));






                // Menu


//                LayoutInflater inflater = (LayoutInflater)this.getSystemService( Context.LAYOUT_INFLATER_SERVICE );


//                View buttons = inflater.inflate(R.layout.bottom_menu, null );


//                buttons.findViewById(R.id.helpButton).setOnClickListener(this);


//                buttons.findViewById(R.id.clearButton).setOnClickListener(this);


//                addContentView(buttons, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));






//                FSDK.Initialize();


//                getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);


//                setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);


//                mDraw = new ProcessImageAndDrawResults(this);


//                mPreview = new Preview(this, mDraw);


//                mDraw.mTracker = new FSDK.HTracker();


//                String templatePath = this.getApplicationInfo().dataDir + "/" + database;


//                if (FSDK.FSDKE_OK != FSDK.LoadTrackerMemoryFromFile(mDraw.mTracker, templatePath)) {


//                    res = FSDK.CreateTracker(mDraw.mTracker);


//                    if (FSDK.FSDKE_OK != res) {


//                        showErrorAndClose("Error creating tracker", res);


//                    }


//                }


//                resetTrackerParameters();


//


//                setContentView(mPreview); //creates MainActivity contents


//                addContentView(mDraw, new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));




                // Menu


//                LayoutInflater inflater = (LayoutInflater)this.getSystemService( Context.LAYOUT_INFLATER_SERVICE );


@@ -407,6 +467,10 @@


            String templatePath = this.getApplicationInfo().dataDir + "/" + database;


            FSDK.SaveTrackerMemoryToFile(mDraw.mTracker, templatePath);


        }


        VisitorRegisterUploadPhotoDialog.getInstance().hide();


        VisitorRegisterSelectPhotoDialog.getInstance().hide();


        AttenderRegisterSelectPhotoDialog.getInstance().hide();


        AttenderRegisterUploadPhotoDialog.getInstance().hide();


    }




    @Override


@@ -466,6 +530,16 @@


        mDraw.mStopping = 0;


    }




    @Override


    protected void onStop() {


        super.onStop();


        VisitorRegisterUploadPhotoDialog.getInstance().hide();


        VisitorRegisterSelectPhotoDialog.getInstance().hide();


        AttenderRegisterSelectPhotoDialog.getInstance().hide();


        AttenderRegisterUploadPhotoDialog.getInstance().hide();


        //Config.sqlMap.getDb().close();


//        db.close();


    }


}






@@ -474,8 +548,9 @@


    public int x1, y1, x2, y2;


}




// Draw graphics on top of the video


class ProcessImageAndDrawResults extends View {


    public FSDK.HTracker mTracker;


    public HTracker mTracker;




    final int MAX_FACES = 5;


    final FaceRectangle[] mFacePositions = new FaceRectangle[MAX_FACES];


@@ -533,12 +608,12 @@


        mPaintGreen.setStyle(Paint.Style.FILL);


        mPaintGreen.setColor(Color.GREEN);


        mPaintGreen.setTextSize(18 * MainActivity.sDensity);


        mPaintGreen.setTextAlign(Paint.Align.CENTER);


        mPaintGreen.setTextAlign(Align.CENTER);


        mPaintBlue = new Paint();


        mPaintBlue.setStyle(Paint.Style.FILL);


        mPaintBlue.setColor(Color.BLUE);


        mPaintBlue.setTextSize(18 * MainActivity.sDensity);


        mPaintBlue.setTextAlign(Paint.Align.CENTER);


        mPaintBlue.setTextAlign(Align.CENTER);




        mPaintBlueTransparent = new Paint();


        mPaintBlueTransparent.setStyle(Paint.Style.STROKE);


@@ -546,13 +621,15 @@


        mPaintBlueTransparent.setColor(Color.BLUE);


        mPaintBlueTransparent.setTextSize(25);




        //mBitmap = null;


        mYUVData = null;


        mRGBData = null;




        first_frame_saved = false;


    }




    public void onDraw(Canvas canvas) {


    @Override


    protected void onDraw(Canvas canvas) {


        if (mStopping == 1) {


            mStopped = 1;


            super.onDraw(canvas);


