Mask off features with those from a second, masking, McFeatures.

None  

object.MaskOff varMcFeaturesSrc

The MaskOff Method syntax has these parts:

The resulting features are those from the original state minus whatever features of the masking features that overlap. The masking source McFeatures is not affected.

This method behaves differently depending on the McFeatures type and state. For McPoints, McLines and McRegions with the mcofKeepRegionsAsUnion OptionFlags off, features that are identical to ones in the subtracted McFeatures are removed; source features that have no match are ignored. In this mode, the source McFeatures must be of the same type (McPoints, McLines or McRegions) as this one.

For McRegions with the mcofKeepRegionsAsUnion OptionFlags on, any McFeatures type may be used as a source. Each pixel overlapping one from the masking source McFeatures, treated as a scan list, is set off. This is useful for creating torrus shaped regions for example (a smaller circular region masking a larger one), or creating a region that's the “outside” of another one (by masking off a rectangular region with the one you want the “outside” of). Or if one subtracts an McLines from an McRegions, one could “split” regions by masking with a line bisecting the region. New Identifiers are assigned to the resulting connected regions.