Yesterday, Google offered Google Glass the newest ROM (XE16). Before the update, I used zxing to scan a QRcode, and this method was feasible, although it didn't have an autofocus function. I changed camera's ZOOM to enlarge the size of the QRcode so that the camera could see clearly the small QRcode.:
parameters.set("zoom", String.valueOf(tenDesiredZoom / 10.0));
Now, the app can't enlarge the size of the QRcode, regardless of what I set ZOOM at.