@@ -670,10 +747,15 @@


                surveillanceQueryItem.setBitmap(bmp);


                surveillanceQueryItem.setWidth("100");


                surveillanceQueryItem.setHeight("100");


                surveillanceQueryItem.setRegisterOrCheckIn(CommonVariables.Surveillance.OFFLINE_SURVEILLANCE_ITEM_TYPE);


                surveillanceQueryItem.setCreateTime(new Date());


                bitmapList.add(surveillanceQueryItem);






                SurveillanceMng.getInstance().addBitmap(bitmapList, nativeImg.image, 0, CommonVariables.Camera.IN+"", nativeImg.image);


                if (BaseApplication.getInstance().networkAvailable()) {


                    SurveillanceMng.getInstance().addBitmap(bitmapList, nativeImg.image, 0, CommonVariables.Camera.IN+"", nativeImg.image);


                } else {


                    SurveillanceMng.getInstance().addOfflineBitmap(bitmapList, nativeImg.image, CommonVariables.Camera.IN+"");


                }


            }




        }


@@ -700,7 +782,7 @@


        }




        super.onDraw(canvas);


    }


    } // end onDraw method






    @Override


@@ -715,6 +797,10 @@


                long IDs[] = new long[MAX_FACES];


                for (int i=0; i<MAX_FACES; ++i) {


                    rects[i] = new FaceRectangle();


                    if(rects[i] == null) {


                        faceLock.unlock();


                        return true;


                    }


                    rects[i].x1 = mFacePositions[i].x1;


                    rects[i].y1 = mFacePositions[i].y1;


                    rects[i].x2 = mFacePositions[i].x2;


@@ -729,6 +815,7 @@




                        mTouchedIndex = i;




                        // requesting name on tapping the face


                        final EditText input = new EditText(mContext);


                        AlertDialog.Builder builder = new AlertDialog.Builder(mContext);


                        builder.setMessage("Enter person's name" )


@@ -746,7 +833,7 @@


                                        mTouchedIndex = -1;


                                    }


                                })


                                .setCancelable(false)


                                .setCancelable(false) // cancel with button only


                                .show();




                        break;


@@ -783,121 +870,12 @@


            }


        }


    }




    public void startFaceDetection() {


        if (mStopping == 1) {


            mStopped = 1;


            return;


        }




        if (mYUVData == null || mTouchedIndex != -1) {


            return;


        }






        decodeYUV420SP(mRGBData, mYUVData, mImageWidth, mImageHeight);




        FSDK.HImage Image = new FSDK.HImage();


        FSDK.FSDK_IMAGEMODE imagemode = new FSDK.FSDK_IMAGEMODE();


        imagemode.mode = FSDK.FSDK_IMAGEMODE.FSDK_IMAGE_COLOR_24BIT;


        FSDK.LoadImageFromBuffer(Image, mRGBData, mImageWidth, mImageHeight, mImageWidth*3, imagemode);


        FSDK.MirrorImage(Image, false);


        FSDK.HImage RotatedImage = new FSDK.HImage();


        FSDK.CreateEmptyImage(RotatedImage);




        int ImageWidth = mImageWidth;


        if (rotated) {


            ImageWidth = mImageHeight;


            FSDK.RotateImage90(Image, -1, RotatedImage);


        } else {


            FSDK.CopyImage(Image, RotatedImage);


        }




        //String surveillancePhotoName11 = "/storage/sdcard1/"+System.currentTimeMillis()+".jpg";


        //FSDK.SaveImageToFile(Image, surveillancePhotoName11);






        FSDK.FreeImage(Image);




        long IDs[] = new long[MAX_FACES];


        long face_count[] = new long[1];








        FSDK.FeedFrame(mTracker, 0, RotatedImage, face_count, IDs);




        System.out.println("face_count="+face_count[0]+", mImageWidth="+mImageWidth+", mImageHeight="+mImageHeight);




        faceLock.lock();




        for (int i=0; i<MAX_FACES; ++i) {


            mFacePositions[i] = new FaceRectangle();


            mFacePositions[i].x1 = 0;


            mFacePositions[i].y1 = 0;


            mFacePositions[i].x2 = 0;


            mFacePositions[i].y2 = 0;


            mIDs[i] = IDs[i];


