裁剪图像ala Google护目镜

@Override
public boolean onTouchEvent(MotionEvent me) {
    if(SETTING_ROI == true){
        if (me.getAction() == MotionEvent.ACTION_DOWN) {
            START_DRAGGING = true;
            myView.selectCorner((int) me.getRawX(), (int) me.getRawY()); // selecst nearest corner
        }
        if (me.getAction() == MotionEvent.ACTION_MOVE){
            Log.d(TAG, \"ACTION_MOVE\");
            myView.moveCorner((int) me.getRawX(), (int) me.getRawY()); // move selected corner continuously
        }
        if (me.getAction() == MotionEvent.ACTION_UP){
            if (START_DRAGGING == true) {
                START_DRAGGING = false;
                myView.moveCorner((int) me.getRawX(), (int) me.getRawY()); // final selected corner move
            }
        }
    }
    return false;
}