Programmer Guide/Command Reference/EVAL/pgiline: Difference between revisions
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{{DISPLAYTITLE:{{SUBPAGENAME}}}} | {{DISPLAYTITLE:{{SUBPAGENAME}}}} | ||
Find all intersections of a line, defined by | Find all intersections of a line, defined by two points, with a polygon. | ||
;Usage: | ;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> | :<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>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>: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 | :;<var>PX1, PY1, PX2, PY2</var>: The points <''PX1'',''PY1''> and <''PX2'',''PY2''> defining the line to be tested. | ||
;Result | ;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. | ||
::{|class="einrahmen" | ::{|class="einrahmen" | ||
! i !! ''r''[i,0], ''r''[i,1] !! ''r''[i,2] | ! i !! ''r''[i,0], ''r''[i,1] !! ''r''[i,2] | ||
| Line 22: | Line 22: | ||
|0 if the end point is outside ''X<sub>IX</sub>''<BR>1 if the end point is inside ''X<sub>IX</sub>'' | |0 if the end point is outside ''X<sub>IX</sub>''<BR>1 if the end point is inside ''X<sub>IX</sub>'' | ||
|} | |} | ||
;See also: [[../pginit|pginit]], [[../pgget|pgget]], [[../ | ;See also: [[../pginit|pginit]], [[../pgget|pgget]], [[../pgitest|pgitest]], [[../pgxgrid|pgxgrid]], [[../pgsplit|pgsplit]], [[../pgtrans|pgtrans]], [[../pghull|pghull]] | ||
[[../#Functions|<function list>]] | [[../#Functions|<function list>]] | ||
Latest revision as of 20:11, 21 April 2011
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 XIX1 .. N-2 intersection point 0 if the line leaves XIX
1 if the line enters XIXN-1 end point of the line 0 if the end point is outside XIX
1 if the end point is inside XIX
