捕獲的圖像分辨率太大

Question

我在做什么 ？

我允許用戶捕獲圖像，將其存儲到SD卡中並上傳到服務器。

但是獲取捕獲的圖像的分辨率為寬度：4608像素和高度：2592像素

現在我想要什么？

如何獲得小分辨率的圖像而又不影響質量，例如最低分辨率，我可以獲取或設置所捕獲圖像的分辨率為原始圖像分辨率的25％。（特定於設備）

CameraCaptureActivity.java：

public class CameraCaptureActivity extends Activity implements OnClickListener, PictureCallback {

    CameraSurfaceView cameraSurfaceView;
    Button shutterButton;
    SimpleDateFormat simpleDateFormat;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_camera_capture);

        FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
        cameraSurfaceView = new CameraSurfaceView(this);
        preview.addView(cameraSurfaceView);

        shutterButton = (Button) findViewById(R.id.shutter_button);
        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 = "Latest.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, "Latest Models");
    }


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

}

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.takePicture(null, null, imageCallback);
    }

}

Answer 1

試試下面的代碼，它可能對您有幫助

首先使用所需的高度和寬度轉換圖像

public static Bitmap scaleImage(String p_path, int p_reqHeight, int p_reqWidth) throws Throwable
{
    Bitmap m_bitMap = null;
    System.gc();
    File m_file = new File(p_path);
    if (m_file.exists())
    {
        BitmapFactory.Options m_bitMapFactoryOptions = new BitmapFactory.Options();
        m_bitMapFactoryOptions.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(m_file.getPath(), m_bitMapFactoryOptions);
        m_bitMapFactoryOptions.inSampleSize = calculateInSampleSize(m_bitMapFactoryOptions, p_reqHeight, p_reqWidth);
        m_bitMapFactoryOptions.inJustDecodeBounds = false;
        m_bitMap = BitmapFactory.decodeFile(m_file.getPath(), m_bitMapFactoryOptions);
    }
    else
    {
        throw new Throwable(p_path + " not found or not a valid image");
    }
    return m_bitMap;
}


private static int calculateInSampleSize(BitmapFactory.Options p_options, int p_reqWidth, int p_reqHeight)
{
    // Raw height and width of image
    final int m_height = p_options.outHeight;
    final int m_width = p_options.outWidth;
    int m_inSampleSize = 1;
    if (m_height > p_reqHeight || m_width > p_reqWidth)
    {
        final int m_halfHeight = m_height / 2;
        final int m_halfWidth = m_width / 2;
        // Calculate the largest inSampleSize value that is a power of 2 and keeps both
        // height and width larger than the requested height and width.
        while ((m_halfHeight / m_inSampleSize) > p_reqHeight && (m_halfWidth / m_inSampleSize) > p_reqWidth)
        {
            m_inSampleSize *= 2;
        }
    }
    return m_inSampleSize;
}

Answer 2

寫入數據后使用FileOutputStream.flush（）...

File file = new File(fileName.toString());
try {
    FileOutputStream stream = new FileOutputStream(file);
    bitmap.compress(CompressFormat.PNG, 100, stream);
    stream.flush();
    stream.close();
} catch (Exception e) {
    // TODO: handle exception
}

您可以保存以下代碼的位圖圖像

Bitmap photo = (Bitmap) "your Bitmap image";
photo = Bitmap.createScaledBitmap(photo, 100, 100, false);
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
photo.compress(Bitmap.CompressFormat.JPEG, 40, bytes);

File f = new File(Environment.getExternalStorageDirectory()
        + File.separator + "Imagename.jpg");
f.createNewFile();
FileOutputStream fo = new FileOutputStream(f);
fo.write(bytes.toByteArray());
fo.close();