NAME

Math::Polygon::Transform - Polygon transformation

INHERITANCE

 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.

polygon_grid(%options, @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, @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, @points)

Returns a list of points which are moved over the indicated distance

 -Option--Default
  dx      0
  dy      0

polygon_resize(%options, @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, @points)

 -Option --Default
  center   [0,0]
  degrees  0
  radians  0

polygon_simplify(%options, @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.

Copyrights 2004-2018 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://dev.perl.org/licenses/