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math::polygon::surface(3pm) [debian man page]

Math::Polygon::Surface(3pm)				User Contributed Perl Documentation			       Math::Polygon::Surface(3pm)

NAME

       Math::Polygon::Surface - Polygon with exclusions

SYNOPSIS

	my $outer   = Math::Polygon->new( [1,2], [2,4], [5,7], [1,2] );
	my $surface = Math::Polygon::Surface->new($outer);

DESCRIPTION

       A surface is one polygon which represents the outer bounds of an array, plus optionally a list of polygons which represent exclusions from
       that outer polygon.

METHODS

   Constructors
       $obj->new([OPTIONS], [POLYGONS], [OPTIONS])
       Math::Polygon::Surface->new([OPTIONS], [POLYGONS], [OPTIONS])
	   You may add OPTIONS after and/or before the POLYGONS.  You may also use the "outer" and "inner" options.  POLYGONS are references to
	   ARRAYs of points, each an ARRAY of X and Y, but better instantiated Math::Polygon objects.

	    -Option--Default
	     inner   []
	     outer   undef

	   inner => ARRAY-OF-POLYGONS
	     The inner polygons, zero or more Math::Polygon objects.

	   outer => POLYGON
	     The outer polygon, a Math::Polygon.

   Attributes
       $obj->inner
	   Returns a list (often empty) of inner polygons.

       $obj->outer
	   Returns the outer polygon.

   Simple calculations
       area
	   Returns the area enclosed by the outer polygon, minus the areas of the inner polygons.  See method Math::Polygon::area().

       $obj->bbox
	   Returns a list with four elements: (xmin, ymin, xmax, ymax), which describe the bounding box of the surface, which is the bbox of the
	   outer polygon.  See method Math::Polygon::bbox().

       $obj->perimeter
	   The length of the border: sums outer and inner perimeters.  See method Math::Polygon::perimeter().

   Clipping
       $obj->fillClip1(BOX)
	   Clipping a polygon into rectangles can be done in various ways.  With this algorithm, the parts of the polygon which are outside the
	   BOX are mapped on the borders.

	   All polygons are treated separately.

       $obj->lineClip(BOX)
	   Returned is a list of ARRAYS-OF-POINTS containing line pieces from the input surface.  Lines from outer and inner polygons are
	   undistinguishable.  See method Math::Polygon::lineClip().

       $obj->string
	   Translate the surface structure into some string.  Use Geo::WKT if you need a standardized format.

	   Returned is a single string possibly containing multiple lines.  The first line is the outer, the other lines represent the inner
	   polygons.

DIAGNOSTICS

       Error: surface requires outer polygon

SEE ALSO

       This module is part of Math-Polygon distribution version 1.02, built on September 19, 2011. Website: http://perl.overmeer.net/geo/

LICENSE

       Copyrights 2004,2006-2011 by Mark Overmeer. For other contributors see ChangeLog.

       This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.  See
       http://www.perl.com/perl/misc/Artistic.html

perl v5.12.4							    2011-09-19					       Math::Polygon::Surface(3pm)

Check Out this Related Man Page

Math::Polygon::Clip(3pm)				User Contributed Perl Documentation				  Math::Polygon::Clip(3pm)

NAME

       Math::Polygon::Clip - frame a polygon in a square

INHERITANCE

	Math::Polygon::Clip
	  is a Exporter

SYNOPSIS

	my @poly  = ( [1,2], [2,4], [5,7], [1, 2] );
	my @box   = ( $xmin, $ymin, $xmax, $ymax );

	my $boxed = polygon_clip @box, @poly;

DESCRIPTION

       Cut-off all parts of the polygon which are outside the box

FUNCTIONS

       polygon_fill_clip1(ARRAY-BOX, LIST-OF-POINTS)
	   Clipping a polygon into rectangles can be done in various ways.  With this algorithm (which I designed myself, but may not be new), the
	   parts of the polygon which are outside the BOX are mapped on the borders.  The polygon stays in one piece.

	   Returned is one list of points, which is cleaned from double points, spikes and superfluous intermediate points.

       polygon_fill_clip2(ARRAY-BOX, LIST-OF-POINTS)
	   To be implemented.  The polygon falls apart in fragments, which are not connected: paths which are followed in two directions are
	   removed.  This is required by some applications, like polygons used in geographical context (country contours and such).

       polygon_fill_clip3(ARRAY-BOX, OUT-POLY, [IN-POLYS])
	   To be implemented.  A surrounding polygon, with possible inclussions.

       polygon_line_clip(ARRAY-BOX, LIST-OF-POINTS)
	   Returned is a list of ARRAYS (possibly 0 long) containing line pieces from the input polygon (or line).

	   example:

	    my @points = ( [1,2], [2,3], [2,0], [1,-1], [1,2] );
	    my @bbox   = ( 0, -2, 2, 2 );
	    my @l      = polygon_line_clip @bbox, @points;
	    print scalar @l;	  # 1, only one piece found
	    my @first = @{$l[0]}; # first is [2,0], [1,-1], [1,2]

SEE ALSO

       This module is part of Math-Polygon distribution version 1.02, built on September 19, 2011. Website: http://perl.overmeer.net/geo/

LICENSE

       Copyrights 2004,2006-2011 by Mark Overmeer. For other contributors see ChangeLog.

       This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.  See
       http://www.perl.com/perl/misc/Artistic.html

perl v5.12.4							    2011-09-19						  Math::Polygon::Clip(3pm)
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