Programmer Guide/Command Reference/EVAL/pgiline

Find all intersections of a line, defined by the starting and the ending point, with the polygon x.

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 start point <PX1,PY1> and the end point <PX2,PY2> of the line to be tested.

Result 3

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

{class="einrahmen"

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

See also

pginit, pgget, pgiline, pgxgrid, pgsplit, pgtrans, pghull

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