ClipPolyline -object study

[Pertti Paasky]

Hi all Polygon Operation masters.
I tried GDL to Clip a polyline with another polyline but failed, Polyline offset works fine yet. Some other options also failed, please check the attacment.
This function is great, but I can´t get it work.

[NBGheikki]

The problem is that you forgot to differentiate between polylines and polygons. The calls that save them should go something like this:

PREPAREFUNCTION ch, "StorePolyline", "polyline1", nVertices4,vertArr4,defaultInhEdgeInfo, inhEdgeInfos
dim cont1[]
cont1[1]=vardim1(vertArr)  ! points to the last vertex of the contour
! Store = Store _polygon_
PREPAREFUNCTION ch, "Store", "poly1", nVertices,1,vertArr,cont1 

Similarly you need two versions of "draw respolyarr" - one that draws polylines that OffsetPolyline and ClipPolyline produce (with GetPolylineVertices), and another to draw the polygons that PolyCut and CopyPolygon produce:

! GetVertices = Get _polygon_ vertices
nVertices = CALLFUNCTION (ch, "GetVertices", polylineID, resPolylineVertices) 

Polygon Operations sure is full of gotchas...