Programmer Guide/Command Reference/EVAL/pgiline: Difference between revisions

Revision as of 08:30, 20 April 2011

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

Usage

pgiline(X, IX, PX1_scalar, PY1_scalar), PX2_scalar, PY2_scalar)

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 point <PX1,PY1> and <PX2,PY2> defining 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.

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

@@ Line 1: / Line 1: @@
 {{DISPLAYTITLE:{{SUBPAGENAME}}}}
-Find all intersections of a line, defined by the starting and the ending point, with the polygon ''x''.
+Find all intersections of a line, defined by two points, with a polygon.
 ;Usage:
 :<code>pgiline(<var>X</var>, <var>IX</var>, <var>PX1<sub>scalar</sub></var>, <var>PY1<sub>scalar</sub></var>), <var>PX2<sub>scalar</sub></var>, <var>PY2<sub>scalar</sub></var>)</code>
 :;<var>X</var>:a [[../#polygons|closed point-list]] or a [[../#polygons|polygon-stream]] defining one or more polygons.
 :;<var>IX</var>:The index of the polygon of ''X'' to be tested; 0 <= <var>IX</var> < <code>[[../pgget|pgget]](''X'')</code>
-:;<var>PX1, PY1, PX2, PY2</var>: The start point <''PX1'',''PY1''> and the end point <''PX2'',''PY2''> of the line to be tested.
+:;<var>PX1, PY1, PX2, PY2</var>: The point <''PX1'',''PY1''> and <''PX2'',''PY2''> defining 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"