如何压缩图像大小

Posted 2023-04-17

【中文标题】如何压缩图像大小

【英文标题】：How Do I compress Size of Image

【发布时间】：2016-01-29 10:28:43

【问题描述】：

这是我用来捕捉图像的代码，但现在我的问题是如何压缩自定义相机拍摄的图像大小

CameraSurfaceView.java：

class CameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback 

    Camera camera;

    CameraSurfaceView(Context context) 
        super(context);

        SurfaceHolder holder = this.getHolder();
        holder.addCallback(this);
    

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
                               int height) 

        camera.setDisplayOrientation(90);
        camera.startPreview();
    

    @Override
    public void surfaceCreated(SurfaceHolder holder) 
        try 
            // Open the Camera in preview mode
            this.camera = Camera.open();
            this.camera.setPreviewDisplay(holder);
         catch (IOException ioe) 
            ioe.printStackTrace(System.out);
        

    

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) 
        camera.stopPreview();
        camera.release();
        camera = null;
    

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) 
        // TODO Auto-generated method stub
    

    public void takePicture(PictureCallback imageCallback) 

        Camera.Parameters params = camera.getParameters();
        params.setRotation(90);
        camera.setParameters(params);

        camera.takePicture(null, null, imageCallback);

    

这是我用来捕获图像的类

CameraCaptureActivity.java：

CameraSurfaceView cameraSurfaceView;

@Override
public void onCreate(Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_camera_capture);   

        // set up our preview surface
        FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
        cameraSurfaceView = new CameraSurfaceView(this);
        preview.addView(cameraSurfaceView);

        // grab out shutter button so we can reference it later
        shutterButton = (Button) findViewById(R.id.btnCapture);
        shutterButton.setOnClickListener(this);


@Override
    public void onClick(View v) 
        takePicture();
    

    private void takePicture() 
        shutterButton.setEnabled(false);
        cameraSurfaceView.takePicture(this);
    

    @Override
    public void onPictureTaken(byte[] data, Camera camera) 
        // TODO something with the image data

        File pictureFileDir = getDir();

        if (!pictureFileDir.exists() && !pictureFileDir.mkdirs()) 

            return;

        

        simpleDateFormat = new SimpleDateFormat("yyyyMMddHHmmss");
        strDateFormat = simpleDateFormat.format(new Date());

        String photoFile = strRecordName+strDateFormat+".jpg";

        String filename = pictureFileDir.getPath() + File.separator + photoFile;

        File pictureFile = new File(filename);

        try 
            FileOutputStream fos = new FileOutputStream(pictureFile);
            fos.write(data);
            fos.close();
            Toast.makeText(CameraCaptureActivity.this, "Image saved:" + photoFile,
                    Toast.LENGTH_LONG).show();

            // Restart the preview and re-enable the shutter button so that we can take another picture
            camera.stopPreview();
            shutterButton.setEnabled(false);                  

         catch (Exception error)             
            Toast.makeText(CameraCaptureActivity.this, "Image could not be saved.",
                    Toast.LENGTH_LONG).show();
        
    

    private File getDir() 
        File sdDir = Environment
          .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
        return new File(sdDir, "CustomCamera");
    


    public void onResume() 
    
        super.onResume();
        shutterButton.setEnabled(true);
    

【问题讨论】：

在哪里使用这个？ @MD

【参考方案1】：

喜欢

@Override
public void onPictureTaken(byte[] data, Camera camera) 

    Bitmap pic = BitmapFactory.decodeByteArray(data, 0, data.length);

    //Rotate the image by 90 degrees before we save it
    Matrix matrix = new Matrix();
    matrix.postRotate(90);
    pic = Bitmap.createBitmap(pic , 0, 0, pic.getWidth(), pic.getHeight(), matrix, true);

     ........
     FileOutputStream fos = new FileOutputStream(pictureFile);
     pic.compress(Bitmap.CompressFormat.PNG, 90, fOut);

【讨论】：

@Sophie Right 试试看，我认为您需要在加载图像时进行压缩

@Sophie 只是缩小了您的位图，然后加载到您的图像视图。 img.setImageBitmap(Bitmap.createScaledBitmap(pic,210, 210, true));