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

NAME

       Math::Polygon::Transform - Polygon transformation

INHERITANCE

	Math::Polygon::Transform
	  is a Exporter

SYNOPSIS

	my @poly = ( [1,2], [2,4], [5,7], [1, 2] );

	my $area = polygon_transform resize => 3.14, @poly;

DESCRIPTION

       This package contains polygon transformation algorithms.

FUNCTIONS

       polygon_grid(OPTIONS, LIST-OF-POINTS)
	   Snap the polygon points to grid points, where artifacts are removed.

	    -Option--Default
	     raster  1.0

	   raster => FLOAT
	     The raster size, which determines the points to round to.	The origin "[0,0]" is always on a grid-point.  When the raster value is
	     zero, no transformation will take place.

       polygon_mirror(OPTIONS, LIST-OF-POINTS)
	   Mirror the polygon in a line.  Only one of the options can be provided.  Some programs call this "flip" or "flop".

	    -Option--Default
	     b	     0
	     line    <undef>
	     rc      undef
	     x	     undef
	     y	     undef

	   b => FLOAT
	     Only used in combination with option "rc" to describe a line.

	   line => [POINT, POINT]
	     Alternative way to specify the mirror line.  The "rc" and "b" are computed from the two points of the line.

	   rc => FLOAT
	     Description of the line which is used to mirror in. The line is "y= rc*x+b".  The "rc" equals "-dy/dx", the firing angle.	If "undef"
	     is explicitly specified then "b" is used as constant x: it's a vertical mirror.

	   x => FLOAT
	     Mirror in the line "x=value", which means that "y" stays unchanged.

	   y => FLOAT
	     Mirror in the line "y=value", which means that "x" stays unchanged.

       polygon_move(OPTIONS, LIST-OF-POINTS)
	   Returns a list of points which are moved over the indicated distance

	    -Option--Default
	     dx      0
	     dy      0

	   dx => FLOAT
	     Displacement in the horizontal direction.

	   dy => FLOAT
	     Displacement in the vertical direction.

       polygon_resize(OPTIONS, LIST-OF-POINTS)
	    -Option--Default
	     center  [0,0]
	     scale   1.0
	     xscale  <scale>
	     yscale  <scale>

	   center => POINT
	   scale => FLOAT
	     Resize the polygon with the indicated factor.  When the factor is larger than 1, the resulting polygon with grow, when small it will
	     be reduced in size.  The scale will be respective from the center.

	   xscale => FLOAT
	     Specific scaling factor in the horizontal direction.

	   yscale => FLOAT
	     Specific scaling factor in the vertical direction.

       polygon_rotate(OPTIONS, LIST-OF-POINTS)
	    -Option --Default
	     center   [0,0]
	     degrees  0
	     radians  0

	   center => POINT
	   degrees => FLOAT
	     specify rotation angle in degrees (between -180 and 360).

	   radians => FLOAT
	     specify rotation angle in rads (between -pi and 2*pi)

       polygon_simplify(OPTIONS, LIST-OF-POINTS)
	    -Option    --Default
	     max_points  undef
	     same	 0.0001
	     slope	 undef

	   max_points => INTEGER
	     First, "same" and "slope" reduce the number of points.  Then, if there are still more than the specified number of points left, the
	     points with the widest angles will be removed until the specified maximum number is reached.

	   same => FLOAT
	     The distance between two points to be considered "the same" point.  The value is used as radius of the circle.

	   slope => FLOAT
	     With three points X(n),X(n+1),X(n+2), the point X(n+1) will be removed if the length of the path over all three points is less than
	     "slope" longer than the direct path between X(n) and X(n+2).

	     The slope will not be removed around the starting point of the polygon.  Removing points will change the area of the polygon.

DIAGNOSTICS

       Error: you need to specify 'x', 'y', 'rc', or 'line'

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::Transform(3pm)