ZBar Camera Preview Stretched Android

Question

I am using Zbar to scan the QRCodes in landscape mode. I have a FrameLayout in xml which is nested in RelativeLayout and FrameLayout size is 300dp X 200dp. I have been googling for two says and almost read all the stackoverflow threads regarding this issue. but nothing seems to work for me.

Here is my code.

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
    private SurfaceHolder mHolder;
    private Camera mCamera;
    private PreviewCallback previewCallback;
    private AutoFocusCallback autoFocusCallback;

    public CameraPreview(Context context, Camera camera,
                         PreviewCallback previewCb,
                         AutoFocusCallback autoFocusCb) {
        super(context);


        mCamera = camera;
        previewCallback = previewCb;
        autoFocusCallback = autoFocusCb;

        /* 
         * Set camera to continuous focus if supported, otherwise use
         * software auto-focus. Only works for API level >=9.
         */
        /*
        Camera.Parameters parameters = camera.getParameters();
        for (String f : parameters.getSupportedFocusModes()) {
            if (f == Parameters.FOCUS_MODE_CONTINUOUS_PICTURE) {
                mCamera.setFocusMode(Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
                autoFocusCallback = null;
                break;
            }
        }
        */

        // Install a SurfaceHolder.Callback so we get notified when the
        // underlying surface is created and destroyed.
        mHolder = getHolder();
        mHolder.addCallback(this);

        // deprecated setting, but required on Android versions prior to 3.0
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // The Surface has been created, now tell the camera where to draw the preview.
        try {
            if(holder != null)
            {
                mCamera.setPreviewDisplay(holder);
                Camera.Parameters parameters = mCamera.getParameters();
                List<Size> sizes = parameters.getSupportedPictureSizes();
                parameters.setPictureSize(sizes.get(0).width, sizes.get(0).height); // mac dinh solution 0
                parameters.set("orientation","landscape");
                //parameters.setPreviewSize(viewWidth, viewHeight);
                List<Size> size = parameters.getSupportedPreviewSizes();
                parameters.setPreviewSize(size.get(0).width, size.get(0).height);
                mCamera.setParameters(parameters);
            }
        } catch (IOException e) {
            Log.d("DBG", "Error setting camera preview: " + e.getMessage());
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // Camera preview released in activity
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        /*
         * If your preview can change or rotate, take care of those events here.
         * Make sure to stop the preview before resizing or reformatting it.
         */
        if (mHolder.getSurface() == null){
          // preview surface does not exist
          return;
        }

        // stop preview before making changes
        try {
            mCamera.stopPreview();
        } catch (Exception e){
          // ignore: tried to stop a non-existent preview
        }

        try {
            // Hard code camera surface rotation 90 degs to match Activity view in portrait
            mCamera.setDisplayOrientation(0);

            mCamera.setPreviewDisplay(mHolder);
            mCamera.setPreviewCallback(previewCallback);
            mCamera.startPreview();
            mCamera.autoFocus(autoFocusCallback);
        } catch (Exception e){
            Log.d("DBG", "Error starting camera preview: " + e.getMessage());
        }
    }



}

Any help will be highly appreciated.

Thanks

Answer 1

The aspect ratio of your surface (300dp X 200dp) seems not to match that one of your camera previewSize. First determine the aspect ratio of your previewSize ( parameters.getPreviewSize() ) and then set the size of your surface to the same aspect ratio. When the aspect ratios are nearly the same, then the streching should be gone. Hope that helps!

Answer 2

ali's right. You can find my code here which is based on Ali's solution.