照相机滤镜使用，优化解码和滤镜导致的预览卡屏现象

这几天看到亚瑟boy的技术连载，也试着做了下带滤镜特效的照相机，效果也出来了，但是发现添加滤镜特效后的预览窗口卡屏现象很严重，于是自己索性试着尝试修改，在亚瑟和其他网友的代码中基本上都是对于照相机data视频流先进行解码，然后对解码出的帧Bitmap进行滤镜算法处理，这个是必走的流程，而每一帧在处理解码和滤镜时都需要用掉大量时间，我测了下，解码需要300毫秒左右，滤镜处理需要600毫秒左右（冰冻滤镜），如此一来，处理完这两个流程需要的时间要在900毫秒甚至更长，我们知道如果看上去比较流畅的话我们需要每秒更新三帧的图片，而这么处理只能更新一张，明显的卡屏。
于是试着去缩小处理的Bitmap大小，在照相机预览返回照片大小中设置：

Camera.Parameters parameters = camera.getParameters();  parameters.setPreviewSize(display.getWidth()/2, display.getHeight()/2);// 设置预览照片的大小

原来默认是返回屏幕大小的预览图片，此时我改成了屏幕大小一半的图片，发现处理过程明显加快了（当然也有稍微的卡屏），最后在预览回调接口PreviewCallBack中再将图片放大到屏幕大小，有雨我预览图片返回时只是缩小了一半，此时放大回屏幕大小时仍然是非常清晰的，如果你想速度更快的话可以继续缩小预览图片的返回大小。
代码如下：

