Locking Parts of an Instrument

    lock(<x>,<y>)
    lockLeft()
    lockRight()
    lockTop()
    lockBottom()
    lockEnds()
    lockCorners()
    lockPerimeter()

The lock method locks the single cell which is nearest to the (<x>,<y>) position specified in instrument coordinates (see section *).

The lockLeft, lockRight, lockTop and lockBottom methods each lock the cells at one extremity of an instrument. For rectangular sheets the behaviour is obvious, but for other instruments some clarification is needed. For strings, only the lockLeft and lockright methods are appropriate. For circular and elliptical sheets only a few cells at the edges of the sheet will be locked by each method.

The lockEnds method is equivalent to issuing a lockLeft and lockRight together and is used mostly with strings.

Finally the lockCorners is only appropriate for rectangular sheets and the lockPerimeter is appropriate for all instruments except strings.