Bitmap Pan Zoom and Crop, How to crop image?

Question

I have an imageview with a touch listener, and I am able to capture all touch inputs into a matrix, and apply that matrix to the imageview where the image pans and zooms appropriately.

My problem: I'd now like to CROP the image in such a way that it ALWAYS ends up the same size of what image i choose in the gallery.

In other words, suppose I have a 512x512 square in the middle of my screen, a user pans and zooms an image until an item of interest fits into that square, and click "done". I would like to have a resulting image that has cropped the photo which contained in the imageview.

this is my Code:

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.customizeimage);

    // imagview = (ImageView) findViewById(R.id.imageView1);
    button = (Button) findViewById(R.id.button1);

    button.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            // To open up a gallery browser
            Intent intent = new Intent();
            intent.setType("image/*");
            intent.setAction(Intent.ACTION_GET_CONTENT);
            startActivityForResult(
                    Intent.createChooser(intent, "Select Picture"), 1);
        }
    });
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    // TODO Auto-generated method stub
    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode == RESULT_OK) {
        if (requestCode == 1) {

            //this is where the image pan and zoom
            final ImageView imageView = (ImageView) findViewById(R.id.imageGet);
            imageView.setOnTouchListener(new OnTouch());

             // currImageURI is the global variable I'm using to hold the
            // content:// URI of the image

            currImageURI = data.getData();
            // String selectedImagePath=getRealPathFromURI(currImageURI);
            imageView.setImageURI(currImageURI);
            Log.e("" + getRealPathFromURI(GalleryImage.this, currImageURI),
                    "" + getImagePath(currImageURI));
        }
    }
}