        }






        for (int i = 0; i < (int)face_count[0]; ++i) {


            FSDK.FSDK_Features Eyes = new FSDK.FSDK_Features();


            FSDK.GetTrackerEyes(mTracker, 0, mIDs[i], Eyes);




            GetFaceFrame(Eyes, mFacePositions[i]);


        }


        if ((int)face_count[0] > 0) {




            FSDK.HImage img2 = new FSDK.HImage();


            FSDK.CreateEmptyImage(img2);


            FSDK.TFacePosition fp = new FSDK.TFacePosition();


            FSDK.DetectFace(RotatedImage, fp);




            int x1 = (int)(fp.xc - 1.2*fp.w/2);


            int y1 = (int)(fp.yc - 1.4*fp.w/2);


            int x2 = (int)(fp.xc + 1.2*fp.w/2);


            int y2 = (int)(fp.yc + 1.4*fp.w/2);




            FSDK.CopyRect(RotatedImage, x1, y1, x2, y2, img2);






            System.out.println("face_count="+face_count[0]);


            String surveillancePhotoName = MainActivity.getInstance().getFilesDir().getAbsolutePath()+System.currentTimeMillis()+".jpg";


            FSDK.SaveImageToFile(img2, surveillancePhotoName);




            List bitmapList = new ArrayList();


            for (int i = 0; i < 1; i++) {


                NativeImg nativeImg = new NativeImg();


                nativeImg.image = FileUtil.readFile(new File(surveillancePhotoName));


                nativeImg.size = nativeImg.image.length;


                SurveillanceQueryItem surveillanceQueryItem = new SurveillanceQueryItem();


                surveillanceQueryItem.setNativeImg(nativeImg);


                nativeImg.st_track_id = 1;


                surveillanceQueryItem.setStTrackId(nativeImg.st_track_id);


                BitmapFactory.Options options = new BitmapFactory.Options();


                options.inMutable = true;


                Bitmap bmp = BitmapFactory.decodeByteArray(nativeImg.image, 0, nativeImg.image.length, options);


                Canvas canvas1 = new Canvas(bmp);




                surveillanceQueryItem.setBitmap(bmp);


                surveillanceQueryItem.setWidth("100");


                surveillanceQueryItem.setHeight("100");


                bitmapList.add(surveillanceQueryItem);






                SurveillanceMng.getInstance().addBitmap(bitmapList, nativeImg.image, 0, CommonVariables.Camera.IN+"", nativeImg.image);


            }


} // end of ProcessImageAndDrawResults class










        }


        FSDK.FreeImage(RotatedImage);


        faceLock.unlock();




    }


}




// Show video from camera and pass frames to ProcessImageAndDraw class


class Preview extends SurfaceView implements SurfaceHolder.Callback {


    Context mContext;


    SurfaceHolder mHolder;


@@ -910,48 +888,46 @@


        mContext = context;


        mDraw = draw;




        //Install a SurfaceHolder.Callback so we get notified when the underlying surface is created and destroyed.


        mHolder = getHolder();


        mHolder.addCallback(this);


        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);




        //new MyThread1().start();


    }




    int count = 0;


    //SurfaceView callback


    public void surfaceCreated(SurfaceHolder holder) {


        mFinished = false;




        // Find the ID of the camera


        int cameraId = 0;


        boolean frontCameraFound = false;


        Camera.CameraInfo cameraInfo = new Camera.CameraInfo();


        for (int i = 0; i < Camera.getNumberOfCameras(); i++) {


            Camera.getCameraInfo(i, cameraInfo);


            //if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_BACK)


            if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {


                cameraId = i;


                frontCameraFound = true;


            }


        }


        //If authorisation not granted for camera


        if (ContextCompat.checkSelfPermission(MainActivity.getInstance(), Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)


            //ask for authorisation


            ActivityCompat.requestPermissions(MainActivity.getInstance(), new String[]{Manifest.permission.CAMERA}, 50);




        if (frontCameraFound) {


            mCamera = Camera.open(cameraId);


        } else {


            mCamera = Camera.open();


