This attribute specifies the centre of the pincushion/barrel distortion implemented by a PcdMap. It takes a separate value for each axis of the PcdMap so that, for instance, the settings " PcdCen(1)=345.0,PcdCen(2)=-104.4" specify that the pincushion distortion is centred at positions of 345.0 and -104.4 on axes 1 and 2 respectively. This attribute is set when a PcdMap is created, but may later be modified. If the attribute is cleared, the default value for both axes is zero.

Note, the value of this attribute may changed only if the PcdMap has no more than one reference. That is, an error is reported if the PcdMap has been cloned, either by including it within another object such as a CmpMap or FrameSet or by calling the AST_CLONE function.

PcdMap

• If no axis is specified, (e.g. " PcdCen" instead of " PcdCen(2)" ), then a " set" or " clear" operation will affect the attribute value of both axes, while a " get" or " test" operation will use just the PcdCen(1) value.