pghull

Calculate the hull polygon of two polygons.

Usage

pghull(X, IX, Y, IY)

X

a closed point-list or a polygon-stream defining one or more polygons.

IX

The index of the polygon of X to be tested; 0 <= IX < pgget(X)

DX, DY

shift values for x and y (default=0, no shift)

• shift the center point <xc,yc> of X_IX

<x[i] , y[i]> -> <x[i]+DX , y[i]+DY>

KX, KY

scaling factors; both factors must be greater than zero (default=1, no scaling)

• scale the distances of corners of X_IX to the center point

<x[i] , y[i]> -> <(x[i]-xc)*KX+xc , (y[i]-yc)*KY'+yc>

A

rotation angle in degree (default=0, no rotation); a scaling factors (default=1)

• rotate the polygon around the center point

Result

The result r is a polygon-stream containing the transformed X_IX.

See also

pginit, pgget, pgitest, pgiline, pgxgrid, pgsplit, pghull

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