public class CameraActivity extends NoSearchActivity {           private static final String TAG = "CameraActivity";           private SurfaceView surfaceView;           private Camera camera;           private boolean preview;           private ImageButton take_picture;           private int width,height;             @Override           public void onCreate(Bundle savedInstanceState) {                   super.onCreate(savedInstanceState);                   Window window = getWindow();                   requestWindowFeature(Window.FEATURE_NO_TITLE);// 没有标题                   window.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,                                   WindowManager.LayoutParams.FLAG_FULLSCREEN);// 设置全屏                   window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);// 高亮                     setContentView(R.layout.camera_view);                     ButtonClickingListener buttonlistener = new ButtonClickingListener();                   surfaceView = (SurfaceView) this.findViewById(R.id.camera_surface);                   WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);                   Display display = wm.getDefaultDisplay();                   width = display.getWidth();                   height = display.getHeight();                     take_picture = (ImageButton) findViewById(R.id.take_picture);//拍照                   take_picture.setOnClickListener(buttonlistener);                   surfaceView.getHolder().setFixedSize(width, height); // 设置分辨率                   /* 下面设置Surface不维护自己的缓冲区，而是等待屏幕的渲染引擎将内容推送到用户面前 */                   surfaceView.getHolder().addCallback(new SurfaceCallback());           }           //按钮监听           private final class ButtonClickingListener implements View.OnClickListener {                   @Override                   public void onClick(View v) {                           if (!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {                                   Toast.makeText(CameraActivity.this, R.string.sdcarderror, 1).show();                                   return;                           }                           try {                                   switch (v.getId()) {                                   case R.id.take_picture:                                           camera.takePicture(null, null, new TakePictureCallback());                                           break;                                   }                           } catch (Exception e) {                                   Toast.makeText(CameraActivity.this, R.string.error, 1).show();                                   Log.e(TAG, e.toString());                           }                   }           }           @Override           protected void onDestroy() {                   // TODO Auto-generated method stub                   if(camera!=null){                           camera.setPreviewCallback(null) ;               camera.stopPreview();               camera.release();               camera = null;                   }                   super.onDestroy();           }           private final class SurfaceCallback implements SurfaceHolder.Callback {                     @Override                   public void surfaceChanged(SurfaceHolder holder, int format, int width,int height) {}                   @Override                   public void surfaceCreated(SurfaceHolder holder) {                           if(camera==null){                                   camera = Camera.open();//打开相机                           }else{                                   Toast.makeText(CameraActivity.this, "相机正在使用中", 1).show();                           }                           WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);                           Display display = wm.getDefaultDisplay();                           Camera.Parameters parameters = camera.getParameters();                           parameters.setPreviewSize(display.getWidth()/2, display.getHeight()/2);// 设置预览照片的大小                           parameters.setPreviewFrameRate(3);// 每秒3帧                           parameters.setPictureFormat(PixelFormat.JPEG);// 设置照片的输出格式                           parameters.set("jpeg-quality", 100);// 照片质量                           parameters.setPictureSize(display.getWidth(), display.getHeight());// 设置照片的大小                                                     camera.setParameters(parameters);                           camera.setPreviewCallback(new PreviewCallBack());// 通过SurfaceView显示取景画面                           camera.startPreview();//开始预览                           preview = true;                   }                     @Override                   public void surfaceDestroyed(SurfaceHolder holder) {                           if (camera != null) {                                   if (preview)                                           camera.stopPreview();                                   camera.release();                           }                   }           }             @Override           public boolean onKeyDown(int keyCode, KeyEvent event) {                   if (camera != null && event.getRepeatCount() == 0) {                           switch (keyCode) {                                   case KeyEvent.KEYCODE_MENU:                                           camera.autoFocus(null);// 自动对焦                                           break;                                   case KeyEvent.KEYCODE_CAMERA:                                   case KeyEvent.KEYCODE_DPAD_CENTER:                                           camera.takePicture(null, null, new TakePictureCallback());                                           break;                                   case KeyEvent.KEYCODE_BACK:                                           new AlertDialog.Builder(CameraActivity.this).setTitle("提示")                                           .setMessage("确定退出照相机?").setPositiveButton("确定",                                                           new DialogInterface.OnClickListener() {                                                   public void onClick(DialogInterface dialog,int whichButton) {                                                           Intent exit = new Intent(Intent.ACTION_MAIN);                                                           exit.addCategory(Intent.CATEGORY_HOME);                                                           exit.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);                                                           startActivity(exit);                                                           System.exit(0);                                                   }                                           }).setNegativeButton("取消",new DialogInterface.OnClickListener() {                                                   public void onClick(DialogInterface dialog,int whichButton) {                                                           // 取消按钮事件                                                           dialog.cancel();                                                   }                                           }).show();                                           break;                           }                   }                   return super.onKeyDown(keyCode, event); // 不会回到 home 页面           }           //预览回调接口           private final class PreviewCallBack implements Camera.PreviewCallback {                   public void onPreviewFrame(byte[] data, Camera camera) {                           if (data != null) {                                   int imageWidth = camera.getParameters().getPreviewSize().width;                                   int imageHeight = camera.getParameters().getPreviewSize().height;                                   int RGBData[] = new int[imageWidth * imageHeight];                                   decodeYUV420SP(RGBData, data, imageWidth, imageHeight); //解码                                   Bitmap bm = Bitmap.createBitmap(RGBData, imageWidth, imageHeight, Config.ARGB_8888);   //                                bm = toGrayscale(bm);//实时滤镜效果，现在是变成黑白效果                                   bm = ice(bm);//冰冻效果                                   Canvas canvas = surfaceView.getHolder().lockCanvas();                       // 判断非null，才能drawBitmap.                       if (bm != null) {                               bm = Bitmap.createScaledBitmap(bm, width, height,false);                           canvas.drawBitmap(bm, 0, 0, null);                       }                       surfaceView.getHolder().unlockCanvasAndPost(canvas);                           }           }           }

灰度效果（黑白照片）

public static Bitmap toGrayscale(Bitmap bmp) {                   int height = bmp.getHeight();                   int width = bmp.getWidth();                     Bitmap bmpGrayscale = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);                   Canvas c = new Canvas(bmpGrayscale);                   Paint paint = new Paint();                   ColorMatrix cm = new ColorMatrix();                   cm.setSaturation(0);                   ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);                   paint.setColorFilter(f);                   c.drawBitmap(bmp, 0, 0, paint);                   return bmpGrayscale;           }

