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 $area = polygon_transform resize => 3.14, @poly;
DESCRIPTION
This package contains polygon transformation algorithms.
FUNCTIONS
 polygon_grid(%options, LISTof$points)

Snap the polygon points to grid points, where artifacts are removed.
OptionDefault raster 1.0
 raster => FLOAT

The raster size, which determines the points to round to. The origin
[0,0]
is always on a gridpoint. When the raster value is zero, no transformation will take place.
 polygon_mirror(%options, LISTof$points)

Mirror the polygon in a line. Only one of the options can be provided. Some programs call this "flip" or "flop".
OptionDefault 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
andb
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
. Therc
equalsdy/dx
, the firing angle. Ifundef
is explicitly specified thenb
is used as constant x: it's a vertical mirror.  x => FLOAT

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

Mirror in the line
y=value
, which means thatx
stays unchanged.
 polygon_move(%options, LISTof$points)

Returns a list of points which are moved over the indicated distance
OptionDefault dx 0 dy 0
 dx => FLOAT

Displacement in the horizontal direction.
 dy => FLOAT

Displacement in the vertical direction.
 polygon_resize(%options, LISTof$points)

OptionDefault 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, LISTof$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, LISTof$points)

Option Default max_points undef same 0.0001 slope undef
 max_points => INTEGER

First,
same
andslope
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 MathPolygon distribution version 1.03, built on January 21, 2014. Website: http://perl.overmeer.net/geo/
LICENSE
Copyrights 2004,20062014 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