Math::Polygon::Transform - Polygon transformation
Math::Polygon::Transform is a Exporter
my @poly = ( [1,2], [2,4], [5,7], [1, 2] ); my $area = polygon_transform resize => 3.14, @poly;
This package contains polygon transformation algorithms.
Snap the polygon points to grid points, where artifacts are removed.
-Option--Default raster 1.0
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.
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
Only used in combination with option rc
to describe a line.
Alternative way to specify the mirror line. The rc
and b
are computed from the two points of the line.
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.
Mirror in the line x=value
, which means that y
stays unchanged.
Mirror in the line y=value
, which means that x
stays unchanged.
Returns a list of points which are moved over the indicated distance
-Option--Default dx 0 dy 0
Displacement in the horizontal direction.
Displacement in the vertical direction.
-Option--Default center [0,0] scale 1.0 xscale <scale> yscale <scale>
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.
Specific scaling factor in the horizontal direction.
Specific scaling factor in the vertical direction.
-Option --Default center [0,0] degrees 0 radians 0
specify rotation angle in degrees (between -180 and 360).
specify rotation angle in rads (between -pi and 2*pi)
-Option --Default max_points undef same 0.0001 slope undef
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.
The distance between two points to be considered "the same" point. The value is used as radius of the circle.
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.
This module is part of Math-Polygon distribution version 1.02, built on September 19, 2011. Website: http://perl.overmeer.net/geo/
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