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Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" Math::Polygon::Calc \- Simple polygon calculations .SH "INHERITANCE" .IX Header "INHERITANCE" .Vb 2 \& Math::Polygon::Calc \& is a Exporter .Ve .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 1 \& my @poly = ( [1,2], [2,4], [5,7], [1, 2] ); \& \& my ($xmin, $ymin, $xmax, $ymax) = polygon_bbox @poly; \& \& my $area = polygon_area @poly; \& MY $L = polygon_perimeter @poly; \& if(polygon_is_clockwise @poly) { ... }; \& \& my @rot = polygon_start_minxy @poly; .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" This package contains a wide variaty of relatively easy polygon calculations. More complex calculations are put in separate packages. .SH "FUNCTIONS" .IX Header "FUNCTIONS" .IP "\fBpolygon_area\fR(LIST\-of\-$points)" 4 .IX Item "polygon_area(LIST-of-$points)" Returns the area enclosed by the polygon. The last point of the list must be the same as the first to produce a correct result. .Sp The algorithm was found at , and sounds: .Sp .Vb 1 \& A = abs( 1/2 * (x1y2\-x2y1 + x2y3\-x3y2 ...) .Ve .IP "\fBpolygon_bbox\fR(LIST\-of\-$points)" 4 .IX Item "polygon_bbox(LIST-of-$points)" Returns a list with four elements: (xmin, ymin, xmax, ymax), which describe the bounding box of the polygon (all points of the polygon are within that area. .IP "\fBpolygon_beautify\fR([\s-1HASH\s0], LIST\-of\-$points)" 4 .IX Item "polygon_beautify([HASH], LIST-of-$points)" Polygons, certainly after some computations, can have a lot of horrible artifacts: points which are double, spikes, etc. This functions provided by this module beautify The optional \s-1HASH\s0 contains the \s-1OPTIONS:\s0 .Sp .Vb 3 \& \-Option \-\-Default \& remove_between \& remove_spikes .Ve .RS 4 .IP "remove_between => \s-1BOOLEAN\s0" 2 .IX Item "remove_between => BOOLEAN" Simple points in-between are always removed, but more complex points are not: when the line is not parallel to one of the axes, more intensive calculations must take place. This will only be done when this flags is set. \&\s-1NOT IMPLEMENTED YET\s0 .IP "remove_spikes => \s-1BOOLEAN\s0" 2 .IX Item "remove_spikes => BOOLEAN" .RE .RS 4 .RE .PD 0 .IP "\fBpolygon_centroid\fR(LIST\-of\-$points)" 4 .IX Item "polygon_centroid(LIST-of-$points)" .PD Returns the centroid location of the polygon. The last point of the list must be the same as the first to produce a correct result. .Sp The algorithm was found at \&\fIhttp://en.wikipedia.org/wiki/Centroid#Centroid_of_polygon\fR .IP "\fBpolygon_clockwise\fR(LIST\-of\-$points)" 4 .IX Item "polygon_clockwise(LIST-of-$points)" Be sure the polygon points are in clockwise order. .IP "\fBpolygon_contains_point\fR($point, LIST\-of\-$points)" 4 .IX Item "polygon_contains_point($point, LIST-of-$points)" Returns true if the point is unside the closed polygon. .IP "\fBpolygon_counter_clockwise\fR(LIST\-of\-$points)" 4 .IX Item "polygon_counter_clockwise(LIST-of-$points)" Be sure the polygon points are in counter-clockwise order. .IP "\fBpolygon_equal\fR(ARRAY\-of\-$points, ARRAY\-of\-$points, [$tolerance])" 4 .IX Item "polygon_equal(ARRAY-of-$points, ARRAY-of-$points, [$tolerance])" Compare two polygons, on the level of points. When the polygons are the same but rotated, this will return false. See \fIpolygon_same()\fR. .IP "\fBpolygon_is_clockwise\fR(LIST\-of\-$points)" 4 .IX Item "polygon_is_clockwise(LIST-of-$points)" .PD 0 .IP "\fBpolygon_is_closed\fR($points)" 4 .IX Item "polygon_is_closed($points)" .IP "\fBpolygon_perimeter\fR(LIST\-of\-$points)" 4 .IX Item "polygon_perimeter(LIST-of-$points)" .PD The length of the line of the polygon. This can also be used to compute the length of any line: of the last point is not equal to the first, then a line is presumed; for a polygon they must match. .Sp This is simply Pythagoras. .Sp .Vb 1 \& $l = sqrt((x1\-x0)^2 + (y1\-y0)^2) + sqrt((x2\-x1)^2+(y2\-y1)^2) + ... .Ve .IP "\fBpolygon_same\fR(ARRAY\-of\-$points, ARRAY\-of\-$points, [$tolerance])" 4 .IX Item "polygon_same(ARRAY-of-$points, ARRAY-of-$points, [$tolerance])" Compare two polygons, where the polygons may be rotated wrt each other. This is (much) slower than \fIpolygon_equal()\fR, but some algorithms will cause un unpredictable rotation in the result. .IP "\fBpolygon_start_minxy\fR(LIST\-of\-$points)" 4 .IX Item "polygon_start_minxy(LIST-of-$points)" Returns the polygon, where the point which is closest to the left-bottom corner of the bounding box is made first. .IP "\fBpolygon_string\fR(LIST\-of\-$points)" 4 .IX Item "polygon_string(LIST-of-$points)" .SH "SEE ALSO" .IX Header "SEE ALSO" This module is part of Math-Polygon distribution version 1.03, built on January 21, 2014. Website: \fIhttp://perl.overmeer.net/geo/\fR .SH "LICENSE" .IX Header "LICENSE" Copyrights 2004,2006\-2014 by [Mark Overmeer]. For other contributors see ChangeLog. .PP This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See \fIhttp://www.perl.com/perl/misc/Artistic.html\fR