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