关于IEnvelop的说明--思思的奔驰车队

关于IEnvelop的说明

IEnvelop返回包含Geometry的矩形，注意IPoint类型返回为0。

对于IEnvelop。 Expand ( double dx, double dy, bool asRatio);

dx is a parameter of type double

dy is a parameter of type double

asRatio

asRatio is a parameter of type VARIANT_BOOL

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.

Expand scales the size of the Envelope. If asRatio = FALSE, the expansion is additive.

XMin = XMin - dx
YMin = YMin - dy
XMax = XMax + dx
YMax = YMax + dy

If asRatio = TRUE, the expansion is multiplicative.

XMin = (XMin - dx*Width)/2
YMin = (YMin - dy*Height)/2 
XMax = (XMax + dx*Width)/2
YMax = (YMax + dy*Height)/2

The Envelope remains centered at the same position.

Post by sisi 发表于 2007-6-20 13:31:00

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