        }




        try {


            mCamera.setPreviewDisplay(holder);




            mCamera.addCallbackBuffer(new byte[((640 * 480) * ImageFormat.getBitsPerPixel(ImageFormat.NV21)) / 8]);




            //mCamera.setPreviewCallback


            mCamera.setPreviewCallbackWithBuffer(new Camera.PreviewCallback() {


                public void onPreviewFrame(final byte[] data, final Camera camera) {


                    mCamera.addCallbackBuffer(data);


            // Preview callback used whenever new viewfinder frame is available


            mCamera.setPreviewCallback(new PreviewCallback() {


                public void onPreviewFrame(byte[] data, Camera camera) {


                    if ( (mDraw == null) || mFinished )


                        return;




                    if (mDraw.mYUVData == null) {


                        // Initialize the draw-on-top companion


                        Camera.Parameters params = camera.getParameters();


                        mDraw.mImageWidth = params.getPreviewSize().width;


                        mDraw.mImageHeight = params.getPreviewSize().height;


@@ -959,6 +935,7 @@


                        mDraw.mYUVData = new byte[data.length];


                    }




                    // Pass YUV data to draw-on-top companion


                    System.arraycopy(data, 0, mDraw.mYUVData, 0, data.length);


                    mDraw.invalidate();


                }


@@ -981,7 +958,11 @@


        }


    }




    //SurfaceView callback


    public void surfaceDestroyed(SurfaceHolder holder) {


        // Surface will be destroyed when we return, so stop the preview.


        // Because the CameraDevice object is not a shared resource, it's very


        // important to release it when the activity is paused.


        mFinished = true;


        if (mCamera != null) {


            mCamera.setPreviewCallback(null);


@@ -991,24 +972,32 @@


        }


    }




    //SurfaceView callback, configuring camera


    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {


        if (mCamera == null) return;




        // Now that the size is known, set up the camera parameters and begin


        // the preview.


        Camera.Parameters parameters = mCamera.getParameters();




        //Keep uncommented to work correctly on phones:


        //This is an undocumented although widely known feature


      /**/


        if (this.getResources().getConfiguration().orientation != Configuration.ORIENTATION_LANDSCAPE) {


            parameters.set("orientation", "portrait");


            mCamera.setDisplayOrientation(90);


            mCamera.setDisplayOrientation(90); // For Android 2.2 and above


            mDraw.rotated = true;


        } else {


            parameters.set("orientation", "landscape");


            mCamera.setDisplayOrientation(0);


            mCamera.setDisplayOrientation(0); // For Android 2.2 and above


        }


        List<Camera.Size> supportedSizes = parameters.getSupportedPreviewSizes();


      /**/




        // choose preview size closer to 640x480 for optimal performance


        List<Size> supportedSizes = parameters.getSupportedPreviewSizes();


        int width = 0;


        int height = 0;


        System.out.println("surfaceChanged");


        for (Camera.Size s: supportedSizes) {


        for (Size s: supportedSizes) {


            if ((width - 640)*(width - 640) + (height - 480)*(height - 480) >


                    (s.width - 640)*(s.width - 640) + (s.height - 480)*(s.height - 480)) {


                width = s.width;


@@ -1016,10 +1005,12 @@


            }


        }




        //try to set preferred parameters


        try {


            if (width*height > 0) {


                parameters.setPreviewSize(width, height);


            }


            //parameters.setPreviewFrameRate(10);


            parameters.setSceneMode(Camera.Parameters.SCENE_MODE_PORTRAIT);


            parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_VIDEO);


            mCamera.setParameters(parameters);


@@ -1033,7 +1024,7 @@


    }




    private void makeResizeForCameraAspect(float cameraAspectRatio){


        ViewGroup.LayoutParams layoutParams = this.getLayoutParams();


        LayoutParams layoutParams = this.getLayoutParams();


        int matchParentWidth = this.getWidth();


        int newHeight = (int)(matchParentWidth/cameraAspectRatio);


        if (newHeight != layoutParams.height) {


@@ -1043,6 +1034,4 @@


            this.invalidate();


        }


    }




}




} // end of Preview class