Code example for Camera.Area

        int previewHeight = mPreviewFrame.getHeight();
        if (mFocusArea == null) {
            mFocusArea = new ArrayList<Area>();
            mFocusArea.add(new Area(new Rect(), 1));
            mMeteringArea = new ArrayList<Area>();
            mMeteringArea.add(new Area(new Rect(), 1));
        // Convert the coordinates to driver format. 
        // AE area is bigger because exposure is sensitive and 
        // easy to over- or underexposure if area is too small. 
        calculateTapArea(focusWidth, focusHeight, 1f, x, y, previewWidth, previewHeight,
        calculateTapArea(focusWidth, focusHeight, 1.5f, x, y, previewWidth, previewHeight,
        // Use margin to set the focus indicator to the touched area. 
        RelativeLayout.LayoutParams p =
                (RelativeLayout.LayoutParams) mFocusIndicatorRotateLayout.getLayoutParams();
        int left = Util.clamp(x - focusWidth / 2, 0, previewWidth - focusWidth);