冰冻特效

public static Bitmap ice(Bitmap bmp) {                   int width = bmp.getWidth();                   int height = bmp.getHeight();                   Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);                   int dst[] = new int[width * height];                   bmp.getPixels(dst, 0, width, 0, 0, width, height);                   int R, G, B, pixel;                   int pos, pixColor;                   for (int y = 0; y < height; y++) {                           for (int x = 0; x < width; x++) {                                   pos = y * width + x;                                   pixColor = dst[pos]; // 获取图片当前点的像素值                                   R = Color.red(pixColor); // 获取RGB三原色                                   G = Color.green(pixColor);                                   B = Color.blue(pixColor);                                   pixel = R - G - B;                                   pixel = pixel * 3 / 2;
if (pixel < 0)                                           pixel = -pixel;                                   if (pixel > 255)                                           pixel = 255;
R = pixel; // 计算后重置R值，以下类同                                   pixel = G - B - R;                                   pixel = pixel * 3 / 2;
if (pixel < 0)                                           pixel = -pixel;                                   if (pixel > 255)                                           pixel = 255;
G = pixel;                                   pixel = B - R - G;                                   pixel = pixel * 3 / 2;
if (pixel < 0)                                           pixel = -pixel;                                   if (pixel > 255)                                           pixel = 255;                                   B = pixel;                                   dst[pos] = Color.rgb(R, G, B); // 重置当前点的像素值                                   } // x                           } // y                   bitmap.setPixels(dst, 0, width, 0, 0, width, height);                   return bitmap;           }

获取照片回调

private final class TakePictureCallback implements PictureCallback {                   @Override                   public void onPictureTaken(byte[] data, Camera camera) {                           try {                                   Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0,data.length);                                   bitmap = ice(bitmap);                                   File file = new File(Environment.getExternalStorageDirectory(),System.currentTimeMillis() + ".jpg");//保存在SD卡根目录下，以当前时间毫秒命名                                   FileOutputStream outStream = new FileOutputStream(file);                                   bitmap.compress(CompressFormat.JPEG, 100, outStream);                                   outStream.close();                                   camera.stopPreview();                                   camera.startPreview();//重新开始照相预览                           } catch (Exception e) {                                   Log.e(TAG, e.toString());                           }                   }           }

解码

static public void decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width, int height) {                   final int frameSize = width * height;                   for (int j = 0, yp = 0; j < height; j++) {                           int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;                           for (int i = 0; i < width; i++, yp++) {                                   int y = (0xff & ((int) yuv420sp[yp])) - 16;                                   if (y < 0)y = 0;                                   if ((i & 1) == 0) {                                           v = (0xff & yuv420sp[uvp++]) - 128;                                           u = (0xff & yuv420sp[uvp++]) - 128;                                   }
int y1192 = 1192 * y;                                   int r = (y1192 + 1634 * v);                                   int g = (y1192 - 833 * v - 400 * u);                                   int b = (y1192 + 2066 * u);                                     if (r < 0)r = 0;                                   else if (r > 262143)r = 262143;                                   if (g < 0)g = 0;                                   else if (g > 262143)g = 262143;                                   if (b < 0)b = 0;                                   else if (b > 262143)                                           b = 262143;                                   rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);                           }                   }           }   }

camera_view 代码：

<?xml version="1.0" encoding="utf-8"?>   <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"           android:orientation="horizontal" android:layout_width="fill_parent"           android:layout_height="fill_parent" android:background="#000000">           <SurfaceView android:id="@+id/camera_surface"                   android:layout_height="fill_parent"                   android:layout_width="fill_parent"                   android:layout_weight="2.0" />           <LinearLayout android:orientation="vertical"                   android:layout_width="50dip"                   android:layout_height="fill_parent"                   android:gravity="center_vertical">                   <ImageButton android:layout_width="48dip"                           android:layout_height="48dip"                           android:src="@android:drawable/ic_menu_camera"                           android:id="@+id/take_picture" />                   <View android:layout_width="40dip"                       android:layout_height="fill_parent"                       android:layout_weight="2.0"/>           </LinearLayout>   </LinearLayout>

效果如下图：照相机冰冻效果



本文出自 “Android小子的” 博客，请务必保留此出处http://androidrigl.blog.51cto.com/7531835/1249385