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 the starting and the ending point, with the polygon ''x''. | |||
;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>PX1, PY1, PX2, PY2</var>: The start point <''PX1'',''PY1''> and the end point <''PX2'',''PY2''> of the line ''P'' to be tested. | ||
;Result 3: The result ''r'' is a scalar. | |||
::{|class="keinrahmen" | |||
|''r''='''0''' || ... the line ''P'' is outside the polygon ''X<sub>IX</sub>'' | |||
|- | |||
|''r''='''1''' || ... the line ''P'' is inside the polygon ''X<sub>IX</sub>'' | |||
|- | |||
|''r''='''2''' || ... the line ''P'' intersects the polygon ''X<sub>IX</sub>'' | |||
|} | |||
---- | |||
;Usage 4: | |||
:<code>pgitest(<var>X</var>, <var>IX</var>, <var>P</var>, <var>IP</var>)</code> | |||
:;<var>P</var>:a [[../#polygons|closed point-list]] or a [[../#polygons|polygon-stream]] defining one or more polygons. | |||
:;<var>IP</var>:The index of the polygon of ''P'' to be tested; 0 <= <var>IP</var> < <code>[[../pgget|pgget]](''P'')</code>) | |||
;Result 4: The result ''r'' is a scalar. | |||
::{|class="keinrahmen" | |||
|''r''='''0''' || ... the polygon ''P<sub>IP</sub>'' is outside the polygon ''X<sub>IX</sub>'' | |||
|- | |||
|''r''='''1''' || ... the polygon ''P<sub>IP</sub>'' is included in the polygon ''X<sub>IX</sub>'' | |||
|- | |||
|''r''='''2''' || ... the polygons ''P<sub>IP</sub>'' and ''X<sub>IX</sub>'' are partly overlapping | |||
|- | |||
|''r''='''3''' || ... the polygon ''X<sub>IX</sub>'' is included in the polygon ''P<sub>IP</sub>'' | |||
|} | |||
---- | |||
;See also: [[../pginit|pginit]], [[../pgget|pgget]], [[../pgiline|pgiline]], [[../pgxgrid|pgxgrid]], [[../pgsplit|pgsplit]], [[../pgtrans|pgtrans]], [[../pghull|pghull]] | |||
[[../#Functions|<function list>]] | |||
;<var>X2, Y2</var> | ;<var>X2, Y2</var> | ||
Revision as of 08:15, 20 April 2011
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)
- PX1, PY1, PX2, PY2
- The start point <PX1,PY1> and the end point <PX2,PY2> of the line P to be tested.
- Result 3
- The result r is a scalar.
r=0 ... the line P is outside the polygon XIX r=1 ... the line P is inside the polygon XIX r=2 ... the line P intersects the polygon XIX
- Usage 4
pgitest(X, IX, P, IP)- P
- a closed point-list or a polygon-stream defining one or more polygons.
- IP
- The index of the polygon of P to be tested; 0 <= IP <
pgget(P))
- Result 4
- The result r is a scalar.
r=0 ... the polygon PIP is outside the polygon XIX r=1 ... the polygon PIP is included in the polygon XIX r=2 ... the polygons PIP and XIX are partly overlapping r=3 ... the polygon XIX is included in the polygon PIP
- X2, Y2
- The x/y coordinate of the last point in the line.
Result:
Detect intersections of the line <X1,Y1>..<X2,Y2> and the polygon XS[IX].
The result IS is an "N x 3" matrix:
row 0: col0,col1 x and y of start-point
col2 0 if start-point outside and 1 if start-point inside the polygon
...
row i: col0,col1 x and y of intersection point i (i = 1 .. N-2)
col2 0 if the line leaves and 1 if the line enters the polygon
...
row N-1: col0,col1 x and y of end-point
col2 0 if end-point outside and 1 if end-point inside the polygon
