def yLP2DP(lpY, lptLT, lPix = 1.0):
    """Convert logical coordinates into device coordinates
        lpY   - y logical coordinate
        lptLT - logical coordinates of left top screen corner
        lPix  - zoom value, number of logical points inside one device point (aka pixel)
        return coordinate in device coordinates
    """
    return (lptLT.y - lpY) / lPix