如何在相机应用程序中将原始字节 [] 转换为位图

Question

This is the picture taking fuction

class Camera {
...

void capturePicture() {
    Camera.Size size = mParams.getPictureSize();
    int bitsPerPixel = ImageFormat.getBitsPerPixel(mParams.getPictureFormat());
    int bufferSize = (int) Math.ceil(size.width * size.height * bitsPerPixel / 8d) ;
    Log.d(TAG, "Picture Size : " + size.width + "\t" + size.height);
    Log.d(TAG, "Picture format : " + mParams.getPictureFormat());
    Log.d(TAG, "Bits per Pixel = " + bitsPerPixel);
    Log.d(TAG, "Buffer Size = " + bufferSize);
    byte[] buffer = new byte[1382400];
    addBuffer(buffer);
    Camera.ShutterCallback shutterCallback = () -> mCameraCallbacks.onShutter();
    Camera.PictureCallback pictureCallback = (data, camera) -> {
        mCameraControllerCallbacks.onPicture(data);
        };
    mCamera.takePicture(shutterCallback, pictureCallback, null, null);
}

public interface CameraCallbacks {
    void onPicture(byte[] bytes);
}

The the picture size should be 3264 x 2448 however the bitsPerPixel returns -1 so I can't use it to calculate. It turn out the minimum buffer size is 1382400 I don't know why.

Here is the Activity receives the callback

public class CameraActivity extends AppCompatActivity implements Camera.CameraCallbacks

    @Override
public void onPicture(byte[] bytes) {

    final ByteBuffer buffer = ByteBuffer.wrap(bytes).order(ByteOrder.LITTLE_ENDIAN);
    final int[] ints = new int[bytes.length / 4];
    buffer.asIntBuffer().put(ints);
    Log.d(TAG,"Creating Bitmap of Size : "+mCameraView.mPictureSize.width +" x "+mCameraView.mPictureSize.height);
    Bitmap bitmap = Bitmap.createBitmap(ints, mCameraView.mPictureSize.width, mCameraView.mPictureSize.height, Bitmap.Config.ARGB_8888);
    Intent intent = new Intent(CameraActivity.this, PicturePreviewActivity.class);
    intent.putExtra("bitmap", bmp);
    startActivityForResult(intent, SAVE_PICTURE_OR_NOT);

}

The code here is obviously wrong and I am having trouble rearrange these byte[] into ints[] the way bitmap accepts because I don't know the data structure inside these bytes.
Also BitmapFactory.decodeByteArray won't work because it can't read raw data.

Can anybody help me on this one?

Answer 1

It is not possible to retrieve uncompressed bitmap data from android camera, so the picture call back need to move from RawCallback to JpegCallback and use decodeByteArray() to obtain Bitmap.Also it is unreliable to pass Bitmap through Intent So the simplest way is to write to the receiving Activity directly.The Code became like this:

    @Override
public void onPicture(byte[] bytes) {
        Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, mJpeg.get().length,null);
        PicturePreviewActivity.mBitmap=new WeakReference<>(bitmap);
        Intent intent = new Intent(CameraActivity.this, PicturePreviewActivity.class);
        startActivityForResult(intent, SAVE_PICTURE_OR_NOT);
    }
}