Programmer Guide/Command Reference/EVAL/pgiline

Find all intersections of a line, defined by two points, with a polygon.

Usage

pgiline(X, IX, PX1scalar, PY1scalar), PX2scalar, PY2scalar)

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)

PX1, PY1, PX2, PY2

The points <PX1,PY1> and <PX2,PY2> defining the line to be tested.

Result

The result r is a Nx3 matrix. Each row of the matrix contains the coordinates of a point of the line and its state.

i	r[i,0], r[i,1]	r[i,2]
0	start point of the line	0 if the start point is outside XIX 1 if the start point is inside XIX
1 .. N-2	intersection point	0 if the line leaves XIX 1 if the line enters XIX
N-1	end point of the line	0 if the end point is outside XIX 1 if the end point is inside XIX

See also

pginit, pgget, pgitest, pgxgrid, pgsplit, pgtrans, pghull

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